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Title: Search for pseudoscalar cold dark matter

Abstract

AH dynamical evidence points to the conclusion that the predominant form of matter in the universe is in a non-luminous form. Furthermore, large scale deviations from uniform Hubble flow, and the recent COBE reports of inhomogeneities in the cosmic microwave background strongly suggest that we live in an exactly closed universe. If this is true, then ordinary baryonic matter could only be a minority component (10% at most) of the missing mass, and that what constitutes the majority of the dark matter must involve new physics. The axion is one of very few well motivated candidates which may comprise the dark matter. Additionally it is a `cold` dark-matter candidate which is preferred by the COBE data. We propose to construct and operate an experiment to search for axions which may constitute the dark matter of our own galaxy. As proposed by Sikivie, dark-matter axions may be detected by their stimulated conversion into monochromatic microwave photons in a tunable high-Q cavity inside a strong magnetic field. Our ability to mount an experiment quickly and take data within one year is due to a confluence of three factors. The first is the availability of a compact high field superconducting magnet and amore » local industrial partner, Wang NMR, who can make a very thermally efficient and economical cryostat for it. The second is an ongoing joint venture with the Institute for Nuclear Research of the Russian Academy of Sciences to do R&D on metalized precision-formed ceramic microwave cavities for the axion search, and INR has commited to providing all the microwave cavity arrays for this experiment, should this proposal be approved. The third is a commitment of very substantial startup capital monies from MIT for all of the state-of-the-art ultra-low noise microwave electronics, to one of our outstanding young collaborators who is joining their faculty.« less

Authors:
; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab., CA (United States)
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
10182465
Report Number(s):
UCRL-ID-114915
ON: DE93019879
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 29 May 1992
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; 72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; NONLUMINOUS MATTER; AXIONS; DETECTION; PSEUDOSCALARS; MICROWAVE EQUIPMENT; COSMIC RADIATION; SUPERCONDUCTING MAGNETS; 661300; 440104; 662440; OTHER ASPECTS OF PHYSICAL SCIENCE; HIGH ENERGY PHYSICS INSTRUMENTATION; PROPERTIES OF OTHER PARTICLES INCLUDING HYPOTHETICAL PARTICLES

Citation Formats

van Bibber, K., Stoeffl, W., and LLNL Collaborators. Search for pseudoscalar cold dark matter. United States: N. p., 1992. Web. doi:10.2172/10182465.
van Bibber, K., Stoeffl, W., & LLNL Collaborators. Search for pseudoscalar cold dark matter. United States. doi:10.2172/10182465.
van Bibber, K., Stoeffl, W., and LLNL Collaborators. 1992. "Search for pseudoscalar cold dark matter". United States. doi:10.2172/10182465. https://www.osti.gov/servlets/purl/10182465.
@article{osti_10182465,
title = {Search for pseudoscalar cold dark matter},
author = {van Bibber, K. and Stoeffl, W. and LLNL Collaborators},
abstractNote = {AH dynamical evidence points to the conclusion that the predominant form of matter in the universe is in a non-luminous form. Furthermore, large scale deviations from uniform Hubble flow, and the recent COBE reports of inhomogeneities in the cosmic microwave background strongly suggest that we live in an exactly closed universe. If this is true, then ordinary baryonic matter could only be a minority component (10% at most) of the missing mass, and that what constitutes the majority of the dark matter must involve new physics. The axion is one of very few well motivated candidates which may comprise the dark matter. Additionally it is a `cold` dark-matter candidate which is preferred by the COBE data. We propose to construct and operate an experiment to search for axions which may constitute the dark matter of our own galaxy. As proposed by Sikivie, dark-matter axions may be detected by their stimulated conversion into monochromatic microwave photons in a tunable high-Q cavity inside a strong magnetic field. Our ability to mount an experiment quickly and take data within one year is due to a confluence of three factors. The first is the availability of a compact high field superconducting magnet and a local industrial partner, Wang NMR, who can make a very thermally efficient and economical cryostat for it. The second is an ongoing joint venture with the Institute for Nuclear Research of the Russian Academy of Sciences to do R&D on metalized precision-formed ceramic microwave cavities for the axion search, and INR has commited to providing all the microwave cavity arrays for this experiment, should this proposal be approved. The third is a commitment of very substantial startup capital monies from MIT for all of the state-of-the-art ultra-low noise microwave electronics, to one of our outstanding young collaborators who is joining their faculty.},
doi = {10.2172/10182465},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1992,
month = 5
}

Technical Report:

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  • The evolution and distribution of galaxies and the intergalactic medium (IGM) have been studied, along with collisionless dark matter in a Universe dominated by cold dark matter. The Einstein-deSitter universe with omega sub 0 = 1 and h = 0.5 was considered (here h = H sub 0 bar 100/kms/Mpc and H sub 0 is the present value of the Hubble constant). It is assumed that initially dark matter composes 90 pct and baryonic matter composes 10 pct of total mass, and that the primordial baryonic matter is comprised of H and He, with the abundance of He equal tomore » 10 pct of H by number. Galaxies are allowed to form out of the IGM, if the total density and baryonic density satisfy an overdensity criterion. Subsequently, the newly formed galaxies release 10 to the 60th ergs of energy into the IGM over a period of 10 to the 8th years. Calculations have been performed with 32 to the 3rd dark matter particles and 32 to the 3rd cells in a cube with comoving side length L = 9.6/h Mpc. Dark matter particles and galaxies have been followed with an N-body code, while the IGM has been followed with a fluid code.« less
  • The cold dark matter spectrum on earth is expected to have peaks in velocity space. We obtain estimates for the sizes and locations of these peaks. To this end we have generalized the secondary infall model of galactic halo formation to include angular momentum of the dark matter particles. This new model is still spherically symmetric and it has self-similar solutions. Our results are relevant to direct dark matter search experiments.
  • A systematic linear analysis of the perturbations induced by cosmic strings in cold dark matter is presented. The power spectrum is calculated and it is found that the strings produce a great deal of power on small scales. It is shown that the perturbations on interesting scales are the result of many uncorrelated string motions, which indicates a much more Gaussian distribution than was previously supposed.
  • The possibility of a flux of high energy neutrinos (100 MeV less than or equal to E/sub nu/ less than or equal to 10GeV) from the sun due to the annihilation within of particles which make up the galactic halo is considered. Specifically, if the halo consists of heavy neutrinos or stable supersymmetric particles with mass greater than or equal to 6GeV, halo particles will be trapped in the sun and annihilate to produce a potentially observable high energy neutrino flux. Detailed estimates of this flux are provided for a variety of candidate halo particles: photinos, higgsinos, scalar neutrinos, heavymore » Dirac neutrinos, and heavy Majorana neutrinos. All of these can (for appropriate ranges of parameters) produce fluxes whose absolute value is at least comparable to atmospheric background. How the solar fluxes could be distinguished from the background is briefly discussed. The effect of trapped halo particles on the solar neutrino problem is also discussed. 42 refs., 3 figs.« less
  • A galactic halo of cold dark matter particles has a sheet-like structure in phase-space. The energy and momentum spectra of such particles on earth has a set of peaks whose central values and intensities form a record of the formation of the Galaxy. Scattering of the dark matter particles by stars and globular clusters broadens the peaks but does not erase them entirely. The giant shells around some elliptical galaxies may be a manifestation of this structure.