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Fall 2010 ITS Seminar


Organizer: Dietrich Belitz

Seminars are at 4pm, Tuesdays, in 472 Willamette Hall and are preceded cookies at 3:45.

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August 19 The simulation of detection of neutrinos from dark matter annihilation in the Sun
Yu Gao
ITS

The topics will cover the production and propagation of dark matter induced neutrinos from the center of the Sun and different detection strategies at the IceCube/DeepCore detector
Jim Isenberg
October 5 Jetting from Hamburg to Geneva: The role of jets and jet substructure in finding new physics at DESY and LHC
Dave Soper
UO Physics and ITS

Quantum chromodynamics (QCD) theory predicts and experiment confirms that particles emerge from hard collisions at hadron colliders in the form of narrow jets of particles. The German laboratory DESY had an important role in the history of the experimental part of this. Roughly, a jet consists of the decay products of a parton (quark or gluon) produced in the hard collision, but there are QCD corrections to this crude picture. To be more precise, one needs a precise definition of a jet. Again, DESY played a role in the development of jet definitions. I will review some of the definitions, emphasizing the role of "infrared safety" of the definition.

Jets contain smaller jets inside them. The substructure of jets is different for normal QCD jets and for jets produced by the decay of heavy particles like top quarks or the Higgs boson. I will review some of the recent ideas on how this difference in substructure can be used to help find non-QCD jets that may come from heavy objects that we hope to discover at the Large Hadron Collider that has now started operations in Geneva.
Jim Isenberg
October 11 Shake, rattle and rip: The far-from-equilibrium dynamics of colloids
Rigoberto Hernandez
Georgia Institute of Technology

Joint seminar with Physical Chemistry,(NOTICE SPECIAL DAY AND TIME)

TBA

Marina Guenza
October 19 Dynamical dark energy or decaying dark matter?
Sourish Dutta
Vanderbilt University

A discovery of a time-varying equation of state (w) of dark energy could rule out the cosmological constant and imply that dark energy is "dynamical". This could potentially signify new physics beyond the standard model and general relativity. In this talk I will first briefly review a few of the major candidates for a dynamical dark energy.

I will next show that a LCDM model with dark matter that decays into inert relativistic energy on a timescale longer than the Hubble time will produce an expansion history that can be misinterpreted as a model consisting of stable dark matter with dynamical dark energy. I will show that this simple scenario can produce cosmological signatures that can mimic a variety of dynamical dark energy models, namely quintessence (w > −1), phantom models (w < −1) or models in which the equation of state parameter crosses the phantom divide, evolving from w > −1 at high redshift to e w < −1 at low redshift. All of these models generically converge toward w= −1 at the present. Finally, I will show that the degeneracy between the LCDM model with decaying dark matter and the corresponding spurious dynamical dark energy model is broken by the growth of density perturbations. [Phys.Rev.D82:043526,2010]
Steve Hsu
October 26 Scotch tape and Dirac fermions: The story of graphene and the 2010 Nobel Prize in Physics
George Nazin
UO Department of Chemistry

Dietrich Belitz
November 2 Friction in fluid-saturated granular media and the mechanics of earthquakes
Alan Rempel
UO Department of Geological Sciences

November 9 The Role of Search Frictions in Modern Economic Theory: the Nobel Prize 2010
Nick Sly
UO Department of Economics

November 23 Higgs searches in the transition from Tevatron to LHC
Michael Spannowsky
ITS

First, I would like to discuss the present status of Standard Model Higgs searches at the Tevatron and prospective searches at the LHC. LEP measurements indicated that nature consists of only three chiral generations but just recently the implications of electroweak precision measurements have been reevaluated and a fourth generation is not ruled out so far. In the second part of the talk I would like to discuss the impact of a fourth generation on Higgs search strategies focusing on the interplay between Tevatron and LHC.
November 30 Calculating Tunneling Splittings in Formic Acid Dimer Using a Diabatic Basis
George Barnes
UO Department of Chemistry

Joint seminar with Physical Chemistry

Formic Acid Dimer (FAD) is the smallest molecule held together by a double hydrogen bond.  This bonding motif is common in large biological molecules, such as DNA and RNA base pairs.  Such systems are quite challenging, from a theoretical standpoint, due to their size.  FAD, on the other hand, is a small molecule that retains the pertinent physical features of these large biological systems.   The presence of several low frequency modes in FAD also allow for qualitative insight into condensed phase proton transfer.  The double hydrogen bond present in FAD implies a double well structure in the underlying potential energy surface.  Quantum mechanically a double well potential results in a series of doublet states due to tunneling between these wells.  The magnitude of the "tunneling splittings" of these states is sensitive to details of the potential energy surface, such as barrier height and width.  In FAD, these splittings are experimentally known to be less than a wavenumber and they are difficult to accurately calculate.  We have developed an efficient method of obtaining these tunneling splittings that can be applied to a wide range of double well problems.  With this technique in hand we have further explore the effects of vibrational excitation on proton transfer in FAD.
Kellman
Last modified: Fr Aug 27 17:54:31 PDT 2010
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