Sommerfeld enhancement from multiple mediators

McDonald, Kristian L.

doi:10.1007/jhep07(2012)145

Cited by 10 publications

(9 citation statements)

References 60 publications

(82 reference statements)

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“…Notice that this decay width goes to zero when d → 2; in this limit the mixing is with a free particle, and the spectral function has no overlap with the Z mass. Comparing equations (41) and (42) gives us a bound on the largest allowed mixing for any model. We plot this bound in Fig.…”

Section: Constraint From Exotic Z Decaysmentioning

confidence: 99%

“…An unusual velocity dependence of dark matter annihilation from the Sommerfeld effect due to exchange of a continuum of states was explored in [37]; related work neglecting the Sommerfeld effect appeared in [38]. Finally, a related scenario involving a Randall-Sundrum realization of a tower of light mediators was studied in [39][40][41][42][43].…”

Section: Introductionmentioning

confidence: 99%

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Continuum-mediated dark matter–baryon scattering

Katz

Reece

Sajjad

2016

Physics of the Dark Universe

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Many models of dark matter scattering with baryons may be treated either as a simple contact interaction or as the exchange of a light mediator particle. We study an alternative, in which a continuum of light mediator states may be exchanged. This could arise, for instance, from coupling to a sector which is approximately conformal at the relevant momentum transfer scale. In the non-relativistic effective theory of dark matter-baryon scattering, which is useful for parametrizing direct detection signals, the effect of such continuum mediators is to multiply the amplitude by a function of the momentum transfer q, which in the simplest case is just a power law. We develop the basic framework and study two examples: the case where the mediator is a scalar operator coupling to the Higgs portal (which turns out to be highly constrained) and the case of an antisymmetric tensor operator O µν that mixes with the hypercharge field strength and couples to dark matter tensor currents, which has an interesting viable parameter space. We describe the effect of such mediators on the cross sections and recoil energy spectra that could be observed in direct detection.

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Section: Constraint From Exotic Z Decaysmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Continuum-mediated dark matter–baryon scattering

Katz

Reece

Sajjad

2016

Physics of the Dark Universe

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“…Refs. [22,25,26,32,38,44,[48][49][50][51][52][53][54]) in light of the cosmic-ray positron/electron excesses reported by PAMELA [3], ATIC [6], and Fermi-LAT [7] etc..…”

Section: Introductionmentioning

confidence: 99%

Sommerfeld enhancements with vector, scalar, and pseudoscalar force carriers

Liu

Zhou

2013

Phys. Rev. D

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The first AMS-02 measurement confirms the existence of an excess in the cosmic-ray positron fraction previously reported by the PAMELA and Fermi-LAT experiments. If interpreted in terms of thermal dark matter (DM) annihilation, the AMS-02 result still suggests that the DM annihilation cross section in the present day should be significantly larger than that at freeze out. The Sommerfeld enhancement of DM annihilation cross section is a possible explanation, which is however subject to the constraints from DM thermal relic density, mainly due to the annihilation of DM particles into force-carrier particles introduced by the mechanism. We show that the effects of the Sommerfeld enhancement and the relic density constraints depend significantly on the nature of the force-carrier. Three scenarios where the force-carrier is a vector boson, scalar and pseudoscalar particle are investigated and compared. The results show that for the case with vector force-carrier, the Sommerfeld enhancement can marginally account for the AMS-02 data for DM particle annihilating into 2µ final states, while for scalar force-carrier the allowed Sommerfeld enhancement factor can be larger by a factor of two. For the case with a pesudoscalar force-carrier, the Sommerfeld enhancement factor can be very large in the resonance region, and it is possible to accommodate the AMS-02 and Fermi-LAT result for a variety of DM annihilation final states. *

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“…Sommerfeld effect induces further nontrivial velocitydependence of the annihilation rate [9,10]. Long-range interactions of DM distort the wave-functions of incoming particles and change the annihilation rate, σv → S σv , by the velocity-dependent Sommerfeld factor S. This effect has been studied extensively in recent years [11][12][13][14][15][16][17][18][19][20], after it was initially invoked [21][22][23] to explain the cosmicray positron excesses [24,25] using a large DM annihilation rate. As this enhancement occurs for small v, again models with dominantly s-wave annihilations are popular.…”

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confidence: 99%

Selection Rule for Enhanced Dark Matter Annihilation

Das

Dasgupta

2017

Phys. Rev. Lett.

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We point out a selection rule for enhancement (suppression) of odd (even) partial waves of dark matter coannihilation or annihilation using Sommerfeld effect. Using this, the usually velocitysuppressed p-wave annihilation can dominate the annihilation signals in the present Universe. The selection mechanism is a manifestation of the exchange symmetry of identical incoming particles, and generic for multi-state DM with off-diagonal long-range interactions. As a consequence, the relic and late-time annihilation rates are parametrically different and a distinctive phenomenology, with large but strongly velocity-dependent annihilation rates, is predicted.PACS numbers: 95.35.+d 1. Introduction.-If DM is a thermal relic of the early Universe, then its cosmological abundance provides a measure of its "annihilation rate" σv [1][2][3]. This annihilation rate has contributions from various partial waves of the scattering amplitude, each with its characteristic dependence on the relative velocity v of the colliding particles,

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Sommerfeld enhancement from multiple mediators

Cited by 10 publications

References 60 publications

Continuum-mediated dark matter–baryon scattering

Continuum-mediated dark matter–baryon scattering

Sommerfeld enhancements with vector, scalar, and pseudoscalar force carriers

Selection Rule for Enhanced Dark Matter Annihilation

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