We present a short review of the current quasar (QSO) absorption line constraints on possible variation of the fine structure constant, α ≡ e2/¯hc. Particular attention is paid to recent optical Keck/HIRES spectra of 49 absorption systems which indicate a smaller α in the past [1, 2]. Here we present new preliminary results from 128 absorption systems: Δα/α = (−0.57±0.10)×10−5 over the redshift range 0.2 < z < 3.7, in agreement with the previous results. Known potential systematic errors cannot explain these results. We compare them with strong ‘local’ constraints and discuss other (radio and millimeter-wave) QSO absorption line constraints on variations in α2gp and α2gpme/mp (gp is the proton g-factor and me/mp is the electron/proton mass ratio). Finally, we discuss future efforts to rule out or confirm the current 5.7 σ optical detection.
Proceedings of the 22nd Physics in Collision Conference (PIC 2002), Stanford, California, United States, 20-22 June 2002,