RIP $H b \bar b$: How other Higgs production modes conspire to kill a rare signal at the LHC

Understand

The hadroproduction of a Higgs boson in association with a bottom-quark pair ($H b \bar b$) is commonly considered as the key process for directly probing the Yukawa interaction between the Higgs boson and the bottom quark ($y_b$).

• However, in the Standard-Model (SM) this process is also known to suffer from very large irreducible backgrounds from other Higgs production channels, notably gluon-fusion ($gg$F).
• In this paper we calculate for the first time the so-called QCD and electroweak complete-NLO predictions for $H b \bar b$ production, using the four-flavour scheme.
• Our calculation shows that not only the $gg$F but also the $ZH$ and even the vector-boson fusion channels are sizeable irreducible backgrounds.