Session H2: Invited Session: The Top Quark

Top Quark Physics and Precision Electroweak Measurements at the Tevatron

Studies of the properties and production of the top quark and of the W and Z gauge bosons provide several important tests of the standard model of particle physics. We present recent measurements by the D0 and CDF experiments at the Fermilab Tevatron of the production of the top quark in ppbar collisions at 1.96 TeV. We also describe new measurements of the top quark mass and other properties such as spin correlations and the forward-backward asymmetry in ttbar production. Precise measurements of the W and Z bosons include those of the W boson mass, production of gauge boson pairs, and the dilepton forward-backward asymmetry and $p_T$ in Z boson events. We present updates to several of these studies. We also update the combined Tevatron constraints on the standard model Higgs boson mass arising from these measurements.   

Results from the LHC on the top quark

This presentation will report on the measurements of top quark properties performed by the ATLAS and CMS experiments using a large sample of top quarks collected during 2011 by the LHC. These measurements provide a comprehensive picture of top physics. Top-quark measurements are of central importance to the LHC physics program, in its own right and as the dominant background to many searches for exotic phenomena. The top quark is the by far the heaviest known fundamental particle. It decays before forming bound states (hadrons), thus providing a unique opportunity to study a bare quark. Deviations in its properties from standard model predictions may indicate new physics.   

Theoretical remarks on top quark physics

I will present a theoretical overview of top quark physics. I will discuss the status of theoretical descriptions of top quark production and decay at hadron colliders, with an emphasis on recent theoretical improvements. In addition, I will describe the use of top quarks as tools for probing new dynamics and states.   

Session H3: Invited Session: Toward Understanding the Origins of Extra-Galactic Cosmic Rays

On the transition from Galactic to extragalactic cosmic rays

The Earth is permanently exposed to a flux of high-energy ionized nuclei - the cosmic rays. Most of these particles are accelerated in our Galaxy, most probably in supernova remnants. Cosmic rays are magnetically bound to our Galaxy up to energies of about $10^{17}$ to $10^{18}$ eV. At higher energies the observed particles most likely originate in other galaxies and are usually referred to as extra-galactic cosmic rays. Thus, the energy region between $10^{17}$ and $10^{18}$ eV is of great astrophysical interest. From a detailed measurement of the composition of cosmic rays in this energy regime we expect deeper insight into both, the origin of Galactic and extra-galactic cosmic rays. The status of the actual research will be reviewed and implications on our understanding of the origin of cosmic rays will be discussed.   

The Highest Energy Cosmic Rays

I refuse to start yet another abstract saying that the origin of cosmic rays is a mystery. Instead, I would like to highlight the progress made by ultra-high energy cosmic ray experiments in the last three years. The Pierre Auger Observatory and the Telescope Array are the largest cosmic ray detectors ever built, and together they cover the entire sky at the highest energies. I will present the most recent experimental results, and discuss their implications toward an understanding of the origin of Extragalactic cosmic rays. Finding the transition between Galactic and Extragalactic origin is an important step forward because it will allow us to concentrate our searches on specific energy ranges and specific objects in the sky.   

Session H4: Invited Session: Science Diplomacy: Accelerator Based Science in Korea

Introduction to Korean Accelerator Science and Activities in Industrial Accelerators

After 20 years of the first large-scale accelerator in Korea, the Pohang Light Source (PLS) of 2.0 GeV at POSTECH, its upgrade (PLS-II) is now under commissioning with energy of 3.0 GeV. The users' service for synchrotron radiation is scheduled in April 2012. There are five big accelerator projects in various stages of construction, namely a high-intensity proton linac of 100 MeV, the PAL-XFEL of 10-GeV, a carbon therapy cyclotron of 400 MeV/u, and rare isotope accelerators for isotope separator on-line (ISOL) and In-flight Fragmentation (IFF). There are also strong demands for industrial uses of accelerators, especially in sterilization applications. In this paper, we report the current status of accelerator projects and its science in Korea, along with a brief review of accelerator R{\&}D going back to the early 1960s at universities.   

Korean Contribution to the Progress of Science and Humanity

Science has problems yet to solve those global issues as the climate change, nuclear waste, water pollution, etc, although science and technology have been major contributors to human progress and will continue to open new doors to economic, medical and environmental advancement. Furthermore the benefits of scientific knowledge are not readily and evenly allocated across the globe. Korea will contribute to the progress of science by providing cooperative opportunities of the future research on the pure and applied scientific issues. Recently Korea launches a project of construction of the rare isotope accelerator, KoRIA, and Institute of Basic Science. Plans are set also to help develop the appropriate technology for developing countries. In this talk two aspects of science policy of Korean government are introduced, which are related to the accelerator KoRIA and to the thought on the establishment of Common Technology Platform. The former is to help the world science society for the expansion of our knowledge on the universe and matter, while the latter is to help the transfer of our knowledge to make our planet more flat.   

Synchrotron Radiation and X-ray FEL Projects in Korea

There are two on-going major projects in Pohang Accelerator Laboratory (PAL), the PLS-II light source upgrade and the construction of PAL-XFEL facility. PLS-II is a new light source upgraded from PLS(Pohang Light Source) which had been operated for 16 years from 1995 and shut down in Dec. 2010. The performance will be improved from ``18.9 nm-rad, 2.5 GeV, and 200 mA'' to ``5.8 nm-rad, 3 GeV, and 400 mA'' using three superconducting RF cavities. The old storage ring has been completely dismantled and new DBA ring has been re-installed in the same tunnel within 6 months, and is under commissioning now. The unique feature of PLS-II is the compact employment of 20 insertion-devices including 14 in-vacuum undulators. The PALXFEL is a 0.1-nm hard X-ray FEL construction project started in 2011 and to compete in 2014 with a total budget of 400 M{\$}. The PAL-XFEL is designed to have hard X-ray undulator lines at the end of 10-GeV linac, and a dog-leg branch line at 2.65 GeV point for a soft X-ray undulator line simultaneously and independently from hard X-ray FEL undulator line. The overview of two projects with current status is presented.   

Session H5: Invited Session: Physicists Advising on National Security

Experience with the President's Science Advisory Committee, Its Panels, and Other Modes of Advice

When Dwight Eisenhower became President in January 1953, the United States had just tested November 1, 1952 its 11 megaton prototype of a hydrogen bomb, and Eisenhower sought enduring peace and economy by basing the U.S. military strategy on nuclear weaponry and a downsizing of the military forces. The detonation by the Soviet Union of a 400-kt fusion-containing device in August 1953 enhanced concern about U.S. vulnerability, and in early 1954 the unexpectedly large yield of the BRAVO test elevated fears for the actual survival of societies against the nuclear threat. Eisenhower initially sought a world moratorium on nuclear tests, but was unable to win over his Administration and met with an obscure Scientific Advisory Committee of the Office of Defense Mobilization (SAC-ODM) on March 27, 1954 for a mutual exploration of what science and technology might bring to national security. The resulting 42-man (!) Technological Capabilities Panel (TCP) had a remarkable impact on the President himself and the direction of the country's strategic missile and intelligence activities and structure, as well as a new emphasis on federal support of university research. Rooted in MIT Summer Studies, the TCP reported on March 17, 1955 on the problems of surprise attack, the overall U.S. offensive capability, and, especially, on its Part~V, ``Intelligence: Our First Defense Against Surprise.'' That panel, chaired by Edwin Land, inventor of polarizing sheet and instant photography, originated the U-2 and OXCART (SR-71) strategic reconnaissance aircraft and the CORONA film-return imaging satellites. The President's Science Advisory Committee (PSAC) was created in the White House in 1957 from the SAC-ODM and had major impact throughout the 1960s until its termination by President Richard Nixon in 1973. The presentation traces its story and that of some of its panels from personal experience of the author and his colleagues.   

Experiences Advising our Government from the Point of View of a JASON

The roles of science and scientists in national security are well recognized, historically important, and changing significantly since the end of the cold war and the emergence of new threats. ~JASON, comprising mainly university-based researchers, has advised agencies of the US government on technical matters related to national security since early cold-war days and continues to do so today. ~I will describe what JASON does now from the perspective of a participant and comment more broadly on some of the technical themes and issues of importance to national security today.   

Advisory Experiences wih the DOD, DOE and the Intelligence Community

Consulting for the U.S. government on national security can be a win-win experience. The consultants participating on panels, committees, boards and commissions are exposed to critical national security challenges and are tasked to provide their findings and recommended actions. University professors participating on a committee bring a wealth of professional scientific experience to the deliberations and they obtain a broader understanding of national security needs and the contribution that can be provided by the university. This process has produced such spectacular contributions as microwave radar, nuclear reactors, nuclear and smart weapons, satellites, lasers and the GPS. Of course, the government doesn't always choose to implement the committee's recommendations, and that can be frustrating. The presentation will describe a number of personal experiences and suggest some ``lessons to be learned'' to make the consulting experience more effective for the government and satisfying for the consultants.   

Session H6: Invited Session: Energy Services for the Developing World I

Fuel efficient stoves for the poorest two billion

About 2 billion people cook their daily meals on generally inefficient, polluting, biomass cookstoves. The fuels include twigs and leaves, agricultural waste, animal dung, firewood, and charcoal. Exposure to resulting smoke leads to acute respiratory illness, and cancers, particularly among women cooks, and their infant children near them. Resulting annual mortality estimate is almost 2 million deaths, higher than that from malaria or tuberculosis. There is a large diversity of cooking methods (baking, boiling, long simmers, brazing and roasting), and a diversity of pot shapes and sizes in which the cooking is undertaken. Fuel-efficiency and emissions depend on the tending of the fire (and thermal power), type of fuel, stove characteristics, and fit of the pot to the stove. Thus, no one perfect fuel-efficient low-emitting stove can suit all users. Affordability imposes a further severe constraint on the stove design. For various economic strata within the users, a variety of stove designs may be appropriate and affordable. In some regions, biomass is harvested non-renewably for cooking fuel. There is also increasing evidence that black carbon emitted from stoves is a significant contributor to atmospheric forcing. Thus improved biomass stoves can also help mitigate global climate change. The speaker will describe specific work undertaken to design, develop, test, and disseminate affordable fuel-efficient stoves for internally displaced persons (IDPs) of Darfur, Sudan, where the IDPs face hardship, humiliation, hunger, and risk of sexual assault owing to their dependence on local biomass for cooking their meals.   

Solar Glitter: Low Cost, Solar Energy Harvesting with Microsystems Enabled Photovoltaics

The sun covers our environment with energy harvesting opportunities throughout the day. Although great progress has been made in developing low-cost, solar photovoltaic technologies to harvest the suns energy, the traditional silicon-based PV module format has remained unchanged for almost 40 years, thereby limiting energy harvesting to rooftops and large open spaces. Thin-film and building-integrated photovoltaics have increased the opportunity for energy harvesting, but suffer from low-efficiency. We have developed, based on micro-electro-mechanical systems (MEMs) and other microsystems technology, a new approach to solar photovoltaics applicable in a wide range of environments -- Microsystems Enabled Photovoltaics (MEPV). MEPV solar cells made from crystalline silicon or III-V compound semiconductors (for example, GaAs) are 5-20 microns thick and with lateral dimensions of 250 microns to 1 mm. These solar cells minimize the amount of expensive semiconductor used, but retain the high efficiency of crystalline materials, and allow novel module and system designs not possible with traditional approaches. This talk will outline the science and engineering of MEPV technology, and highlight several novel applications.   

Session H7: Extragalactic Astronomy and Gamma Ray Bursts

Rapid TeV Gamma-Ray Variability of Active Galactic Nuclei: the Case of BL Lacertae

Gamma-ray emitting active galactic nuclei (AGN) are characterized by variability on a wide range of timescales across nearly the entire electromagnetic spectrum. This is an indication of the dominant role that the jet plays in radiation production. The variability provides a valuable tool to study, in a relatively model-independent way, the emission processes and geometry as well as the energetics of the jet in AGN. Here, we present the discovery of a rapid TeV gamma-ray flare from BL Lacertae with VERITAS. It is the first low-frequency peaked BL Lac object that shows the phenomenon. We discuss the implications of the observation.   

The Impact of Gamma-ray Halos on the Angular Anisotropy of the Extragalactic Gamma-ray Background

The study of the development of electromagnetic cascades in intergalactic magnetic fields (IGMF) serves as a robust probe into the strength and structure of these magnetic fields. Charged particles in electromagnetic cascades are deflected by magnetic fields giving rise to gamma-ray halos around extragalactic sources of VHE gamma rays (e.g., BL Lacertae-type objects). Such gamma-ray halos can have a profound impact on the intensity and angular properties of the contribution of extragalactic VHE sources to the extragalactic gamma-ray background (EGB) as measured by the Fermi-LAT at GeV energies. We demonstrate the impact of the deflection of cascades by the IGMF on the collective spectrum of extragalactic VHE sources, as well as the impact on the angular anisotropy of the EGB as a function of energy.   

Radio continuum emission and HI gas accretion in the NGC 5903/5898 compact group of galaxies

We investigate the nature of the multi-component radio continuum and HI emission associated with the nearby galaxy group comprised of two dominant ellipticals, NGC 5898 and NGC 5903 and a dwarf lenticular ESO514-G003. Striking new details of radio emission come from the ongoing TIFR.GMRT.SKY.SURVEY (TGSS) which provides images with a resolution of $\sim 24^{\prime \prime} \times 18^{\prime \prime}$ and rms noise of 5 mJy at 150 MHz. Previous observations of this compact triplet include images at higher frequencies of the radio continuum as well as huge HI trails originating from the vicinity of NGC 5903. The TGSS 150 MHz image has revealed a large asymmetric radio halo around NGC 5903 and also established that the dwarf SO galaxy ESO514$-$G003 is the host to a previously known bright double radio source. The radio emission from NGC 5903 is found to have a very steep radio spectrum ($\alpha \sim -1.5$) and to envelope a network of radio continuum filaments bearing a spatial relationship to the HI trails. Both its radio loud members are also the only galaxies that are seen to be connected to an HI filament. This correlation is consistent with the premise that cold gas accretion is of prime importance for triggering powerful jet activity in the nuclei of early-type galaxies.   

Stellar-mass compact object evolution from the deepest X-ray surveys of the extragalactic Universe

The ever-increasing depth of X-ray surveys raises the possibility of detecting extremely X-ray faint source populations, including the X-ray faint early-type galaxy population. Such a population of galaxies presents the opportunity to study the long-term evolution of low-mass X-ray binary (LMXB) populations. To this end, we have assembled a sample of $\sim 400$ low-luminosity early-type galaxies over $0.05 < z < 1.2$ in the three deep {\it Chandra} surveys (the CDF-S, E-CDF-S and CDF-N). Even with the 4~Ms {Chandra} Deep Field coverage currently available, the deepest survey of the extragalactic sky ever conducted at X-ray wavelengths, the vast majority of these galaxies ($>90$\%) are undetected, so our work relies heavily on stacking analysis. We compare our observational constraints with new theoretical models and discuss possibilities for future deep X-ray observations.   

Fermi Observations of Gamma-ray Bursts

The Fermi Gamma-ray Space Telescope, launched in June 2008, is a satellite based observatory to study the high energy gamma-ray sky. With their wide fields of view and enormous energy ranges, the two instruments on Fermi are especially well suited to the study of gamma-ray bursts - the brightest explosions in the Universe. The Gamma-ray Burst Monitor (GBM), with a $>$9 steradian field of view, is the most prolific detector of GRB currently in orbit and provides coverage from 8 keV to 40 MeV. The Large Area Telescope (LAT), also with a large ($>$2 steradian) field of view, provides ground-breaking high energy observations from 20 MeV to over 300 GeV. In this talk, I will describe the somewhat unexpected results revealed by Fermi observations of gamma-ray bursts and discuss how these have impacted our understanding of these exotic objects.   

Prospects for GRB detection with the HAWC scaler system

HAWC, the High Altitude Water Cherenkov observatory, is a high energy cosmic gamma-ray detector. It is currently under construction at Sierra Negra in Mexico. Due to its very high duty cycle, the large effective area and extended sky coverage, HAWC is an ideal detector for transient gamma-ray emission. Gamma-ray burst (GRB) spectra are well known up to GeV energies. The HAWC scaler DAQ has a significant effective area down to 10GeV and is an excellent complementary system to existing detectors. This talk will demonstrate the prospects of the HAWC detector to detect GRBs and evaluate spectral their parameters at high energies.   

Recent Results from Gamma-ray-burst Neutrino Searches in IceCube

IceCube, a cubic kilometer neutrino detector located in glacial ice at the South Pole, has recently become the first neutrino telescope with a sensitivity below the TeV-PeV neutrino flux predicted from gamma-ray bursts if GRBs are responsible for the observed extragalactic cosmic-ray flux. These neutrinos are produced in interactions between the accelerated cosmic ray protons and the photons present in the burst fireball, allowing neutrino observations to directly constrain or confirm proton acceleration in these sources. Recent results from searches for this flux using the IceCube detector will be presented, as well as implications of this result for cosmic-ray acceleration in GRBs and prospects for future searches.   

Probing cosmic baryons with X-ray spectroscopy of GRB afterglows

Gamma-Ray Bursts (GRBs) provide a unique probe of the cosmic history of baryons from the first stars to the present epoch. Reconstructing the cosmic history of metals is a key observational challenge, which we plan to address with high resolution X-ray measurement. We also characterize the chemical composition of gas in clusters of galaxies and the Warm-Hot Intragalactic Medium (WHIM). Cluster measurements will take advantage of wide field of view telescopes. These goals can be fulfilled with a medium-size mission, proposed to ESA and NASA by an international consortium. The latest incarnation proposed to ESA is ORIGIN, which evolved from the EDGE and Xenia mission profiles and builds upon those previous concepts. The mission utilizes fast and autonomous satellite re-pointing following the detection of a GRB (this requires a sensitive hard X-ray detector with a large field of view) and a wide-field imaging spectrometer in the soft X-ray band. This measures the emission and absorption lines in hot and cold gas, providing diagnostics of temperature, ionization state, dynamics and abundances in clusters beyond their vir   

An New Analysis of Sloan Digital Sky Survey (SDSS) Data

An analysis of SDSS data is presented, which challenges key assumptions underlying the standard cosmological model. In particular, easily-reproduced, statistically-significant empirical data for the theta-z relationship, the redshift-magnitude relationship and the AGN redshift-population density relationship are presented. These data do not conform with canonical predictions based on the Hubble expansion; they instead confirm a set of three interrelated predictive equations, which are based on a temporal relativistic interpretation of the cosmological redshift.   

Session H8: Numerical Relativity: Neutron Stars and Black Holes

Binary neutron stars with spin

Astrophysical neutron stars are expected to be spinning. Due to the existence of millisecond pulsars we know that these spins can be substantial. Spin periods of a few dozen milliseconds will influence the inspiral and potentially also the merger of binary neutron stars. We have developed a new method to set up binary neutron star initial data, where both stars can have arbitrary spins. We use these new initial data as a starting point for numerical simulations. We present preliminary results where we compare simulations of equal mass binaries with and without spin.   

Simulations of Binaries Neutron Star with Arbitrary Spins using the Einstein Toolkit

Binary neutron stars are among the most important sources of the gravitational waves and potential engines of short gamma-ray bursts. Observations of millisecond pulsars suggest that neutron stars can have substantial spins pointing in arbitrary directions. Thus realistic numerical simulations of the late inspiral and merger require initial data with arbitrary spins. We are presenting method of a constructing such an initial data by combining a solutions of two single rotating neutron stars. We report on our recent progress in simulating the merger of neutron star binaries with an arbitrary spins using Einstein Toolkit.   

Binary NS simulations using SpEC

NSNS binaries are expected to be one of the major sources of gravitational radiation detectable by Advanced LIGO. Together with neutrinos, gravitational waves are our only means to learn about the processes deep within a merging pair of NS, shedding light on the as yet poorly understood, equation of state governing matter at nuclear densities and beyond. We report on binary neutron star simulations using the Spectral Einstein Code (SpEC) developed by the Caltech-Cornell-CITA-WSU collaboration. We simulate the inspiral through many orbits, follow the post-merger evolution, and compute the full gravitational wave signal. We provide estimates on the accuracy required for the LIGO scientific goals of constraining EOS parameters.   

Tidal excitation of normal modes in eccentric binary neutron stars

Neutron star binaries offer a rich phenomenology in terms of gravitational waves and merger remnants. However, most general relativistic studies have been performed for nearly circular binaries, with the exception of head-on collisions. We present the first numerical relativity investigation of mergers of eccentric neutron-star binaries that probes the regime between head-on and circular. Upon variation of the initial eccentricity, covering cases from direct plunge to more adiabatic inspiral, we study the outcome of a binary composed of two $1.4M_\odot$ neutron stars. We characterize the gravitational wave emission, the internal dynamics of the stars and the properties of the merger remnant. In addition to gravitational waves generated by the orbital motion, we find that the signal also contains a strong component due to stellar oscillations ($f$-modes) induced by tidal forces, extending a classical result for Newtonian binaries. Such signatures may be used to constrain the NS equation of state. With the exception of extreme eccentricities (near head-on collisions) the merger leads generically to rather massive disks, which in some cases can be on the order of 10\% of the total initial mass. All merger remnants form a black hole making such encounters a plausible SGRB engine.   

Neutron star evolutions using tabulated equations of state with a new execution model

The addition of nuclear and neutrino physics to general relativistic fluid codes allows for a more realistic description of hot nuclear matter in neutron star and black hole systems. This additional microphysics requires that each processor have access to large tables of data, such as equations of state, and in large simulations the memory required to store these tables locally can become excessive unless an alternative execution model is used. In this talk we present neutron star evolution results obtained using a message driven multi-threaded execution model known as ParalleX as an alternative to using a hybrid MPI-OpenMP approach. ParalleX provides the user a new way of computation based on message-driven flow control coordinated by lightweight synchronization elements which improves scalability and simplifies code development. We present the spectrum of radial pulsation frequencies for a neutron star with the Shen equation of state using the ParalleX execution model. We present performance results for an open source, distributed, nonblocking ParalleX-based tabulated equation of state component capable of handling tables that may even be too large to read into the memory of a single node.   

Fully General Relativistic Simulations of Magnetized Neutron Star--Black Hole Binary Mergers

As a neutron star (NS) is disrupted by black hole (BH) tidal fields at the end of a BH--NS binary inspiral, its magnetic fields will be stretched and amplified. These magnetic fields may impact the gravitational waveforms, merger evolution and mass of the remnant disk. Formation of highly-collimated magnetic field lines in the remnant may launch relativistic jets, driving an SGRB. We analyze this scenario through fully general relativistic, magnetohydrodynamic BH--NS simulations from inspiral through merger and disk formation. Multiple seed magnetic field configurations are chosen, starting with both nonspinning and moderately-spinning ($a/M$=0.75) BHs aligned with the orbital angular momentum. Only strong ($B_{max}\sim10^{17}$G) initial magnetic fields in the NS significantly influence merger dynamics, enhancing the remnant disk mass by 100\% and 40\% in the nonspinning and spinning BH cases, respectively. We find that detecting the effects of even strong magnetic fields may be challenging for Advanced LIGO. While there is no evidence of outflows during the preliminary simulations we have explored, longer disk evolutions, improved resolution and different field topologies will be required to more thoroughly assess the plausibility of BHNS binaries as SGRB progenitors.   

Relativistic MHD in dynamical spacetimes: Improved EM gauge condition for AMR grids

We recently developed a new GRMHD code with AMR that evolves the electromagnetic (EM) vector potential $A_i$ instead of the magnetic fields directly. Evolving $A_i$ enables one to use any interpolation scheme on refinement level boundaries and still guarantee that the magnetic field remains divergenceless. As in classical EM, a gauge choice must be made when evolving $A_i$, and we chose a straightforward ``algebraic'' gauge condition to simplify the $A_i$ evolution equation. However, magnetized black hole-neutron star (BHNS) simulations in this gauge exhibit unphysical behavior, including the spurious appearance of strong magnetic fields on refinement level boundaries. This spurious behavior is exacerbated when matter crosses refinement boundaries during tidal disruption of the NS. We demonstrate via an eigenvalue analysis and a numerical study that zero-speed modes in the algebraic gauge, coupled with the frequency filtering that occurs on refinement level boundaries, are responsible for the creation of spurious magnetic fields. We show that the EM Lorenz gauge exhibits no zero-speed modes, and as a consequence, spurious magnetic effects are quickly propagated away, allowing for long-term, stable magnetized BHNS evolutions.   

Eccentric Compact Object Mergers

Mergers of black holes and neutron stars are expected to be an important source of gravitational radiation for upcoming observatories. Such mergers are also a leading candidate for short gamma-ray burst progenitors and may be source for other electromagnetic counterparts. An interesting class of compact object binaries are those that form in dense stellar regions such as globular clusters and may merge with significant eccentricity. We present results from general-relativistic hydrodynamics simulations that are performed in order to explore the dynamics and possible observational signatures of such systems.   

Black Hole-Neutron Star Mergers for 10 Solar Mass Black Holes

Black hole-neutron star (BHNS) mergers are expected to be observed by gravitational wave detectors within the next few years, and are also thought to be promising candidates as short gamma-ray burst progenitors. The parameters of BHNS binaries which affect the dynamics of the merger the most (black hole mass and spin, nuclear equation of state) are highly uncertain. For the black hole mass, population synthesis models indicate that fairly massive black holes ($>10M_\odot$) are probably the norm in such systems. Numerical simulations of BHNS mergers in general relativity have however been focused on lower mass black holes ($\sim 3-7M_\odot$). I will present recent numerical simulations of BHNS mergers for $10 M_\odot$ black holes, and show how they differ from lower mass systems in the emitted gravitational waveform as well as in their ability to form the massive discs required to power short gamma-ray bursts.   

Session H9: Bottom Quark Physics

Recent Bottomonium Results from Belle

Using a 121 $fb^{-1}$ data sample collected in e+e- collisions near the peak of the $\Upsilon(5S)$ resonance, the Belle Collaboration has over the past year obtained several significant results concerning singlet-P ($h_b$) and singlet-S ($\eta_b$) states of the bottomonium system, and, additionally, for charged bottomonium-like states denoted $Z_b$. In this talk we will present results of measurements of the masses of singlet-P and singlet-S states, branching fractions for radiative transitions from singlet-P to singlet-S, and studies of the charged $Z_b$ states through which the singlet-P state production is understood to occur.   

A Search for Bottomonium-like Resonances at the Collider Detector at Fermilab

The Belle experiment recently reported evidence for two bottomonium-like charged resonances, \(Z_b^+(10610)\) and \(Z_b^+(10650)\), observed in decays from the \(\Upsilon(5S)\). We present a search for these resonances in CDF data. In contrast to the Belle observation, we search for \(Z_b\) states directly produced in \(p\bar{p}\) collisions and decaying to an \(\Upsilon(1S, 2S, 3S)\) plus a charged pion. Since such a state must both be charged and contain a bottom and an anti- bottom quark, it would indicate a new hadronic state, for example, a tetraquark state. Starting from a sample of \(\Upsilon(1S, 2S, 3S)\) candidates selected by their decay to \(\mu^+\mu^-\), we add a pion and search for the \(Z_b\) resonances. We check the sensitivity by reconstructing \(\Upsilon(2S, 3S) \to \Upsilon(1S)\mu^+\mu^-\) decay.   

Measurements of quark fragmentation using kaons produced in association with prompt \(D_{(s)}^+\) mesons at CDF

We report the first study of quark fragmentation through identification of kaons produced during the fragmentation of charm quarks, produced in \(1.96\,\mathrm{TeV}\) \(p\bar{p}\) collisions, to form \(D_s^+\) or \(D^+\) mesons. We apply particle identification techniques to measure the fraction of events in which a track produced in association with the prompt charm meson is a kaon and compare the observed kinematic properties with predictions of fragmentation models implemented in standard Monte Carlo event generators providing valuable validation and tuning information.   

Measurement of the \(B^0_s \to J/\psi\phi \) branching fraction at CDF

We present a measurement of the branching fraction of the decay \(B^0_s \to J/\psi\phi\) with the Collider Detector at Fermilab. Using a data sample corresponding to an integrated luminosity of \(10\,\mathrm{fb}^{-1}\) of \(p\bar{p}\) collisions at \(\sqrt{s}=1.96\,\mathrm{TeV}\), we utilize a low transverse momentum dimuon trigger to acquire a large sample of \(J/\psi\to\mu^+\mu^-\) decays. We form fully reconstructed \(B^0_s \to J/\psi\phi\) and \(B^0\to J/\psi K^{\ast}\) candidates using information from the central tracking system and determine the branching fraction of \(B^0_s \to J/\psi\phi\) by normalizing with the \(B^0\to J/\psi K^{\ast}\) decay. The measurement improves the current world average value and can be used to extract information about the ratio of fragmentation fractions \(f_s/f_d\) between \(B^0_s\) and \(B^0\) production rates.   

Search for $B^0_s\rightarrow\mu^+\mu^-$ at D0

In this talk we present an update of the search for $B^0_s\rightarrow\mu^+\mu^-$ using the full D0 data set, $\sim~11~\textrm{fb}^{-1}$. In this analysis, the backgrounds have been significantly reduced by adding isolation variables and reconstructing additional vertices near the $B^0_s$ decay vertex. Other changes from the previous D0 result include the addition of $4~\textrm{fb}^{-1}$ of additional data and the use of a Boosted Decision Tree to discriminate between signal and background.   

$b$-tagging calibration of ATLAS data using the System8 method

We present results of calibrating the efficiency of various $b$-tagging algorithms using data taken with the ATLAS detector in 2011. The calibration method, called $System8$, separates a sample of jets containing muons into 8 subsamples based on whether they pass or fail three different methods for selecting $b$-jets: passing a Soft Muon tagging algorithm, passing a Lifetime tagging algorithm, and the presence of a corresponding $b$-tagged jet opposite the one under study. A system of 8 equations, which relates the fraction of $b$-jets, the tagging efficiencies and the correlations between the three subsamples to the observed numbers of events in each subsample, is then solved to extract the $b$-tagging efficiencies. We will show the basic procedures behind System8 and the measured efficiencies with statistical and systematic uncertainties. These efficiencies will be compared to those obtained from Monte Carlo truth information. Scale factors relating the measured efficiencies to those obtained from Monte Carlo will also be presented.   

$B^{\pm}_{c}$ meson observation at ATLAS

We observed $B^{\pm}_{c}$ mesons with the ATLAS detector at the LHC through the hadronic decay of $B^{\pm}_{c}\rightarrow J/\psi(\mu^{+}\mu^{-}) \pi^{\pm}$, with 4.3 $fb^{-1}$ 2011 data from 7 TeV pp collisions. The resulting $B^{\pm}_{c}$ mass distribution is fitted with an unbinned maximum likelihood fit. The mass value is consistent with the world average value.   

Search for Double J/Psi Resonances in CMS at the LHC

We have analyzed an integrated luminosity of 4.5 fb$^{-1}$ of proton-proton collision data from the LHC with the CMS detector in search for the J/Psi J/Psi decay of the eta-b meson, the pseudo-scalar ground-state of bottomonium. The cross-section times decay width is predicted at a level of 10$^{-4}$ to 10$^{-8}$. We perform a maximum likelihood fit to the 4-muon invariant mass and the decay length to extract the signal yield.   

Session H10: Few-nucleon Systems

Beam-Target Double Spin Asymmetry in $\vec{D}(\vec{e},e'p)n$

Using the CLAS detector at Jefferson Lab, double spin asymmetries ($A_{||}$) for quasi-elastic electron scattering off the deuteron have been measured at several beam energies. The data were collected during the EG1 experiment, which scattered longitudinally polarized electrons from 1.6 to 5.8 GeV off a longitudinally polarized cryogenic ND$_{3}$ target. The double spin asymmetries were measured as a function of photon virtuality $Q^{2}$ (0.13-3.17 GeV), missing momentum (0.0-0.5 GeV), and the angle between the (inferred) ``spectator'' neutron and the momentum transfer direction ($\theta_{nq}$). The results from EG1b were compared with a recent model that includes final state interactions using a complete parameterization of nucleon-nucleon scattering. We will discuss our results for the double spin asymmetry and compare them to this model as well as a simplified model using the plane wave impulse approximation.   

Determination of the Azimuthal Asymmetry for Deuteron Photodisintegration at $E_\gamma=1.1-2.3$~GeV

Deuteron photodisintegration is a benchmark process for investigating the role of quarks and gluons in nuclei. Existing theoretical models of this process describe the cross sections with the same degree of success. Therefore, to distinguish between models, spin-dependent observables are crucial for a better understanding of the underlying dynamics. The induced polarization ($P_y$) and the polarization transfers ($C_{x'}$ and $C_{z'}$) have been instrumental in proving that a pQCD treatment is not applicable at medium energies; however, these observables are relatively insensitive to different non-perturbative models and do not provide further insight into the physics of the process. By contrast, the azimuthal asymmetry $\Sigma$ is predicted to have a large sensitivity and can help in identifying the energy at which the transition from the hadronic to the quark-gluon picture takes place. We present results for the azimuthal asymmetry for deuteron photodisintegration at photon energies $E_\gamma=$ 1.1-2.3~GeV and proton center-of-mass angles $\theta_p=$ 20$^\circ$-160$^\circ$ taken with the CLAS detector at Jefferson Lab. Our preliminary analysis shows that our results have the kinematic coverage and statistics needed to test the available non-perturbative QCD-inspired models.   

Isobar configurations in the $^3$He ground state

The probabilities of short-range correlations (SRC), meson-exchange currents and final-state interactions in nuclei contribute to the measured observables that are mostly being interpreted within strongly model-dependent pictures. Studying the short-distance structure and virtual nucleon excitations, especially isobar configurations in the nuclear ground state, are important subjects in experimental nuclear physics. Since the SRC are local high-density regions, it is likely that the quark distributions of nucleons would make a transition to non-nucleonic configurations. A number of theoretical calculations predict the probability of finding one or more nucleons in an excited state. In some studies, isobar excitations have been explicitly included in the few-body models. In this work we have explored a recent data set of photon-induced reactions from nuclear targets to study various photoproduction channels that contain one or more $\Delta$-isobar configurations, for example, the $\gamma$$^3$He $\rightarrow \Delta^{++}nn$ or $\gamma$$^3$He $\rightarrow \Delta^{++} \Delta^0 n$ reactions. Data were taken with CLAS in Hall B at Jefferson Laboratory using an incident photon-beam energy of 0.5-1.5 GeV on a $^3$He target. Preliminary results and future plans will be discussed.   

Three-body photodisintegration of 3He with double polarizations at incident photon energies E 12.8 MeV and 14.7 MeV

We report on the study of three-body photo-disintegration of polarized $^3$He using a circularly polarized $\gamma$ beam at incident photon energies 12.8 MeV and 14.7 MeV. The experiment was carried out at the High Intensity $\gamma$ Source (HI$\gamma$S) facility located at Triangle Universities Nuclear Laboratory. A high-pressure $^3$He cell was employed as target and it was polarized using the spin exchange optical pumping (SEOP) technique of hybrid alkali. The neutrons from the three-body photo-disintegration were detected using 16 liquid scintillator fast neutron detectors positioned in the reaction plane at 8 angles varying from 30$^\circ$ to 165$^\circ$. Preliminary results on asymmetry and spin-dependent differential cross sections for both energies will be presented and compared with the three-body calculations using both CD Bonn and AV18 potentials.   

A$_y$ Measurement from $^3\mbox{He}^\uparrow(e,e'n)$ Scattering at Jefferson Lab

Recently A$_y$ asymmetry measurements have been conducted in Jefferson Lab's Hall A through electron scattering from a vertically polarized $^3$He target. Experiment E08-005 measured the target single-spin asymmetry A$_y$ in the quasi-elastic $^3\mbox{He}^\uparrow(e,e'n)$ reaction. Plane wave impulse approximation (PWIA) predicts that A$_y$ should be exactly zero. A previous experiment at Q$^2$ of 0.2 (GeV/c)$^2$, where full calculations of Laget and Nagorny indicated A$_y$ to be small, showed a large asymmetry as calculated by the Bochum group using Faddeev calculations to solve the three-body problem exactly. The recent experiment measured this asymmetry at Q$^2$ of 0.1 (GeV/c)$^2$, 0.5 (GeV/c)$^2$ and 1.0 (GeV/c)$^2$. This is the first measurement of A$_y$ at large Q$^2$, which is another region where A$_y$ is expected to be small. Any non-zero result is an indication of effects beyond simple impulse approximation. This measurement will test the models used to extract neutron form factors from polarized $^3$He. Details of the measurement will be presented.   

Cluster calculations for the $^6$He and $^9$Be spectra

The $^6$He and $^9$Be nuclei are considered as a mirror cluster systems $\alpha nn$ and $\alpha \alpha n$. The excitation energies of the low-lying levels for $^6$He and $^9$Be nuclei are evaluated. These cluster calculations are based on the configuration-space Faddeev equations. The method of analytical continuation in a coupling constant is used to calculate resonance parameters [1]. Our goal is to show possibility for a reliable description of the $^6$He and $^9$Be within the cluster model using pair local potentials. We focus on the new $\alpha n$ interaction model proposed in [1]. We assume that both, central $p$-wave component and spin-orbital component of $\alpha n$ potential mainly determine the excitation spectra structure of these nuclei. The low-lying spectrum of $^9$Be is well reproduced with this potential. The results for excitation resonance energies of the $\alpha nn$(0+,2+,1+) systems are presented and compared with the experimental data (http://www.tunl.duke.edu/nucldata/chain/06.shtml) and those from other calculations [2]. \\[4pt] [1] I. Filikhin, V.M. Suslov and B. Vlahovic, Few-Body Systems 50, 255 (2011). \\[0pt] [2] S.N. Ershov, T. Rogde, B.V. Danilin, J.S. Vaagen, I.J. Thompson, F.A. Gareev, Phys. Rev. C 56, 1483 (1997).   

Dynamics of dud, dut in superstrong laser fields for laser induced nuclear fusion

Nuclear fusion occurs during the collision of selected isotopes of hydrogen with relative energy in the MeV(10**6 eV) regime. Such high energy ions can be generated by high power lasers applied to clusters [1] via the accumulated ponderomotive energies. However in such schemes laser induced collisions are random whereas as shown previously ultrashort superintense laser pulses can be used to control collisions in muonic molecules [2]. We present full 3-D dynamics from accurate Time-dependent Schroedinger equations, TDSE, s, of the isotopomers, pud, dud, dut in super intense laser pulses with intensities I~ 10**23 W/cm**2 to illustrate the possibility of inducing always head-on(zero-impact) collisions leading in principle to laser induced nuclear fusion, LINF. Due to its heavy mass(mu/me=185.8) the muonic molecular ions are stable to ionization up to intensities I=10**23 W/cm**2 and recollision of the heavy particles (p,td,t) will be shown to be controllable by few cycle superintense laser pulses leading to LINF.The nonsymmetric isotopomers dut and put manifest enhanced fusion due to the presence of permanent dipole moments.\\[4pt] [1] KWD Ledingham et al, Science 300, 1107 (2003)\\[0pt] [2] S Chelkowski, PB Corkum, AD Bandrauk, Phys Rev Lett 93, 083602(2004)   

Observation of Electron Cloud Stabilized 1 MeV Beam-Beam d+d Reactons in Self-Colliding Orbits and Feasibility of Electric Isotope Breeder

D-D Self-Collider $^{1,2}$ is only system in which beam-beam nuclear reactions demonstrated MeV energies. 1.45 MeV DC beam of D$_{2}^{+}$ was injected into center of a weak-focusing magnetic field (Ni Ti) B=3.12 Tesla, and dissociated into 2 d$^{+}$ stored in Self-Colliding Orbits$^{3}$. Energy confinement time T = 23 s (vacuum limited p=10$^{-9}$ torr), stabilized by driven electron oscillations$^{4}$. A simulation$^{5}$ shows that 1 DD neutron is produced at an energy cost of 5.36 MeV/n i.e. 140 MWh/g= {\$}8,360/g vs. {\$}160,000/g from beam - target. Simultaneously produced He$^{3}$ and T are not only free, but bring 45 fold gain. 5 d's of 0.75 MeV generate 1He$^{3}$ +1T +1p+ 1n at cost 5.36 MeV. Hence, it will produce 2 He$^{3}$ nuclei (1 He-3, 1 T) plus energy gain of 161 MeV. This will be reduced by the energy gain thus reducing cost to 4.5 from 5.6 MeV. Assumed ion density 5x10 $^{14}$ was achieved in plasmas. Beam injection 100 mA. 1. PRL 54, 796 (1985) NIM A 271 p,.1-167; 2. AIP CP 311, 292 (93); 3. PRL 70, 1818 (93); 4.Part. Acc.1, (70); 5. ``50 Years with Fission'' Symp.Nat. Ac Sci., p. 761 (89)   

Session H11: Nuclear Astrophysics

Alpha production via electromagnetic dissociation

Light ions produced from the interactions of galactic cosmic rays (GCR) provide a significant contribution to the space radiation environment inside spacecraft. Among the most important light ions are alpha particles. In relativistic nucleus-nucleus collisions, which are the type of collisions relevant for GCR interactions, light ions are produced from both strong and electromagnetic forces. Electromagnetic dissociation (EMD) is the process whereby a virtual photon from one nucleus knocks out a particle from the other nucleus. Therefore, in predicting space radiation environments one must include a correct description of alpha production via EMD. A calculation of this process, using a theoretical photonuclear model, is presented and compared to experimental data.   

$^{18}$O($p$,$\gamma$)$^{19}$F resonance strength measurement at low energies

As a 0.4M$_{\bigodot}$ $\leq$ M $\leq$ 8M$_{\bigodot}$ approaches the end of its stellar evolution, it will enter the asymptotic giant branch (AGB) stage and ascend the giant branch one final time. During the AGB stage, a star experiences significant mass loss, and grain condensation occurs in the stellar atmosphere. A subset of presolar oxide grains recovered from comet and meteorite samples can be attributed to this stellar environment; these grains feature $^{18}$O depletion that cannot be explained by existing AGB stellar models. An extra mixing process referred to as ``cool bottom processing" (CBP) was proposed by Wasserburg et al. (1995) for low-mass AGB stars. The $^{18}$O depletion observed in these presolar grains may result from the $^{18}$O+$p$ process during CBP. A low energy, unobserved, narrow resonance exists within the ($p$,$\gamma$) reaction that may affect thermonuclear reaction rates near the CBP temperature regime. Though the E$_{R}^{lab}$ = 95 keV resonance strength ($\omega\gamma$) has been constrained previously, measurements at the Laboratory for Experimental Nuclear Astrophysics (LENA) have improved the resonance strength upper limit. The effect this improvement has on $^{18}$O($p$,$\gamma$)$^{19}$F thermonuclear reaction rates will be discussed.   

The Simulation of a Nuclear Astrophysics Detection System

The Laboratory for Experimental Nuclear Astrophysics (LENA), which is part of TUNL, houses a gamma-ray spectrometer designed for directly measuring stellar fusion reactions. The detection systems are made up of multiple detectors, taking advantage of multi-photon coincidence counting in order to reduce environmental background. This talk will describe the various methods of coincidence gating and associated Geant4 simulations. A number of examples will be presented and discussed: point source data, in-beam data, and an extended source -- the detection of aluminum-26 in a meteorite fragment.   

Experimental techniques to use the $(d,n)$ reaction for spectroscopy of low-lying proton-resonances

Studies of rp-process nucleosynthesis in stellar explosions show that establishing the lowest $l=0$ and $l=1$ resonances is the most important step to determine reaction rates in the astrophysical $rp$--process path. At the {\sc resolut} facility, we have used the $(d,n)$ reaction to populate the lowest $p$-- resonances in $^{26}$Si, and demonstrated the usefulness of this approach to populate the resonances of astrophysical interest [1]. In order to establish the $(d,n)$ reaction as a standard technique for the spectroscopy of astrophysical resonances, we have developed a compact setup of low-energy Neutron-detectors, {\sc resoneut} and tested it with the stable beam reaction $\mathrm{^{12}C(d,n)^{13}N}$ in inverse kinematics. Performance data from this test-experiment and future plans for this setup will be presented. \\[4pt] [1] P.N. Peplowski {\it et al.} Phys.Rev.{\bf C 79}, 032801 (2009)   

The commissioning of a summing NaI(Tl) (SuN) gamma detector

Proton rich nuclei more massive than iron cannot be produced by s- or r-processes, as the $\beta $-decay of neutron rich seed nuclei stops at the valley of stability. The most favorable scenario for the creation of these nuclei is a chain of photodisintegration reactions, namely ($\gamma $,p), ($\gamma $,$\alpha )$ and ($\gamma $,n), the so called p-process. The p-process can be studied via the reverse reactions, radiative capture. To develop a more lucid picture of the p-process through this capture process at energies relevant to astrophysical environments a summing NaI(Tl) (SuN) gamma detector has been commissioned and developed at the NSCL. SuN is a 16x16 in. cylindrical barrel divided into eight optically separated segments, each of which contains three photomultipliers. The segmentation of the crystal as well as a high summing efficiency (about 70{\%} for 60-Co) make the detector a perfect tool for investigation of (p,$\gamma )$ and ($\alpha $,$\gamma )$ reactions during inverse kinematics experiments. Utilizing radioactive beams from the ReA3 facility, SuN will provide a great opportunity for precise measurement of p-process relevant reactions cross sections for proton rich nuclei. Results of the first measurements utilizing the SuN detector and various beams from a Van de Graaff accelerator at the University of Notre Dame will be presented.   

R-Process Nucleosynthesis in the Neutrino Pair Heated Collapsar MHD Jet

The collapsar scenario is a model for long-duration gamma ray bursts (GRBs). It is also a possible site for r-process nucleosynthesis. We present numerical r-process calculations in the context of a MHD + neutrino pair heated collapsar simulation. This model begins with relativistic magnetohydrodynamic simulations including ray-tracing neutrino transport to describe the development of the black hole accretion disk and the heating of the funnel region to produce a relativistic jet. The late time evolution of the jet then utilizes axisymmetric special relativistic hydrodynamics to follow the temperature, entropy, electron fraction, and density for representative test particles flowing with the jet from temperatures of $9 \times 10^9$ to $3 \times 10^8$ K. The evolution of nuclear abundances from nucleons to heavy nuclei for representative test particle trajectories was solved in a large nuclear reaction network. We show that a robust $r$-process successfully occurs within the collapsar jet outflow and argue that sufficient mass is ejected within the flow to account for the observed r-process abundance distribution along with the large dispersion in r-process elements observed in metal-poor halo stars.   

$^{176}$Lu/$^{175}$Lu thermometry for Oklo natural reactors: a new look at old data

Lutetium thermometry has been used to analyze Oklo natural nuclear reactor zones but leads to widely varying and puzzling predictions for the temperatures $T_O$, which in turn impacts Oklo bounds on the time variation of the fine structure constant $\alpha$. We revisit results for reactor zone RZ10 in light of new astrophysical measurements of the isomer branching ratio $B^g$ in $^{175}$Lu neutron capture at 5 and 25 keV. We recalculate predictions for $T_O$ as a function of $B^g$ using realistic models of the Oklo neutron flux. We find $T_O = 100 \pm 30$ C using a new value of $B^g$, in contrast to $350 < T_O < 500 $ C using the evaluated value at thermal energy. Lutetium thermometry can be applicable to analyses of Oklo reactor data, but a better measurement of $B^g$ with thermal neutrons is needed to confirm the reliability of temperature predictions.   

High Amplitude Bulk Viscosity of Dense Matter and Probing the Phases of Dense matter with Neutron Star Physics

Neutron stars are the only laboratory for studying cold ultra-dense matter. Since the density at the core of a neutron star is extremely high one could expect the existence of exotic matter such as degenerate quarks, boson condensate and etc in the core. Studying the transport properties of the different phases of dense matter that can occur in a compact star is important because transport properties such as viscosity, emissivity, heat capacity and etc, in addition to depending on the equation of state of matter, also depend on the low-energy degrees of freedom and therefore can discriminate between different phases more efficiently. In this talk I will present our results for the high amplitude bulk viscosity of dense matter and I will explain how spin-down evolution of neutron stars can be used as a probe of the phases of matter at low temperatures and high densities.   

Bulk viscosity of strange quark matter

It is known that the interior of neutron stars is made of very dense baryonic matter, but our knowledge regarding the actual state of such matter is incomplete. The way to test the idea regarding the presence of quark matter inside stars is to make predictions regarding physics processes that affect observable features of stars. Bulk viscosity is one of important properties which determines the suppression of the rotational instabilities. In this talk, I will introduce the bulk viscosity of strange quark matter by taking into account the interplay between the nonleptonic and semileptonic week processes. The result is very important in order to relate accessible observables of compact stars to their internal composition.   

Session H12: Invited Session: New Measurements of Fundamental Constants and Materials

New Experimental Limits on Non-Newtonian Forces in the Micrometer range

Using a torsion balance, we measure forces between macroscopic bodies at separations on the order of a micron. Measurements with Au-coated plates detect the Casimir effect due to quantum fluctuations of the electromagnetic field, as well as the thermal Casimir effect, due to thermal fluctuations, and confirm the validity of the Drude model of permittivity dispersion used in Casimir force calculations. We use our measurements to place new upper bounds on short-range (distance scales 0.4 - 4 mirometers) exotic forces, arising, for example, in quantum gravity theories with extra dimensions.   

Muon capture on the proton -- Final results from the MuCap experiment

The singlet rate $\Lambda_S$ of ordinary muon capture (OMC) is the most direct probe for extracting the nucleon's pseudoscalar form factor, g$_P$. The experimental determination of g$_P$ spans a long history including OMC efforts and one experiment using radiative muon capture. However, the situation prior to MuCap was inconclusive due to ambiguities in the interpretation as well as technical challenges. The MuCap experiment was designed to give an unambiguous measurement of g$_P$. It uses a negative muon beam stopped in a time projection chamber as an active target filled with ultra-pure hydrogen gas which is surrounded by a decay electron detector. The capture rate is obtained from the difference of the negative muon's disappearance rate in hydrogen and the positive muon's decay rate recently measured to 1 ppm precision by the MuLan collaboration. A first-stage result, g$_P = 7.3 \pm 1.1$, has been published in 2007. Since then, the MuCap system underwent some important upgrades before the full statistics were acquired. Two main data sets taken with different TPC gain were analyzed independently, and our final data selection cuts were established. The analysis is completed and all systematic errors have been evaluated. The final result presented in this talk will determine g$_P$ with four times improved precision compared to OMC results prior to MuCap. It is also immune to the above mentioned ambiguities in the interpretation of former OMC and RMC results. Therefore, it can be compared to the prediction from chiral perturbation theory and provides an important test of QCD symmetries at low energies.   

Trapped Antihydrogen

Atoms made of a particle and an antiparticle are unstable, usually surviving less than a microsecond. Antihydrogen, the bound state of an antiproton and a positron, is made entirely of antiparticles and is believed to be stable. It is this longevity that holds the promise of precision studies of matter-antimatter symmetry. Low energy (Kelvin scale) antihydrogen has been produced at CERN since 2002. I will describe the experiment which has recently succeeded in trapping antihydrogen in a cryogenic Penning trap for times up to approximately 15 minutes.   

Session H14: Hot Topics in Computational Astrophysics

The Challenge of Modeling Dense Stellar Systems

Galaxy nuclei and the cores of globular clusters are regions where the density of stars can reach millions per cubic parsec. Modeling the dynamical evolution of such systems is critical for understanding a number of fundamental processes, including core collapse, the creation of massive black holes, and the generation of gravitational waves. But the computational challenges are severe, due to the large range in time scales; the steepness of gravitational force gradients near a massive compact object; the need to include relativistic corrections to the equations of motion; and finite-size (collisional) effects, among other factors. This talk reviews recent progress in this area, with a highlight on the extreme-mass-ratio inspiral (EMRI) problem.   

Relaxation in axisymmetric stellar cusps around black holes

We consider two-body relaxation in flattened axisymmetric stellar cusps around supermassive black holes and associated rates of star capture by the black hole. Inside the black hole radius of influence, the motion of stars in the mean field can be described analytically. Perturbations from discreteness of the mass distribution lead to diffusion of stars in the phase space, which is described by a Fokker-Planck equation. We solve this equation for various values of the capture boundary and degree of flattening, and find that capture rates increase with respect to spherical case, up to a factor of few. We also perform a set of collisional N-body simulations to confirm the predictions of the Fokker-Planck models. We discuss implications for the rates of stellar tidal disruption in nuclear star clusters, and extreme mass ratio inspirals in Milky Way and external galaxies.   

The Changing Landscape of Type Ia Supernova Progenitors

In the past, scientists studying progenitors of Type Ia supernova progenitors were faced with a problem getting agreement between the progenitors that population synthesis studies could get in large enough numbers to explain the SNIa population and the progenitors that engine theorists felt worked. This landscape has rapidly changed in the past few years with the dramatic change in our understanding of thermonuclear explosions. I will review the current situation of these engines in the context of supernova progenitors. These new results are prompting new population synthesis studies and I will review some of the recent results in this field. We may be able to distinguish these progenitors based on detailed spectra. I will conclude with a discussion of the current work on SNIa light-curve and spectra calculations and their relevance to SNIa progenitors.   

Cracking the Most Luminous Supernovae: Multidimensional Simulations of Pulsational Pair-Instability Supernovae

The extremely luminous supernovae such as SN 2006gy challenge the traditional view of core collapse supernovae, because they seem too luminous by more than one order of magnitude. Their unusual brightness might be explained by the collisions between shells of matter ejected by these massive stars at the end of their lives, so called pulsational pair-instability supernovae (PPSNe). We present the results from our multidimensional simulations of PPSNe with the state-of-the-art radiation-hydro code, CASTRO. We find significant amounts of fluid instabilities occurred during the shells apostrophe collisions and discuss how the resulting mixing affects the observational signature of PPSNe.   

A New Monte Carlo Method for Velocity-Dependent Neutrino And Photon Transport

Monte Carlo approaches to radiation transport have several attractive properties compared to deterministic methods. These include simplicity of implementation, high accuracy, and good parallel scaling. Moreover, Monte Carlo methods are relatively easy to extend to multiple spatial dimensions, which makes them particularly interesting in modeling complex astrophysical phenomena such as neutrino transport in core-collapse supernovae. We present a generalization of the Implicit Monte Carlo and Discrete-Diffusion Monte Carlo schemes to multi-energy and velocity-dependent neutrino transport and demonstrate that our scheme represents an attractive approach to modeling neutrino transport in core-collapse supernovae. We also show that our scheme can easily be adapted to photon transport.   

Session H15: Cosmic Rays Education II and Faster-than-Light Controversies

Students using large muon detectors to investigate an array of cosmic ray phenomena

During the summers of 2004 to 2008 high school students were given the opportunity to refurbish, characterize and ultimately experiment with large muon detectors at the University of Rochester. The 2.3 m$^{2}$ panels used for the cosmic ray investigations were remnants of the NuTeV experiment conducted at Fermilab in the late 1990's, and provided a means for measuring surface cosmic ray muon rates with high precision over many years of time. The first set of experiments carried out by students used data from two stacked paddles running in coincidence mode to detect significant muon fluctuations due to solar events, model an indirect relationship between muon frequency and atmospheric pressure, and determine if muon rates were dependent of the time of day. Current and archived data can be accessed at http://muon2.pas.rochester.edu/data/. In subsequent summers, students and teachers utilized four panel arrays to characterize directionality, angular distribution and frequency of atmospheric muon shower events. For all investigations students presented their findings to their peers and mentors via weekly seminars, e-logs, and poster sessions.   

The Mile Deep Muon Detector at Sanford Underground Laboratory

For educating students and teachers about basic nuclear and particle physics, you can't go wrong with cosmic rays muons as a cheap and reliable source of data. A simple and relatively inexpensive detector gives a myriad of possibilities to cover core material in physical science, chemistry, physics, and statistics and gives students opportunities to design their own investigations. At Sanford Underground Laboratory at Homestake, in Lead, SD, cosmic ray muon detectors are being used to answer the first question always asked by any visitor to the facility, ``Why are you building the lab a mile underground'' A conventional Quarknet-style detector is available in the education facility on the surface, with a much larger companion detector, the Mile Deep Muon Detector, set up 4850 feet below the surface. Using the Quarknet data acquisition board, the data will be made available to students and teachers through the Cosmic Ray E-lab website. The detector was tested and installed as part of a summer program for students beginning their first or second year of college.   

The Cosmic Muon Detector Array at Westmont College

At Westmont College we have designed and constructed the Cosmic Muon Detector Array (CMDA), consisting of 8 1-m long position-sensitive scintillator detector bars arranged in two layers of 4 detectors each, one above the other. The purpose of the array has been to measure and monitor the cosmic muon flux over a large angular range in the sky - approximately $\pm$ 50$^o$ (north-south) by $\pm$ 30$^o$ (east-west), by correlating event positions between the two layers. The CMDA also monitors the long term north-south sky flux ratio, binned by sidereal hour, to look for possible flux correlations from cosmic sources including the galactic core. The detectors, electronics, and analysis software was modeled after the Modular Neutron Array (MoNA) located at the NSCL, Michigan State University, and simultaneous flux correlations for the CMDA and MoNA were monitored for approximately 1 week. After taking over a year's worth of data, the original array burned in a campus wildfire, which was then replaced by the second generation array (currently in operation). The CMDA serves both as a training ground for students preparing for participation in MoNA collaboration experiments as well as for Westmont student research experience.   

Cosmic Ray Physics at a Community College: Assembly, Detection and Measurement

During an in-depth eight week summer research program at Hartnell Community College in Salinas, CA, we constructed two complementary experimental systems to measure cosmic rays. One system used NIM electronic modules configured for coincidence measurement. To detect the comic rays, two photomultiplier tubes each coupled to plastic scintillator paddles were assembled. The other system was build from a circuit board designed by the LBL Cosmic Ray Project. Extensive prototype and diagnosis for this board were done prior to final soldering of the parts. The dependence of the cosmic ray flux on the separation between scintillator paddles was measured and showed reasonable agreement with the accepted value. The flux dependence on the square of the cosine of the polar angle was also tested, and our result showed closely the expected cosine behavior using the NIM setup. As for the LBL Lab circuit board, it was difficult to obtain reliable coincidence counts for large polar angles probably due to the lack of an adjustable discriminator control. This was compensated for by operating the detectors at a lower high voltage which reduced the random counts, without affecting signals. This strategy gave a more reliable cosmic ray flux result using the Berkeley Lab circuit board.   

The Public Event Display of the Pierre Auger Observatory

The Pierre Auger Observatory is the largest cosmic ray detector ever built in the search for the unknown sources of the highest-energy cosmic rays ever observed. The Auger Collaboration has made 1\% of its cosmic ray data available to the general public. The U.S.\ mirror of this public event display is hosted at Colorado State. Our web site allows browsing over the ultra-high energy cosmic rays collected by the Auger Observatory since 2004, and it is updated daily. Users can display plots online, obtain detailed information on individual cosmic rays, and download an ASCII file with the complete data set. The Auger Observatory has also been recording the count rates of low energy secondary cosmic ray particles for the self-calibration of its particle detectors on the ground. After correcting for atmospheric effects, modulations of galactic cosmic rays due to solar activity and transient events are observed. The Auger data rates are also available to the general public through our website at Colorado State. In this talk, I will describe the available data together with the opportunities to utilize ultra-high energy cosmic rays as an educational tool.   

Superluminal Neutrinos: The Good Kind of Science Controversy

After OPERA released results indicating neutrinos were traveling faster than the speed of light, a number of vocal of scientists said that they shouldn't have prematurely engaged in ``science by press release.'' However, controversial claims like this, if handled right, can actually be a boon to science. Getting the public interested in cutting edge physics is notoriously difficult, but the public is always interested in hearing about a controversy. The press conference and following debate becomes a great teaching moment that offers the public a unique opportunity to get an inside and have an in-depth look at how science works. Scientists willing to publicly engage in this kind of civil controversy are important because when other scientific controversies arise, ones with major public policy implications, the public starts out with a better understanding of how science works, and scientists have better practice managing questions from the public.   

Controversial Physics: Perfect Public Outreach Opportunity

The goal of public outreach is to excite and engage the public in physics. What can be more exciting than controversy? When OPERA announced their discover of superluminal neutrinos, controversy within the physics community quickly followed. This result could overturn a century of established physics. From a public outreach perspective there was no better way to bring people usually unaware of current research into the discussion of this result. If handled well this could be used as a gateway to interest in other physics research. The public drive to learn more about this particular result can be harnessed to create interest in other cutting edge physics research and drive the public to continue their informal physics learning. If the results of OPERA and eventually proven incorrect as many physicists believe they will, that will not erase the public's new-found interest in physics but hopefully continue to fuel it.   

Controversial Science and the Media

The possibility that the OPERA collaboration has detected superluminal neutrinos was among the most controversial topics in physics news in decades, and one of the most widely covered stories in all of science in 2011. Word of the research initially reached journalists and the public prior to publication in peer-reviewed journals. Understandably, many physicists are concerned that the significance of controversial science may be exaggerated or distorted when news organizations report on science at such an early stage. I will offer an overview of the ways the story was promoted by the media relations personnel, and outline the rationales that motivate media relations efforts along with the associated benefits and drawbacks that can result. Finally, I will examine the accuracy and completeness of the superluminal neutrino news stories that ultimately were made available to the general public.   

Selectively Bringing Down the Curtain on OPERA Superluminal Neutrino Papers

Picture this: instead of watching from afar the daily flow of superluminal proposals trying to explain OPERA's preliminary data, you are the PRL Editor charged with deciding, via a peer review process, what to do with each paper. How do you address the validity of a manuscript whose starting point involves circumventing Einstein? I'll discuss the general issues of controversial claims and data-driven floods of theory papers through the unusual lens of the OPERA-motivated papers.   

Session H16: Sherwood II

Gyrokinetic Simulations with External Resonant Magnetic Perturbations: Island Torque and Nonambipolar Transport with Rotation

Static external resonant magnetic perturbations (RMPs) have been added to the $\delta f$ gyrokinetic code GYRO. This allows nonlinear gyrokinetic simulations of the nonambipolar radial current flow $j_r$ and the corresponding plasma torque (density) $R[j_rB_\theta/c]$, induced by islands that break the toroidal symmetry of a tokamak. This extends previous GYRO simulations for the transport of toroidal angular momentum (TAM) [1,2]. The focus is on full torus radial slice electrostatic simulations of induced q=m/n=6/3 islands with widths 5\% of the minor radius. The island torque scales with the radial electric field $E_r$ the island width $w$, and the intensity $I$ of the high-n micro-turbulence, as $wE_rI^{1/2}$. The net island torque is null at zero $E_r$ rather than at zero toroidal rotation. This means that there is a small co-directed magnetic acceleration to the small diamagnetic co-rotation corresponding to the zero $E_r$ which can be called the residual stress [2] from an externally induced island. Finite-beta GYRO simulations of a core radial slice demonstrate island unlocking and the RMP screening.\par \vskip6pt\noindent [1]~R.E. Waltz, et al., Phys. Plasmas {\bf 14}, 122507 (2007).\par\noindent [2]~R.E. Waltz, et al., Phys. Plasmas {\bf 18}, 042504 (2011).   

A Self-Consistent Mechanism for Incomplete Reconnection in Sawteeth

A prevailing impediment to core confinement in fusion devices is the occurrence of large sawtooth events. Experiments show that the crash phase often ends before all available magnetic flux is reconnected, i.e., reconnection is incomplete, but this is inconsistent with the Kadomtsev model. We present a model for incomplete, or partial, reconnection in sawtooth crashes [1]. The reconnection inflow self-consistently convects the high pressure core and low pressure edge of a tokamak toward the m=n=1 rational surface, thereby increasing the pressure gradient at the reconnection site. If the pressure gradient at the rational surface exceeds a threshold, incomplete reconnection will occur. We show that predictions of this model are borne out in large-scale simulations of reconnection. The predictions are also consistent with data from the Mega Ampere Spherical Tokamak. Physically, we attribute the suppression to the interaction of the exterior pressure gradient with the pressure quadrupole that inherently occurs during collisionless (Hall) reconnection with a strong guide-field. The results should apply across tokamaks, including ITER.\\[4pt] [1] M. T. Beidler and P. A. Cassak, Phys. Rev. Lett., 107, 255002 (2011)   

Rotation of tokamak halo currents

Halo currents, which can be tenths of the total plasma current, flow at the plasma edge along the magnetic field lines that intercept the chamber walls. Non-axisymmetric halo currents are required to maintain force balance as the plasma kinks when the edge safety factor drops to about two in a vertical displacement event. The plasma quickly assumes a definite toroidal velocity $v_a(r)$ with respect to the magnetic kink, where $v_a(r)$ is determined by the radial electric field required for ambipolarity. The plasma velocity near the edge is set by interaction with neutrals or by the radial derivative of the electric potential in the halo required for quasi-neutrality on open magnetic field lines, so the magnetic kink tends to rotate. If the magnetic field lines of the halo plasma intercept the wall at locations of very different electrical conductivity, the toroidal rotation of the halo currents can intermittently lock, as seen in experiments, at wall locations of high conductivity though the toroidal velocity of the magnetic kink itself is essentially smooth. A major concern cited by ITER engineers is that the time varying force of the rotating halo could substantially increase the disruption loads on in-vessel components.