The XENON1T collaboration has observed an excess in electronic recoil events below 5 keV over the known background, which could originate from beyond-the-standard-model physics. The solar axion is a well-motivated model that has been proposed to explain the excess, though it has tension with astrophysical observations. The axions traveling from the Sun can be absorbed by the electrons in the xenon atoms via the axion-electron coupling. Meanwhile, they can also scatter with the atoms through the inverse Primakoff process via the axion-photon coupling, which emits a photon and mimics the electronic recoil signals. We found that the latter process cannot be neglected. After including the keV photon produced via the inverse Primakoff process in the detection, the tension with the astrophysical constraints can be significantly reduced. We also explore scenarios involving additional new physics to further alleviate the tension with the astrophysical bounds.
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http://dx.doi.org/10.1103/PhysRevLett.125.131806 | DOI Listing |
Nature
November 2024
School of Physics, University of Melbourne, Parkville, Victoria, Australia.
Nature
September 2024
Steward Observatory, University of Arizona, Tucson, AZ, USA.
The first observations of the James Webb Space Telescope (JWST) have revolutionized our understanding of the Universe by identifying galaxies at redshift z ≈ 13 (refs. ). In addition, the discovery of many luminous galaxies at Cosmic Dawn (z > 10) has suggested that galaxies developed rapidly, in apparent tension with many standard models.
View Article and Find Full Text PDFSpace Sci Rev
June 2024
Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 USA.
Multiply lensed images of a same source experience a relative time delay in the arrival of photons due to the path length difference and the different gravitational potentials the photons travel through. This effect can be used to measure absolute distances and the Hubble constant ( ) and is known as time-delay cosmography. The method is independent of the local distance ladder and early-universe physics and provides a precise and competitive measurement of .
View Article and Find Full Text PDFPhys Rev Lett
May 2024
Laboratoire Univers and Particules de Montpellier, CNRS and Université de Montpellier (UMR-5299), 34095 Montpellier, France.
Phys Rev Lett
May 2024
Center for Theoretical Astrophysics, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
The disagreement in the Hubble constant measured by different cosmological probes highlights the need for a better understanding of the observations or new physics. The standard siren method, a novel approach using gravitational-wave observations to determine the distance to binary mergers, has great potential to provide an independent measurement of the Hubble constant and shed light on the tension in the next few years. To realize this goal, we must thoroughly understand the sources of potential systematic bias of standard sirens.
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