Session T1: DPF/DPB Prize Session

Three Snapshots in the History of Asymmetric B-Factories

I will present three snapshots in time in the development and use of asymmetric B-factories. The first snapshot, in the late eighties, will describe the origin of the idea and the early debates on its feasibility. Next we will jump to today and briefly review the results and the underlying physics picture that has emerged from the work at the two asymmetric B-factories, PEPII and KEKB. Finally, we will jump ten years into the future and speculate on what the evolution of B-factories may bring, with two orders of magnitude more data and consequently much higher precision measurements.   

Wilson Prize Talk

In the late 1950's and the 1960's the MURA (Midwestern Universities Research Association) working group developed fixed field alternating gradient (FFAG) particle accelerators. FFAG accelerators are a natural corollary of the invention of alternating gradient focusing. The fixed guide field accommodates all orbits from the injection to the final energy. For this reason, the transverse motion in the guide field is nearly decoupled from the longitudinal acceleration. This allows a wide variety of acceleration schemes, using betatron or rf accelerating fields, beam stacking, bucket lifts, phase displacement, etc. It also simplifies theoretical and experimental studies of accelerators. Theoretical studies included an extensive analysis of rf acceleration processes, nonlinear orbit dynamics, and collective instabilities. Two FFAG designs, radial sector and spiral sector, were invented. The MURA team built small electron models of each type, and used them to study orbit dynamics, acceleration processes, orbit instabilities, and space charge limits. A practical result of these studies was the invention of the spiral sector cyclotron. Another was beam stacking, which led to the first practical way of achieving colliding beams. A 50 MeV two-way radial sector model was built in which it proved possible to stack a beam of over 10 amperes of electrons.   

Session T2: The Link between Neutrinos and the Origin of the Elements

Overview: Neutrinos and Nucleosynthesis

The astrophysical site of the r-process nucleosynthesis is not yet identified, but the neutrino-driven wind in a core-collapse supernova is one of the leading candidates. Neutrino interactions play a crucial role in such supernovae. Neutrino fluxes control the neutron-to-proton ratio in the high-entropy hot bubble which is where r-process nucleosynthesis is thought to take place. In this talk our current understanding of the role of neutrinos in core-collapse supernovae and the associated r-process nucleosynthesis will be reviewed. This work was supported in part by the U.S. National Science Foundation Grant No. PHY-0244384 and in part by the University of Wisconsin Research Committee with funds granted by the Wisconsin Alumni Research Foundation.   

Recent progress in neutrino - astrophysics connections

Of all the constituents within the standard model of particle physics our understanding of the neutrino has benefited the most from the interaction of astrophysics and `terraphysics.' Much has been learned about the properties of the neutrino from each: experiments here on Earth temper our appreciation of the role that neutrinos play in the cosmos while astrophysics can provide the densities and temperatures in which the neutrinos do more than simply flee. But the reluctance of neutrinos to interact means that it is not until we venture into the most extreme environments of astrophysics that we observe neutrinos `pushing back' as hard as they are being `pushed'. We review two sites where this occurs: the early Universe and the accretion disk `engines' of gamma ray bursts. Neutrinos play an important role in the evolution of the early Universe with a particular focus upon the electron neutrino in determining the primordial elemental composition via its participation in the most important reaction at that time. Within gamma ray burst accretion disks we again see the electron neutrinos at work in the nuclear reactions and through their function as the `coolant' for the disk. Removal of the disk energy, and its deposition into the remnants of the massive star surrounding the disk, may lead to the formation of highly relativistic jets that will later be observed as the burst. We show what has been learned so far about the neutrino and its properties from the study of such environments.   

Nucleosynthesis in Gamma Ray Bursts

Recent developments in the understanding of the astrophysical site of gamma-ray bursts have opened up an exciting new area of nucleosynthesis research. Within the gamma-ray burst environment, nucleosynthesis can occur as explosive burning, in the jet, or in the outflow from the accretion disk. Here we consider the latter, focusing on the prospects that gamma-ray bursts may be responsible for the galactic production of certain rare nuclear species, such as $r$-process nuclei and light proton-rich nuclei.   

Session T3: Active Galactic Nuclei

X-raying Active Galaxies Both Near and Far: Exploring the Environments of Supermassive Black Holes

X-ray emission appears to be a universal property of active galactic nuclei (AGN). This emission originates primarily in a supermassive black hole's immediate vicinity, and X-ray investigations probe the accretion processes by which black holes grow as well as their larger scale environments. I will review some of the recent dramatic advances made in supermassive black hole studies, obtained using data from NASA's Chandra X-ray Observatory and ESA's X-ray Multi-Mirror Mission-Newton. Specifically, I will discuss (1) X-ray spectroscopy of AGN accretion disks and outflows, (2) ultra-sensitive X-ray surveys that have discovered the highest density and diversity of supermassive black holes throughout the Universe, and (3) X-ray studies of the first supermassive black holes to form in the Universe. Upcoming X-ray missions and some long-term prospects for X-ray astronomy will also be described. Research funding from NASA and NSF is gratefully acknowledged.   

Unrobing `Dressed' Black Holes in Galactic Nuclei

From the event horizon of a massive black hole in a galactic nucleus to the radius on which stars dominate the gravitational potential is a dynamic range of $10^7$. Not surprisingly, the structure of such a galactic nucleus changes greatly over this span of scales. Through a combination of observational data and theoretical reasoning, we now know about many of the principal features. Thick clouds of molecular gas and dust occupy a toroidal region on the largest scale; examples have been interferometrically imaged in the infrared and in H$_2$O maser emission. This toroidal symmetry makes active galactic nuclei differ drastically in appearance depending on our viewing angle. Hot outflowing ionized gas occupies the axial hole in the torus, made visible by polarizing reflection of light from deeper inside and X-ray absorption spectroscopy. A factor of 1000 closer in, UV emission features indicate the presence of cooler ionized gas moving at $0.01c$. In some cases, we see evidence for outflows travelling at $0.1c$ at roughly the same distance scale. Still closer to the center, large-scale numerical simulations now show us how matter flows toward the black hole as a result of magnetic stresses created by internally-generated MHD turbulence. Thermal UV emission and hard X-rays created in coronal regions carry off the accreting matter's lost energy. Immediately outside the event horizon, spinning black holes can seize on the magnetic field created in the flow to transfer their angular momentum to matter in the inflow or drive a relativistic axial outflow.   

Gamma-Ray Observations of Active Galactic Nuclei: From GRO to GLAST

Some fraction of accreting black holes generate powerful collimated relativistic outflows; when these jets are pointed towards us, such Active Galactic Nuclei are known as blazars. Particles in blazar jets radiate in two broad peaks: by synchrotron radiation in the radio to soft X-ray band, and by photons boosted by inverse Compton processes at hard X-ray and gamma-ray energies. Formation of these powerful jets (with bulk Lorentz factor ~10) and the acceleration of particles in the jets (to electron Lorentz factors up to 10$^6$) are not understood - especially since the formation region is too compact to be directly imaged. Our best hope for understanding the jet structure is through multiwavelength variability studies. The upcoming launch of the Gamma-ray Large Area Space Telescope (GLAST), together with current and future X-ray and hard X-ray observatories promise dramatic improvements in data quality. I will review the current observational status, and discuss the advances in understanding we expect from these new capabilities.   

Session T4: Earth Based Gravitational Wave Detection

Sensitivity and Stability of the LIGO Interferometers

Gravitational wave astronomy promises to be a surprising, new way of listening to the universe. In the past 18 months, intensive work on the kilometer scale LIGO (Laser Interferometer Gravitational-wave Observatory) interferometers has led to an order of magnitude improvement in the sensitivity of all three interferometers. Parallel efforts have yielded substantial increases in the duty cycles of the detectors and improved stationarity of the noise. The current state of the detectors will be discussed, the recent sensitivity improvements described in detail, and a path for future upgrades will be mapped out.   

Science results from LIGO observing runs

We will report on the latest results obtained by the LIGO Scientific Collaboration in its searches for different kinds of gravitational wave signals in data collected by the LIGO detectors in the last two years. We have searched for signals originated by inspiraling binary systems and by rotating neutron stars; we also have looked for unmodelled transient signals and for a stochastic background. We will present direct observational upper limits arising from each of these searches. We will discuss the performance of different search methods in real data, in the presence with detector artifacts.   

Plans for Advanced LIGO Instruments

The proposed Advanced LIGO detector will have an increase in sensitivity over initial LIGO by a factor of ten, with an increased bandwidth in the region of highest sensitivity and the ability to tune for specific astrophysical sources. Advanced LIGO will achieve the equivalent of the one-year integrated observation time of initial LIGO in just several hours, allowing observation of astrophysical gravitational waves on a regular basis. The Advanced LIGO detector will replace the existing detector at the LIGO Observatories while retaining the existing building and vacuum system infrastructure. The new instruments build on the initial LIGO Fabry-Perot Michelson Interferometer layout and take advantage of significant advances in technology since the design of initial LIGO in the 1990's. Signal strength/sensitivity will be improved by increasing the laser power, lowering optical absorption, and adding signal recycling to the Fabry-Perot arm cavities. Stray forces on the test masses will be controlled by reducing thermal noise sources in the suspensions and optics and using a multi-staged seismic isolation system with inertial sensing and feedback control. The LIGO laboratory, the LIGO Science Collaboration, and international partners have undertaken a structured program of research and development, including testing of full-scale prototypes in context. Significant progress has been made on several of the detector subsystems. The Advanced LIGO project has been through National Science Foundation peer review and the National Science Board has recommended it for funding. Based on a proposed funding start in 2007, detector installation will begin in 2010, with observations at an advanced level of commissioning in 2013.   

Session T5: Oh, the Places You Will Go, Interesting Careers in Physics

What Can You Do with a Physics Education...in Addition to Becoming a Professor

Physics professors have often said that an education in physics will prepare you for just about anything. Certainly, the numerical and computer skills of physics students are widely known. The broad mathematical skills of physicists regularly lead to positions throughout the financial or engineering world, and the computer skills are a basis for employment in essentially all areas. However, these are features of all technical educations. What a physics curriculum provides as well, through the understanding of classical and quantum physics, is the basis for a quick understanding of the essential features of the world around us, and the devices we use to negotiate that world. This talk will discuss examples of how physics arguments have influenced a number of major government programs by providing decision makers with a simple and clear yet technically sound understanding of the underlying issues. In addition, examples of current problems in Defense that are subject to active research and debate will be discussed. The talk will conclude with a description of qualities and qualifications needed for a physicist to successfully transition to becoming an analyst. \\ Cynthia Dion-Schwarz, Ph.D., (George Mason University, B.S. Physics and Mathematics, 1988, University of Maryland, Ph.D. Physics, 1995) is an Assistant Director in a technical studies and analysis research organization serving the Department of Defense. She has also worked in the Pentagon as a Science Advisor in the Office of the Secretary of Defense. Before transitioning to a career as a defense analyst and technical manager, she conducted Astrophysics research at Los Alamos National Laboratory and the Naval Research Laboratory. She has published over 50 articles in both physics- and defense-related venues, is an officer in the American Physical Society/Forum for Industrial and Applied Physics, and has won numerous awards for research and community service.   

Doing physics on the nearest planet, or the next one over

Spaceflight produces a steady supply of physics problems. Recent research at the Kennedy Space Applied Physics Laboratory includes topics as diverse as the active shielding of cosmic radiation, the cratering of Martian soil by landing rockets, re-entry physics, and numerous imaging and detection techniques. Even something as simple as extracting water from a space shuttle thermal tile requires new thinking about physics. Often a concept must be formulated, developed and delivered to operational status within just a year or two, and so it helps to have a broad understanding of nature. My own career began in systems engineering for the Space Shuttle navigation systems and slowly developed into full-time research specializing in theoretical statistical mechanics. The key to making this transition was to identify some problems that would need to be solved and then to position myself as someone who could solve them. That strategy, along with a lot of patience and sincere effort, has allowed me to move into a very satisfying career as a full-time scientist. I hope to share some of the excitement of doing physics in the space program and where it is headed, both on Earth and on Mars, and how you might use the same strategy to create a physics career on your own nearest planet.   

Session T6: Forum on Physics and Society and Forum on History of Physics Award Session (Followed by FPS Business Meeting)

FHP Pais Award Talk: Physics, History, and the History of Physics

This first Abraham Pais Lecture will begin with the story of my own transformation from theoretical physicist to historian of physics. I will go on by illustrating my historian’s approach through a discussion of the issues raised by Einstein’s first paper of 1905; this is the paper physicists refer to so often – and so inadequately -- as his ``paper on the photoelectric effect.'' The lecture will conclude with a few, brief remarks on how the history of physics is essentially like any other sort of history.   

Burton Award Talk: Science Under Attack: Intelligent Design

Science is under attack in many places throughout our society, from the White House to the classroom. I will concentrate my remarks here on the emerging threat to science education associated with the effort to have Intelligent Design incorporated into high school science curricula. While this may appear to be primarily an attack on evolutionary biology, it is in fact motivated by an effort to undermine the teaching of science itself as a discipline based on the scientific method. Moreover, the key proponents of this methodology are not misguided scientists, they are highly refined political operatives who are motivated by a desire to incorporate religion directly in science classes.   

Leo Szilard and the role of physicists in countering nuclear threats

Even before the first nuclear bomb was tested, Leo Szilard led efforts by physicists to assert leadership on the use of nuclear weapons. He warned about the future possibility of delivering nuclear weapons by missiles and also pointed out the ease by which nuclear bombs could simply be carried across borders. The U.S. has had an anti-ballistic missile program since the 1950's. Initially it was intended to counter a Soviet nuclear threat but with the end of the cold war the goal was changed to dealing with accidental or unauthorized launches of Russian ICBMs. More recently, the goal of the U.S. missile defense program was shifted to countering a possible future threat posed by emerging missile states. The APS Study of boost- phase intercept was carried out in the Szilard tradition of physicists providing leadership on public policy issues involving science ad technology, in the hope that factual analysis of technical problems can contribute to better public policy.   

Current nuclear threats and possible responses

Over the last 50 years, the United States has spent more than \$100 billion developing and building a variety of systems intended to defend its territory against intercontinental-range ballistic missiles. Most of these systems never became operational and ultimately all were judged ineffective. The United States is currently spending about \$10 billion per year developing technologies and systems intended to defend against missiles that might be acquired in the future by North Korea or Iran. This presentation will discuss these efforts ad whether they are likely to be more effective than those of the past. It will also discuss the proper role of anti-ballistic programs at a time when the threat of a nuclear attack on the U.S. by terrorists armed with nuclear weapons is thought to be much higher than the threat of an attack by nuclear-armed ballistic missles.   

The impact of the APS study and the future of boost-phase defense against ballistic missiles

The APS study Boost-Phase Intercept Systems for National Missle Defense has provided a foundation for all policy and technical discussions of the topic, and has arguably affected the evolution of U.S. boost-phase defense programs. This presentation will summarize critiques and responses to the study, particularly the analysis of of space-based defense. It will describe the impact of the study and conclude with a discussion of where boost-phase missile defense is headed.   

Technical approaches to reducing the threat of nuclear terrorism

The threat of a nuclear attack on the United States by terrorists using a smuggled weapon is now considered more likely than an attack by a nuclear-armed ballistic missle. Consequently it is important to understand what can be done to detect and intercept a nuclear weapon being smuggled into the United States. A significant quantity of smuggled nuclear material has been intercepted already, but science and technology have so far contributed little to its interception. The critical special nuclear materials, plutonium and highly enriched uranium, are only weakly radioactive and detection of their radioactivity is limited both by atmospheric attenuation and by competition with natural backgrounds. Although many schemes for long-range detection of radioactivity have been proposed, none so far appears feasible. Detection of nuclear radiation can be improved using new technologies and sensing systems, but it will still be possible only at relatively small distances. Consequently the best approach to containing dangerous nuclear materials is at their sources; containment within lengthy borders and large areas is extremely difficult.   

Session T7: Top Quark Pair Production II

Simulation of Top Quark Pair Production as a Background for Higgs Events at the Compact Muon Solenoid

In this study, we simulated top-antitop (tt-bar) quark events at the Compact Muon Solenoid (CMS), an experiment presently being constructed at the Large Hadron Collider in Geneva, Switzerland. The tt-bar process is an important background for Higgs events. We used a chain of software to simulate and reconstruct processes that will occur inside the detector. CMKIN was used to generate and store Monte Carlo Events. OSCAR, a GEANT4 based CMS detector simulator, was used to simulate the CMS detector and how particles would interact with the detector. Next, we used ORCA to simulate the response of the readout electronics at CMS. Last, we used the Jet/MET Root maker to create root files of jets and missing energy. We are now using this software analysis chain to complete a systematic study of initial state radiation at hadron colliders. This study is essential because tt-bar is the main background for the Higgs boson and these processes are extremely sensitive to initial state radiation. Results of our initial state radiation study will be presented. We started this study at the new LHC Physics Center (LPC) located at Fermi National Accelerator Laboratory, and we are now completing the study at the University of Rochester.   

Measurement of the t$\bar{t}$ Production Cross-Section in Dilepton Events with Secondary Vertex b-tagging

We report on a measurement of the $t\bar{t}$\ production cross section in 340 pb$^{-1}$\ of $t\bar{t}$\ events collected with the CDF detector at the Tevatron containing two identified high p$_T$\ leptons, missing energy and at least one $b$-jet candidate. We reconstruct b-jets using secondary vertices in the silicon vertex detecor. By adding the b-quark identification we can relax some of the selection criteria used to identify top decay in the dilepton channel while keeping the non top contamination to a minimum. We finally compare selected kinematic properties of these events with the prediction of the Standard Model for the $t\rightarrow Wb$\ vertex.   

Measurement of top pair production cross section in Lepton plus Jets events at CDF with event kinematics.

A major goal of the CDF physics program at the Tevatron is the precise measurement of the properties of the top quark. We present a measurement of the $t\bar t$ production cross section in $p\bar{p}$ collisions at $\sqrt{s}$ = 1.96 TeV, using 340 pb$^{-1}$ of data collected by the CDFII detector at the Fermilab Tevatron. We select events with a high transverse momentum electron or muon, 3 or more jets, and missing $E_T$. We develop an artifical neural network method that uses a variety of kinematic quantities to distinguish $t\bar{t}$\ events from the primary background of W boson production with associated jets.   

$t\bar{t}$\ Cross-section Measurement into Multi-Jet Final States

We present a $t\bar{t}$\ production cross section measurement in the multi-jet final state channel from collisions of protons and anti-protons at 1.96 TeV at the Collider Detector at Fermilab (CDF). We study events, selected using optimized kinematical criteria, that contain jets that are identified in the Silicon Vertex Detector as originating from b-quarks. Contributions to the measurement from events with hadronically decaying taus are also discussed.   

Measurement of the $t\bar t$ Production Cross Section in $p\bar p $ Collisions at $\sqrt{s}=1.96$ TeVUsing Lepton Plus Jets Events with Secondary Vertex b-Tagging

We present a preliminary measurement of the $t\bar{t}$ pair production cross section in $p\bar{p}$ collisions at $\sqrt{s}$ = 1.96 TeV using 340 pb$^{-1}$ of data collected by the CDFII detector at the Fermilab Tevatron. We measure the cross section in events with one high high transverse momentum lepton and 3 or more jets, where at least one $b$-jet is identified via a displaced vertex algorithm.   

Measurement of the $t\bar t$ Production Cross Section in $p\bar p $ Collisions at $\sqrt{s}=1.96$ TeV Using Lepton Plus Jets Events with Soft Muon b-Tagging

We present a measurement of the $t\bar t$ production cross section in $\sim 200 \mathrm{pb^{-1}}$ of CDF Run 2 data using events with a high transverse momentum electron or muon, 3 or more jets, and missing $E_T$. Events consistent with $t\bar t$ decay are found by identifying jets containing candidate heavy- flavor semileptonic decays to muons. Backgrounds are computed from a combination of Run 2 data and simulation. Signal acceptance is determined from Run 2 $t \bar t$ PYTHIA Monte Carlo. Based on 20 candidate events with 3 or more jets and an expected background of 9.6 events, a production cross section of $5.2^{+2.9~+1.3}_{-1.9~-1.0}~\mathrm{pb}$ is measured.   

Measurement of $t\bar t$ production cross section in the lepton+jets channel using Jet Probability $b$-tagging at CDF

We present a preliminary measurement of the $t\bar t$ pair production cross section in the collisions of protons and anti-protons at 1.96\~TeV at the Collider Detector at Fermilab (CDF). The measurement uses $t\bar t$ decays into final states which contain one high transverse momentum lepton and multiple jets, where one of the jets is required to be identified as a $b$-jet candidate from the information of the track´s impact parameter resolution using the SVXII Silicon Vertex detector. The performance of the tagging algorithm used in this analysis is also discussed.   

Combination of top pair production cross sections at CDF.

A major goal of the CDF physics program at the Tevatron is the precise measurement of the properties of the top quark. We discuss the gain in precision from combination of the various CDF measurements of the $t\bar t$\ production cross section in $p\bar{p}$\ collisions at $\sqrt{s}$\ = 1.96 TeV. We present the combined cross section using 340 pb$^{-1}$\ of data collected by the CDFII detector at the Fermilab Tevatron.   

Session T8: Higgs Searches with W's and Z's

Measurement of $Wb\bar{b}$\ cross section at CDF

We present a preliminary measurement of the $Wb\bar{b}$\ cross section in $p\bar{p}$\ collisions at $\sqrt{s}$=1.96 TeV at the Collider Detector at Fermilab. We measure the cross section using events which contain one high transverse momentum lepton, missing transverse energy, and one or two jets including one jet tagged with a displaced secondary vertex. We use the invariant mass and pseudo-lifetime of the vertex to discriminate between b-quark jets, charm jets, and mistags.   

Measurement of the $W\to e\nu + \ge n-jet$ Cross Section at the Tevatron

Understanding direct $W$ + jets production is crucial to making accurate background predictions to both top quark production and many of the Higgs production channels. We present a measurement of the $W\to e\nu + \ge n-jet$ cross section at $\sqrt{s} = 1.96$~${\rm TeV}$ using $320$~${\rm pb^{-1}}$ of CDF Run II data. Distributions of various kinematic variables are compared with two different Monte Carlo matrix element plus parton shower (ME-PS) predictions: Enhanced Leading Order ALPGEN+HERWIG samples, and `ME-PS matched' CKKW MADGRAPH+PYTHIA samples.   

Search for a New Particle $X$($\to b\bar{b}$) Production in Association with a $W^{\pm}$ Boson at the Tevatron

We present an updated search for a new particle that decays into $b\bar{b}$ and is produced in association with $W^{\pm}$ boson in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV. The search uses a Run II dataset accumulated by the CDF experiment at the Fermilab corresponding to an integrated luminosity of about $300$ pb$^{-1}$. We select events with an electron or muon, large missing transverse energy, and two jets, with at least one of the jets $b$-tagged. We present results as a function of new particle mass. In particular, we place upper limits on the cross section of $W^\pm h \to W^\pm b\bar{b}$ and $\rho_{TC} \to W^\pm \pi_{TC} \to W^\pm b\bar{b}$ production.   

Search for Higgs Boson Production via the Process $p\bar{p}\rightarrow ZH \rightarrow l^{+}l^{-}b\bar{b}$ at CDF

We are conducting a search for the Higgs boson via the process $p\bar{p} \rightarrow ZH \rightarrow l^{+}l^{-} b\bar{b}$ using 300 pb$^{-1}$ of data from CDF Run II. The Higgs Boson is predicted by the Standard Model but has yet to be observed. The main background of this $ZH$ signal is $Z + b\bar{b}$, where the $Z$ decays into two charged leptons. The background is distinguished from the signal using an artificial neural network that we have developed. We will report on the status of the search and the future prospects using the anticipated large data samples from Run II.   

Search for $Wb\bar{b}$ and $WH$ production in $p\bar{p}$ collisions at $\sqrt s=1.96$ TeV

We present a study of $Wb\bar{b}$ production and a search for $WH$ production of the SM Higgs boson masses between 105 and 135 GeV in $p\bar{p}$ collisions at $\sqrt{s}$ = 1.96 TeV. The search is performed in events containing one election, an imbalance in the transverse enegy($E_T$) and two $b$-tagged jets in 400 $pb^{-1}$ of integrated luminosity accumulated collected by the D\O\ experiment at Fermilab.   

Search for Associated Production of $Z$ and Higgs Bosons in $\mu^+\mu^-b\bar{b}$ final states

We present the preliminary results from the D\O\ experiment at Fermilab on a search for the light mass Standard Model Higgs Boson produced in association with a $Z$ boson in the $\mu^+\mu^-b\bar{b}$ channel. We present an optimized analysis strategy for the most significant background of this process, the QCD production of $b\bar{b}$ associated with the $Z$ boson, and introduce the topological analysis method for the selection and reconstruction of this kind of signals.   

Search for Associated Production of $Z$ and Higgs Bosons in $e^+e^-b\bar{b}$ final states

Studies are presented of the search for a light Standard Model Higgs boson produced in association with a $Z$ boson in the $Z \rightarrow e^+e^-$ and $h \rightarrow b\bar{b}$ decay channel using Run II data collected by the D\O\ detector at the Fermilab $p\bar{p}$ collider at $\sqrt{s} = 1.96$ TeV. A preliminary measurement of the cross section of the $Z$-boson associated production with jets is also presented.   

Session T9: Particles and Cosmology

Short Distance and Initial State Effects in Inflation

We consider general homogeneous isotropic initial states in inflation, such as might be generated by novel short distance physics, and determine their observational consequences for the CMB power spectrum. We also compute the stress-energy tensor of these general states and give the quantitative criteria necessary for initial state effects not to disturb the inflationary expansion.   

A Thermal Graviton Background from Extra Dimensions

Inflationary cosmology predicts a low-amplitude graviton background across a wide range of frequencies. We demonstrate that the presence of extra spatial dimensions will modify the primordial graviton spectrum. If the fundamental scale of these extra dimensions is below the reheat temperature, the high-frequency modes of the graviton background may have a thermal spectrum instead. The energy density in this background is significant enough that nucleosynthesis may be affected in a substantial way. Examining the 21-cm hydrogen line may allow for direct detection of a thermal graviton background.   

Evolution of cosmic strings

We investigate the evolution of cosmic strings network in flat space. We give a dynamical argument that the structures on infinite strings should obey a scaling law. We perform a simulation of the network which uses functional forms for the string position and thus is exact to the limits of computer arithmetic. Our results confirm that the wiggles on the strings obey a scaling law with equal power per logarithmic interval of wavelength up to a cutoff that scales with the simulation time. The average distance between long strings also scales accurately with the time. We also discuss the questions of loop production and fragmentation, and the evolution of strings with intercommutation probabilities $p<1$.   

Rotating Brane Worlds and the Global Rotation of the Universe

We introduce a class of brane-world models in which a single brane is embedded in an anti-de Sitter spacetime containing a rotating (Kerr) black hole. In this Letter we consider the case of slow rotation, calculating the metric and dynamics of the brane world to first order in the angular momentum of the black hole. To this order we find that the cosmic fluid on the brane rotates rigidly relative to a Robertson-Walker frame of reference, which in turn rotates rigidly relative to the original Kerr-anti-de Sitter coordinate frame. Corrections to the Friedmann equations and the shape of the brane occur only at higher order. We construct models for which the geometry on the brane is either closed or open, but the open models are described only for small distances from the rotation axis, and may very likely develop pathologies at larger distances. Finally we discuss the effect of rotation as a dark energy when we look at the Friedmann equations beyond the first order in the angular momentum of the bulk black hole.   

Constrained Perturbative Expansion of the DGP Model

We address the vDVZ discontinuity of the 5D DGP model which consists of a 3-brane residing in a flat, infinite-volume bulk. It was argued by Gabadadze [hep-th/0403161] that the breakdown of the 5D perturbative expansion is due to the weak-field expansion itself and is avoided when a different expansion - the constrained perturbation theory - is adopted. Expanding on this work, we subject the DGP model to more general regulating conditions and solve the field equations. The solution reduces to the standard DGP and Gabadadze solutions for special choices of the brane ``gauge'' parameter.   

An Alternative to Dark Energy: $\Lambda = 0$ Accelerating Cosmologies with Exchange between the Bulk and Brane

We study the cosmological brane world scenario in which the bulk dimension is not {\it empty}. Rather, exchange of mass-energy between the bulk and the brane is allowed. The evolution of matter fields to an observer on the brane is then modified by new terms in the energy momentum tensor describing this exchange. In this paper we specifically investigate the constraints from various cosmological observations on the flow of matter from the bulk to the brane. Interestingly, we show that it is possible to have a $\Lambda = 0$ cosmology in the brane which satisfies all presently available cosmological constraints. At the same time this model also accounts for the suppression of the CMB power spectrum at low multipoles. In this cosmology, the observed cosmic acceleration is attributable to the so-called "dark radiation" associated with the projection of the flow of matter from the bulk to the brane. A peculiar aspect of this cosmology is that the universal dark matter content may be significantly larger than that of a standard $\Lambda CDM$ cosmology. Its influence, however, is offset by the dark-radiation term. Possible other observational tests of this new cosmological paradigm are suggested.   

Nonlinear quantum inflaton fluctuations in the early universe

The significance of nonlinear quantum fluctuations in a massless, minimally coupled, inflaton is studied in the limit of very slow roll. In particular we examine their effect, to linear order, on the metric fluctuations they induce by consistently solving the regularized Einstein equations. We find that the quantum state describing these flucuations must be $SO(4,1)$ invariant if perturbation theory is to be consistent to second order.   

Cosmology from decaying dark energy, primordial at the Planck scale

The consideration of dark energy's quanta, required also by thermodynamics, introduces its chemical potential into the cosmological equations. Isolating its main contribution, we obtain solutions with dark energy decaying to matter or radiation. When dominant, their energy densities tend asymptotically to a constant ratio, explaining today's dark energy-dark matter coincidence, and in agreement with supernova redshift data, and an age-of-the-universe constraint. This also connects the Planck and today's scales through time. This decay may be manifested in the highest-energy cosmic rays, recently detected.   

Session T10: Focus Session: Non-Perturbative Quantum Gravity

Recent Advances in Quantum gravity

This talk will review the most significant of the recent advances in loop quantum gravity. It will be addressed to non-experts.   

Pre-classical solutions in Bianchi I loop quantum cosmology

Loop quantum cosmology, the symmetry reduction of quantum geometry for the study of various cosmological situations, leads to a difference equation for its quantum evolution equation. To ensure that solutions of this equation act in the expected classical manner far from singularities, additional restrictions are imposed on the solution. Here we consider the range of solutions for the anisotropic Bianchi I model that meet these restrictions, and find that they are rather limited. The implications of these results for the full theory of quantum geometry will be discussed.   

Horizon Constraints and Black Hole Entropy

To ask a question about a black hole in quantum gravity, one must restrict initial or boundary data to ensure that a black hole is actually present. For two-dimensional dilaton gravity, and probably a much wider class of theories, I show that the imposition of a``stretched horizon'' constraint modifies the algebra of symmetries at the horizon, inducing a central term. Standard conformal field theory techniques then fix the asymptotic density of states, reproducing the Bekenstein-Hawking entropy. The states responsible for black hole entropy can thus be viewed as ``would-be gauge'' states that become physical because the symmetries are altered.   

Perturbation Theory in Covariant Canonical Quantization

I investigate a new idea of perturbation theory in covariant canonical quantization. This idea is motivated by computability of the ``evolving constants'' idea introduced by Rovelli---an outstanding obstacle to which has been the lack of exact general solutions in 3+1 dimensional general relativity. I present preliminary results for a toy model of a harmonic oscillator with a quartic perturbation, and show that this method reproduces the quantized spectrum of standard quantum theory. This result indicates that when the exact solutions to classical equations are not known, covariant canonical quantization via perturbation theory could be a viable approximation scheme for finding observables, and suggests a physically interesting way of extending the scope of covariant canonical quantization in quantum gravity.   

Plugging holes in constraints on linearly Planck suppressed Lorentz violation

Over the past few years much work has gone into constraining the possibility that, due to quantum gravity effects, Lorentz invariance may not be an exact symmetry of nature. A number of astrophysical phenomena, such as polarization of light from distant sources, high energy gamma rays, and the spectrum of the Crab nebula have been used to put stringent limits on Lorentz violation in particle dispersion relations that is suppressed by a single power of the Planck scale. However, despite these attempts there have been some holes in the various constraints, mainly due to the fact that this type of Lorentz violation is CPT violating. In this talk we discuss the existing holes and show that consideration of particular helicity states for threshold reactions significantly strengthens some constraints, thereby plugging these holes. We conclude that the entire parameter space of linearly suppressed Lorentz violation is bounded at a least an order of magnitude below one.   

Causal Sets, Hypergraphs and Cosmology

Causal sets are discrete structures consisting of points and causal links; they show great promise as the starting point for quantization of spacetime and general relativity. A graph is a discrete set of nodes and connecting links. A hypergraph is a generalized graph, wherein every subset of the node set may be included as an edge, which is analogous to a (2-node) link. A fundamental correspondence is presented between causal sets and hypergraphs. This is used to define a time index for each causal set point, which well-orders the set, as well as a spatial distance between points, which obeys the triangle inequality. The complete hypergraph is considered as the prime example. The time and spatial measures provide local and global structure for the corresponding causal set, as well as a simple derivation of the Hubble Law.   

Quantum gravity with real clocks, fundamental decoherence and the black hole information puzzle

We present work in collaboration with Rodolfo Gambini and Rafael Porto. Using the consistent discretization scheme we introduced, general relativity can be approximated by a constraint-free theory. This allows its quantization using the ideas of Page and Wootters, where one chooses a quantum physical variable as a clock. The resulting evolution in terms of the quantum clock is shown to be lose unitarity, even if one chooses the best possible clock. We present an estimate of such an effect, and show that it is large enough to render the black hole information puzzle unobservable: pure states would lose coherence due to this fundamental mechanism at a rate similar to the one that could be achieved by collapsing a pure state into a black hole that evaporates.   

Session T11: Teacher Preparation and Public Outreach

UTeach: Teacher preparation at The University of Texas at Austin

UTeach prepares secondary teachers of science, mathematics, and computer science at The University of Texas at Austin. It began with a pilot group of 28 students in the fall of 1997, and now has over 400 students enrolled, with over 70 new teachers graduating per year. Important features of the program include \begin{itemize} \item All students in College of Natural Sciences are invited to try out teaching at any time at no cost. \item All degree plans can be completed in 4 years. \item Students begin carefully supervised teaching in real classrooms within a few weeks of beginning the program. \item Close collaboration of Colleges of Natural Sciences and Education \item Many courses taught by a team of former secondary Master Teachers employed in College of Natural Sciences \item Emphasis upon inquiry instruction \end{itemize} Graduates are in heavy demand, and their retention rate after 4 years is over 80\%. However, one of the few dark spots in a generally bright picture is that the number of physics majors receiving certification remains small. See {\tt uteach.utexas.edu}   

TOPS, A Program for Undergraduates to Stimulate Teaching Careers in Pre-College Physical Science

TOPS$^{1}$ (Teaching Opportunity in Physical Science) is a six-week summer program for undergraduate physics and engineering majors who are considering teaching careers. The program is hosted by the Center for Ultracold Atoms (CUA) at MIT and Harvard. The goal is to provide these students with an experience that could be pivotal in leading them to choose a teaching career. Participants work in two teams of four, each team under the supervision of an experienced teacher. They design courses that emphasize hands-on experiences, which they teach to middle school students at the Museum of Science in Boston and to high school students at MIT. TOPS is now in its third year. The themes of this summer's courses will be light and heat. \newline \newline *Co-author: Dan Kleppner, MIT \newline $^{1}$TOPS is sponsored by the CUA which is funded by the National Science Foundation   

The Cosmic Ray Observatory Project in Nebraska and Public Outreach for the Pierre Auger Observatory in Argentina

The Cosmic Ray Observatory Project (CROP) is a statewide education and research experiment involving Nebraska high school students, teachers, and college undergraduates in the study of extensive cosmic-ray air showers. A network of high school teams construct, install, and operate school-based detectors in coordination with University of Nebraska physics professors and graduate students. The detector system at each school is an array of scintillation counters recycled from the Chicago Air Shower Array in weather-proof enclosures on the school roof, with a GPS receiver providing a time stamp for cosmic-ray events. The detectors are connected to triggering electronics and a data-acquisition PC inside the building. Students share data via the Internet to search for time coincidences with other sites. CROP has enlisted 26 schools in its first 5 years of operation with the aim of expanding to the 314 high schools in the state over the next several years. The presenter also serves as the Task Leader for Education and Outreach for the Pierre Auger Cosmic Ray Observatory, and selected public outreach activities related to the experiment will be described.   

Bringing Technology into High School Physics Classrooms

In an effort to help high school physics teachers bring technology into their classrooms, we at JSU have been offering professional development to secondary education teachers. This effort is part of Project IMPACTSEED (IMproving Physics And Chemistry Teaching in SEcondary Education), a No-Child Left Behind (NCLB) grant funded by the Alabama Commission on Higher Education, serving high school physics teachers in Northeast Alabama. This project is motivated by a major pressing local need: A large number of high school physics teachers teach out of field. To achieve IMPACTSEED's goals, we have forged a functional collaboration with school districts from about ten counties. This collaboration is aimed at achieving a double aim: (a) to make physics and chemistry understandable and fun to learn within a hands-on, inquiry-based setting; (b) to overcome the fear- factor for physics and chemistry among students. Through a two-week long summer institute, a series of weekend technology workshops, and onsite support, we have been providing year-round support to the physics/chemistry teachers in this area. This outreach initiative has helped provide our students with a physics/chemistry education that enjoys a great deal of continuity and consistency from high school to college.   

Learner-Centered Teaching and Improving Learning by Writing Down the Statement of Problems in an Introductory Physics Course

In a calculus-based introductory physics course, students were assigned to write the statements of word problems (along with the accompanying diagrams if any), analyze these, identify important concepts/equations and try to solve these end-of- chapter homework problems. They were required to bring to class their written assignment until the chapter was completed in lecture. These were quickly checked at the beginning of the class. In addition, re-doing selected solved examples in the textbook were assigned as homework. Where possible, students were asked to look for similarities between the solved-examples and the end-of-the-chapter problems, or occasionally these were brought to the students' attention. It was observed that many students were able to solve several of the solved-examples on the test even though the instructor had not solved these in class. This was seen as an improvement over the previous years. It made the students more responsible for their learning. Another benefit was that it alleviated the problems previously created by many students not bringing the textbooks to class. It allowed more time for problem solving/discussions in class.   

Session T12: Weak Interactions and Physics Beyond the Standard Model

General classification and analysis of neutron beta-decay experiments

A method for general analysis of the sensitivities of neutron beta-decay experiments to manifestations of possible deviations from the Standard model is proposed. We take into account all known (radiative and recoil) corrections which are consistent with the Standard model for description of angular correlations in neutron decay in the first order of approximation, or up to level of 10$^{-5}$ (see, for example ref.[1]). The contributions from models beyond the Standard model are, for low energy neutron decay, parameterized in terms of vector, axial-vector, scalar and tensor coupling constants [2] and in terms of parameters related to specific models [3]. For the present analysis we derive the exact expressions for neutron beta decay probability which includes all possible manifestations models beyond the Standard one up to level of 10$^{-5}$ without time-reversal violation. Based on the general expressions for manifestation of the deviation from the standard model we present analysis of the sensitivities for selected neutron decay experiments. 1. S. Ando, H. W. Fearing, V. Gudkov, K. Kubodera, F. Myhrer, S. Nakamura and T. Sato, Phys. Lett. B 595, 250 (2004 ). 2. J. D. Jackson, S.B. Treiman and H. W. Wyld Jr., Nucl. Phys. 4, 206 (1957). 3. P. Herczeg, Prog. Part. Nucl. Phys. 46, 413 (2001).   

Design of an Improved Apparatus for a Measurement of the Neutron Lifetime Using Magnetically Trapped Ultracold Neutrons

As a part of an on-going program that seeks to measure the neutron lifetime using magnetically trapped ultracold neutrons (UCN), we are in the process of incorporating a larger and deeper superconducting magnetic trap into our apparatus. The experiment works by loading the trap with UCN through inelastic scattering of 0.89 nm neutrons with phonons in superfluid $^{4} $He. Trapped neutrons are detected when they decay; charged decay electrons ionize helium atoms in the superfluid resulting in scintillation light that is recorded in real time using photomultiplier tubes. We will discuss the design and performance of the new Ioffe-type trap and provide an overview of the statistical sensitivity we expect to reach with the improved apparatus.   

Status of the Twist Measurement of the Muon Decay Parameter P$_{\mu}\xi$

Muon decay, a purely leptonic decay, is a relatively simple interaction to study when looking for physics not explained by the standard Vector minus Axial Vector (V-A) theory of electroweak interactions. The TWIST spectrometer measures the doubly differential spectrum of decay positrons for a wide range in reduced energy and angle between muon and decay positron momentum. By measuring a large part of muon decay spectrum, TWIST is sensitive to the exact shape of the decay spectrum, and can simultaneously measure three of the muon decay parameters with a high degree of accuracy. I will review the status of the TWIST experiment, and physics related to the muon decay parameter P$_{\mu}\xi$. TWIST will measure P$_{\mu}\xi$ by about an order of magnitude better than previous direct measurements. The status of analysis of systematic uncertainties in the measurement of P$_{\mu}\xi$ is presented.   

TWIST Measurement of the Decay Parameters rho and delta of Normal Muon Decay

The TWIST collaboration is improving the precision on the characterization of normal muon decay, $\mu^+\rightarrow e^+\nu_e\bar{\nu}_{\mu}$, through measurements of the decay parameters $\rho$, $\delta$ and $P_{\mu}\xi$. The analysis of the initial TWIST measurements of $\rho$ and $\delta$ have been completed. We find $\rho=0.75080\pm0.00032(stat.)\pm0.00097(syst.)\pm0.00023 $ and $\delta=0.74964\pm0.00066(stat.)\pm0.00112(syst.)$, consistent with the Standard Model. The improved precision places new limits on physics beyond the Standard Model, such as the parameters describing left-right symmetric models. The current results and implications will be discussed.   

Precision Measurement of Muon Capture on the Proton - the MuCAP experiment.

PNPI-PSI-UC Berkeley-UI Urbana-Champaign-UC de Louvain-Boston University - UK Lexington-TU M\"unchen. The goal of the MuCAP experiment is the determination of the singlet muon capture rate on the proton to 1\%. Such a measurement would allow us to extract g$_{P}$, the induced pseudoscalar form factor of the proton, to a few percent. In comparison with the other weak form factors, the pseudoscalar one is known orders of magnitude worse. Moreover, the most precise experimental values are ambiguous, in mutual disagreement, and partially in conflict with theory. In contrast to the experimental situation, recent calculations within chiral perturbation theory agree and are accurate on the few percent level. A precise unambiguous measurement would thus provide a stringent test of the underlying accurate QCD relations. The MuCAP collaboration completed an improved setup last fall with the installation of a second wire chamber allowing for electron tracking to the decay muon vertex, and a continuous hydrogen high-Z purification system. We successfully operated our active muon-stop target, a time-projection chamber, in sub-ppm pure hydrogen over weeks and collected data, doubling the statistics of cleanly observed $\mu^{-}$-decay events of all previous experiments. We will discuss plans for the experiment and progress of the present analysis which should lead to a significant improvement on the current world data on g$_{P}$.   

Proposed Searches for Electric Dipole Moments of the Muon, Deuteron and Proton in Storage Rings

We will describe a new, highly-sensitive method of probing for electric dipole moments (EMD) on charged particles, such as muons, deuterons, and protons in magnetic storage rings. These techniques utilize the strong electric fields present in the particle's rest frame due to relativistic effects. We will discuss the physics reach for a range of sensitivities: $10^{-27}$ to $10^{-29}\ {\rm e}\kern-1pt\cdot\kern-1pt{\rm cm}$ for the deuteron/proton and $<10^{-24}\ {\rm e}\kern-1pt\cdot\kern-1pt {\rm cm}$ for the muon (see also \urllink{The storage ring EDM collaboration web page} {http://www.bnl.gov/edm/}). We will compare ring designs that (a) cancel the precession of the anomalous magnetic moment using electric fields and (b) accumulate an EDM precession using a resonance between the anomalous precession and synchrotron oscillations. The mere existence of an EDM for a fundamental particle at these levels would imply a new source of CP-violation that is several orders of magnitude above Standard Model predictions but within the range of speculative models containing new physics.   

VLADD : An Extra Dimensions Detector

The existence of extra-dimensions may be detected by observing the invisible decay of orthopositronium (oPs) at a branching ratio of $10^{- 10}$. Previous experiments have searched for invisible decays at a branching ratio of $10^{-6}$ but were unable to achieve greater precision due to electron backgrounds. None of these experiments attempted to utilize a detector which would distinguish positrons from electrons. The VLADD experiment proposes to use a mini-TPC placed in a small, stable magnetic field as a means to separate $e^+$ from $e^-$. VLADD will be a demonstration experiment to verify that this technique will in fact work and will allow adequate rejection of backgrounds. Should the techniques used in VLADD reach a branching ratio sensitivity on the order of the most sensitive current measurements ($10^{-6}$), then a proposal will be made to build a larger version of VLADD for a more sensitive extra-dimensions search.   

Session T13: Intermediate Energy Accelerators, Radiation Sources, and New Acceleration Methods

Barrier RF Stacking in the Fermilab Main Injector

A novel wideband RF system, nicknamed ``Barrier RF,'' has been designed, fabricated and installed in the Fermilab Main Injector. The cavity is made of seven Finemet cores, and the modulator made of two bipolar high-voltage fast solid-state switches. The system can deliver $\pm 7\;$kV square pulses at 90~kHz. The main application is to stack two proton batches injected from the Booster and squeeze them into the size of one so that the bunch intensity can be doubled. This increased intensity will be of significant benefit to experiments like MINOS in which the 120~GeV Main Injector beam is extracted into the NuMI beam line to generate neutrinos. High intensity beams have been successfully stacked and accelerated to 120~GeV with small losses. The problem of large longitudinal emittance growth is the focus of the present study. An upgraded system with two barrier RF cavities for continuous stacking is under construction. This work is part of the US-Japan collaborative agreement.   

Brookhaven Super Neutrino Beam Project

Super neutrino beam facilities are used to accurately determine the neutrino mixing amplitudes and phase, as well as the CP violation parameters with the long distance and wideband nature of the neutrino beam for the observation of several oscillations from one species of the neutrino to the other. The Super Neutrino Beam Project was proposed at the Brookhaven National Laboratory based on an upgrade of the AGS proton facility from the current 0.14 MW to over 1 MW beam power. The project consists of three major parts: a 1.5 GeV superconducting RF linac that replaces the booster as injector for the AGS, performance upgrade of the AGS itself for a higher intensity and repetition rate, and finally the target and horn system for the neutrino production. This talk gives an overview of the project with emphasis on the design consideration to achieve high intensity and low beam loss for the accelerator systems.   

Center for Accelerator Science and Technology at MIT -- A New Initiative

MIT is proposing to establish a new interdisciplinary Center for Accelerator Science and Technology (CAST) led by faculty from across the Schools of Science and Engineering that would carry out frontier R{\&}D and have a strong educational program. The initial research focus includes development of technologies relevant to major accelerator initiatives such as the JLab 12 GeV Upgrade, RHIC II, e-RHIC, the ILC, and a laser-seeded FEL light source. The MIT Bates Linear Accelerator Center, which will soon complete its role as a nuclear physics user facility, is foreseen as the major laboratory focus for CAST. The facility staff and polarized injector, electron accelerator and the South Hall storage ring are outstanding resources for investigating important problems in accelerator science and the facility provides a premier test facility for training students. The CAST proposal may be found at the URL: \href{http://www2.lns.mit.edu/cast/}{http://www2.lns.mit.edu/cast/}.   

The AWA BPM Project

Our project investigates methods of studying the transverse electron beam profile at the Argonne Wakefield Accelerator (AWA). Currently we are testing the resolutions of two beam position measurement systems: direct imaging using Yttrium Aluminum Garnet (YAG) crystal, and the Beam Position Monitoring (BPM) system. The ultimate goal is to employ a dependable and high-resolution beam position measuring system to study the accelerating capability of the wakefield structure.   

Terahertz Coherent Synchrotron Radiation in the MIT-Bates South Hall Ring

We investigate the terahertz coherent synchrotron radiation (CSR) potential of the South Hall Ring (SHR) at MIT-Bates Linear Accelerator Center. The SHR is equipped with a unique single cavity, 2.856 GHz RF system. The high RF frequency is advantageous for producing short bunch length and for having higher bunch current threshold to generate stable CSR. Combining with other techniques such as external pulse stacking cavity, femtosecond laser slicing, the potential for generating ultra-stable, high power, broadband terahertz CSR is very attractive. Our first research effort will be the operation of low momentum compaction (alfa) lattice and stable CSR radiation generation from the existing SHR. Initial tests of low alfa manipulation and bunch length measurements are presented.   

Angiography employing channeling radiation or coherent bremsstrahlung

Angiography (imaging of coronary arteries) using synchrotron radiation has been carried out at the Stanford and later the Brookhaven Synchrotron. Digital subtraction angiography (DSA) with a contrast agent based on iodine is used above and below the K-edge (33.16 keV) employing a monochromatized beam of intensity reduced by a thousand. Channeling radiation or coherent bremsstrahlung furnish quasi-monochromatic beams, allowing efficient DSA at a photon flux of ten to the twelfth photons/sec. This requires an about 100 MeV electron linac for channeling radiation, or (better) an about 20 MeV linac for coherent bremsstrahlung. In the latter case, a large, broad incoherent bremsstrahlung peak accompanies the monochromatic spike (leading to inadmissible overexposure of the patient), but with the use of Kumakhov's capillary optics (see S. B. Dabagov, Physics Uspekhi 46, 2003, 1053-1075) the low-energy spiked radiation can be deflected towards the patient, while the incoherent peak continues forward, avoiding the patient who is placed several meters from the source.   

Amplifying Laser Radiation by an Implosion inside a Reflecting Capillary Liner

It is shown that the energy of a pulsed laser beam can be amplified by orders of magnitude by letting it pass through an imploding capillary liner possessing a high wall reflectivity. The implosion can be accomplished with the pinch effect, letting a large current flow over the liner surface, or by the ablation of its outer surface through a burst of soft X-rays. If the inner radius of the liner can be imploded thirty-fold, the laser energy would be increased a thousand-fold. Because the amplification is through the conversion from longer to shorter wavelengths, the concept has the potential for intense short wavelength pulsed laser beams. The most important application of this laser amplification scheme seems to be for the fast ignition of thermonuclear microexplosions.   

Electromagnetic Radiation of a Decelerating Moving de Broglie Particle: An Always Redshift

%___Symbol Definition:___ \def\w{\omega}\def\g{\gamma}\def\W{{\mit \Omega}} \def\Lam {{\mit\Lambda}}\def\lam{\lambda} %___ABSTRACT:____ We observe that the electromagnetic (EM) radiation from the deceleration of a de Broglie particle as a moving source is always red-shifted, a phenomenon also clearly demonstrated in e.g. the moving hydrogen experiment by H.E. Ives and G.R. Stilwell, J. Opt. Soc. Am. {\bf 28}, 215(1938)[1]. The redshift in [1] is $\delta \lam/\lam_0 = (\sqrt{v^2}/c) /\g$ with $\g=1/ \sqrt{1-(v/c)^2}$, for the EM radiation of an orbiting electron decelerated by falling to an inner orbit which, following its hydrogen ion driven by an applied field, has a translational velocity $v$; $c$ is the velocity of light. In other words, by the redshift in radiation of the above type one is unable to tell whether the particle is moving away or toward the observer except for the $|v|$. Here the radiation frequency equals the de Broglie frequency $\w_d$ of a corresponding particle (effectively the difference between electron's initial and final states in [1]) which adds in full to the particle's mass $M$ as $M c^2 + (1/2)\hbar \w_d$. This is characteristically distinct from a conventional moving source which exhibits the usual Doppler effect informing the direction of source motion. The latter source is typically a charged object brought into oscillation of frequency $\W_a$ by an applied disturbance transverse to its EM wave propagation and source translation; $\W_a$ in general does not add coherently to the oscillator's mass. The two mechanisms can be clearer expounded in our particle formation scheme outlined e.g. in physics/0501037.