Duke HEP Seminars 2006/2007

High Energy Physics Seminars

Organizers: Ashutosh Kotwal and Kate Scholberg

Duke Physics Room 278 (old Room 246)
(Unless otherwise noted)

Regular time for Spring '07 semester: Monday, 2 pm

September 25: Clarence Virtue, Laurentian U., 2 pm
Particle Astrophysics at SNOLAB
The resolution of the solar neutrino problem by the Sudbury Neutrino Observatory has paved the way for the creation of a new International Facility for "Underground Science" 2 km underground in Northern Ontario. This great depth is required to reduce backgrounds, created by cosmic rays, to the point where sensitive large-scale particle physics experiments, with a high discovery potential, can be successfully performed. The new facility, dubbed SNOLAB, is in an advanced stage of its construction and will soon host a number of these of challenging next generation experiments in particle astrophysics. Proposed experiments fall into four areas: low energy solar neutrino physics, dark matter searches, neutrinoless double beta decay searches, and supernova monitoring. SNOLAB, its current status, motivation, and its initial scientific programme will be described in the talk.

October 30: Valentin Necula, U. of Florida, 1 pm
Search for resonant ttbar production in ppbar collisions at sqrt(s) = 1.96 TeV
A search for narrow-width vector particles decaying into a top-antitop pairs is performed using Run II data collected with the Collider Detector at Fermilab. Model independent 95% confidence level upper limits on the cross-section times branching ratio are derived. If we assume the same production model that was used in the previous Run I search, we can extend the resonance mass exclusion region up to 725 GeV/c^2.

December 18: Ulrich Baur, U. of Buffalo, 2 pm
Future Di-boson and Top Quark Measurements at the Tevatron
I will discuss di-boson and top quark measurements at the Tevatron and LHC, which I think will be important in the coming years. Selection criteria are scientific gain/physics motivation, and availability of data. Specifically, I shall discuss Z boson pair production, single top production, measurements of the electroweak couplings of the top quark and high P_T top quark production.

December 18: David Rainwater, FNAL, 4 pm
Higgs and BSM Physics: opportunities at the LHC
The LHC should be a wonderful exploration machine for new physics, from the mechanisms responsible for electroweak symmetry breaking to possible extensions that would explain dark matter and other mysteries. However, preparations for new physics is lacking, except for a few biased scenarios. Even then it has serious deficiencies. I present a laundry list of must-do items to properly simulate new physics, and a range of theoretical ideas deserving of more phenomenological attention by experimentalists.

January 29: Gabriella Sciolla, MIT, 2 pm
Searching for New Physics in Rare B Decays
The study of CP violation at the B factories allows us to perform quantitative tests of the CP sector of the Standard Model. Accurate measurements of the sides and angles of the Unitarity Triangle determine the parameters rho and eta of the theory, while redundant measurements of the same quantities allow us to probe physics Beyond the Standard Model. The recent measurements of the B_s mixing frequency at the Tevatron have dramatically improved our knowledge of |V_td/V_ts|, the right side of the Unitarity Triangle. This opens up a new opportunity for probing New Physics through an independent determination of the same quantity. In this talk, I will discuss how such a measurement can be made using rare B decays, and show our recent results.

April 23: Ashutosh Kotwal, Duke, 2 pm
First Run II Measurement of the W Boson Mass by CDF
The measurement of the W boson mass provides a stringent test of the Standard Model, and constrains the mass of the Higgs boson via electroweak radiative corrections. We describe a new measurement of the W boson mass at CDF, using both the electron and muon decay channels and 200/pb of Run II data at the Fermilab Tevatron. We measure Mw = 80.413 +- 0.034(stat) +- 0.034(syst) GeV. With a total measurement uncertainty of 48 MeV, this CDF result is now the most precise single measurement to date of the W boson mass. Combining it with other measurements worldwide leads to an average value of the W-boson mass of 80,398 +/- 25 MeV/c^2. We will discuss the implications of this measurement for the Standard Model Higgs boson.