Abstract
Within the context of composite Higgs models, recent hints on lepton-flavour non-universality in $B$ decays can be explained by a vector resonance $V$ with sizeable couplings to the Standard Model leptons ($\ell$). We argue that, in such a case, spin-$1/2$ leptonic resonances ($L$) are most probably light enough to open the decay mode $V \rightarrow L\ell$. This implies, in combination with the fact that couplings between composite resonances are much larger than those between composite and elementary fields, that this new decay can be important. In this paper, we explore under which conditions it dominates over other decay modes. Its discovery, however, requires a dedicated search strategy. Employing jet substructure techniques, we analyse the final state with largest branching ratio, namely $\mu^+\mu^- Z/h, Z/h \rightarrow$ jets. We show that (i) parameter space regions that were believed excluded by di-muon searches are still allowed, (ii) these regions can already be tested with the dedicated search we propose and (iii) $V$ masses as large as $\sim 3.5$ TeV can be probed at the LHC during the high-luminosity phase.
Highlights
Experimental data collected during the last few years by LHCb [1,2,3,4,5,6], Belle [7] and the LHC [8,9] suggest departures from lepton flavor universality (LFU) in B meson decays with respect to Standard Model (SM) predictions
We obtain that values of mV above 1 TeV are not constrained. Other studies, such as searches for evidence of the typeIII seesaw mechanism [52], focus on final states with more than two leptons, which are almost absent in our scenario. We find it imperative to develop a dedicated search to unravel the origin of LFU in composite Higgs models (CHMs)
If the origin of the apparent breaking of lepton flavor universality (LFU) in B meson decays is due to a composite spin-1 resonance V, this has to couple to rather composite light leptons as well as quarks
Summary
Within the context of composite Higgs models, recent hints on lepton flavor nonuniversality in B decays can be explained by a vector resonance V with sizeable couplings to the Standard Model leptons (l). In such a case, spin-1=2 leptonic resonances (L) are most probably light enough to open the decay mode V → Ll. We argue that, in such a case, spin-1=2 leptonic resonances (L) are most probably light enough to open the decay mode V → Ll This implies, in combination with the fact that couplings between composite resonances are much larger than those between composite and elementary fields, that this new decay can be important. We show that (i) parameter space regions that were believed excluded by dimuon searches are still allowed, (ii) these regions can already be tested with the dedicated search we propose and (iii) V masses as large as ∼3.5 TeV can be probed at the LHC during the high-luminosity phase
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
