Seminars in Particle Physics Phenomenology at the Physics Department of Torino

Although the computation of a vast class of $e^+e^-$ cross sections is fully doable in perturbative QED, the perturbative series is not well behaved unless a mechanism is devised that allows one to take into account, to all orders in the coupling constant, the effects due to multiple emissions of photons and $e^+e^-$ pairs off the incoming particles. I shall discuss one such mechanism, the collinear factorisation approach, that has a strict analogy with its counterpart in QCD and leads to the definition of "Parton" Distribution Functions (PDFs) of the electron and the positron. I shall present recent results that have improved the accuracy to which these PDFs are known, as well as some preliminary predictions for physical observables at high-energy $e^+e^-$ colliders

*Wednesday, 6th April 2022, 14:30 — Sala Wataghin *

The recent measurement of the muon g-2 at Fermilab confirms the previous Brookhaven result. At the same time, a new lattice determination of the leading hadronic vacuum polarization (HVP) contribution to the muon g-2 by the BMW collaboration hints to a substantial agreement between the Standard Model and the g-2 experiment. However, the BMW result turns out to be in tension with the traditionally used data-driven approach to the HVP contribution. In this talk I will review recent attempts to solve this tension, referred to as the new muon g-2 puzzle, by invoking a low-energy new physics contamination in the experimental extraction of the hadronic cross-section.

*Wednesday, 3rd March 2022, 14:30 — Zoom seminar *

Inclusive Higgs production at LHC is known with great precision — its QCD corrections have been computed to N3LO in the Higgs effective theory. That requires to know with a matching precision tiny effects like the heavy-quark mass or the electroweak contributions. I will talk about that, as well as about infrared currents for N3LO QCD corrections to generic production rates.

*Wednesday, 23rd February 2022, 14:30 — Sala Fubini *

I will review the potential offered by the study of the Drell-Yan processes at the LHC, in view of high-precision tests of the Standard Model. I will then illustrate the main features of the recent calculation of the exact set of NNLO mixed QCD-EW corrections to the neutral current Drell-Yan process, and the prospects for the charged-current case.

*Wednesday, 9th February 2022, 14:30 — Sala Wataghin *