Collider physics and precise extraction of SM parameters

A very precise determination of Standard Model (SM) parameters is relevant for flavor physics and the search for physics beyond the Standard Model. Heavy quark bound states may be used to extract precise determinations of some of the Standard Model parameters like the heavy quark masses (charm, bottom and top masses) and the strong coupling constant alphas. To this aim suitable observables have to be calculated at high orders in perturbation theory within the EFT formalism, taking appropriate care of the ambiguities of the perturbative series (renormalons), resumming large logarithmic terms and factorizing the genuine nonperturbative effects. We contribute to this research activity with determinations of the mass of the charm and bottom quark from quarkonium and with multiple extractions of alphas from different observables. We use pNRQCD, the EFT we developed for heavy quarkonium, to appropriately encode bound state and threshold effects in the physical observables.

The alpha_s extraction reported in the figure in red and compared to other alphas extractions has been obtained via a comparison between the QCD static energy evaluated on the lattice at short distance between the quark-antiquark probe and the corresponding perturbative calculation performed at order NNNLO. Such work is an example of the research methods of our group that tend to put together lattice and EFTs calculation. It is a high order (NNNLO) determination fully independent of the other lattice extractions.

Written by Nora Brambilla


Nora Brambilla, Antonio Vairo, Xavier Garcia (Bern), Peter Petreczky (Brookhaven), Joan Soto (Barcelona)

Some related publications

Nora Brambilla, Piotr Pietrulewicz, Antonio Vairo
Determination of alpha_s from the QCD static energy: an update
Phys. Rev. D 90, (2014) 074038
arXiv:1407.8437 Inspire