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Title: Finding the Axion: The Search for the Dark Matter of the Universe

Abstract

The nature of dark matter has been a mystery for over 70 years. One plausible candidate is the axion, an extremely light and weakly interacting particle, which results from the Peccei-Quinn solution to the strong CP problem. In this proceedings I will briefly review the evidence for dark matter as well as the motivation for the existence of the axion as a prime dark matter candidate. I will then discuss the experimental methods to search for axion dark matter focusing on a sensitive cavity experiment (ADMX) being run at Lawrence Livermore National Laboratory.

Authors:
 [1]
  1. LLNL, L-270, 7000 East Ave, Livermore, CA, 94550 (United States)
Publication Date:
OSTI Identifier:
21057151
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 899; Journal Issue: 1; Conference: 6. international conference of the Balkan Physical Union, Istanbul (Turkey), 22-26 Aug 2006; Other Information: DOI: 10.1063/1.2733035; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; AXIONS; COSMOLOGY; CP INVARIANCE; LAWRENCE LIVERMORE NATIONAL LABORATORY; NONLUMINOUS MATTER; PARTICLE IDENTIFICATION; REVIEWS; UNIVERSE

Citation Formats

Carosi, G. Finding the Axion: The Search for the Dark Matter of the Universe. United States: N. p., 2007. Web. doi:10.1063/1.2733035.
Carosi, G. Finding the Axion: The Search for the Dark Matter of the Universe. United States. doi:10.1063/1.2733035.
Carosi, G. Mon . "Finding the Axion: The Search for the Dark Matter of the Universe". United States. doi:10.1063/1.2733035.
@article{osti_21057151,
title = {Finding the Axion: The Search for the Dark Matter of the Universe},
author = {Carosi, G.},
abstractNote = {The nature of dark matter has been a mystery for over 70 years. One plausible candidate is the axion, an extremely light and weakly interacting particle, which results from the Peccei-Quinn solution to the strong CP problem. In this proceedings I will briefly review the evidence for dark matter as well as the motivation for the existence of the axion as a prime dark matter candidate. I will then discuss the experimental methods to search for axion dark matter focusing on a sensitive cavity experiment (ADMX) being run at Lawrence Livermore National Laboratory.},
doi = {10.1063/1.2733035},
journal = {AIP Conference Proceedings},
number = 1,
volume = 899,
place = {United States},
year = {Mon Apr 23 00:00:00 EDT 2007},
month = {Mon Apr 23 00:00:00 EDT 2007}
}
  • The nature of dark matter has been a mystery for over 70 years. One plausible candidate is the axion, an extremely light and weakly interacting particle, which results from the Peccei-Quinn solution to the strong CP problem. In this proceedings I will briefly review the evidence for dark matter as well as the motivation for the existence of the axion as a prime dark matter candidate. I will then discuss the experimental methods to search for axion dark matter focusing on a sensitive cavity experiment (ADMX) being run at Lawrence Livermore National Laboratory.
  • This Letter reports the results from a haloscope search for dark matter axions with masses between 2.66 and 2.81 μ eV . The search excludes the range of axion-photon couplings predicted by plausible models of the invisible axion. This unprecedented sensitivity is achieved by operating a large-volume haloscope at subkelvin temperatures, thereby reducing thermal noise as well as the excess noise from the ultralow-noise superconducting quantum interference device amplifier used for the signal power readout. Finally, ongoing searches will provide nearly definitive tests of the invisible axion model over a wide range of axion masses.
  • This Letter reports the results from a haloscope search for dark matter axions with masses between 2.66 and 2.81 μ eV . The search excludes the range of axion-photon couplings predicted by plausible models of the invisible axion. This unprecedented sensitivity is achieved by operating a large-volume haloscope at subkelvin temperatures, thereby reducing thermal noise as well as the excess noise from the ultralow-noise superconducting quantum interference device amplifier used for the signal power readout. Finally, ongoing searches will provide nearly definitive tests of the invisible axion model over a wide range of axion masses.
  • We calculate the relic abundance of mixed axion/neutralino cold dark matter which arises in R-parity conserving supersymmetric (SUSY) models wherein the strong CP problem is solved by the Peccei-Quinn (PQ) mechanism with a concommitant axion/saxion/axino supermultiplet. By numerically solving the coupled Boltzmann equations, we include the combined effects of 1. thermal axino production with cascade decays to a neutralino LSP, 2. thermal saxion production and production via coherent oscillations along with cascade decays and entropy injection, 3. thermal neutralino production and re-annihilation after both axino and saxion decays, 4. gravitino production and decay and 5. axion production both thermally andmore » via oscillations. For SUSY models with too high a standard neutralino thermal abundance, we find the combined effect of SUSY PQ particles is not enough to lower the neutralino abundance down to its measured value, while at the same time respecting bounds on late-decaying neutral particles from BBN. However, models with a standard neutralino underabundance can now be allowed with either neutralino or axion domination of dark matter, and furthermore, these models can allow the PQ breaking scale f{sub a} to be pushed up into the 10{sup 14}−10{sup 15} GeV range, which is where it is typically expected to be in string theory models.« less
  • This talk reviews the original motivation for the axion as a solution to the strong CP problem and the constraints that have been placed on the axion by experimental searches and by astrophysical and cosmological considerations. As a result of the bounds, the axion mass is presently restricted to a window extending from about 10{sup {minus}2}&hthinsp;eV to about 10{sup {minus}6}&hthinsp;eV. In this window, axions are a form of cold dark matter. It is possible to detect galactic halo axions by stimulating their conversion to photons in a laboratory magnetic field. I{close_quote}ll report on two experiments of this type, one atmore » Lawrence Livermore National Laboratory and the other at Kyoto University. I{close_quote}ll also discuss what can be learned about the structure of our galactic halo if a signal is found. {copyright} {ital 1998 American Institute of Physics.}« less