Collider constraints on light pseudoscalars

Haisch, Ulrich; Kamenik, Jernej F.; Malinauskas, Augustinas; Spira, M.

doi:10.1007/jhep03(2018)178

Cited by 56 publications

(73 citation statements)

References 71 publications

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“…We apply the same event selection described in Eqs. (43) and (44) . We generate both signal and background using MadGraph5, interfaced with Pythia8 for parton showering.…”

Section: For This Channel We Focus On the 4 -Lepton Final Statementioning

confidence: 96%

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Light hidden mesons through the Z portal

Cheng

Salvioni

et al. 2019

J. High Energ. Phys.

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Confining hidden sectors are an attractive possibility for physics beyond the Standard Model (SM). They are especially motivated by neutral naturalness theories, which reconcile the lightness of the Higgs with the strong constraints on colored top partners. We study hidden QCD with one light quark flavor, coupled to the SM via effective operators suppressed by the mass M of new electroweak-charged particles. This effective field theory is inspired by a new tripled top model of supersymmetric neutral naturalness. The hidden sector is accessed primarily via the Z and Higgs portals, which also mediate the decays of the hidden mesons back to SM particles. We find that exotic Z decays at the LHC and future Z factories provide the strongest sensitivity to this scenario, and we outline a wide array of searches. For a larger hidden confinement scale Λ ∼ O(10) GeV, the exotic Z decays dominantly produce final states with two hidden mesons. ATLAS and CMS can probe their prompt decays up to M ∼ 3 TeV at the high luminosity phase, while a TeraZ factory would extend the reach up to M ∼ 20 TeV through a combination of searches for prompt and displaced signals. For smaller Λ ∼ O(1) GeV, the Z decays to the hidden sector produce jets of hidden mesons, which are long-lived. LHCb will be a powerful probe of these emerging jets.Furthermore, the light hidden vector meson could be detected by proposed dark photon searches.

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“…We apply the same event selection described in Eqs. (43) and (44) . We generate both signal and background using MadGraph5, interfaced with Pythia8 for parton showering.…”

Section: For This Channel We Focus On the 4 -Lepton Final Statementioning

confidence: 96%

“…where ρ denotes the phase space for isotropic 3-body decays [43], and take m s * = 450 MeV as motivated by a perturbative spectator model [44]. The resulting width for decay to strange hadrons is ∼ 0.15 of that to muons.…”

Section: B Decaysmentioning

confidence: 99%

Light hidden mesons through the Z portal

Cheng

Salvioni

et al. 2019

J. High Energ. Phys.

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“…• Scalar: The addition of a new scalar shifts Higgs boson couplings away from SM predictions, as well as contributing to new loop contributions to EW precision parameters. Additionally, many searches have been performed for new scalar production at the LHC [62][63][64][65][66][67][68] as well as at LEP [69][70][71]. However, the most stringent constraints [72] come from precision measurements of the observed M 1 = 125 GeV Higgs boson for M 1 M 2 650 GeV and precision W -mass constraints [51,52,73] for 650 GeV M 2 1 TeV.…”

Section: A Electroweak Precision and Direct Searchesmentioning

confidence: 99%

Searching for dark photons with maverick top partners

et al. 2020

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In this paper, we present a model in which an up-type vector-like quark (VLQ) is charged under a new U (1) d gauge force which kinetically mixes with the SM hypercharge. The gauge boson of the U (1) d is the dark photon, γ d . Traditional searches for VLQs rely on decays into Standard Model electroweak bosons W, Z or Higgs. However, since no evidence for VLQs has been found at the Large Hadron Collider (LHC), it is imperative to search for other novel signatures of VLQs beyond their traditional decays. As we will show, if the dark photon is much less massive than the Standard Model electroweak sector, M γ d M Z , for the large majority of the allowed parameter space the VLQ predominately decays into the dark photon and the dark Higgs that breaks the U (1) d . That is, this VLQ is a "maverick top partner" with nontraditional decays.One of the appeals of this scenario is that pair production of the VLQ at the LHC occurs through the strong force and the rate is determined by the gauge structure. Hence, the production of the dark photon at the LHC only depends on the strong force and is largely independent of the small kinetic mixing with hypercharge. This scenario provides a robust framework to search for a light dark sector via searches for heavy colored particles at the LHC.Some of the most important searches for Beyond the Standard Model (BSM) physics at the Large Hadron Collider (LHC) are searches for new vector like quarks (VLQs). Up-type VLQs, so-called top partners T , are ubiquitous in composite [1][2][3][4][5][6][7] and Little Higgs [8][9][10][11][12][13][14][15] models where new fermionic top partners help solve the hierarchy problem. Traditionally, searches for VLQs rely on decays into the Standard Model (SM) electroweak (EW) bosons: W/Z/Higgs. However, there is a a class of "maverick top partners" with non-traditional decays into photons [16][17][18][19][20][21], gluons [16][17][18][19][20][21], new scalars [22][23][24][25], etc. These new decays can easily be dominant with minor tweaks to the simplest VLQ models. We consider a VLQ that is charged under both the SM and a new abelian gauge symmetry U (1) d , where the SM is neutral under the U (1) d . As we will show, for a very large range of parameter space, this opens new dominant decays of VLQs that have not yet been searched for.This new U (1) d can be motivated by noting that dark matter may very well have selfinteractions through this new force. The U (1) d gauge boson, the so-called dark photon, kinetically mixes with the SM hypercharge through a renormalizable interaction [26][27][28]. This kinetic mixing can be generated via new vector like fermions charged under both the SM and the new U (1) d [26,29,30], as considered here. In the limit that the dark photon is much less massive than the Z and the kinetic mixing is small, the dark photon inherits couplings to SM particles of the form ε J µ EM , where J µ EM is the electromagnetic current and ε is the kinetic mixing parameter. Hence, the name dark photon. Most of the searches for the dark photon...

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“…In these models it becomes essential to include loop effects, which may reintroduce spin-independent interactions and thereby substantially boost the expected event rates [13][14][15][16][17][18][19]. Particular attention has been paid to models in which DM scattering is mediated by a pseudoscalar exchange particle [19][20][21][22][23], motivated partially by the interesting implications for collider [24][25][26][27][28][29][30][31][32][33] and flavour [34][35][36][37][38][39] physics. At leading order the resulting interactions are so strongly suppressed in the non-relativistic limit that they are well below the "neutrino floor" which indicates the ultimate reach of direct detection experiments [40].…”

Section: Introductionmentioning

confidence: 99%

Loop-induced direct detection signatures from CP-violating scalar mediators

Ertas

Kahlhoefer

2019

J. High Energ. Phys.

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We investigate direct detection signatures of dark matter particles interacting with quarks via a light spin-0 mediator with general CP phases. Since tree-level scattering may be strongly suppressed in the non-relativistic limit, loop contributions play an important role and can lead to observable signals in near-future experiments. We study the phenomenology of different mediator masses and CP phases with an emphasis on scenarios with maximal CP violation and Higgs portal models. Intriguingly, the sum of the rates obtained at tree-and loop-level can give a characteristic recoil spectrum not obtainable from a single type of interaction. We furthermore develop a novel method for decomposing the two-loop contribution to effective interactions between dark matter and gluons into two separate one-loop diagrams, which in our case substantially simplifies the calculation of the important top-quark contribution.

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Collider constraints on light pseudoscalars

Cited by 56 publications

References 71 publications

Light hidden mesons through the Z portal

Light hidden mesons through the Z portal

Searching for dark photons with maverick top partners

Loop-induced direct detection signatures from CP-violating scalar mediators

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