# Internal Seminars SS 16

### Tue 26.04.2016 16:30 (26C402)

Domenico Bonocore (NIKHEF Amsterdam)

Next-to-soft factorization in Drell-Yan processes

**Abstract:**

Soft and collinear radiation originates logarithms that might damage the predictivity of perturbation theory and need to be resummed to all orders. Much is known about this resummation at leading power (LP) while no systematic framework is known for next-to-leading power (NLP) threshold logarithms. A possibility is given by the extension of the traditional soft-collinear factorization formalism to subleading level, known as "next-to-soft". In this talk I review recent results in this investigation. Specifically, considering the real-virtual interference diagrams of the NNLO Drell-Yan K-factor, I will discuss next-to-soft corrections with three different approaches: the use of diagrammatic techniques, the method of regions, and an approach based on the soft-collinear factorization formula. In this investigation special care is needed for collinear effects, which lead to the definition of a radiative jet function. The final result of this analysis is a full control of NLP logarithms that paves the way for a full resummation formalism.

### Fri 13.05.2016 10:00 (28B201)

Verteidigung der Doktorarbeit:

Leila Ali Cavasonza (RWTH)

Searches for leptophilic dark matter with astrophysical experiments

### Fri 27.05.2016 10:00 (26 C 202)

Presentation of the master thesis:

Tobias Tolksdorf (RWTH Aachen)

Top Decay in Narrow-Width-Approximation at the LHC

### Mon 30.05.2016 16:30 (conference room MBP 1)

Pasquale Serpico (LAPTH Annecy)

Cosmic ray "anomalies": some possible causes and implications

**Abstract:**

Direct techniques for cosmic ray observations have reached an unprecedented level of precision, unveiling fine-details of the energy spectra. I will introduce the evidence for new spectral features which has been accumulated by new experiments over the past few years, and review the main ideas invoked in the theoretical explanations of the revealed spectral breaks and elemental spectra non-universality. Some implications for the antimatter channels will be highlighted, notably in the context of indirect WIMP dark matter searches.

### Fri 03.06.2016 11:30 (MBP1 015)

M. Chianese (Univ. & INFN, Naples)

Dark Matter scenarios at IceCube

**Abstract:**

IceCube evidence for extraterrestrial neutrinos poses the intriguing puzzle concerning their origin. The strange features of the measured flux could favor a top-down explanation instead of a more standard astrophysical one. The PeV neutrinos could be indeed originated by the decay of very heavy Dark Matter particles. In particular, we consider a leptophilic four body interaction term that has the characteristics to be "natural" in the coupling (no fine tuning required), and defined by a small number of free parameters. Moreover, the latest IceCube data show a 2-sigma excess at low energy (60 - 100 TeV) with respect to an astrophysical power-law with spectral index -2. We perform a statistical tests of hypothesis on the angular distribution of the arrival directions of neutrino events, in order to infer about the origin of such an excess.

### Mon 27.06.2016 10:00 (MBP1 026)

Subinoy Das (Bangalore)

Astrophysical small scale signatures of non-WIMP dark matter

**Abstract:**

From cosmological observations we know that DM must display clustering properties similar to CDM, at least on the largest scales. However, the particle nature of DM is still not known. The linear LSS observations, such as WiggleZ, BOSS, and Planck data on CMB temperature and polarization anisotropies can be used to place very stringent constraints on any dark matter models that show deviation from the ΛCDM model for k < 0.1 Mpc−1. However, at smaller scales the situation remains unclear from astrophysical observables, e.g. the missing satellite problem, too big to fail problem. This points to a need to study plausible dark matter models that allow for significant deviation from ΛCDM models at small scales and confront them with astrophysical and cosmological observables. I will discuss two class of such models ( non-trivial axion and neutrino physics) which with strong particle physics motivation, where dark matter shows non-standard features at galactic scales and will discuss how high-redshift universe can give smoking gun signature of these models if they are present in nature as entire or sub-dominant component of dark matter.

### Wed 29.06.2016 11:00 (MBP 1, meeting room 1st floor)

Presentation of the bachelor thesis:

David Wierichs (RWTH Aachen)

Gravitational interaction of light in the context of quantum field theory

### Mon 11.07.2016 13:30 (MBP1 015)

Presentation of the master thesis:

Benedikt Eiteneuer (RWTH Aachen)

The Galactic Center Excess

### Mon 11.07.2016 14:30 (MBP1 015)

Presentation of the master thesis:

Cristian Joana (RWTH Aachen)

Simulations of the Onset of Inflation

### Fri 22.07.2016 from 8:30am (MBP1 026)

| |

8:30-9:00 | Jonas Rongen |

9:00-9:30 | Jasper Albers |

9:30-10:00 | Nils Sujata |

10:00-10:30 | Qi Shao |

10:30-11:00 | Daniel Meuser |

11:00-11:30 | Fabian Esser |

11:30-12:00 | Sebastian Pögel |

12:00-12:30 | Max Merkel |

### Wed 03.08.2016 11:00 (26C402)

Daniel Jon Mitchell (University of Cambridge)

Making Sense of Absolute Measurement

**Abstract:**

Thanks to absolute measurement, we could, if we wished, represent all measurements in terms of powers of base units. The Newton, for example, can be written as kgms-2. This notation is widespread in both academic physics and practical application and offers advantages for converting between units. Like many apparently straightforward concepts and techniques in physics, however, its genesis was surprisingly difficult and its origins comparatively recent. Central to the story was Maxwell’s invention of the dimensional formula in 1863 as part of the BAAS Committee on Electrical Standards and his subsequent development of a ‘physical algebra’ in which unit symbols could be manipulated like numbers. These efforts were motivated in large part by the need for industry to convert between Imperial and metric measures at a time of increasing international trade. On the other hand, their legitimation depended upon a modern view of mathematics as an abstract system of signs and symbols that had barely been established by the mid-nineteenth century. I will attempt to explain how this remarkable intersection between the worlds of practice and mathematical physics in Maxwell’s day left its mark upon the algebraic representation and manipulation of units in ours.

### Thu 08.09.2016 9:00 (MBP 026)

PhD Defense:

Manfred Kraus (RWTH)

A comprehensive study of top-quarks with a jet at the LHC

### Tue 27.09.2016 10:00 (MBP 026)

Presentation of the Master Thesis:

Deanna Hooper (RWTH)

Cosmological fluctuations from an oscillating inflaton field

### Tue 27.09.2016 11:00 (MBP coffee room 1st floor)

Presentation of the Bachelor Thesis:

Marius Leyendecker (RWTH)

Neural nets for fast SUSY cross-sections

### Wed 28.09.2016 09:00 (28 B 110)

Presentation of the Master Thesis:

Anke Biekötter (RWTH)

Simplified models and effective field theory for Higgs physics at the LHC

### Wed 28.09.2016 10:00 (MBP 015)

Presentation of the Master Thesis:

Jan-Lukas Wynen (RWTH)

Theoretically consistent description of lineshapes for near threshold resonances

### Fri 30.09.2016 09:00 (MBP1 026)

Presentation of the Master Thesis:

Jerry Dormans (RWTH)

NLO QCD Corrections to Z+jet Production at the LHC

### Fri 30.09.2016 10:00 (MBP1 026)

Presentation of the Master Thesis:

Jan Schütte-Engel (RWTH)

Searching for physics beyond the Standard Model at the LHC in the framework of the pMSSM-11 by using

a neural network approach

### Fri 30.09.2016 11:00 (MBP1 026)

Presentation of the Master Thesis:

Tim Keller (RWTH)

Neural Nets for Model Independent SUSY Fits