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Title:
Limits on Variations in Fundamental Constants from 21-cm and Ultraviolet Quasar Absorption Lines
Authors:
Tzanavaris, P.; Webb, J. K.; Murphy, M. T.; Flambaum, V. V.; Curran, S. J.
Affiliation:
AA(School of Physics, The University of New South Wales, Sydney, NSW 2052, Australia), AB(School of Physics, The University of New South Wales, Sydney, NSW 2052, Australia), AC(School of Physics, The University of New South Wales, Sydney, NSW 2052, Australia), AD(School of Physics, The University of New South Wales, Sydney, NSW 2052, Australia), AE(School of Physics, The University of New South Wales, Sydney, NSW 2052, Australia)
Publication:
Physical Review Letters, vol. 95, Issue 4, id. 041301 (PhRvL Homepage)
Publication Date:
07/2005
Origin:
APS
DOI:
10.1103/PhysRevLett.95.041301
Bibliographic Code:
2005PhRvL..95d1301T

Abstract

Quasar absorption spectra at 21-cm and UV rest wavelengths are used to estimate the time variation of x≡α2gpμ, where α is the fine structure constant, gp the proton g factor, and me/mp≡μ the electron/proton mass ratio. Over a redshift range 0.24≲zabs≲2.04, <Δx/x>weightedtotal=(1.17±1.01)×10-5. A linear fit gives x˙/x=(-1.43±1.27)×10-15 yr-1. Two previous results on varying α yield the strong limits Δμ/μ=(2.31±1.03)×10-5 and Δμ/μ=(1.29±1.01)×10-5. Our sample, 8× larger than any previous, provides the first direct estimate of the intrinsic 21-cm and UV velocity differences ˜6 km s-1.
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