Coloured coannihilations: dark matter phenomenology meets non-relativistic EFTs

Biondini, Simone

doi:10.1007/jhep02(2019)016

Cited by 46 publications

(51 citation statements)

References 93 publications

(204 reference statements)

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“…[29][30][31], where radiative capture processes were neglected, and subsequently in ref. [32] which incorporated BSF via gluon emission. Recently, ref.…”

Section: )mentioning

confidence: 99%

Higgs-mediated bound states in dark-matter models

Harz

Petraki

2019

J. High Energ. Phys.

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It has been recently demonstrated that the 125 GeV Higgs boson can mediate a long-range force between TeV-scale particles, that can impact considerably their annihilation due to the Sommerfeld effect, and hence the density of thermal relic dark matter. In the presence of long-range interactions, the formation and decay of particle-antiparticle bound states can also deplete dark matter significantly. We consider the Higgs boson as mediator in the formation of bound states, and compute the effect on the dark matter abundance. To this end, we consider a simplified model in which dark matter co-annihilates with coloured particles that have a sizeable coupling to the Higgs. The Higgs-mediated force affects the dark matter depletion via bound state formation in several ways. It enhances the capture cross-sections due to the attraction it mediates between the incoming particles, it increases the binding energy of the bound states, hence rendering their ionisation inefficient sooner in the early universe, and for large enough couplings, it can overcome the gluon repulsion of certain colour representations and give rise to additional bound states. Because it alters the momentum exchange in the bound states, the Higgs-mediated force also affects the gluon-mediated potential via the running of the strong coupling. We comment on the experimental implications and conclude that the Higgs-mediated potential must be taken into account when circumscribing the viable parameter space of related models.

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“…[29][30][31], where radiative capture processes were neglected, and subsequently in ref. [32] which incorporated BSF via gluon emission. Recently, ref.…”

Section: )mentioning

confidence: 99%

Higgs-mediated bound states in dark-matter models

Harz

Petraki

2019

J. High Energ. Phys.

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“…[14, 15] for reviews).Recently, we have developed a framework which permits to estimate the thermally averaged pair annihilation rate, including bound-state effects, beyond perturbation theory [16]. The framework can be applied to a number of cosmological models [17], particularly the prototypical framework mentioned above [18,19], where bound-state effects have been seen to be important from other considerations as well [20][21][22][23].The purpose of the present work is to extend ref.[16] from the s-wave to the p-wave case. Even if the p-wave contribution is suppressed by v 2 , its "standard" Sommerfeld enhancement is larger than for s-wave [24,25].…”

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confidence: 99%

Studies of a thermally averaged p-wave Sommerfeld factor

Kim

Laine

2019

Physics Letters B

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Thermal pair annihilation of heavy particles, such as dark matter or its co-annihilation partners, can be strongly influenced by attractive interactions. We investigate the case that pair annihilation proceeds through a velocity-suppressed p-wave operator, in the presence of an SU(3) gauge force. Making use of a non-relativistic effective theory, the thermal average of the pair-annihilation rate is estimated both through a resummed perturbative computation and through lattice simulation, in the range M/T ∼ 10...30. Bound states contribute to the annihilation process and enhancement factors of up to ∼ 100 can be found.Inelastic processes between a dilute ensemble of heavy particles moving slowly in a thermal environment are encountered in many physical situations. A classic example is given by nuclear reactions taking place within the electromagnetic plasma of stars [1]. In particle physics, we may consider heavy dark matter particles pair-annihilating into Standard Model particles in the early universe, or a heavy quark and anti-quark pair-annihilating into light quarks and gluons in a quark-gluon plasma generated in heavy ion collision experiments.The theoretical treatment of slow annihilation processes is facilitated by noting that the average kinetic energy of the annihilating particles is small compared with their rest mass, M v 2 ∼ T ≪ M . Such a scale separation permits for a factorized description of annihilation processes in terms of a series of long-distance matrix elements times short-distance Wilson coefficients [2]. In particular, the thermal average of an annihilation rate can be expanded as σv = a + b v 2 + · · · , where v denotes the relative velocity. The term a is said to originate from "s-wave" matrix elements, whereas b may be associated with "p-wave" ones.In the presence of long-range interactions, the coefficients a and b may get large corrections compared with a tree-level treatment. For scattering states, this is known as the "Sommerfeld (-Gamow-Sakharov) effect" [3][4][5][6]. Sommerfeld factors are nowadays routinely included in Boltzmann equations for dark matter pair annihilation (cf., e.g., refs. [7][8][9][10][11]).Long-range interactions may also lead to the appearance of bound states in the dark sector, which opens up a fast pair-annihilation channel (cf., e.g., refs. [12, 13]). Bound states are particularly important if the dark sector contains particles charged under QCD, as is the case for instance in a prototypical model in which dark matter is a singlet Majorana fermion and the mediator is a slightly heavier strongly coupled scalar (cf. refs. [14, 15] for reviews).Recently, we have developed a framework which permits to estimate the thermally averaged pair annihilation rate, including bound-state effects, beyond perturbation theory [16]. The framework can be applied to a number of cosmological models [17], particularly the prototypical framework mentioned above [18,19], where bound-state effects have been seen to be important from other considerations as well [20][21][22][23].Th...

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“…where 20) and the latter has to be understood as HTL resummed if the temperature has been integrated out before the scale M F v. Then [34]…”

Section: Thermal Potentials and Pnreftsmentioning

confidence: 99%

“…m DM ≥ 500 GeV, we do not discuss it further. For a more detailed discussion of indirect detection in coannihilation scenarios see for example [20].…”

Section: Phenomenologymentioning

confidence: 99%

Scalar dark matter coannihilating with a coloured fermion

Biondini

2019

J. High Energ. Phys.

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We analyze the phenomenology of a simplified model for a real scalar dark matter candidate interacting with quarks via a coloured fermionic mediator. In the coannihilation regime, the dark matter abundance is controlled by the dynamics of the coloured fermions which can be significantly affected by non-perturbative effects. We employ a non-relativistic effective field theory which allows us to systematically treat the Sommerfeld effect and bound state formation in the early Universe. The parameter space compatible with the dark matter relic abundance is confronted with direct, indirect and collider searches. A substantial part of the parameter space, with dark matter masses up to 18 TeV, is already excluded by XENON1T. Most of the remaining thermal relics can be probed by a future Darwin-like experiments, when taking properly into account the running of the relevant couplings for the direct detection processes.

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Coloured coannihilations: dark matter phenomenology meets non-relativistic EFTs

Cited by 46 publications

References 93 publications

Higgs-mediated bound states in dark-matter models

Higgs-mediated bound states in dark-matter models

Studies of a thermally averaged p-wave Sommerfeld factor

Scalar dark matter coannihilating with a coloured fermion

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