Dark Matter abundance via thermal decays and leptoquark mediators

Belfatto, Benedetta; Buttazzo, Dario; Groß, Christian; Panci, Paolo; Струмиа, Алессандро; Vignaroli, Natascia; Vittorio, Ludovico; Watanabe, Ryoutaro

doi:10.1007/jhep06(2022)084

Cited by 6 publications

(2 citation statements)

References 64 publications

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“…A left-handed fermion mediator singlet can also couple to right-handed quarks. For instance, the down-quark singlet d R couples to ψ L with a leptoquark scalar ϕ [85][86][87][88][89]: y ψ,i di,R ψ L ϕ + h.c. , (6.10) where the scalar ϕ is now an SU(3) c triplet and SU(2) L singlet, carrying the hypercharge Y = −1/3 so that ψ is a SM singlet. The thermal mass in this case is given by m 2 ψ (T ) = where the factor of 3 accounts for the color degrees of freedom.…”

Section: Left-handed Fermion Mediatormentioning

confidence: 99%

Dark matter freeze-in via a light fermion mediator: forbidden decay and scattering

2023

J. Cosmol. Astropart. Phys.

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The connection between a hidden nonthermal sector and a thermal plasma can be established by a light thermal fermion mediator. When the fermion mediator is much lighter than the hidden species, kinematically forbidden decay of the mediator can be opened at finite temperatures to produce the hidden species. Unlike bosons having quartic couplings, renormalizable forbidden fermion decay generically shares the same order of couplings with the scattering. We present a dedicated investigation into the freeze-in dark matter production via a thermal fermion mediator. We demonstrate that the plasma-induced decay rate differs from that calculated via the tree-level amplitude, but the former can be obtained from the latter via constant rescaling. Furthermore, we find that the relative effect of the forbidden decay and the scattering on the dark matter relic density can be simply estimated via the thermal coupling between the plasma and the mediator. Applying to different thermal interactions, we show that the forbidden decay contribution can reach the level of 4%- 45% for a thermal coupling at 0.1- 1.

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Section: Left-handed Fermion Mediatormentioning

confidence: 99%

Dark matter freeze-in via a light fermion mediator: forbidden decay and scattering

2023

J. Cosmol. Astropart. Phys.

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“…For the freeze-in mechanism, in which the coupling with the SM plasma is feeble and therefore the dark matter is never in thermal equilibrium, the dark matter density, starting from zero or very small values, slowly grows up to the point it gets frozen-in at its cosmological abundance. Models of this type have a dark matter candidate in the BSM sector featuring also a vector LQ addressing the anomalies [197]. Here the dark matter state is a light (order JHEP08(2022)125 10 KeVs) right-handed neutrino, produced via freeze-in through its interactions with the massive (order TeVs) LQ.…”

Section: Dark Side Of the Anomaliesmentioning

confidence: 99%

Standard model anomalies: lepton flavour non-universality, g − 2 and W-mass

d'Alise

Nardo

Grazia

et al. 2022

J. High Energ. Phys.

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We critically analyze the body of results that hints to the existence of New Physics from possible violations of lepton universality observed by the LHCb experiment in the μ/e ratios RK and $$ {R}_{K^{\ast }} $$ R K ∗ to the g − 2 lepton anomalies. The analysis begins with a theoretical, in depth, study of the μ/e ratios RK and $$ {R}_{K^{\ast }} $$ R K ∗ as well as the process Bs→ μ+μ−. Here we consider the impact of complex Wilson coefficients and derive constraints on their imaginary and real parts. We then move to a comprehensive comparison with experimental results. We show that, by fitting a single Wilson coefficient, the deviations from the Standard Model are at the 4.7σ level when including only the hadronic insensitive observables while it increases to 6.1σ when including also the hadronic sensitive ones. When switching on all relevant Wilson coefficients and combining both hadronic sensitive and insensitive data into the fit, the deviation from the Standard Model peaks at 7.2σ and decreases at the 4.9σ level if we assume that the central values of RK and $$ {R}_K^{\ast } $$ R K ∗ are taken to be unity. We further estimate other unaccounted for SM contributions and show that their inclusion still requires New Physics to fit the data. We then introduce the g − 2 lepton anomalies as well as the most recent W-mass results. Different theoretical models are considered that can explain the discrepancies from the Standard Model. In the final part of our work we estimate the impact of the forthcoming data from LHCb (coming from LHC Run3) and Belle II, when it will have accumulated about 5 ab−1.

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Drell-Yan production in third-generation gauge vector leptoquark models at NLO+PS in QCD

Haisch

Schnell

Schulte

2023

J. High Energ. Phys.

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Motivated by the long-standing hints of lepton-flavour non-universality in the b → cℓν and b → sℓ+ℓ− channels, we study Drell-Yan ditau production at the Large Hadron Collider (LHC). In the context of models with third-generation gauge vector leptoquarks (LQs), we calculate the complete $$ \mathcal{O} $$ O (αs) corrections to the pp → τ+τ− process, achieving next-to-leading order (NLO) plus parton shower (NLO+PS) accuracy using the POWHEG method. We provide a dedicated Monte Carlo code that evaluates the NLO QCD corrections on-the-fly in the event generation and use it to study the numerical impact of NLO+PS corrections on the kinematic distributions that enter the existing experimental searches for non-resonant ditau final states. Based on our phenomenological analysis we derive NLO accurate constraints on the masses and couplings of third-generation gauge vector LQs using the latest LHC ditau search results corresponding to an integrated luminosity of around 140 fb−1 of proton-proton collisions at $$ \sqrt{s} $$ s = 13 TeV. The presented NLO+PS generator allows for an improved signal modelling, making it an essential tool for future ATLAS and CMS searches for vector LQs in τ+τ− final states at LHC Run III and beyond.

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Dark Matter abundance via thermal decays and leptoquark mediators

Cited by 6 publications

References 64 publications

Dark matter freeze-in via a light fermion mediator: forbidden decay and scattering

Dark matter freeze-in via a light fermion mediator: forbidden decay and scattering

Standard model anomalies: lepton flavour non-universality, g − 2 and W-mass

Drell-Yan production in third-generation gauge vector leptoquark models at NLO+PS in QCD

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