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 28th, 2024, at 11:30 in WBGB/021

Speaker: Dr. Sebastian Eike Pögel (PSI)

Title:  Geometries, Calabi-Yau Manifolds, and Feynman Integrals

Abstract

In studying Feynman integrals "beyond polylogarithms", intricate geometries appear, such as Calabi-Yau manifolds and (hyper)elliptic curves, which dictate the appropriate function spaces for their evaluation. Such geometries play a significant role in integrals relevant to both particle physics and classical gravity. In this talk, I will explore how geometric insights can be extracted from Feynman integrals even before their explicit evaluation. Focusing on Calabi-Yau integrals, I will then discuss techniques for computing these integrals in dimensional regularization, providing a bridge between geometry and physics.

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The last seminar took 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.