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: http://zebu.uoregon.edu/~uochep/seminars/seminars-spr03.html
Дата изменения: Fri Dec 19 01:40:50 2003 Дата индексирования: Tue Oct 2 08:56:38 2012 Кодировка: Поисковые слова: п п п п п п п п п р п р п |
| Fall 2002 | Winter 2003 | ||
|---|---|---|---|
| Fall 2001 | Winter 2002 | Spring 2002 | Summer 2002 |
| Fall 2000 | Winter 2001 | Spring 2001 | Summer 2001 |
| Fall 1999 | Winter 2000 | Spring 2000 | Summer 2000 |
NOTE SPECIAL DAY AND TIME
It is widely believed that new particles beyond those of the Standard Model of Particle Physics must exist in nature in order to explain both inconsistencies in the standard theory and resolve outstanding cosmological problems. Direct searches for production of these particles are underway at the world's highest energy accelerators. However the rare decays of mesons at much lower energies are also sensitive to the presence of such new particles manifest in the virtual "loops" of their decay processes. I will describe how the BaBar experiment provides a copious source of low energy B mesons ideal for these searches and give the latest results.
4:00 pm, 472 Willamette Hall
Refreshments served at 3:45
The possible existence of light bottom squarks and light guinos was proposed to explain the excess production of bottom quarks in hadron collider experiments. Predictions will be presented in this scenario for the branching fractions of Upsilon decays into bottom squarks, including radiative decays to an S-wave bound state. If light bottom squarks are present in nature, light neutral Higgs bosons may decay predominately into a pair of bottom squarks compromising the discover potential of the LHC, although possibilities remain solid for its discovery at an e+e- linear collider.
4:00 pm, 472 Willamette Hall
Refreshments served at 3:45
The E-158 experiment at SLAC has made the first measurement of parity violation in Moller scattering. E-158 measures the left-right cross-section asymmetry (A_LR) in the elastic scattering of a 45-GeV polarized electron beam with unpolarized electrons in a liquid hydrogen target. The mean Q2 is 0.03 (GeV/c)2. E-158 will ultimately measure the weak mixing angle with a precision of 0.001 and provide the best measurement of this quantity away from the Z-pole. This precision will provide sensitivity to physics at the TeV scale -- probing effects of additional Z bosons with masses of 800 GeV and probing contact interactions with a compositness scale of 10 TeV. E-158 had its first physics run in spring 2002 and preliminary results from this run will be presented in this talk. A second physics run occurred in fall 2002 and a final physics run will occur in summer 2003.
4:00 pm, 472 Willamette Hall
1:00 pm, 472 Willamette Hall
NOTE SPECIAL DAY AND TIME
Rare hadronic charmless B-meson decays into final states with a phi meson are dominated by the b -> s(d) s-bar s gluonic penguins, possibly with a significant contribution from electroweak penguins, while other Standard Model contributions are strongly suppressed. Since no 3rd-to-1st--generation quark transitions are involved, the SM predicts the values of direct CP asymmetries in these modes to be very close to zero. Many models of new physics, however, introduce new heavy particles that would contribute to these decays at the loop level, potentially leading to large deviations of the CP-violating observables. In this talk, I will give a brief overview of the physics of CP violation, describe the analysis technique, and, finally, present and discuss the most recent results on these modes from BaBar and Belle.
2:00 pm, 472 Willamette Hall
Refreshments served at 1:45
4:00 pm, 472 Willamette Hall
Refreshments served at 3:45
4:00 pm, 472 Willamette Hall
Refreshments served at 3:45
The search for gravitational waves, and continuing efforts to improve the sensitivity of existing gravitational wave detectors, promise to open a new window into the Universe. For two weeks in August and September 2002, the Laser Interferometer Gravitational Wave Observatory (LIGO) was operated to produce its first data for scienctific analysis. This talk will present the status of LIGO, and science results from the first science run.
4:00 pm, 472 Willamette Hall
Refreshments served at 3:45
NOTE SPECIAL DAY AND TIME
QCD predicts the existence of exotic mesons which lie outside of the scope of constituent quark model. The JPC = 1-+ exotic state is of particular interest since it has exotic quantum numbers and it is predicted to be the lightest hybrid meson. A partial wave analysis (PWA) was performed of the omega pi-pi0 system from the reaction pi- + p--> 2pi+2pi-pi0 p at 18 GeV/c. The data were collected from the 1995 run of BNL experiment E852 with the MPS facility. In the b1pi decay channel, the JPC = 1-+ state pi1(1600) was confirmed at M = 1664±8MeV/c2 and Gamma = (185±25)MeV/c2. A new JPC = 1-+ state is discovered at M = (2014±20)MeV/c2 and Gamma = (230±32)MeV/c2.
4:00 pm, 472 Willamette Hall
Refreshments served at 3:45
4:00 pm, 472 Willamette Hall
Refreshments served at 3:45