Particle Theory Seminars

The particle theory seminars are organized by the Theory Group of the Laboratory for Particle Physics (LTP) at PSI.

The next seminar will take place on Thursday, November 21st, 2024, at 11:30 in WBGB/020

Speaker: Dr. Yelyzaveta Yedelkina (PSI)

Title:  Vector-quarkonium production in photon-photon and photon-proton collisions up to one loop in quantum chromodynamics

Abstract

The primary subject of my thesis is one of the most studied particles at high-energy colliders, the quarkonium, which is a bound state of a heavy quark-antiquark pair. We present a novel methodology to compute vector quarkonium production cross sections up to the next-to-leading order corrections in the strong coupling in the Colour-Singlet Model. We have used this methodology to study inclusive production of vector quarkonium states, J/psi and Upsilon, in the photoproduction limit in lepton-hadron collisions and in photon fusion in electron-positron collisions. We have performed phenomenological predictions for quarkonium production at different experimental facilities, such as LHC, HERA and for some future experiments such as the CEPC, the FCC, the EIC, the CLIC, which can provide a valuable opportunity to extend our knowledge of quantum chromodynamics and, in particular, of the Non-Relativistic QCD framework used to describe quarkonium production.

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The last seminar took place on Friday, 2.8.2024, at 11:00 in WHGA/001

Speaker:  Prof. Dr. Vincenzo Cirigliano (INT, U. Washington)

Title: The first row of the CKM matrix: puzzles and perspectives

Abstract

In this talk I will discuss the so-called Cabibbo universality test of charged-current weak interactions. I will start with an overview of the paths to precisely extract the elements of the first row of the Cabibbo-Kobayashi-Maskawa (CKM) matrix. I will then describe in some detail the extraction of Vud (the cosine of the Cabibbo angle) from pion, neutron, and nuclear beta decays, as well as recent efforts to reduce the theoretical uncertainty using effective field theory methods. Finally, I will review the existing tensions in the Cabibbo universality test and discuss possible explanations of these tensions in terms of physics beyond the Standard Model.