HD as a probe for detecting mass variation on a cosmological time scale

The strong electronic absorption systems of the B{sup 1}{sigma}{sub u}{sup +}-X{sup 1}{sigma}{sub g}{sup +} Lyman and the C{sup 1}{pi}{sub u}-X{sup 1}{sigma}{sub g}{sup +} 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 H{sub 2} 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 {delta}{lambda}/{lambda}{approx}5x10{sup -8}, forming a database for comparison with astrophysical data. Sensitivity coefficients K{sub i}=dln{lambda}{sub i}/dln{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.