Duke HEP Seminars 2004/2005

High Energy Physics Seminars

Organizers: Ashutosh Kotwal and Kate Scholberg

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

Regular time for Spring '06 semester: Monday, 2 pm

August 30: A. B. Balantekin, U. of Wisconsin-Madison, 2 pm
Neutrinos, Supernovae, and Nucleosynthesis
I will first discuss the role of neutrinos in the dynamics of core-collapse supernovae. Since the neutrinos control the neutron-to-proton ratio, neutrino properties (such as mass and mixings) impact nucleosynthesis by changing this ratio. The possibility of identifying black-hole (as opposed to neutron star) formation through the nucleosynthesis yields will be elucidated.

November 5: Brian Foster, Oxford U., 11 am
Status of the International Linear Collider
The current status of the Global Design Effort for the International Linear Collider is reviewed. The Baseline design will be a conservative approach that can be built today. Some of the considerations that need to be taken into account for some of the important subsystems will be discussed. The program of work for immediate future will be outlined.

November 9: M. Morii, Harvard University, 2 pm
B physics beyond CP violation: Semileptonic B decays
The success of the B Factories at SLAC and KEK has advanced our knowledge of CP violation, a prerequisite for the creation of the matter-dominant universe. Steady increase of data has brought a new era of precision CP measurements, in which the unitarity of the Cabibbo-Kobayashi-Maskawa matrix is scrutinized for signs of New Physics. One of the crucial information, surprisingly, comes not from CP violation but from studies of semileptonic decays of the B mesons. I will discuss how various measurements of the B semileptonic decays mesh together to determine the size of the smallest CKM matrix element |Vub|, and how such measurements are made possible through progresses in the theory of B decays.

March 27: J. Pretz, U. of Maryland, 1 pm
Neutrino Astronomy with IceCube
Neutrinos are a relatively new way to observe astrophysical objects. There is however a window of energy between the TeV and PeV scales where neutrinos are the only particles that can reach us from cosmological distances unimpeded by intervening matter. IceCube is a neutrino telescope under construction at the geographic South Pole built to observe neutrinos in this critical energy range. I will discuss high energy neutrino astrophysics and the design and status of the IceCube experiment.

April 7: A. Everett, U. of Wisconsin, 2 pm
Measurements of Event Shapes in Deep Inelastic Scattering at HERA with ZEUS
Mean values and differential distributions of event-shape variables have been studied in neutral current deep inelastic scattering using an integrated luminosity of 82.2 inverse pico-barns collected with the ZEUS detector at HERA. The kinematic range was Q^2 from 80 to 20480 GeV^2 and Bjorken-x from 0.0024 to 0.6, where Q^2 is the virtuality of the exchanged boson. The Q-dependence is compared with a model based a combination of next-to-leading-order QCD calculations with next-to-lead-logarithm corrections and the Dokshitzer-Webber non-perturbative power corrections.

April 11: B. Jayatilaka, U. of Michigan, 2:30 pm
Top Quark Mass Measurement in the Dilepton Channel at CDF
The surprisingly large mass of the top quark hints that the top quark may play a special role in electroweak symmetry breaking. Precision measurements of the top quark mass, along with the W boson mass, are the critical limiting factors in predictions of the mass of a Standard Model Higgs boson. Top quark pair events in which two leptons are produced in the final state, called the dilepton channel, constitute a small branching fraction but are less reliant on jet energy scale calibration than other channels. Precision measurement of the top quark mass in this channel can identify possible contribution to the sample from new sources. I will present the most recent measurement of the top quark mass in the dilepton channel at CDF. This measurement utilizes a leading-order matrix element to calculate a likelihood in top mass and produces the single most precise measurement of the top quark mass to date in this channel.

April 17: T. Adams, Florida State, 1 pm
Searching for Neutral, Long-Lived Particles at D0
The search for new physics beyond the Standard Model takes many forms. Recently I've added a new technique to D0's searches. I look for pair production of neutral particles where one of them decays to two muons after travelling at least 5cm. This is a region which previous collider experiments (LEP and Tevatron) have not explored. I'll discuss the results of the search and show how it relates to the previously published excess of dimuon events observed at the fixed target experiment NuTeV.

April 26: F. Yumiceva, William and Mary, 2 pm
First Accelerator Neutrino Results from the MINOS Experiment
The long-baseline MINOS experiment is composed of a near and a far magnetized detectors, separated by 735 km. The NuMI neutrino beam at Fermilab has been providing beam for MINOS since March 2005. We have accumulated a beam neutrino sample with an exposure of over 10^20 protons on target. The performance of the MINOS experiment and the first accelerator-based neutrino results will be presented.