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تسجيل مستخدم جديدDoes the proton-to-electron mass ratio vary in the course of cosmological evolution?
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A.Ivanchik
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The possible cosmological variation of the proton-to-electron mass ratio was estimated by measuring the H_2 wavelengths in the high-resolution spectrum of the quasar Q~0347-382. Our analysis yielded an estimate for the possible deviation of mu value in the past, 10 Gyr ago: for the unweighted value $Delta mu / mu = (3.0pm2.4)times10^{-5}$; for the weighted value [ Delta mu / mu = (5.02pm1.82)times10^{-5}] Since the significance of the both results does not exceed 3$sigma$, further observations are needed to increase the statistical significance. In any case, this result may be considered as the most stringent estimate on an upper limit of a possible variation of mu (95% C.L.): [ |Delta mu / mu| < 8times 10^{-5} ] This value serves as an effective tool for selection of models determining a relation between possible cosmological deviations of the fine-structure constant alpha and the elementary particle masses (m$_p$, m$_e$, etc.).
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Multidimensional cosmologies allow for variations of fundamental physical constants over the course of cosmological evolution, and differe
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7 km/s) of two damped Lyman-alpha systems at z_{abs}=2.3377 and 3.0249 observed along the lines of sight to the quasars Q 1232+082 and Q 0347-382 respectively. The most conservative result of the analysis is a possible variation of mu over the last ~ 10 Gyrs, with an amplitude Deltamu/mu = (5.7+-3.8)x10^{-5}. The result is significant at the 1.5sigma level only and should be confirmed by further observations. This is the most stringent estimate of a possible cosmological variation of mu obtained up to now.
A new limit on the possible cosmological variation of the proton-to-electron mass ratio mu=m_p/m_e is estimated by measuring wavelengths of H_2 lines of Lyman and Werner bands from two absorption systems at z_abs = 2.5947 and 3.0249 in the spectra of
quasars Q 0405-443 and Q 0347-383, respectively. Data are of the highest spectral resolution (R = 53000) and S/N ratio (30div70) for this kind of study. We search for any correlation between z_i, the redshift of observed lines, determined using laboratory wavelengths as references, and K_i, the sensitivity coefficient of the lines to a change of mu, that could be interpreted as a variation of mu over the corresponding cosmological time. We use two sets of laboratory wavelengths, the first one, Set (A) (Abgrall et al.), based on experimental determination of energy levels and the second one, Set (P) (Philip et al.), based on new laboratory measurements of some individual rest-wavelengths. We find Deltamu/mu = (3.05+-0.75)10^-5 for Set (A), and Deltamu/mu = (1.65+-0.74)10^-5 for Set (P). The second determination is the most stringent limit on the variation of mu over the last 12 Gyrs ever obtained. The correlation found using Set (A) seems to show that some amount of systematic error is hidden in the determination of energy levels of the H$_2$ molecule.
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