On the behaviour of composite resonances breaking lepton flavour universality

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 $V\to L\ell$. 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 ${\mu }^{+}{\mu }^{-}Z/h,Z/h\to$ 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.

7 pages, 7 figures. V2: extended discussion on models, matches published version

References in corpus (15)

• PYTHIA 6.4 Physics and Manual
• The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
• Jet substructure as a new Higgs search channel at the LHC
• Test of lepton universality using $B^{+}\to K^{+}{\ell }^{+}{\ell }^{-}$ decays
• Light custodians in natural composite Higgs models
• Measurement of angular parameters from the decay ${\mathrm{B}}^0\to {\mathrm{K}}^{\ast 0}{\mu }^{+}{\mu }^{-}$ in proton-proton collisions at $\sqrt{s}=$ 8 TeV
• Implications of a Light Higgs in Composite Models
• One constraint to kill them all?
• Flavor Physics and Flavor Anomalies in Minimal Fundamental Partial Compositeness
• Flavourful $Z^{\prime }$ models for $R_{K^{(\ast )}}$
• LHCb anomalies from a natural perspective
• Search for evidence of the type-III seesaw mechanism in multilepton final states in proton-proton collisions at sqrt(s) = 13 TeV
• Tau Custodian searches at the LHC
• The Elusive Gluon
• HERA and the LHC - A workshop on the implications of HERA for LHC physics: Proceedings - Part A

Cited by in corpus (15)

• Unleashing the full power of LHCb to probe Stealth New Physics
• Search for new phenomena in two-body invariant mass distributions using unsupervised machine learning for anomaly detection at $\sqrt{s}=13$ TeV with the ATLAS detector
• Dark matter for $b\to s{\mu }^{+}{\mu }^{-}$ anomaly in a gauged $U(1{)}_X$ model
• Recent $\mathbf{B}$ Physics Anomalies - a First Hint for Compositeness?
• Testing Leptoquark and $Z^{\prime }$ Models via $B\to K_1(1270,1400){\mu }^{+}{\mu }^{-}$ Decays
• Searching new physics in rare $B$-meson decays into multiple muons
• B Anomalies and Leptoquarks at the LHC: Beyond the Lepton-Quark Final State
• $b\to s{\mu }^{+}{\mu }^{-}$ anomalies and related phenomenology in $U(1{)}_{B_3-x_{\mu }{L}_{\mu }-x_{\tau }{L}_{\tau }}$ flavor gauge models
• Effective field theory for vector-like leptons and its collider signals
• Search for new phenomena in multi-body invariant masses in events with at least one isolated lepton and two jets using $\sqrt{s}=13$ TeV proton-proton collision data collected by the ATLAS detector
• Novel $B$-decay signatures of light scalars at high energy facilities
• A Flavorful Composite Higgs Model : Connecting the B anomalies with the hierarchy problem
• Rare nonleptonic ${\bar{B}}_s^0$ decays as probes of new physics behind $b\to s\mu \bar{\mu }$ anomalies
• Search for opposite sign muon-tau pair and a b-jet at LHC in the context of flavor anomalies
• Model-independent searches for new physics in multi-body invariant masses