Slight excess at 130 GeV in search for a charged Higgs boson decaying to a charm quark and a bottom quark at the Large Hadron Collider

• Searches for a charged Higgs boson (H-+/-) decaying to a charm quark and a bottom quark (H +/- -> cb) have been carried out at the Large Hadron Collider (LHC) in the decay of top quarks (t -> H(+/-)b). In a recent search by the ATLAS collaboration (with all run II data, 139 fb(-1)) a local excess of around 3 sigma has been observed, which is best fitted by a charged Higgs boson with a mass (m(H)+/-) of around 130 GeV and a product of branching ratios (BRs) given by BR(t -> H(+/-)b) x BR(H-+/- -> cb) = 0.16% +/- 0.06%. In the context of two-Higgs-doublet models (2HDM) with independent Yukawa couplings for H-+/- we present the parameter space for which this excess (assuming it to be genuine) can be accommodated, taking into account the limits from LHC searches for H-+/- -> cs and H-+/- -> tau nu at m(H)+/- = 130 GeV and the constraint from b -> s gamma. It is then shown that such an excess cannot be explained in 2HDMs with natural flavour conservation, but can be accommodated in the flipped three-Higgs-doublet model (3HDM) and in the aligned 2HDM (A2HDM). Upcoming searches with 139 fb(-1) in the channels H-+/- -> cb (CMS), H-+/- -> cs (ATLAS/CMS) and H-+/- -> tau nu (ATLAS/CMS) will determine if the excess is the first sign of an H-+/- with m(H)+/- = 130 GeV.

Ämnesord

NATURVETENSKAP  -- Fysik -- Subatomär fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Subatomic Physics (hsv//eng)

Nyckelord

charged Higgs boson

Large Hadron Collider

top quark decay

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