dr Rafał Staszewski (IFJ PAN): Recent ATLAS measurement of elastic pp scattering and what it tells us about strong interactions at high energies

Friday Oct 28, 2022, 10:15 AM → 11:00 AM Europe/Warsaw

Abstract:

Elastic scattering of protons, where the incoming particles barely bounce off each other, has intrigued particle physicists for decades. Its non-perturbative nature prohibits calculations from first principles. However, by measuring this process, fundamental quantities of strong interactions can be determined, in particular the total cross section. I will present the most precise determination to date of the total pp cross section at a center-of-mass energy of 13 TeV as well as a measurement and the so-called rho parameter, the ratio of the real to imaginary parts of the forward elastic scattering amplitude. 

The measurements are performed using data collected with a dedicated special LHC optics with beta* equal to 2.5 km. The scattering angles of the protons are measured with the ALFA detectors, housed in Roman pots placed 240 m from the ATLAS interaction point. Such setup provides access to the Coulomb-nuclear interference region at small momentum transfer. The new high-precision measurement provides important information on the energy evolution of the total cross section and rho parameter, which is necessary to improve the modeling of hadronic scattering at high energy.

Important: This seminar is held in building D-11 room 104. 

28102022-RafalStaszewski-SigmaTotATLAS.pdf