> College of Science > Physics Dept > Talks > Particle/Nuclear/Astro Seminars
Particle, Nuclear & Astronomical Sciences Seminars
Fall 2004 - Spring 2005
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2003-2004

2005-2006
September 2004
Sept 6 (Mon)
2:30pm - 3:30pm
101 Robeson
 
Sept 13 (Mon)
2:30pm - 3:30pm
101 Robeson
Saifuddin Rayyan (Virginia Tech) and Alexey Pronin (Virginia Tech)

Report from this year's TASI and SSI

Sept 20 (Mon)
2:30pm - 3:30pm
101 Robeson
Sandor Benczik (Virginia Tech)

"The minimal length uncertainty relation and the Hydrogen Atom"

Sept 27 (Mon)
2:30pm - 3:30pm
101 Robeson
 
October 2004
Oct 4 (Mon)
2:30pm - 3:30pm
101 Robeson
 
Oct 11 (Mon)
2:30pm - 3:30pm
101 Robeson
Prof. Harry B. Thacker (University of Virginia)

"Topological Charge Membranes in 2D and 4D Gauge Theories"

A recente lattice study of local topological charge distributions in QCD using the exactly chiral overlap Dirac operator has revealed the existence of extended membrane-like regions of sign-coherent topological charge. Analogous structures have also been found in 2D CP(N-1) sigma models. A possible theoretical framework for interpreting these Monte Carlo results is provided by the holographic string theory view of theta dependence of gauge theory.

Oct 18 (Mon)
2:30pm - 3:30pm
101 Robeson
Zack Lewis (Virginia Tech)

"Consistent Quantum Mechanics"

A formulation of quantum mechanics has been developed over the past two decades that claims to provide a logically consistent framework for interpretation. The essentials of this framework will be presented and its views on historical paradoxes (e.g. EPR) will be discussed.

Oct 25 (Mon)
2:30pm - 3:30pm
101 Robeson
Dr. Oleksandr Yelnykov (Virginia Tech)

"Hamiltonian analysis of 2+1 D Yang-Mills on a torus"

Following the recent progress in explaining certain nonperturbative aspects of the (2+1)-dimensional Yang-Mills theory at zero temperature, I would like to describe our current efforts to understand the thermal properties of that theory, in particular confinement-deconfinement phase transition. We perform a Hamiltonian analysis of the (2+1)-dimensional Yang-Mills compactified on a torus. In Euclidean-rotated version one of the compact space dimensions can be treated as compactified time thus providing some information about thermal properties of the theory. After introducing the matrix parameterization of the space components of the gauge connection on a torus, I will describe the calculation of the functional measure as well as of the Laplacian on the Hilbert space of the theory. The vacuum wavefunction, string tension and propagator mass for gluons will also be discussed.

November 2004
Nov 1 (Mon)
2:30pm - 3:30pm
101 Robeson
Dr. Hael Collins (Univ. of Massachusetts Amherst)

"Initial Conditions and Renormalization"

Understanding how a field theory propagates the information contained in an initial state is essential for extracting the sensitivity of the cosmic microwave background to physics above the Hubble scale during inflation. In this talk I shall examine the renormalization of a scalar theory with non-trivial initial conditions in the simpler setting of flat space. The renormalization of the bulk theory proceeds exactly as for the vacuum state. The short distance features of the initial conditions can produce new divergences which are confined to the surface on which the conditions were imposed. I shall show how the addition of boundary counterterms removes these divergences, corresponding to a renormalization of the initial conditions.

Nov 8 (Mon)
2:30pm - 3:30pm
101 Robeson
Dr. Zack Sullivan (Fermilab)

"Understanding single-top-quark production"

Single-top-quark production provides an exciting test-bed for our understanding of both the Standard Model, and subtleties of perturbative QCD. The discovery of this process at Run II of the Tevatron will provide a direct measure of the CKM matrix element Vtb, and may lead to the discovery of new physics. However, our ability to extract this information has been severely limited by our theoretical understanding of the process. I will discuss how, despite the seemingly simple structure, we have had to improve our general understanding of problems with multiple scales, parton distribution uncertainties, modeling of jet distributions, and comparison to showering event generators.

Nov 15 (Mon)
2:30pm - 3:30pm
101 Robeson
Prof. Chris Carone (College of William and Mary)

"Noncommutative Phenomenology"

I discuss the viability of noncommutative extensions of the standard model. I review the most stringent bounds from searches for the violation of Lorentz invariance, and propose ways of evading these bounds through noncommutative extra dimensions.

Nov 22 (Mon)
2:30pm - 3:30pm
101 Robeson
Thanksgiving Break
Nov 29 (Mon)
2:30pm - 3:30pm
101 Robeson
Dr. Masafumi Koike (Virginia Tech)

"Muon-electron conversion in nuclei"

The coherent muon-electron conversion rates in various nuclei are calculated for general lepton flavor violating (LFV) interactions. For any types of operators, the results of our calculation indicate a tendency that the conversion branching ratio is larger for the nuclei with moderate atomic numbers than that for light or heavy nuclei. Although the tendency is the same, there are significant differences in Z dependences of the conversion rate for various LFV couplings. The experiments in various nuclei are therefore useful for model discrimination because each theoretical model predicts different Z dependences.

December 2004
Dec 1 (Wed)
5:00pm - 6:00pm
101 Robeson
Special Seminar
Note day and time
Prof. Alessandro Bettini (University of Padua, Italy)
Previous Director of the Gran Sasso National Laboratory, Italy.

"Status and perspectives of neutrino physics"

In the last several years neutrino physics has made revolutionary progress. For the first time we have evidence of phenomena beyond the Standard Model of particle physics. This evidence came first from experiments on natural neutrino sources, the Sun and the cosmic rays, performed in underground laboratories. In parallel with the new neutrino physics a new cosmology has emerged, with important cross fertilisation between them. After a few words on the general characteristics of the underground laboratories and experiments, I will concentrate on the present status of neutrino physics and on its perspectives, in my view, for the next years.

Dec 6 (Mon)
2:30pm - 3:30pm
101 Robeson
Dr. David E. Jaffe (Brookhaven National Lab)

"K → π ν ν Results and Prospects"

K → π ν ν decays have the potential to provide unambiguous and precise information on the CKM matrix. The latest results from BNL experiment E949 on K+ → π+ ν ν will be presented. Prospects for the measurement of the K0L → π0 ν ν branching fraction with the KOPIO experiment at BNL will also be presented.

Dec 8 (Wed)
4:00pm - 5:00pm
103 Robeson
Special Colloquium
Note day, time, and location.
Prof. Joseph Polchinski (Kavli Institute for Theoretical Physics, Santa Barbara)

"Cosmic Superstrings"

It is possible that superstrings, as well as other one-dimensional `branes', could have been produced in the early universe and then expanded to cosmic size today. I discuss the conditions under which this will occur, and the signatures of these strings. Such cosmic superstrings could be the brightest objects visible in gravitational wave astronomy, and might be distinguishable from gauge theory cosmic strings by their network properties.

Dec 13 (Mon)
2:30pm - 3:30pm
101 Robeson
 
January 2005
Jan 17 (Mon)
2:30pm - 3:30pm
116 Robeson
 
Jan 24 (Mon)
2:30pm - 3:30pm
116 Robeson
 
Jan 31 (Mon)
2:30pm - 3:30pm
116 Robeson
 
February 2005
Feb 7 (Mon)
2:30pm - 3:30pm
116 Robeson
 
Feb 14 (Mon)
2:30pm - 3:30pm
116 Robeson
 
Feb 21 (Mon)
2:30pm - 3:30pm
116 Robeson
 
Feb 28 (Mon)
2:30pm - 3:30pm
116 Robeson
 
March 2005
March 7 (Mon)
2:30pm - 3:30pm
116 Robeson
Spring Break
March 14 (Mon)
2:30pm - 3:30pm
116 Robeson
 
March 21 (Mon)
2:30pm - 3:30pm
116 Robeson
 
March 28 (Mon)
2:30pm - 3:30pm
304 Robeson
Dr. Naotoshi Okamura (KIAS)

"Solving the degeneracy by measuring the T2K off-axis beam in Korea"

April 2005
April 4 (Mon)
2:30pm - 3:30pm
304 Robeson
 
April 7 (Thu)
Special Seminar
2:00pm - 3:00pm
304 Robeson
Prof. Al Shapere (University of Kentucky)

"Production of Microscopic Black Holes by Cosmic Rays"

Cosmic ray events may create black holes if extra dimensions exist and are sufficiently large. In particular, neutrino cosmic rays may produce black holes deep in the atmosphere, initiating characteristic quasi-horizontal showers far above the standard model rate. The fact that no such showers have been observed to date places an upper bound on the size of these extra dimensions. Continued nonobservation of such events over the next few years would improve these bounds significantly, and sharply limit the rate of black hole production at LHC. On the other hand, if black hole mediated showers are observed in the next few years, they could provide the first experimental evidence for extra dimensions, string theory, and the formation and decay of microscopic black holes.

April 11 (Mon)
2:30pm - 3:30pm
304 Robeson
 
April 18 (Mon)
2:30pm - 3:30pm
304 Robeson
 
April 25 (Mon)
2:30pm - 3:30pm
304 Robeson
 
May 2005
May 2 (Mon)
2:30pm - 3:30pm
304 Robeson
 
May 9 (Mon)
2:30pm - 3:30pm
304 Robeson