Revisiting Vh(→ b b ¯ $$ b\overline{b} $$ ) at the LHC and FCC-hh

Abstract

Abstract Diboson production processes provide good targets for precision measurements at present and future hadron colliders. We consider Vh production, focusing on the h → b b ¯ $$ b\overline{b} $$ decay channel, whose sizeable cross section makes it accessible at the LHC. We perform an improved analysis by combining the 0-, 1- and 2-lepton channels with a scale-invariant b-tagging algorithm that allows us to exploit events with either a boosted Higgs via mass-drop tagging or resolved b-jets. This strategy gives sensitivity to 4 dimension-6 SMEFT operators that modify the W and Z couplings to quarks and is competitive with the bounds obtained from global fits. The benefit of the h → b b ¯ $$ b\overline{b} $$ decay channel is the fact that it is the only Vh channel accessible at the LHC Run 3 and HL-LHC, while at FCC-hh it is competitive with the effectively background-free h → γγ channel assuming ≲ 5% systematic uncertainty. Combining the boosted and resolved categories yields a 17% improvement on the most strongly bounded Wilson coefficient at the LHC Run 3 with respect to the boosted category alone (and a 7% improvement at FCC-hh). We also show that, at FCC-hh, a binning in the rapidity of the Vh system can significantly reduce correlations between some EFT operators. The bounds we obtain translate to a lower bound on the new physics scale of 5, 8, and 20 TeV at the LHC Run 3, HL-LHC, and FCC-hh respectively, assuming new-physics couplings of order unity. Finally, we assess the impact of the Vh production channel on anomalous triple gauge coupling measurements, comparing with their determination at lepton colliders.

Keywords

• Anomalous Higgs Couplings
• Electroweak Precision Physics
• SMEFT