Аннотация
(abridged) Quasar absorption lines provide a precise test of the assumed
constancy of the fundamental constants of physics. We have investigated
potential changes in the fine-structure constant, alpha, and the
proton-to-electron mass ratio, mu.
The many-multiplet method allows one to use optical fine-structure
transitions to constrain (Delta alpha)/alpha at better than the 10^(-5) level.
We present a new analysis of 154 quasar absorbers with 0.2 < z <3.7 in VLT/UVES
spectra. From these absorbers we find 2.2 sigma evidence for angular variations
in alpha under a dipole+monopole model. Combined with previous Keck/HIRES
observations, we find 4.1 sigma evidence for angular (and therefore spatial)
variations in alpha, with maximal increase of alpha occurring in the direction
RA=(17.3 +/- 1.0) hr, dec=(-61 +/- 10) deg. Under a model where the observed
effect is proportional to the lookback-time distance the significance increases
to 4.2 sigma. Dipole models fitted to the VLT and Keck samples and models
fitted to z<1.6 and z>1.6 sub-samples independently yield consistent estimates
of the dipole direction, which suggests that the effect is not caused by
telescope systematics. We consider a number of systematic effects and show that
they are unable to explain the observed dipole effect.
We have used spectra of the quasars Q0405-443, Q0347-383 and Q0528-250 from
VLT/UVES to investigate the absorbers at z=2.595, 3.025 and 2.811 in these
spectra respectively. We find that (Delta mu)/mu=(10.1 +/- 6.6) x 10^(-6), (8.2
+/- 7.5) x 10^(-6) and (-1.4 +/- 3.9) x 10^(-6) in these absorbers
respectively. A second spectrum of Q0528-250 provides an additional constraint
of (Delta mu)/mu=(0.2 +/- 3.2_stat +/- 1.9_sys) x 10^(-6). The weighted mean of
these values yields (Delta mu)/mu=(1.7 +/- 2.4) x 10^(-6), the most precise
constraint on evolution in mu at z>1.
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