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An experiment to search for galactic axions

Thesis/Dissertation ·
OSTI ID:5918351
Results are presented from a search for axions in the mass range of .51 X 10{sup {minus}5} to 1 X 10{sup {minus}5}eV, which may make up the dark matter halo of the galaxy. The detector used in the search consists of a microwave cavity placed in the strong magnetic field of a superconducting solenoid magnet. The energy in the TM{sub 010} mode of the cavity is monitored by a sensitive microwave receiver as the frequency of the mode is swept. The predicted experimental signature of galactic halo axions is a narrow signal, with a Q{sub a} = f/{Delta}f {approx} 3 X 10{sup 6}, which is expected when the resonant frequency of the cavity corresponds to the mass of the axion. An experimental limit on the coupling times the density of (g{sub a{gamma}{gamma}}/m{sub a}){sup 2} {rho}{sub a} {le} 2 x 10{sup {minus}40} for an axion linewidth {le} 400 Hz with a 97% confidence level has been obtained. The theoretical prediction is (g{sub a{gamma}{gamma}}/m{sub a}){sup 2}{rho}{sub a} {approx} 3.9 {times} 10{sup {minus}44} with {rho}{sub a} = 300 MeV/cm{sup 3}. The corresponding limit in g{sub a{gamma}{gamma}} {le} 7 x 10{sup {minus}14} GeV{sup {minus}1} at an axion frequency f = 2 GeV and depends linearly on axion mass.
Research Organization:
Rochester Univ., NY (USA)
OSTI ID:
5918351
Country of Publication:
United States
Language:
English