Taming a leading theoretical uncertainty in HH measurements via accurate simulations for bb̄H production

This is the authors' abstract. We don't add key points for this paper.

A bstract We present a new simulation for Higgs boson production in association with bottom quarks ( bb̄H b b ¯ H ) at next-to-leading order (NLO) accuracy matched to parton showers in hadronic collisions. Both contributions, the standard one proportional to the bottom-quark Yukawa coupling and the loop-induced one proportional to the top-quark Yukawa coupling from the gluon-fusion process, are taken into account in a scheme with massive bottom quarks. Therefore, we provide the full simulation of the bb̄H b b ¯ H final state in the Standard Model, which constitutes also a crucial background to measurements for Higgs-boson pair ( HH ) production at the Large Hadron Collider when at least one of the Higgs bosons decays to bottom quarks. So far, the modeling of the bb̄H b b ¯ H final state induced one of the dominant theoretical uncertainties to HH measurements, as the gluon-fusion component was described only at the leading order (LO) with uncertainties of O O (100%). Including NLO corrections in its simulation allows us to reduce the scale dependence to O O (50%) so that it becomes subdominant with respect to other systematic uncertainties. As a case study, we provide an in-depth analysis of the bb̄H b b ¯ H background to HH measurements with realistic selection cuts in the 2 b 2 γ channel. We also compare our novel simulation with the currently-employed ones, discussing possible issues and shortcomings of a scheme with massless bottom quarks. Finally, we propagate the effect of the new bb̄H b b ¯ H simulation to HH searches in the 2 b 2 γ and 2 b 2 τ final states, and we find an improvement of up to 10% (20%) on the current (HL-LHC) limits on σSMHH σ SM HH .