Experimental Particle and Astro-Particle Physics Seminar

Universality classes for inflation and primordial GW from pseudoscalar inflation.

My seminar is divided in two parts:
In the first part of my seminar I propose a classification of inflationary models by using the most basic property of inflation: the approximate scaling invariance. This framework relies on the possibility of describing inflation in terms of a renormalization group equation. The slow rolling regime in this context is interpreted as the slow evolution close to a fixed point. In this framework we can thus explain in part the universality observed in the predictions of a certain number of inflationary models.
In the second part of my seminar I discuss the possibility of generating an observable gravitational wave (GW) background by coupling a pseudoscalar inflaton to some abelian gauge fields. The analysis is performed by dividing inflationary models into universality classes. One of the most promising scenarios is Starobinsky-like inflation, which may lead to observable signatures both in direct GW detectors as well as in upcoming CMB detectors. The complementarity between CMB and direct GW detection may be used to extract informations on the microphysics of inflation.

Franz Muheim
(University of Edinburgh)

The beauty quark at 40

In 1977 the beauty or b quark was discovered at Fermilab. Since then this new particle has continued to surprise us. I will shortly review a few of the major results obtained from measurements involving b-quarks. Furthermore, I will report on results from the LHCb experiment which is collecting huge samples of decays from decays of particles containing b-quarks, including CP violation, rare decays and exotic spectroscopy. I'll then present a forward look for physics with  b-quarks, including the potential of the upgrades of the LHCb experiments.

Indirect detection of dark matter - status and perspectives

Indirect detection of dark matter, i.e. the attempt to detect dark matter annihilation or decay products produced in space, is one of the three pillars of particle dark matter detection, the others being detection of dark matter scattering (direct detection) and collider production. In this talk I will give present the status and outlook, especially with the advent of the Cherenkov Telescope Array (CTA) . Time allowing I will discuss some recent work on comparing CTAs capabilities with LHC and direct detection in effective field theory and simplified models framework.

Search for K+ -> pi+ nu nu at the NA62 experiment at CERN SPS.

The K+->pi+nunu decay is one of the theoretically cleanest meson decay where to look for indirect effects of new physics complementary to LHC searches. The NA62 experiment at CERN SPS is designed to measure the branching ratio of this decay with 10% precision. NA62 is taking physics data since 2016, after two commissioning runs in 2014 and 2015. The quality of data collected in view of the final measurement will be presented

Searches for Dark Matter at the LHC

The understanding of Dark Matter is one of the big puzzles of physics, and the search for its production in proton-proton collisions is one of the main goals of the LHC experiments. Since the start of Run-2, there have been significant developments in the analysis methods, theoretical interpretations, as well as the variety of searches. I will give an overview of the main developments, with particular attention for the complementarity to LHC resonance searches and the results of Direct Detection experiments.

Gigantic black hole binary in quasar OJ287 and its predicted General Relativity centenary flare

Blazars are active galactic nuclei with strong jets. They tend to exhibit dramatic and unpredictable flux variations, namely outbursts. However, certain observed outbursts from an exceptional Blazar OJ287 suggest that it may contain a spinning supermassive black hole binary that spirals in due to the emission of gravitational waves. This deduction is based on the fact that prominent outbursts of OJ287 are inherent in our binary black hole model. Few years ago, detailed General Relativistic modeling allowed us to predict a major optical outburst during November 2015. The outburst did occur within the expected time range, peaking on 5/12/2015. An observational campaign that involved two dozen optical observatories and the SWIFT satellite revealed the presence of a major thermal component in the flare. The timing of this component provided, for the first time, an accurate measurement for the spin of the primary black hole in a massive binary. This accurate measurement opens up the possibility of employing sophisticated instruments to probe General Relativistic properties of OJ287.

Exceptionally light Thermal Dark Matter

Dark matter can be a thermal relic exponentially lighter than the weak scale without being exponentially weakly coupled. I will present three mechanisms to obtain light thermal dark matter that can have sizable self-interactions and observable couplings to the Standard Model.

Searches for strong SUSY in CMS

During 2016 the LHC delivered an unprecedented  amount of proton-proton collision data at a center-of-mass energy of 13 TeV, which is the basis for the latest results of the CMS collaboration. 

This review will focus on strong production of squarks and gluinos and discuss experimental techniques and interpretations of the results in terms of simplified SUSY models.