Study of charmonium production using decays to hadronic final states with the LHCb experiment

by Mr Andrii Usachov

Tuesday 23 Jul 2019, 14:00 → 16:00 Asia/Shanghai

Since more than 40 years the charmonium production mechanism is still not entirely understood. Following the era of investigations at e+e− machines, nowadays, charmonium states are copiously produced at hadron colliders, that allows systematic studies of their resonance parameters, production observables and decays. Despite large production rates, many charmonium states are barely studied due to the complications of their reconstruction against a large background level. The LHCb experiment provides a unique opportunity to study S-wave and P-wave charmonium states using their decays to hadrons. This allows measuring production observables of ηc and χc charmonium states. According to the theoretical formalism of Non-Relativistic QCD (NRQCD), the production observables of the same wave charmonium states are linked. Hence, the LHCb measurements provide a series of stringent tests of NRQCD. I will discuss the first measurement of the ηc(1S) differential production cross-section at 13TeV. In addition, the production of the χc and ηc(2S) states in b-hadron decays is studied using decays to φφ. The obtained results will be confronted with existing theory predictions. About the speaker: Andrii Usachov October 2016 – July 2019, LAL AND UNIVERSITY PARIS-SUD, ORSAY, FRANCE 2013-2015,Master thesis student,LAL, ORSAY, FRANCE