HEP Colloquia 2022

by Dr Giuseppe Bozzi (Cagliari State University)

Thursday 14 Jul 2022, 14:30 → 16:30 Europe/Rome

Aula C (Department of Physics)

The role of theoretical uncertainties in the determination of M_W at hadron colliders

The high-precision measurement of the W-boson mass offers the possibility of a stringent test of the Standard Model: any significant deviation from the SM prediction (obtained from a global fit of EW observables) might provide some indirect hints of physics beyond the SM. 

M_W is extracted by means of a template fit technique applied to different observables of the charged-current Drell–Yan process, namely the lepton and neutrino transverse momenta and the lepton pair transverse mass. The differential distributions are computed with Monte Carlo simulation codes for different values of M_W and are subsequently compared with the corresponding data: the value that maximizes the agreement is chosen as the preferred value for M_W. 

The theoretical contribution to the final systematic error enters in the analysis of the data via the templates. 

A careful investigation of all perturbative and non-perturbative sources of theoretical uncertainty is thus mandatory to match the ever-increasing precision reached by experimental collaborations.

In the seminar, I will describe the whole procedure and I will mainly focus on the role of hadronic (initial state) theoretical uncertainties.