E.J. Salumbides, M.L. Niu, J. Bagdonaite, N. De Oliveira, D. Joyeux, L. Nahon, W. Ubachs
The A1Π-X1Σ + band system of carbon monoxide, which has been detected in six highly redshifted galaxies (z=1.6-2.7), is identified as a probe method to search for possible variations of the proton-electron mass ratio (μ) on cosmological time scales. Laboratory wavelengths of the spectral lines of the A-X (v,0) bands for v=0-9 have been determined at an accuracy of Δλ/λ=1.5×10 -7 through VUV Fourier-transform absorption spectroscopy, providing a comprehensive and accurate zero-redshift data set. For the (0,0) and (1,0) bands, two-photon Doppler-free laser spectroscopy has been applied at the 3×10 -8 accuracy level, verifying the absorption data. Sensitivity coefficients K μ for a varying μ have been calculated for the CO A-X bands so that an operational method results to search for μ variation. © 2012 American Physical Society.
Department of Physics and Astronomy, LaserLaB, VU University, 1081 HV Amsterdam, De Boelelaan 1081, Netherlands; Department of Physics, University of San Carlos, Cebu City 6000, Philippines; Synchrotron Soleil, Orme des Merisiers, 91192, GIF sur Yvette Cedex, St Aubin BP 48, France
