# Internal Seminars SS 15

### Thu 16.04.2015 9:15 (26C402)

Presentation of the master thesis:

Meriem Boubdir (RWTH)

Effects of right-handed Majorana neutrinos in low-energy reactions

### Wen 06.05.2015 14:15 (28A301)

Presentation of the master thesis:

Konstantin Fischer (RWTH)

W boson pair production and transverse momentum subtraction

### Mon 08.06.2015 14:00 (26C402)

Midterm-presentation of the master-thesis project:

Frederic Poncza (RWTH)

NLL resummation for Dark matter production at the LHC

### Tue 16.06.2015 13:30 (MBP1 015)

PhD Defense:

Mathieu Pellen (RWTH)

Precision Calculations for Physics Beyond the Standard Model

### Tue 14.07.2015 12:00 (MBP1 026)

Habilitation lecture:

Malgorzata Worek (RWTH)

Kilogram as a relic in physics: In search of a universal definition of the unit of mass

**Abstract:**

Since 1889, the international prototype of the kilogram has served to define the unit of mass in what is now known as the International System of Units (SI). This definition, which continues to serve mas metrology well, is an anachronism for twenty-first century physics. Indeed, as of 2014 the kilogram is the only SI unit that is stil directly defined by an artifact rather than a fundamental physical property that can be reproduced in different laboratories. Therefore, the kilogram will no doubt be redefined in the future in terms of a physical constant like the Planck constant. In this presentation I will give a brief historical perspective on the developments that led to the current definition of the kilogram. In the next step, I will present an overview of current mass measurement procedures. And finally, I will conclude with an outlook into the future possible redefinition of the unit of mass based on fundamental principles.

### Fri 17.07.2015 14:15 (26 C 402)

Special seminar:

N. Rana (Chennai)

Threshold and RG improved cross sections for Drell-Yan and Higgs productions in N3LO QCD

**Abstract:**

Precise theoretical predictions for Drell-Yan and the Higgs boson production play an important role to put the Standard Model of particle physics in firm footing. Often the fixed order predictions are plagued by large logarithms resulting from certain kinematical regions or from unphysical scales such as renormalization and factorization scales. The solution to this problem is provided by the resummation. In this talk, we will discuss QCD amplitudes and it's factorisation properties and the role of renormalization group invariance in order to understand the soft gluon contributions to both the DY and the Higgs boson productions up to N3LO level for the LHC. Using the universality of the soft distribution function we obtain the threshold corrections of DY at N3LO using the results for the Higgs boson production, for the first time. Also the full N3LO result for the Higgs boson production is recently available. These corrections reduce the renormalisation scale uncertainties significantly in the canonical range [mH/4 , 2 mH]. We will present a novel approach to further reduce the uncertainty arising from the renormalization scale by systematically resuming the renormalisation group (RG) accessible logarithms to all orders in the strong coupling constant. We will also demonstrate numerically the improvement over the fixed order predictions.

### Thu 17.09.2015 16:00 (26C402)

Presentation of the master thesis:

Frederic Poncza(RWTH)

Resummation for dark matter production at the LHC

### Wed 23.09.2015 14:00 (MBP1 026)

PhD Defense:

David Heymes (RWTH)

A general subtraction scheme for NNLO computations in perturbative QCD

### Tue 29.09.2015 14:00 (26C401)

Presentation of the master thesis:

Daniel Schroeder (RWTH)

Constraining BSM Physics at the LHC with four top final states