| Physics at the University of Virginia | ||||||
| Academics | People | Research | Announcements | Facilities | Administration | Classes |
| Wednesday, August 26, 2009 | Nikos Varelas [Host: Bob Hirosky] | |
| 3:30 PM, Room 204 | Univ. of Illinois, Chicago | |
| Physics Building | “QCD Physics at CMS” |
| The Large Hadron Collider (LHC) at CERN will soon be at the frontier of experimental High Energy Physics. It is expected to start colliding proton-proton beams later this year at an initial center-of-mass energy of 10 TeV. It will be a unique tool for fundamental physics research with an unprecedented physics potential,probing distances down to 10 (-20) m. In this talk, I will discuss the potential of the Compact Muon Solenoid Detector (CMS), one of four experiments at the LHC, to study the fundamental theory of the strong interactions – Quantum Chromodynamics (QCD) – using a variety of final states and observables with the first experimental data. |
| Wednesday, September 2, 2009 | RESERVED | |
| 3:30 PM, Room 204 | ||
| Physics Building |
| Wednesday, September 9, 2009 | Available | |
| 3:30 PM, Room 204 | ||
| Physics Building |
| Wednesday, September 16, 2009 | Available | |
| 3:30 PM, Room 204 | ||
| Physics Building |
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Thursday, September 17, 2009 Note Special Day |
Ralf Ehrlich [Host: Craig Dukes] | |
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4:00 PM, Room 313 Note Special Time |
University of Maryland | |
| Physics Building | “The Search for Neutralino Dark Matter with the AMANDA Neutrino Telescope” |
| There is convincing indirect evidence based on cosmological data that approximately one quarter of the universe is made of dark matter. However, to this date there is no direct detection of the dark matter and its nature is unknown. Many theories suggest that dark matter is made of supersymmetric particles, and the most promising candidate out of the supersymmetric particles is the lightest neutralino. These neutralinos can get gravitationally trapped in the Earth, where they eventually annihilate. The annihilation products decay and a fraction of the decay products are muon-neutrinos, which can be detected with the AMANDA/IceCube neutrino telescope in the ice at the South Pole. Neutrinos cannot be detected directly. However, there is a small possibility that they interact with the nuclei of the ice via a charged current interaction and "create" charged leptons. These charged leptons continue to travel in almost the same direction as the neutrinos. As long as their speed is higher than the speed of light of the ice, they emit Cherenkov radiation which can be captured by photomultipliers installed inside the ice. A hypothetical muon-neutrino flux from neutralino annihilations inside Earth should show up as an excess over the expected muon-neutrino flux from atmospheric neutrinos produced in the northern hemisphere. No significant excess has been observed, yielding an upper limit on the neutrino flux that could have come from neutralino annihilation. |
| Wednesday, September 23, 2009 | Eugene Galyaev [Host: Craig Dukes] | |
| 3:30 PM, Room 204 | CERN | |
| Physics Building | “Commissioning and Status of the ATLAS pixel detector at the LHC” |
| The ATLAS Pixel Detector is the innermost detector of the ATLAS experiment at the Large Hadron Collider at CERN. With approximately 80 million readout channels, the ATLAS silicon pixel detector is high-acceptance, high-resolution, low-noise tracking device providing the desired refinement in charged track pattern recognition capability in order to meet the stringent track reconstruction requirements of ATLAS, largely defining its ability to effectively resolve primary and secondary vertices and perform efficinet flavor tagging essential for discovery of new physics. Being the last sub-system installed in ATLAS by the end of June 2007, Pixel Detector was successfully connected, commissioned, and tested in situ while meeting an extremely tight operations schedule, and is ready to take data upon the projected turn-on of the LHC at the end of 2009. UT Dallas group has successfully deployed and commissioned the environmental controls for the opto-links, crucial for stable operation of the readout electronics of the pixel detector. Since fall 2008, Pixel Detector was included in the combined ATLAS detector operation, collecting physics data with cosmic muons. Details from the Pixel Detector installation and commissioning, as well as the details on major calibration procedures and the results obtained with collected cosmic data, are presented along with the current ATLAS detector status summary. |
| Wednesday, September 30, 2009 | RESERVED | |
| 3:30 PM, Room 204 | ||
| Physics Building |
| Wednesday, October 7, 2009 | Oleg Perevozchikov [Host: Craig Dukes] | |
| 3:30 PM, Room 204 | University of Tennessee | |
| Physics Building | “Search for electron antineutrinos from the Sun with KamLAND detector” |
| I will present the results of the search for the electron antineutrinos from the Sun with Kamioka Liquid scintillator Anti-Neutrino Detector (KamLAND). There is no known direct production of the electron antineutrinos in the Sun. However, in the some theoretical models with the large neutrino magnetic moment antineutrinos from the Sun can be produced e.g. via Spin Flavor Precession mechanism (SFP). Search for solar antineutrinos potentially can provide new information about fundamental properties of neutrinos. The most sensitive one-kiloton antineutrino detector KamLAND gives the possibility to search for such antineutrinos. The analysis described in this dissertation is based on 1425.9 days of data collection in KamLAND. The search for the electron antineutrinos have been made within 8.8-16.3MeV antineutrino energy range, that is above energies of reactor antineutrinos and where properties of the solar B8 neutrinos are well studied. Based on the number of observed candidates and estimated background rates the upper limit on the electron antineutrino flux and probability of conversion electron neutrinos produced in the Sun to electron antineutrinos was set. The same limit can be used on the diffuse Supernovae neutrino flux. The estimated background rates during this study can make significant impact on the design of the future neutrino scintillator detectors. |
| Wednesday, October 14, 2009 | Laura Fields [Host: Craig Dukes] | |
| 3:30 PM, Room 204 | Cornell University | |
| Physics Building | “Studies of D -> pi e nu and D -> K e nu at CLEO-c” |
| Many precision tests of the Standard Model require input from Lattice QCD (LQCD). Of particular importance are the semileptonic form factors used to extract Vub in semileptonic B decays. Similarities between the D and B sector make charm semileptonic decays an excellent testing ground for the increasingly precise predictions of LQCD. CLEO-c has recently used its entire data sample to produce a set of measurements involving the decays D0 → pi e nu, D0 → K e nu, D+ → pi0 e nu and D+ → K0 e nu. These results, which include the worlds most precise branching fraction and D -> pi form factor measurements, will be discussed. |
| Wednesday, October 21, 2009 | Jose Repond [Host: Craig Dukes] | |
| 3:30 PM, Room 204 | Argonne National Laboratory | |
| Physics Building | “Development of a Digital Hadron Calorimeter” |
| We present the concept of a Digital Hadron Calorimeter (DHCAL) for use in a detector optimized for the application of Particle Flow Algorithms to the measurement of jet energies. Resistive Plate Chambers (RPCs) with 1 x 1 cm^2 readout pads are used as active elements. The front-end electronic readout is integrated on the pad-boards of the chambers and applies a single threshold (1-bit) to the signal charges, hence the designation of digital readout. We report on detailed measurements with a small scale prototype in the Fermilab test beam using muons, positrons, pions, and protons and in the laboratory using cosmic rays. The results validate the concept and serve as basis for the design of a large prototype calorimeter. An update on the ongoing construction of the latter will be given. |
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Tuesday, October 27, 2009 Note Special Day |
Michael Strickland [Host: Peter Arnold ] | |
| 3:30 PM, Room 204 | Gettysburg College | |
| Physics Building | “Reorganizing the QCD pressure at intermediate coupling” |
| The perturbative expansion of the pressure of QCD is known to order g^6 log(g), however, the resulting series is poorly convergent at phenomenologically relevant temperatures/couplings. I will discuss a method for improving the convergence of the successive approximations to the QCD pressure in a systematic manner which exactly reproduces the perturbative series in the weak-coupling limit. The method relies on folding in information about the correct high-temperature degrees of freedom via the hard-thermal-loop (HTL) resummation scheme. In order to give some background I will also discuss the poor convergence of quantum mechanics for the ground state of an anharmonic oscillator and present results for the three loop HTL-improved pressure of QED. Finally, I will present new results of an HTL-improved calculation of QCD thermodynamics to three-loops and critically discuss how this compares to available lattice data. |
| Wednesday, October 28, 2009 | Available | |
| 3:30 PM, Room 204 | ||
| Physics Building |
| Wednesday, November 4, 2009 | Johannes Schmude [Host: Diana Vaman] | |
| 3:30 PM, Room 204 | Swansea University | |
| Physics Building | “Flavor-branes in gauge/string duality and M-theory” |
| Over the last years, gauge/string duality has been extended to include gauge theories with an arbitrary number of flavors. We study the flavoring procedure in the light of calibrated geometry and discuss the special case of a type IIA dual of N=1 super Yang-Mills with flavors. Relating our results to the standard type IIA/M-theory duality, we find that the usual oxidation formulas cannot accommodate for the additional flavor branes. We address and solve this issue by considering M-theory with torsion, which allows us to construct source-modified equations of motion for eleven-dimensional supergravity. |
| Wednesday, November 11, 2009 | Available | |
| 3:30 PM, Room 204 | ||
| Physics Building |
| Wednesday, November 18, 2009 | Lidija Zivkovic [Host: Bob Hirosky] | |
| 3:30 PM, Room 204 | Columbia University | |
| Physics Building | “Closing in on the Higgs Boson” |
| The Standard Model describes the unification of electromagnetic and weak interactions. It was thoroughly tested over past thirty years, and represents one of the major successes of modern physics. This theory predicted the existence and the masses of the weak bosons. The last remaining piece of the puzzle is the Higgs boson whose existence is crucial for our understanding of the origin of particle masses. Direct searches at LEP put a lower limit on the Higgs boson mass, and together with precision measurement constrained it to <~200 GeV. The D0 and CDF experiments at the Tevatron recently excluded a new interval in the Higgs mass. In this time when we are entering LHC era, we are coming closer to the discovery or exclusion of the SM Higgs boson. I will discuss current searches for the SM Higgs boson with the D0 experiment at Tevatron, highlighting the most important techniques. I will also draw a parallel with future searches at LHC, showing what we can learn from Tevatron experience. |
| Wednesday, December 2, 2009 | Manuel Toharia [Host: Diana Vaman] | |
| 3:30 PM, Room 204 | University of Maryland | |
| Physics Building | “Collider and Flavor Phenomenology in the Scalar sector of Warped Extra Dimensions” |
| I will review and present new results regarding the phenomenology of the two (presumably) lightest scalars in the context of warped extra dimensions: the Higgs and the radion. This last one, could be the lightest "new physics" state to be discovered at the LHC in this type of models. Its phenomenology is very similar to the Standard Model (SM) Higgs. When SM fields are allowed to live in the bulk of the extra dimension, new interesting effects appear in the scalar sector of the model. In particular, both the Higgs and the radion can now typically mediate Flavor Changing Neutral Currents at tree level. These will impose bounds on the flavor structure of the model, but also allow for interesting probes in current and future collider experiments. |
To add a speaker, send an email to bbc2x@Virginia.EDU. Include the seminar type (e.g. High Energy Physics Seminars), date, name of the speaker, title of talk, and an abstract (if available). [Please send a copy of the email to phys-seminars@Virginia.EDU.]
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