Bulletin of the American Physical Society
APS April Meeting 2013
Volume 58, Number 4
Saturday–Tuesday, April 13–16, 2013; Denver, Colorado
Session L2: Invited Session: DPF Prize Session I |
Hide Abstracts |
Sponsoring Units: DPF Chair: Ian Shipsey, Purdue University Room: Plaza D |
Sunday, April 14, 2013 3:30PM - 3:57PM |
L2.00001: W.K.H. Panofsky Prize Talk: The Search for Weakly Interacting Massive Particle Dark Matter: Science Motivation and CDMS strategy Invited Speaker: Bernard Sadoulet For the last 25 years, Weakly Interacting Massive Particles (WIMPs) have remained one of the favored candidates to explain the ubiquitous dark matter in the universe. We will review the generic aspects of this class of models, and describe the complementarity between three observational approaches: the direct detection of terrestrial interactions of the halo WIMPs, the search for WIMP annihilation products in the cosmos and the attempt to produce these particles at the Large Hadron Collider. After a rapid review of the current status of these three searches, we will focus on the experimental strategy pursued by the Cryogenic Dark Matter Search as one of the leading direct detection effort in the world. We will conclude with the CDMS results obtained so far, in particular for low mass dark matter particles. In an accompanying talk, Blas Cabrera will describe the basic technology that we are using and the promise of our new generation of detectors. [Preview Abstract] |
Sunday, April 14, 2013 3:57PM - 4:24PM |
L2.00002: W. K. H. Panofsky Prize Talk: The Search for WIMP Dark Matter: CDMS Detectors Invited Speaker: Blas Cabrera As described in the accompanying talk by Bernard Sadoulet, the CDMS (cryogenic dark matter search) program has succeeded in pushing down by several orders of magnitude the sensitivity in the search for dark matter in the form of weakly interacting particles or WIMPs. In this talk we describe the technology that has enabled the CDMS detectors made of Ge and Si crystals to discriminate on an event by event basis electron recoils (most backgrounds from gammas) from nuclear recoils (the expected WIMP signal and neutrons). This rejection is accomplished by simultaneously measuring the ionization (electrons and holes in the semiconductor) and the phonons (lattice heat). To achieve the phonon measurement, the crystals are cooled to 0.05 K which allows the use of ultra low noise superconducting circuits. The phonon energy is collected at the surface of the crystals using Al films which absorb athermal phonons and produce quasiparticle excitations from the dissociated Cooper pairs. These excitations diffuse until the are trapped in superconducting tungsten transition edge sensors (TESs). The major advance of voltage biased TESs which are self biased in their transition region through negative feedback has been adopted very successfully for xray spectroscopy, gamma ray spectroscopy and CMB (cosmic microwave background) instruments. The most recent advance detectors called iZIPs (interleaved z-dependent ionization and phonon) provide a large improvement in surface electron rejection and remove that background for the next 200 kg Ge experiment and even for future ton scale experiments. [Preview Abstract] |
Sunday, April 14, 2013 4:24PM - 4:51PM |
L2.00003: Observation of time-reversal violation in B meson transitions at BABAR Invited Speaker: Fernando Martinez-Vidal In the standard model of elementary particle physics, charge-parity (CP) violation in the quark sector of weak interactions arises from the single physical phase of the three-generation Cabibbo-Kobayashi-Maskawa matrix. This mechanism has been validated by more than a decade of intense experimental work probing CP violation, particularly with the studies with B mesons at B factories, BABAR at SLAC (USA) and Belle at KEK (Japan). The success of the three-generation theory was recognized by the award of a share of the 2008 Nobel Prize in Physics to Kobayashi and Maskawa. Since the standard model is CPT invariant, it predicts a time-reversal (T) symmetry breaking matching the large observed CP asymmetry in B mesons. However, until recently, there has been no direct observation of this expected, large T asymmetry. In this talk we shall discuss how the BABAR experiment at the SLAC National Accelerator Laboratory has conducted a data analysis where the decays of entangled neutral B mesons allow comparisons between the rates of four different transitions between quantum states and their inverse, as a function of the time evolution of the B meson. The results lead to the first direct observation with high significance of time-reversal non-invariance through the exchange of initial and final states in transitions that can only be connected by a time-reversal symmetry transformation. [Preview Abstract] |
Sunday, April 14, 2013 4:51PM - 5:18PM |
L2.00004: The Heart of Darkness: Dark Matter Searches for Supersymmetry with Heavy Scalars Invited Speaker: David Sanford With the end of the initial LHC run with 4.7 fb$^{-1}$ and 13.0 fb$^{-1}$ and center of mass energies of 7 and 8 TeV respectively, the non-observation of colored superpartners has placed significant contraints on the paradigm of weak-scale supersymmetry. However, precision tests of flavor and CP violating observables have long been consistent with heavier superpartners, and the observed Higgs mass motivates consideration of colored superpartners somewhat beyond LHC reach. I discuss the role dark matter searches can play in such scenarios, focusing on the case of focus point supersymmetry and neutralino dark matter with a significant bino-higgsino mixture. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700