Speaker
Description
The Large Hadron Collider at CERN is currently our only tool for direct exploration of physics at the electroweak scale and above and the high-luminosity phase is planned to last until the late 2030s. Rare flavour-changing neutral current transitions $𝑏→𝑠𝜇^+𝜇^−$ probe higher energy scales than what is directly accessible at the LHC and therefore the presence of new physics in such transitions, as suggested by the present-day LHCb anomalies, would have a major impact on the motivation and planning of future colliders, with the 100 TeV future circular hadron collider (FCC-hh) and multi-TeV muon collider (MuC) being the most promising options for the energy frontier. In particular the latter has the advantages of both proton-proton and electron-positron colliders, combining high energy reach with high precision measurements.
The theoretical study of processes at a future MuC should take into account the fact that leptons, which are elementary particles in the Standard Model, can emit soft and collinear radiation, which for small transverse momentum can be factorized from the hard scattering and a description in terms of parton distribution functions (PDFs) can be introduced, similarly to what is done in case of proton colliders and the parton content of a proton.
In this talk, after a short presentation of the two future colliders mentioned above, I will quickly review our computation of the muon PDFs, which will be published at the beginning of the next year [1]. Then, following the work in [2], I will show some applications to New Physics searches at MuC and FCC-hh, focusing on 𝑍′ and Leptoquarks. Since a final word on the flavour anomalies (due to either new physics or experimental systematics) might take a while, I will show the results we obtained with and without taking into account LHCb data.
References
[1] F. Garosi, D. Marzocca, S. Trifinopoulos; Standard Model parton distribution functions for lepton colliders (in progress)
[2] A. Azatov, F. Garosi, A. Greljo, D. Marzocca, J. Salko, S. Trifinopoulos; New physics in $𝑏→𝑠𝜇𝜇$: FCC-hh or a muon collider?, JHEP 10 (2022) 149, [2205.13552]
