Limits on variations in fundamental constants from 21-cm and ultraviolet quasar absorption lines
Abstract
21-cm and UV quasar absorption spectra are used to estimate the time variation of x=alpha^2 g_p mu, where alpha is the fine structure constant, g_p the proton g factor, and m_e/m_p=mu the electron/proton mass ratio. Our sample is 8 times larger than previously used. The intrinsic line-of-sight velocity difference between 21-cm and UV absorption redshifts, z_abs, is estimated to be \~6 km s^-1. For 0.24 ~< z_abs ~< 2.04, _total_weighted=(1.17+-1.01) x 10^-5. A linear fit gives d/dt{x}/x=(-1.43+-1.27) x 10^-15 yr^-1. Using two previous results on varying alpha yields the best limits Delta mu/mu=(2.31+-1.03) x 10^-5 and Delta mu/mu=(1.29+-1.01) x 10^-5.Keywords
All Related Versions
This publication has 0 references indexed in Scilit: