Diphoton channel at the LHC experiments to find a hint for a new heavy gauge boson

Kaneta, Kunio; Kang, Subeom; Lee, Hye-Sung

doi:10.1142/s0217751x16501591

Cited by 5 publications

(3 citation statements)

References 34 publications

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“…Our proposed setup is motivated by the natural assumption that a particle whose properties are reminiscent of the SM Higgs is perhaps best thought of as a Higgs boson that breaks a new symmetry (For a sample of works that consider a Higgs field interpretation of the excess, see Refs. [8][9][10][11][12]). The simplicity and minimal nature of the SU (2) e group make it a compelling choice, however we go a step further and will assume that it is responsible for generating the non-zero baryon asymmetry in the early universe, thereby addressing one of the main open questions in cosmology and particle physics.…”

Section: Introductionmentioning

confidence: 99%

Higgs-like boson at 750 GeV and genesis of baryons

2016

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We propose that the diphoton excess at 750 GeV reported by ATLAS and CMS is due to the decay of an exo-Higgs scalar η associated with the breaking of a new SU (2)e symmetry, dubbed exo-spin. New fermions, exo-quarks and exo-leptons, get TeV-scale masses through Yukawa couplings with η and generate its couplings to gluons and photons at 1-loop. The matter content of our model yields a B − L anomaly under SU (2)e, whose breaking we assume entails a first order phase transition. A non-trivial B − L asymmetry may therefore be generated in the early universe, potentially providing a baryogenesis mechanism through the Standard Model (SM) sphaleron processes. The spontaneous breaking of SU (2)e can in principle directly lead to electroweak symmetry breaking, thereby accounting for the proximity of the mass scales of the SM Higgs and the exo-Higgs. Our model can be distinguished from those comprising a singlet scalar and vector fermions by the discovery of TeV scale exo-vector bosons, corresponding to the broken SU (2)e generators, at the LHC.

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Section: Introductionmentioning

confidence: 99%

Higgs-like boson at 750 GeV and genesis of baryons

2016

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“…Furthermore, the absence of a significant signal in the previous run of the LHC at √ s = 8 TeV may have favoured certain production modes. The excess inspired a number of theoretical investigations [5] - [27].…”

Section: Introductionmentioning

confidence: 99%

Implications of diphoton searches for a radion in the bulk-Higgs scenario

Cox

Medina

Ray

et al. 2017

Int. J. Mod. Phys. A

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In this work we point out that the apparent diphoton excess initially presented by the ATLAS and CMS collaborations could have originated from a radion in the bulk Higgs scenario within a warped extra dimension. In this scenario the couplings of the radion to massive gauge bosons are suppressed, allowing it to evade existing searches. In the presence of mixing with the Higgs, due to the strong constraints from diboson searches, only points near what we denominate the alignment region were able to explain the diphoton signal and evade other experimental constraints. In light of the new measurements presented at ICHEP 2016 by both LHC collaborations, which do not confirm the initial diphoton excess, we study the current and future collider constraints on a radion within the bulk-Higgs scenario. We find that searches in the diphoton channel provide the most powerful probe of this scenario and already exclude large regions of parameter space, particularly for smaller warp factors. The radion has a sizeable branching ratio into top pairs and this channel may also give competitive constraints in the future. Finally, diHiggs searches can provide a complementary probe in the case of non-zero radion-Higgs mixing but strong alignment.

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“…If the decay length of Y is commensurate with the linear geometry of the detector (e.g., of the inner tracker and eletro-magnetic calorimeter) and its mass is in the MeV-GeV range, then emergent highly collimated pairs of photons and/or electron-positron pairs may successfully mimic actual photons. Therefore, the interesting part of this scenario is that a new 750 GeV resonance opens the door to light weakly coupled states coupled to the SM sector, which is a particular realization of the "hidden valley" idea [53][54][55][56][57][58][59][60][61][62][63][64].…”

Section: Introductionmentioning

confidence: 99%

Diphoton excess through dark mediators

Chen

Lefebvre

Pospelov

et al. 2016

J. High Energ. Phys.

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Preliminary ATLAS and CMS results from the first 13 TeV LHC run have encountered an intriguing excess of events in the diphoton channel around the invariant mass of 750 GeV. We investigate a possibility that the current excess is due to a heavy resonance decaying to light metastable states, which in turn give displaced decays to very highly collimated e + e − pairs. Such decays may pass the photon selection criteria, and successfully mimic the diphoton events, especially at low counts. We investigate two classes of such models, characterized by the following underlying production and decay chains: gg → S → A A → (e + e − )(e + e − ) and qq → Z → sa → (e + e − )(e + e − ), where at the first step a heavy scalar, S, or vector, Z , resonances are produced that decay to light metastable vectors, A , or (pseudo-)scalars, s and a. Setting the parameters of the models to explain the existing excess, and taking the ATLAS detector geometry into account, we marginalize over the properties of heavy resonances in order to derive the expected lifetimes and couplings of metastable light resonances. We observe that in the case of A , the suggested range of masses and mixing angles is within reach of several new-generation intensity frontier experiments.

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Diphoton channel at the LHC experiments to find a hint for a new heavy gauge boson

Cited by 5 publications

References 34 publications

Higgs-like boson at 750 GeV and genesis of baryons

Higgs-like boson at 750 GeV and genesis of baryons

Implications of diphoton searches for a radion in the bulk-Higgs scenario

Diphoton excess through dark mediators

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