Default Location: 503 Keen Building | |
Date | Description |
December | |
| Tuesday, Dec 1 | Paolo Rottmann, FSU tba |
November | |
| Tuesday, Nov 24 | Liantao Wang GeV dark sector and its signal at high energy colliders Abstract: Motivated by recent excesses in the cosmic ray observations, such as PAMELA, Fermi-LAT, it has been suggested that dark matter could have GeV range self-interaction. The properties of such a GeV dark sector has been the subject of active theoretical speculation and phenomenological study. I will review the basic structure of the dark sector models, and discuss their experimental signatures. I will focus on their signals, such as the so called lepton jet, at the Tevatron and the LHC. |
| Monday, Nov 23 | Sascha Bornhauser, U. of New Mexico Prospects for the Detection of Rapidity Gap Events in Squark Pair Production at the LHC Abstract: The exchange of electroweak gauginos in the t- or u-channel allows squark pair production at hadron colliders without color exchange between the squarks. This can give rise to events where little or no energy is deposited in the detector between the squark decay products. I will talk about the potential for detection of such rapidity gap events at the Large Hadron Collider (LHC). The numerical analysis is divided into two parts. First, the rapidity gap signal is evaluated in a simplified framework at the parton level. The second part covers an analysis with full event simulation using PYTHIA as well as Herwig++, but without detector simulation. The transverse energy deposited between the jets from squark decay is analyzed, as well as the probability of finding a third jet in between the two hardest jets. For the mSUGRA benchmark point SPS1a we find statistically significant evidence for a color singlet exchange contribution. Special Note: Special Seminar on Monday, Nov 23rd |
| Tuesday, Nov 10 | Thomas Schutzmeier, FSU The B -> X_s gamma decay at NNLO Abstract: One of the most interesting rare B-meson decays is the inclusive B->Xs gamma mode, which, being a flavour changing neutral current, appears in the Standard Model (SM) only at the loop level. Therefore, it is highly sensitive to non-standard effects and gives an opportunity to observe new physics contributions indirectly. Experimentally, the branching ratio of this decay was measured with an excellent accuracy that has to be accompanied with precise SM predictions to provide a reliable test of the flavor sector or bounds on new physics contributions. Theoretically, the decay rate is dominated by QCD effects and in view of the above a next-to-next-to-leading order (NNLO) evaluation in the strong coupling is necessary. In this talk, I'm going to review the current experiment and theory status of the NNLO programme and present recent results required for a final NNLO prediction of the B->Xs gamma branching ratio. |
October | |
| Friday, Oct 30 | Bernard Peyaud, CEA Saclay CP violation in the Charged Kaon System and Rare Kaon decays Abstract: After five years devoted to the measurement of CP violation in the neutral kaon system, the experiment NA48 at CERN has studied direct CP violation of CP in the charged kaon system with the measurement of the asymmetry of the Dalitz plots K+- -> Pi+- Pi0 Pi0 and K+- -> Pi +- Pi+ Pi−. The experiment has accumulated more than 4 billions decays from high intensity charged kaons beams corresponding to 200 TB of data. The physics results obtained with this data will be presented and will cover CP violation and rare decays. Quantum Chromo Dynamic (QCD) at low energy has been tested through accurate measurements of Pi Pi diffusion lengths allowing precise test of the Chiral Perturbation Theory (ChPT). Special Note: Special Seminar on Friday, Oct. 30th, 11:00am |
September | |
| Tuesday, Sep 22 | Alejandro Jenkins, FSU Looking for life in the mulitverse Abstract: We review the notion of the multiverse, as motivated by both eternal inflation and the string theory landscape, as well as the "anthropic" suggestion that some of the parameters of the Standard Model might be constrained by the requirement that complexity in general, and intelligent life in particular, be possible. While this anthropic argument offers a plausible solution to the fine-tuning problem in the case of the cosmological constant, when applied to particle physics we find that there could exist certain exotic worlds that can nevertheless sustain life, suggesting skepticism about a purely anthropic explanation of the particle physics interactions. This talk will be based in part on an article commissioned by Scientific America, which I am currently working on with G. Perez, of the Weizmann Institute. |
| Tuesday, Sep 8 | Dr. Matilde Marcolli Early Universe Models from Noncommutative Geometry Abstract: In joint work with Elena Pierpaoli, we analyze cosmological applications of particle physics models based on noncommutative geometry. The peculiar aspect of these models is a coupling of matter with gravity where the coefficients of the gravitational and cosmological terms in the Lagrangian depend upon the Yukawa couplings of the particle physics content of the model, and therefore run with the renormalization group flow. This provides a cosmological model of the early universe (between the unification and the electroweak epochs) with a running effective gravitational constant and a running effective cosmological constant. We analyze the effects on gravitational waves and on the evaporation law of primordial black holes, and resulting Linde type models of negative gravity in the early universe. We also discuss inflationary mechanisms related to a Higgs based slow-roll potential and to the running effective cosmological constant. Special Note: Location changed to 707 Keen Building! |