Phenomenology of a very light scalar (100 MeV < mh< 10 GeV) mixing with the SM Higgs

• Published in: The journal of high energy physics Vol. 2014; no. 2; p. 1
• Main Authors: Clarke, Jackson D., Foot, Robert, Volkas, Raymond R.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.02.2014; Springer Nature B.V
• Subjects: Classical and Quantum Gravitation; Elementary Particles; High energy physics; Physics; Physics and Astronomy; Quantum Field Theories; Quantum Field Theory; Quantum Physics; Relativity Theory; String Theory; Phenomenological Models; Hadronic Colliders
• ISSN: 1029-8479; 1029-8479
• DOI: 10.1007/JHEP02(2014)123

A bstract In this paper we investigate the phenomenology of a very light scalar, h , with mass 100 MeV  < m h   <  10 GeV, mixing with the SM Higgs. As a benchmark model we take the real singlet scalar extension of the SM. We point out apparently unresolved uncertainties in the branching ratios and lifetime of h in a crucial region of parameter space for LHC phenomenology. Bounds from LEP, meson decays and fixed target experiments are reviewed. We also examine prospects at the LHC. For m h ≲ m B the dominant production mechanism is via meson decay; our main result is the calculation of the differential p T spectrum of h scalars originating from B mesons and the subsequent prediction of up to thousands of moderate (triggerable) p T displaced dimuons possibly hiding in the existing dataset at ATLAS/CMS or at LHCb. We also demonstrate that the subdominant V h production channel has the best sensitivity for m h ≳ m B and that future bounds in this region could conceivably compete with those of LEP.