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Title: Severely Constraining Dark Matter Interpretations of the 21-cm Anomaly

Abstract

The EDGES Collaboration has recently reported the detection of a stronger-than-expected absorption feature in the global 21-cm spectrum, centered at a frequency corresponding to a redshift of z ~ 17. This observation has been interpreted as evidence that the gas was cooled during this era as a result of scattering with dark matter. In this study, we explore this possibility, applying constraints from the cosmic microwave background, light element abundances, Supernova 1987A, and a variety of laboratory experiments. After taking these constraints into account, we find that the vast majority of the parameter space capable of generating the observed 21-cm signal is ruled out. The only range of models that remains viable is that in which a small fraction, ~ 0.3-2%, of the dark matter consists of particles with a mass of ~ 10-80 MeV and which couple to the photon through a small electric charge, epsilon ~ 10^{-6}-10^{-4}. Furthermore, in order to avoid being overproduced in the early universe, such models must be supplemented with an additional depletion mechanism, such as annihilations through a L_{\mu}-L_{\tau} gauge boson or annihilations to a pair of rapidly decaying hidden sector scalars.

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [2]; ORCiD logo [2]
  1. SLAC
  2. Fermilab
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
OSTI Identifier:
1458596
Alternate Identifier(s):
OSTI ID: 1437302
Report Number(s):
arXiv:1803.02804; FERMILAB-PUB-18-066-A
1658929
Grant/Contract Number:
AC02-07CH11359; DEAC02-76SF00515
Resource Type:
Journal Article: Published Article
Journal Name:
Phys.Rev.Lett.
Additional Journal Information:
Journal Volume: 121; Journal Issue: 1
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS

Citation Formats

Berlin, Asher, Hooper, Dan, Krnjaic, Gordan, and McDermott, Samuel D. Severely Constraining Dark Matter Interpretations of the 21-cm Anomaly. United States: N. p., 2018. Web. doi:10.1103/PhysRevLett.121.011102.
Berlin, Asher, Hooper, Dan, Krnjaic, Gordan, & McDermott, Samuel D. Severely Constraining Dark Matter Interpretations of the 21-cm Anomaly. United States. doi:10.1103/PhysRevLett.121.011102.
Berlin, Asher, Hooper, Dan, Krnjaic, Gordan, and McDermott, Samuel D. Tue . "Severely Constraining Dark Matter Interpretations of the 21-cm Anomaly". United States. doi:10.1103/PhysRevLett.121.011102.
@article{osti_1458596,
title = {Severely Constraining Dark Matter Interpretations of the 21-cm Anomaly},
author = {Berlin, Asher and Hooper, Dan and Krnjaic, Gordan and McDermott, Samuel D.},
abstractNote = {The EDGES Collaboration has recently reported the detection of a stronger-than-expected absorption feature in the global 21-cm spectrum, centered at a frequency corresponding to a redshift of z ~ 17. This observation has been interpreted as evidence that the gas was cooled during this era as a result of scattering with dark matter. In this study, we explore this possibility, applying constraints from the cosmic microwave background, light element abundances, Supernova 1987A, and a variety of laboratory experiments. After taking these constraints into account, we find that the vast majority of the parameter space capable of generating the observed 21-cm signal is ruled out. The only range of models that remains viable is that in which a small fraction, ~ 0.3-2%, of the dark matter consists of particles with a mass of ~ 10-80 MeV and which couple to the photon through a small electric charge, epsilon ~ 10^{-6}-10^{-4}. Furthermore, in order to avoid being overproduced in the early universe, such models must be supplemented with an additional depletion mechanism, such as annihilations through a L_{\mu}-L_{\tau} gauge boson or annihilations to a pair of rapidly decaying hidden sector scalars.},
doi = {10.1103/PhysRevLett.121.011102},
journal = {Phys.Rev.Lett.},
number = 1,
volume = 121,
place = {United States},
year = {Tue Jul 03 00:00:00 EDT 2018},
month = {Tue Jul 03 00:00:00 EDT 2018}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record at 10.1103/PhysRevLett.121.011102

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