The UVES large program for testing fundamental physics II : constraints ∆ μ / μ towards quasar HE 0027 − 1836

We study the variation of proton-to-electron mass ratio, μ, using the H2 absorption lines from the zabs ∼ 2.4018 DLA system towards HE 0027 − 1836 observed with the VLT/UVES as a part of the ESO Large Program for testing fundamental physics. A crosscorrelation analysis between individual exposures and the combined spectrum and asteroid observations show the existence of a possible wavelength dependent drift in the UVES observation. We find that a two component Voigt profile model can best fit the H2 absorption profile and give ∆μ/μ = −2.5 ± 8.1stat ± 6.2sys ppm. When we apply the correction to the wavelength dependent velocity drift we find ∆μ/μ = −7.6 ± 8.1stat ± 6.3sys ppm.