Alternative signatures of the quintuplet fermions at the LHC and future linear colliders

Abstract

Quintuplet fermions appear in different extensions of the Standard Model (SM), which are essential to predict the small neutrino mass, correct dark matter (DM) relic abundance, and the measured value of muon anomalous magnetic moment. Moreover, the existence of scalar multiplets, along with the quintuplet fermions, can address the recent anomalies in the flavor sector while the model gets constrained from the ρ parameter. A unique nature of these models is that they predict non-standard signatures at colliders, when the components of the quintuplet fermion (doubly and singly charged fermions, neutral fermion) are produced at the colliders and they decay via the components of the scalar multiplets (charged and neutral scalars). In standard scenarios, exotic fermions (such as vectorlike) couple with the SM particles and there exists a strong limit on their masses from collider experiments such as the Large Hadron Collider (LHC). In this paper, we choose a particular scenario with both fermionic quintuplet and scalar multiplets where the quintuplet fermions are heavier than the scalars, which is naturally motivated from the muon (g-2) data. We study these non-standard interactions and provide alternative search strategies for these exotic quintuplet fermions at the LHC and future linear colliders such as e + e − collider and discuss the exclusion and discovery limits.

Search for exotic leptons in final states with two or three leptons and fat-jets at 13 TeV LHC

“…The presence of several charged exotic leptons within the new weak gauge fermionic multiplets is a common yet salient feature of many new physics models [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][31][32][33][34][35] which are well-placed to address various shortcomings of the SM (see Table 3 for an incomplete list of such models and their motivations). Aplenty production of these exotic leptons and their decays to the SM particles offers an up-and-coming way to probe them at the LHC.…”

“…Model-5 F 0 [35,42] neutrino mass and dark matter [18,24,29,31,34] neutrino mass [32,33,43] dark matter…”

“…Copious production of different such charged exotic leptons, driven by their electroweak couplings to the W and Z bosons and the photon, and their eventual decays to the SM leptons and bosons (W/Z/h-boson) offer interesting ways to probe them at the Large Hadron Collider (LHC). Phenomenology of such exotics leptons (in particular, the doubly-charged one) at the LHC has been studied extensively in the literature [26][27][28][29][35][36][37][38][39][40]. However, all of these searches considered multileptons, missing transverse momentum (p miss T ) and jets in the final states.…”

“…[14,24], in generating neutrino masses via effective dimension nine operators, introduced several fermionic multiplets, namely vector-like SU (2) L triplets with Y = 1, vector-like SU (2) L quadruplets with Y = 1/2 and chiral SU (2) L quintuplets with Y = 0. The presence of several charged exotic leptons within the new weak gauge leptonic multiplets is a common yet salient feature of most of these neutrino mass models [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][31][32][33][34][35]. Copious production of different such charged exotic leptons, driven by their electroweak couplings to the W and Z bosons and the photon, and their eventual decays to the SM leptons and bosons (W/Z/h-boson) offer interesting ways to probe them at the Large Hadron Collider (LHC).…”

Anomalous gauge couplings vis-$\grave{a}$-vis $(g-2)_μ$ and flavor observables

“…Examples are provided by numerous scenarios that contain higher gauge-multiplet fermions such as those in a wide class of scenarios seeking to explain, amongst others, neutrino masses and mixings [56]. In this sense, the analysis presented here serves to assess the viability of such explicit models (many of which, potentially, lead to interesting, albeit complicated signals at the LHC [57,58]) when juxtaposed with the most recent limits on the low-energy observables, to be described later.…”