HD as a Probe for Detecting Mass Variation on a Cosmological Time Scale

International audienceThe strong electronic absorption systems of the BSigmau+1-XSigmag+1 Lyman and the CPiu1-XSigmag+1 Werner bands can be used to probe possible mass-variation effects on a cosmological time scale from spectra observed at high redshift, not only in H2 but also in the second most abundant hydrogen isotopomer HD. High resolution laboratory determination of the most prominent HD lines at extreme ultraviolet wavelengths is performed at an accuracy of Deltalambda/lambda˜5×10-8, forming a database for comparison with astrophysical data. Sensitivity coefficients Ki=dlnf lambdai/dlnf mu are determined for HD from quantum ab initio calculations as a function of the proton-electron mass ratio mu. Strategies to deduce possible effects beyond first-order baryon/lepton mass ratio deviations are discussed