Probing variations in fundamental constants with radio and optical quasar absorption-line observations
Probing variations in fundamental constants with radio and optical quasar absorption-line observations
Nine quasar absorption spectra at 21-cm and ultraviolet (UV) rest-frame wavelengths are used to estimate possible variations in x≡α2gpμ, where α is the fine structure constant, gp the proton g-factor and μ≡me/mp is the electron-to-proton mass ratio. We find 〈Δx/x〉weightedtotal= (0.63 ± 0.99) × 10−5 over a redshift range 0.23 …