Limits from BBN on light electromagnetic decays

Forestell, Lindsay; Morrissey, David E.; White, Graham

doi:10.1007/jhep01(2019)074

Cited by 67 publications

(101 citation statements)

References 84 publications

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“…Another assumption in order to derive these bounds is that the baryon-to-photon ratio remains constant between the end of BBN and recombination. This is well justified on the basis that late time electromagnetic energy injections are strongly constrained by BBN [157][158][159] and CMB spectral distortions [160,161].…”

Section: Vii2 Modified Cosmological Historiesmentioning

confidence: 97%

Refined bounds on MeV-scale thermal dark sectors from BBN and the CMB

Sabti

Alvey

Escudero

et al. 2020

J. Cosmol. Astropart. Phys.

182

174

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New light states thermally coupled to the Standard Model plasma alter the expansion history of the Universe and impact the synthesis of the primordial light elements. In this work, we carry out an exhaustive and precise analysis of the implications of MeV-scale BSM particles in Big Bang Nucleosynthesis (BBN) and for Cosmic Microwave Background (CMB) observations. We find that BBN observations set a lower bound on the thermal dark matter mass of mχ > 0.4 MeV at 2σ. This bound is independent of the spin and number of internal degrees of freedom of the particle, of the annihilation being s-wave or p-wave, and of the annihilation final state. Furthermore, we show that current BBN plus CMB observations constrain purely electrophilic and neutrinophilic BSM species to have a mass, mχ > 3.7 MeV at 2σ. We explore the reach of future BBN measurements and show that upcoming CMB missions should improve the bounds on light BSM thermal states to mχ > (10 − 15) MeV. Finally, we demonstrate that very light BSM species thermally coupled to the SM plasma are highly disfavoured by current cosmological observations. S nashwan.sabti@kcl.ac.uk

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Section: Vii2 Modified Cosmological Historiesmentioning

confidence: 97%

Refined bounds on MeV-scale thermal dark sectors from BBN and the CMB

Sabti

Alvey

Escudero

et al. 2020

J. Cosmol. Astropart. Phys.

182

174

View full text Add to dashboard Cite

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“…• For m S < 2m e , the scalar S can decay only into photons, which leads to a drastically increased lifetime. Consequently, for comparably small values of sin θ, the mediator outlives the creation of the light elements, thereby acting as an additional relativistic degree of freedom, whose presence can be robustly excluded by current BBN constraints (even stronger constraints in the case of such late decays arise from photodisintegration of light elements [105,111,112] and the CMB [113]). For very large values of sin θ, on the other hand, S again decays during BBN -but since this case is strongly excluded by other considerations, c.f.…”

Section: Big Bang Nucleosynthesismentioning

confidence: 99%

Direct detection and complementary constraints for sub-GeV dark matter

Bondarenko

Boyarsky

Bringmann

et al. 2020

J. High Energ. Phys.

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Traditional direct searches for dark matter, looking for nuclear recoils in deep underground detectors, are challenged by an almost complete loss of sensitivity for light dark matter particles. Consequently, there is a significant effort in the community to devise new methods and experiments to overcome these difficulties, constantly pushing the limits of the lowest dark matter mass that can be probed this way. From a model-building perspective, the scattering of sub-GeV dark matter on nucleons essentially must proceed via new light mediator particles, given that collider searches place extremely stringent bounds on contact-type interactions. Here we present an updated compilation of relevant limits for the case of a scalar mediator, including a new estimate of the near-future sensitivity of the NA62 experiment as well as a detailed evaluation of limits from Big Bang nucleosynthesis. We also derive updated and more general limits on DM particles upscattered by cosmic rays, applicable to arbitrary energy-and momentum dependences of the scattering cross section. Finally we stress that dark matter self-interactions place stringent limits independently of the dark matter production mechanism. These are, for the relevant parameter space, generically comparable to those that apply in the commonly studied freeze-out case. We conclude that the combination of existing (or expected) constraints from accelerators and astrophysics, combined with cosmological requirements, puts robust limits on the maximally possible nuclear scattering rate. In most regions of parameter space these are at least competitive with the best projected limits from currently planned direct detection experiments.arXiv:1909.08632v2 [hep-ph]

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“…Energetic photons in the electromagnetic cascades triggered by the injection of high energy particles can photo-dissociate light elements produced by BBN, changing their abundances. BBN can constrain energy injection upto very high redshifts, until the pair production threshold on CMB photons becomes comparable to photo-dissociation thresholds for helium-4, deuterium and helium-3 [13][14][15]. Once the pair-production on CMB photons becomes important, the fraction of injected energy going into destruction of elements drops and BBN constraints on energy injection become weak.…”

Section: Introductionmentioning

confidence: 99%

CMB spectral distortions constraints on primordial black holes, cosmic strings and long lived unstable particles revisited

Acharya

Khatri

2020

J. Cosmol. Astropart. Phys.

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We calculate the spectral distortions from Hawking evaporation of primordial black holes before the epoch of recombination, taking into account emission of all standard model particles, including quark and gluons, and evolving the resulting particle cascades in the expanding Universe. We show that the constraints on the abundance of primordial black holes are stronger by more than an order of magnitude compared to the previous calculations which take only the primary photon emission into account. We also show that the shapes of the spectral distortions is different from the y or i-type distortions and are sensitive to the mass of the primordial black holes. We also extend previous constraints on the decay of long lived unstable particles before recombination to additional decay channels. We show that for dark matter mass 1 GeV, the spectral distortion shape is a function of the dark matter mass as well as the decay channel to standard model particles. We also provide new spectral distortion constraints on superconducting cosmic string decay. We explicitly show that consideration of emitted photon spectrum from string decay is not only important for the future experiments but also for already available COBE-FIRAS data.

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Limits from BBN on light electromagnetic decays

Cited by 67 publications

References 84 publications

Refined bounds on MeV-scale thermal dark sectors from BBN and the CMB

Refined bounds on MeV-scale thermal dark sectors from BBN and the CMB

Direct detection and complementary constraints for sub-GeV dark matter

CMB spectral distortions constraints on primordial black holes, cosmic strings and long lived unstable particles revisited

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