HEP Theory Seminars SS 18

 

Thu 12.04.2018, 16.30 h

J. Heeck (Université libre de Bruxelles)

Rare processes and the fate of baryon and lepton numbers

Abstract:
Neutrino oscillations are a definite proof of lepton flavor violation, but we have yet to see charged lepton flavor violation. We categorize lepton-flavor-violating processes by their quantum numbers and show how their discovery can be interpreted model independently, studying in particular which processes are required to establish that the entire flavor group is broken. Including baryon number in the discussion allows us to identify new proton decay modes that could dominate over the usually considered channels.

 

Thu 19.04.2018, 16.30 h

T. Tenkanen (Queen Mary University of London)

The Dawn of FIMP Dark Matter

Abstract:
I will present an overview of scenarios where the observed Dark Matter (DM) abundance consists of Feebly Interacting Massive Particles (FIMPs), produced non-thermally by the so-called "freeze-in" mechanism. In contrast to the usual freeze-out scenario, frozen-in FIMP DM interacts very weakly with particles in the visible sector and never attained thermal equilibrium with them in the early Universe. This makes frozen-in DM very difficult but not impossible to test. In this talk I will present the freeze-in mechanism and its variations previously considered in the literature, compare them to the standard DM freeze-out scenario, discuss several aspects of model building, and pay particular attention to observational properties of such feebly interacting DM.

 

Thu 26.04.2018, 16.30 h

H. Chawdhry (Cambridge)

PMC renormalisation scale-setting in top pair production

Abstract:
In perturbative QCD, uncertainties in theoretical predictions are estimated by varying the renormalisation scale. The Principle of Maximum Conformality (PMC) has been proposed as a way to choose values for this scale. In this talk I will review the PMC and will identify 3 ambiguities in the PMC scale-setting procedure. I will then apply the PMC to top pair production and study the numerical impact of these ambiguities.

 

Thu 03.05.2018, 16.30 h

L. Darme (Warschau)

Hunting light dark sectors in sub-GeV dark matter scenarios

Abstract:
Minimal scenarios with light (sub-GeV) dark matter are usually accompanied by a correspondingly light "dark sector". We will show that the presence of the latter usually leads to strong bounds from cosmology and
bright detection prospects at fixed target experiments and colliders. In particular, we will focus on the consequences of the presence of an often long-lived dark Higgs boson whose mass scale is the same as that of the typical vector mediator.

 

Thu 17.05.2018, 16.30 h

S. Ferrario (University of Milano-Bicocca)

Top-mass studies via new NLO+PS generators

Abstract:
The most precise measurements of the top mass heavily rely on the use of Monte Carlo event generators. Recently, many efforts have been made in order to implement NLO generators able to handle radiation in presence of intermediate resonances. In this talk I will show comparison among kinematic distributions obtained with three POWHEG BOX generators for top-pair production which describe the leptonic top decay with different level of accuracy. These NLO generators must be matched to a shower Monte Carlo program, like Pythia or Herwig. I will present the results obtained for both showering models.

 

Thu 24.05.2018, 16.30 h

M. Valli (INFN Rome)

Hints for New Physics from b to s transitions

 

Thu 07.06.2018, 16.30 h

M. Gerbino (Stockholm)

TBA

 

Thu 14.06.2018, 16.30 h

D. Schwarz (Bielefeld)

TBA

 

Thu 21.06.2018, 16.30 h

F. Herzog (NIKHEF)

TBA

 

Thu 28.06.2018, 16.30 h

S. Sint (Dublin)

TBA

 

Thu 05.07.2018, 16.30 h

H. B. Hartanto (Durham)

TBA

 

Thu 12.07.2018, 16.30 h

E. Komatsu (MPI für Astrophysik, München)

TBA

 

Thu 19.07.2018, 16.30 h

McCabe (King's College London)

TBA