Pico-charged particles explaining 511 keV line and XENON1T signal

Farzan, Yasaman; Rajaee, Meshkat

doi:10.48550/arxiv.2007.14421

Cited by 2 publications

(2 citation statements)

References 35 publications

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“…Intriguingly, the XENON1T collaboration recently reported an excess of events consistent with electron recoils with an energy deposition of (2 − 3) keV [20]. This may be consistent with a variety of recently proposed new physics models, all of which invoke a substantial flux of particles that feebly interact with normal matter (e.g., dark photons [21,22], neutrinos and dark radiation [23][24][25][26][27], and exothermic DM [23,[28][29][30]). In this Letter, we find that the observed rate at XENON1T may be explained as a result of a strongly-coupled particle that makes up an extremely small fraction f χ of the galactic DM density.…”

supporting

confidence: 72%

Low-Energy Signals from the Formation of Dark Matter-Nuclear Bound States

Berlin¹,

Liu²,

Pospelov³

et al. 2021

Preprint

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Dark matter particles may bind with nuclei if there exists an attractive force of sufficient strength. We show that a dark photon mediator of mass ∼ (10−100) MeV that kinetically mixes with Standard Model electromagnetism at the level of ∼ 10 −3 generates keV-scale binding energies between dark matter and heavy elements, while forbidding the ability to bind with light elements. In underground direct detection experiments, the formation of such bound states liberates keV-scale energy in the form of electrons and photons, giving rise to mono-energetic electronic signals with a time-structure that may contain daily and seasonal modulations. We show that data from liquid-xenon detectors provides exquisite sensitivity to this scenario, constraining the galactic abundance of such dark particles to be at most ∼ 10 −18 − 10 −12 of the galactic dark matter density for masses spanning ∼ (1 − 10 5 ) GeV. However, an exponentially small fractional abundance of these dark particles is enough to explain the observed electron recoil excess at XENON1T.

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supporting

confidence: 72%

Low-Energy Signals from the Formation of Dark Matter-Nuclear Bound States

Berlin¹,

Liu²,

Pospelov³

et al. 2021

Preprint

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“…The long list of candidates has been proposed. It includes radioactive decay of unstable isotopes produced in nucleosynthesis sources throughout the Galaxy [9], accreting binary systems (microquasars) [10], old neutron stars (former pulsars) [11], various sources inside the supermassive black hole in our Galaxy's center [12,13,10], dark matter decay or annihilation [14,13], as dark matter would be gravitationally concentrated in the inner Galaxy etc. Quantitative estimates of their contributions leave considerable uncertainties.…”

Section: Sources Of Positrons and Positroniamentioning

confidence: 99%

Positronia' clouds in Universe

Dremin¹

2021

Preprint

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The intense emission of 511 keV photons from the Galactic center and within terrestrial thunderstorms is attributed to the formation of parapositronia' clouds. Unbound electron-positron pairs and positronia can be created by strong electromagnetic fields produced in interactions of electrically charged objects, in particular, in collisions of heavy nuclei. Kinematics of this process favours abundant creation of the unbound electron-positron pairs with very small masses and the confined parapositronia states which decay directly to two 511 keV quanta. Therefore we propose to consider interactions of electromagnetic fields of colliding heavy ions as a source of low-mass pairs which can transform to 511 keV quanta. Intensity of their creation is enlarged by the factor Z 4 (Z is the electric charge of a heavy ion) compared to protons with Z=1. These processes are especially important at very high energies of nuclear collisions because their cross sections increase proportionally to cube of the logarithm of energy and can even exceed the cross sections of strong interactions which may not increase faster than the squared logarithm of energy. Moreover, production of extremely low-mass e + e − -pairs in ultraperipheral nuclear collisions is strongly enhanced due to the Sommerfeld-Gamow-Sakharov (SGS) factor which accounts for mutual Coulomb attraction of non-relativistic electrons to positrons in case of low pair-masses. This attraction may lead to their annihilation and, therefore, to the increased intensity of 511 keV photons. It is proposed to confront the obtained results to forthcoming experimental data at NICA collider.

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Pico-charged particles explaining 511 keV line and XENON1T signal

Cited by 2 publications

References 35 publications

Low-Energy Signals from the Formation of Dark Matter-Nuclear Bound States

Low-Energy Signals from the Formation of Dark Matter-Nuclear Bound States

Positronia' clouds in Universe

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