The case for future hadron colliders from B → K(*)μ+μ− decays

Abstract

Abstract Recent measurements in B → K (*) μ + μ − decays are somewhat discrepant with Standard Model predictions. They may be harbingers of new physics at an energy scale potentially accessible to direct discovery. We estimate the sensitivity of future hadron colliders to the possible new particles that may be responsible for the anomalies at tree-level: leptoquarks or Z′s. We consider luminosity upgrades for a 14 TeV LHC, a 33 TeV LHC, and a 100 TeV pp collider such as the FCC-hh. In the most conservative and pessimistic models, for narrow particles with perturbative couplings, Z′ masses up to 20 TeV and leptoquark masses up to 41 TeV may in principle explain the anomalies. Coverage of Z′ models is excellent: a 33 TeV 1 ab−1 LHC is expected to cover most of the parameter space up to 8 TeV in mass, whereas the 100 TeV FCC-hh with 10 ab−1 will cover all of it. A smaller portion of the leptoquark parameter space is covered by future colliders: for example, in a μ + μ − jj di-leptoquark search, a 100 TeV 10 ab−1 collider has a projected sensitivity up to leptoquark masses of 12 TeV (extendable to 21 TeV with a strong coupling for single leptoquark production).