Stefano Manzoni | Searcharxiv

arXiv2025

Modelling $b\bar b H$ production for the LHC at 13.6 TeV

We present new state-of-the-art predictions for Standard Model Higgs boson production in association with a bottom-quark pair ($b\bar bH$). Updated cross sections are computed in accordance with the recommendations of the LHC Higgs Working Group, including the use of the PDF4LHC21 set of parton distribution functions, with a center-of-mass energy of 13.6 TeV. For the total inclusive cross section, we provide matched predictions of the massless five-flavour scheme and the massive four-flavour scheme at the fixed-order level. We further present recently obtained simulations matched to parton showers in both flavour schemes within the Standard Model, and also discuss them in the context of potential Beyond-the-Standard-Model scenarios. In the massless scheme, we compare different next-to-next-to-leading order predictions matched to parton showers obtained through the MiNNLOPS and GENEVA generators. In addition, the role of four-flavour scheme predictions is studied as a background to $HH$ searches, considering both the top-quark and bottom-quark Yukawa contributions to $b\bar bH$ production. Finally, we analyse the sensitivity of the Higgs transverse momentum spectrum to light-quark Yukawa couplings in the diphoton decay channel based on MiNNLOPS simulations.

hep-ph↗

arXiv2023

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

We present a new simulation for Higgs boson production in association with bottom quarks ($b\bar{b}H$) 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 $b\bar{b}H$ 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 $b\bar{b}H$ 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 $\mathcal{O}(100\%)$. Including NLO corrections in its simulation allows us to reduce the scale dependence to $\mathcal{O}(50\%)$ so that it becomes subdominant with respect to other systematic uncertainties. As a case study, we provide an in-depth analysis of the $b\bar{b}H$ background to $HH$ measurements with realistic selection cuts in the $2b2γ$ 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 $b\bar{b}H$ simulation to $HH$ searches in the $2b2γ$ and $2b2τ$ final states, and we find an improvement of up to 10% (20%) on the current (HL-LHC) limits on the $HH$ cross section.

hep-ph↗