RIP Hb b ˉ documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$$ Hboverline{b} $$end{document} : how other Higgs production modes conspire to kill a rare signal at the LHC

摘要

A bstract The hadroproduction of a Higgs boson in association with a bottom-quark pair ( Hb b ˉ documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$$ Hboverline{b} $$end{document} ) 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 Hb b ˉ documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$$ Hboverline{b} $$end{document} 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. Moreover, we demonstrate that, at the LHC, the rates of these backgrounds are very large with respect to the “genuine” and y _( b )-dependent Hb b ˉ documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$$ Hboverline{b} $$end{document} production mode. In particular, no suppression occurs at the differential level and therefore backgrounds survive typical analysis cuts. This fact further jeopardises the chances of measuring at the LHC the y _( b )-dependent component of Hb b ˉ documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$$ Hboverline{b} $$end{document} production in the SM. Especially, unless y _( b )is significantly enlarged by new physics, even for beyond-the SM scenarios the direct determination of y _( b )via this process seems to be hopeless at the LHC.