Towards ruling out the charged Higgs interpretation of the $$ {R}_{D^{\left(\ast \right)}} $$ anomaly

Abstract

A bstract Motivated by the notorious anomaly in the lepton flavor universality ratios $$ {R}_{D^{\left(\ast \right)}} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>R</mml:mi> <mml:msup> <mml:mi>D</mml:mi> <mml:mfenced> <mml:mo>∗</mml:mo> </mml:mfenced> </mml:msup> </mml:msub> </mml:math> , we study the sensitivity of the Large Hadron Collider (LHC) to a low-mass charged Higgs boson H − lighter than 400 GeV in a generic two Higgs doublet model. A combination of current constraints from the B c → τν decay, B s meson mixing data, tau sleptons and di-jet searches at the LHC allows to explain the $$ {R}_{D^{\left(\ast \right)}} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>R</mml:mi> <mml:msup> <mml:mi>D</mml:mi> <mml:mfenced> <mml:mo>∗</mml:mo> </mml:mfenced> </mml:msup> </mml:msub> </mml:math> anomaly at the 1 σ level by a low-mass charged Higgs. In this context, we estimate the reach of an LHC search for resonant H − production, where the final state contains an energetic τ lepton decaying hadronically, a neutrino with large transverse momentum, and an additional b -jet ( pp → b + τ h + ν ). Requiring the additional b -tagged jet in the τν resonance search profits from the suppression of the Standard Model background, and therefore it allows us to judge the low-mass H − interpretation of the $$ {R}_{D^{\left(\ast \right)}} $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>R</mml:mi> <mml:msup> <mml:mi>D</mml:mi> <mml:mfenced> <mml:mo>∗</mml:mo> </mml:mfenced> </mml:msup> </mml:msub> </mml:math> anomaly. To demonstrate this, we perform a fast collider simulation for the τν resonance search with an additional b -tagged jet, and find that most of the interesting parameter region of the whole mass range can already be probed with the current integrated luminosity of 139 fb − 1 .

Topics & Concepts