Bulletin of the American Physical Society
2006 APS April Meeting
Saturday–Tuesday, April 22–25, 2006; Dallas, TX
Session S6: Panofsky Prize Session |
Hide Abstracts |
Sponsoring Units: DPF Chair: Bill Carithers, Lawrence Berkeley National Laboratory Room: Hyatt Regency Dallas Cumberland J |
Monday, April 24, 2006 3:30PM - 4:06PM |
S6.00001: Lifetime Measurements with Mark II's First Vertex Detector Invited Speaker: The lifetimes of the (then) newly discovered tau lepton and b hadrons were unmeasured when detectors began studying 30 GeV e+e- collisions at the PEP and PETRA storage rings. The addition of a high precision drift chamber, the Mark II Secondary Vertex Detector, led the Mark II collaboration to make its first significant measurements of the tau and charmed particle lifetimes. The b hadron lifetime was popularly presumed to be very short, and out of reach. But with a healthy dose of luminosity during 1982-1983, both the MAC and Mark II experiments at PEP saw unmistakable signs that the b lifetime was in fact long, measured it, and showed that the responsible CKM element, Vbc, was small. I'll review this history, talk about the rather far reaching implications of a long b lifetime, and chart the rapid progress in the art of vertex detection. [Preview Abstract] |
Monday, April 24, 2006 4:06PM - 4:42PM |
S6.00002: B meson decay and CP symmetry violation from e+e- experiments Invited Speaker: The study of structure in the time evolution of neutral B - B-bar pairs has provided a a key ingredient in the quantitative understanding of quark flavor mixing and its role in accounting for CP violation in weak decays. After some recollections regarding the determination of the time scale of b quark decay, I review the observations that have emerged from experiments at electron-positron colliders of B - B-bar mixing and CP-violation asymmetries. I consider some of the ongoing measurements that serve to over constrain the Standard Model of weak interactions in the quark sector, and potentially to indicate the limits of the model. I conclude by describing the prospects for future gains in the sensitivity of these and successor experiments. [Preview Abstract] |
Monday, April 24, 2006 4:42PM - 5:18PM |
S6.00003: Impact of the Long B-Lifetime on Other Areas of Particle Physics Invited Speaker: The surprisingly long b-lifetime has had an amazing impact on many physics topics since it was first measured in 1983. The development of sophisticated silicon vertex detectors needed to ``tag'' the long lived $b$-quark followed at LEP, the Tevatron, the $B$-factories, and today at the LHC. These technological developments and the history of the first measurement in the MarkII detector will be discussed by J. Jaros in this session. This presentation will concentrate primarily on physics topics pursued at the Tevatron Collider and CDF in particular that were made possible by the long lifetime of the $b$-quark. First, the TeV collider program, LEP, and the $B$ factories at SLAC and KEK have made remarkably precise measurements of the $B$ mesons and baryons that utilized the long $b$-lifetime in addition to the pioneering $B$ measurements at Cornell and DESY. The B-factory measurements, including $CP$ violation, will be discussed by W.T. Ford in this session as well as the first measurement in the MAC detector. The Tevatron and LEP have made remarkable measurements of the $B_s$ and $\Lambda_b$ which continue to improve. Perhaps the biggest role of the long b-lifetime has been in the discovery and study of the top quark. Both CDF and D0 use the lifetime as one of the main selection criteria of top events in addition to a high $P_T$ lepton. Our present knowledge of the top cross section and mass are a result of measurements that identify top by tagging the $b$-jets. CDF also had a first look at $CP$ violation in the B system resulting in a 2-sigma measurement, which hinted that $CP$ violation in the $b$-system appeared to be large and consistent with the standard model. Presently, the long lifetime of the $B_s$ meson is being used to measure mixing in that system, a much anticipated result expected from the Tevatron. The long $b$-lifetime is critical for searches of the standard model and supersymmetric Higgs bosons decaying into $b \bar b$ quarks. The LHC$_b$ experiment at the LHC will make next generation measurements in the $b$-quark system, again, made possible by the long $b$-lifetime. The Atlas and CMS detectors at the LHC will exploit the long $b$-lifetime in their searches for the Higgs bosons and supersymmtry and the detectors being designed for the International Linear Collider will also utilize the long lived $b$-quark. A brief discussion of these measurements will be presented. [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