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Calendar of Physics Talks Vienna
| Misaligned Supersymmetry and Anti-D-branes |
| Speaker: | Flavio Tonioni (Liverpool U.) |
| Abstract: | In this talk, I will review the concept of misaligned supersymmetry and discuss its relationship with anti-D-branes in type II string theories. Misaligned supersymmetry characterises a variety of non-supersymmetric string models: even if the particle spectrum lacks a one-by-one matching between particles with a different spin, there exist theories in which an infinite oscillation between fermionic and bosonic surpluses at each mass level results in a net cancellation that allows for a finite one-loop cosmological constant. Such a scenario is often discussed with regard to closed-string theories, but I will show that the spectrum of an anti-D-brane on top of an orientifold plane presents essentially the same properties. Anti-D-branes are crucial tools [•••] - see the rest on https://www.univie.ac.at/jointtheoryseminar/ |
| Date: | Tue, 24.11.2020 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | https://moodle.univie.ac.at/mod/bigbluebuttonbn/guestlink.php?gid=x8o6ILSKJuC9 |
| Contact: | Céline Zwikel |
| Differential predictions for Top-quark production at NNLO |
| Speaker: | Massimiliano Grazzini (INFN, Zürich) |
| Abstract: | We report on a new fully differential calculation of the next-to-next-to-leading-order (NNLO) QCD radiative corrections to the production of top-quark pairs at hadron colliders. The calculation is performed by using the qT subtraction formalism to handle and cancel infrared singularities in real and virtual contributions. We review the theoretical framework in which the calculation is carried out and we illustrate our computation of the missing soft contributions needed to complete it. We then present NNLO predictions for single- and double-differential kinematical distributions in pp collisions at 13 TeV and we compare them with recent CMS data. We finally present further results obtained by using the MSbar scheme for the renormalisation of the top-quark mass, and we discuss the sensitivity to running mass effects.
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| Date: | Tue, 24.11.2020 |
| Time: | 16:00 |
| Duration: | 60 min |
| Location: | ZOOM - The link will be provided via email by Simon Plätzer (simon.plaetzer@univie.ac.at) |
| Contact: | A. Hoang, M. Procura, S. Plätzer |
| Extension of symmetries from conformal boundaries of vacuum asymptotically Anti-de Sitter spacetimes |
| Speaker: | Arick Shao (Univ. Queen Mary, London) |
| Abstract: | In this talk, we investigate whether correspondences exist between vacuum asymptotically Anti-de Sitter spacetimes and properties of their conformal boundaries. Here, we focus primarily on the question of whether a symmetry on such a conformal boundary must be inherited by the spacetime itself. In particular, we present the first positive results in this direction for non-stationary settings, and we discuss recent developments in unique continuation theory that lead to these results.
The presentation involves joint works with Gustav Holzegel and Alex McGill (as well as work in progress with Athanasios Chatzikaleas). |
| Date: | Thu, 26.11.2020 |
| Time: | 14:00 |
| Duration: | 60 min |
| Location: | ZOOM https://zoom.us/j/92376135485?pwd=LzlUemhvcU5rL0hhZGxPOUVieDgxZz09 Meeting ID: 923 7613 5485 Passcode: Yjc3ct |
| Contact: | Piotr Chrusciel, David Fajman |
| Weyl symmetry and anomaly in asymptotically locally AdS_3 |
| Speaker: | Francesco Alessio (Naples) |
| Abstract: | I will discuss an enhancement of Brown-Henneaux boundary conditions in 3d AdS General Relativity to encompass Weyl transformations of the boundary metric. The consequences on the asymptotic symmetry algebra and the dual theory of imposing a conformally flat boundary condition are explored. In particular, I will show that the corresponding asymptotic symmetries include a new sector of Weyl rescalings with integrable but not conserved surface charges. The holographic counterpart of this result can be consistently described by an anomalous Ward-Takahashi identity in the boundary. |
| Date: | Thu, 26.11.2020 |
| Time: | 16:00 |
| Duration: | 60 min |
| Location: | https://tuwien.zoom.us/j/95482849369?pwd=SkU2WU5hMVJBQWsyVlFXRlRvQlIvdz09 |
| Contact: | Laura Donnay, Romain Ruzziconi |
| Rabbits, dust devils, volcanoes, planets: mysteries and consequences of granular tribocharging |
| Speaker: | Scott WAITUKAITIS (IST Ausria) |
| Abstract: | Tribocharging—the transfer of electrical charge between materials during contact—is a ubiquitous effect, yet one we hardly understand. Despite scientific description dating back to ancient Greece, issues as basic as what is being transferred (ions vs. electrons) are unresolved. One of the most perplexing observations is that objects of the same material, when touched, still systematically exchange charge. In this talk, I will discuss same-material tribocharging in the context of granular systems. I will show how in ensembles of spherical particles, symmetry is broken by size—larger spheres tend to charge positively and smaller ones negatively. Comparing these results to thermoluminescence measurements, we provide strong evidence that charge transfer is not caused by defect-state electrons. I will also discuss the dynamic behaviors arising from charged interactions, including attracti |
| Date: | Fri, 27.11.2020 |
| Time: | 10:00 |
| Duration: | 45 min |
| Location: | on-line |
| Contact: | Philipp Haslinger |
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