Seminars WS22/23

Thursday, February 02, 2023, 4:30pm

Special day Thursday instead of Tuesday, 02.02.23 at 16:30 


Thea Klaeboe Aarrestad (ETH Zurich)

Ultrafast Machine Learning Inference at the Large Hadron Collider



At the CERN Large Hadron Collider, protons are brought to collide hundreds of millions of times per second. The collision debris allows us to study the fundamental building blocks of the universe and look for hints of new forces and particles. The vast majority of the collision data are immediately discarded by a real-time event filtering system due to storage and computational limitations. While most of these data are uninterresting, signals of new physics might be inadvertendly thrown away in the process. The first stage of this event filtering system consists of hundreds of field-programmable gate arrays (FPGAs), tasked with rejecting over 98% of the proton collisions within a few microseconds. With the start of High Luminosity LHC in 2029, a more granular detector and more particles per collision will increase the event complexity significantly, and ultimately require the FPGA farm to process an amount of data comparable to 5% of the total internet traffic.


In this talk, I will discuss how real-time Machine Learning (ML) is used to process and filter this enormous amount of data in order to improve physics acceptance, and how ML can be used to select data in ways never before performed at colliders.


Host: Michael Krämer



Tuesday, January 31, 2023, 4:30pm (online)

Geraldine Servant (DESY)

Baryogenesis during the electroweak phase transition



Ten years after the Higgs-boson discovery, it remains a possibility that the electroweak phase transition happened as a rather violent process, with a large departure from thermal equilibrium, via Higgs-bubble nucleations and collisions. This is a fascinating scenario for three reasons: it provides a framework for explaining the matter–antimatter asymmetry of the universe; it predicts the existence of at least one new weak-scale scalar field and thus is testable at colliders; and it would leave a unique signature of gravitational waves detectable by the future space-based interferometer LISA. I will discuss these ideas and the challenges that a viable model of electroweak baryogenesis has to face. In particular, I will present the updated situation and the prospects in the context of the minimal composite Higgs framework.


Host: Michal Czakon




Tuesday, January 24, 2023, 4:30pm (online)

Susanne Kühn (CERN)

The ECFA Detector R&D Roadmap and its implementation



The European Strategy for Particle Physics Update recommended that “ Organised by ECFA, a roadmap should be developed by the community to balance the detector R&D efforts in Europe, taking into account progress with emerging technologies in adjacent fields “. This Roadmap which is based on the input of the community and was developed within the ECFA Detector R&D Panel, was approved by ECFA and published at the end of 2021.  Moreover, the process of the implementation of its recommendations started in 2022. One is that ew Detector R&D Collaborations are foreseen to be formed.  In this talk the findings of the Task forces and b y this the detector technology areas or cross-cutting activities will be presented.  The important drivers and general strategic  recommendations for future Detector R&D will be highlighted. The ongoing and next steps of the implementation will as well be described


Host: Kerstin Borras




Tuesday, 17.01.2023, 4:30 pm Physics lecture hall

Felix Kahlhöfer (KIT)

The collider cosmology connection



At first sight, the Large Hadron Collider (LHC) and Early Universe Cosmology have little in common, probing respectively the smallest and largest scales in nature. Nevertheless, one of the greatest successes of modern physics has been to demonstrate the deep connections between the two fields: The properties of fundamental particles affect the evolution of the early universe, and many models that modify cosmological observables can be tested at colliders. In my talk, I will illustrate this connection with three specific examples. First, I will demonstrate that searches for long-lived particles at the LHC can probe models that modify the expansion rate of the universe through non-thermal dark radiation. Second, I will show that early universe structure formation points towards self-interacting dark matter particles, which may give rise to highly unusual collider signatures. Finally, I will discuss how a global analysis of LHC searches may help us pin down the properties of dark matter particles.


Host: Alexander Schmidt




Tuesday, January 10, 2023, 4:30pm (online)

Thomas Teubner  (University of Liverpool)

g-2 puzzles: a status update



In this talk we will review the status of g-2 of the muon. The main 

emphasis will be on the Standard Model prediction and in particular  

the determination of the hadronic contributions which are the 

limiting factor. Recent developments, the current state of the 

discrepancy between experiment and theory as well as future 

prospects will be discussed


Host: Malgorzata Worek




Tuesday, December 06, 2022, 4:30pm, Physics lecture hall

Felix Eschment, Florian Mausolf, Tom Schellenberger (RWTH Aachen University, GRK)

Student talks


Host: Michal Czakon




Tuesday, November 22, 2022, 4:30pm, Physics lecture hall

A. Stahl (RWTH Aachen University)

Tau physics - exact title TBA



I will discuss the properties of the tau leptons, our understanding of these properties and their impact on analysis with tau-leptons.


Host: Thomas Hebbeker