Measurement of the relative Χb2(1P) /Χb1(1P) polarization in proton-proton collisions at √s=13 TeV

Abstract

The chi_b meson is a bound state of a bottom quark and its antiquark and belongs to the familiy of quarkonia, which designate the bound states of heavy quarks and their respective antiquarks. Quarkonium physics is an active field of fundamental research since it serves as an excellent laboratory for testing the standard model of particle physics and quantum chromodynamics, the theory of the strong interaction. The Large Hadron Collider (LHC), which reaches unprecedented collision energies, provides an ideal source of quarkonia. This thesis deals with a first polarization analysis of the chi_b(1P) states using data taken at CMS in the years 2016 and 2017 at a center-of-mass energy of sqrt(s) = 13 TeV. The relative polarization of chi_b2(1P) to chi_b1(1P) mesons is measured using two different methods.