5. Theoretical Physics (CSN4)

Heavy flavours and the W-boson mass measurement at the LHC

by Dr Emanuele Angelo Bagnaschi (DESY Hamburg)

Aula Seminari (LNF)

Aula Seminari


Via Enrico Fermi, 40 00044 Frascati (Roma)
The inclusive transverse-momentum spectrum of the Z boson is measured with high precision at the LHC and used a standard candle to tune Monte Carlo event generators. In turn, this implies that any change in its theoretical description will affect the Monte Carlo predictions for other Standard Model precision measurements, such as the W mass. One of the uncertainties that currently affects the theoretical prediction of the Z transverse momentum comes from the fact that in the usually used five-flavour scheme (5FS) heavy flavours are treated as massless parton in the initial state. In this work we aim at improving the description of the inclusive Z-boson transverse momentum, by including the effects of the four-flavour scheme (4FS) computation of Z production in association with bottom-quark pairs (where the bottom quarks are massive and there are no bottom PDFs in the proton), on the top of the 5FS description of the neutral-current Drell-Yan process. Finally, we estimate the impact of these effects on the measurement of the W mass.