Calendar of Physics Talks Vienna

Factorization and dispersion relations for radiative leptonic B decay
Speaker:Yu-Ming Wang
Abstract:im Rahmen des Teilchenphysik-Seminars
Date: Tue, 04.10.2016
Time: 16:15
Duration: 60 min
Location:Fakultät für Physik, Erwin-Schrödinger-Hörsaal, Boltzmanngasse 5, 5. Stock
Contact:A. Hoang, H. Neufeld

Generalizing Minimal Dark Matter: Millicharge or Decay
Speaker:Eugenio Del Nobile (INFN Padova)
Abstract:The Minimal Dark Matter (DM) framework classifies viable DM candidates obtained by simply augmenting the Standard Model of particle interactions with a new multiplet, without enforcing new ad hoc symmetries to ensure DM stability. A Majorana SU(2) quintuplet is singled out as the only viable candidate. The model has no free parameters and is therefore extremely predictive, and can be constrained by both direct and indirect DM searches. We propose and explore two distinct generalizations of this framework. One is to abandon the assumption of DM electric neutrality in favor of absolutely stable, millicharged DM candidates. We explicitly study a few examples, and find that a Dirac SU(2) triplet is the least constrained candidate. Another possibility is to lower the cutoff of the model, which was originally fixed at the Planck scale, to allow for decays of the DM quintuplet.
Date: Wed, 05.10.2016
Time: 14:00
Duration: 60 min
Location:HEPHY, Nikolsdorfer Gasse 18, Library
Contact:Josef Pradler

Mathur's inequality and the black hole information paradox
Speaker:Ferdinand Horvath (Univ. Wien)
Abstract:Ever since Stephen Hawking discovered that black holes emit radiation, the physics community has been trying to accommodate the effects of this phenomenon. One of its consequences is the so-called information paradox. This paradox arises once a black hole evaporates through the emission of Hawking radiation, when those parts of the radiation that left the black hole can't be described as entangled with the hole anymore. While the theory assumes a pure initial state and hence full information about the particles in the hole and those emitted, information is lost once the hole is gone. This implies a loss of unitarity. Several ways to avoid this prospect are conceivable but few of them seem favourable. One such resort is the supposition that Hawking radiation has been treated too superficially since higher order corrections of its state are usually neglected. Their contribution . . .
Date: Thu, 06.10.2016
Time: 14:00
Duration: 60 min
Location:Arbeitsgruppe Gravitation, Währinger Strasse 17, Seminarraum A, 2. Stock, 1090 Wien
Contact:P.T. Chrusciel

Speaker:Javier Matulich (CECS, Valdivia)
Abstract:An extension of the Poincare group with half-integer spin generators is explicitly constructed. It is shown that hypergravity in three spacetime dimensions can be formulated so as to incorporate this structure as its local gauge symmetry. The asymptotic structure is analyzed, where the algebra of the canonical generators of the asymptotic symmetries turns out to be given by a hypersymmetric nonlinear extension of BMS_3. The presence of hypersymmetry generators allows to construct bounds for the energy, which turn out to be nonlinear and saturate for spacetimes that admit globally-defined Killing vector-spinors. The generalization of these results in the case of gravity minimally coupled to arbitrary half-integer spin fields is also carried out. Finally, a hyperparticle action is constructed in arbitrary spacetime dimensions.
Date: Thu, 06.10.2016
Time: 16:00
Duration: 60 min
Location:SEM 136, TU Wien, Freihaus, 10th floor (Wiedner Hauptstr. 8-10, A-1040 Vienna)
Contact:Daniel Grumiller