arXiv subjects

J. S. Vorotyntseva

Publications and source records attributed to J. S. Vorotyntseva.

9 recordsLinked to original sources

arXiv2026

Constraints on mu-variations from the methanol CH3OH thermal lines in the Galaxy at galactocentric distances of 1.5 < D_GC < 13 kpc

In this study, constraints are set on hypothetical variations of the fundamental physical constant mu = m_e/m_p - the electron-to-proton mass ratio - based on thermal emission lines of E-methanol (CH3OH) in the 216-220 GHz frequency range. Molecular spectra toward seven massive clouds located across a wide range of galactocentric distances (1.5 < D_GC < 13 kpc) have been analyzed. The obtained weighted mean value = (0.5+/-0.5)*10^(-7) does not indicate statistically significant changes in mu at the 1 sigma confidence level of 5*10^(-8), which is in good agreement with previously established upper limits in a number of molecular clouds in the Galactic disk.

astro-ph.GA↗

arXiv2026

Indications of electron-to-proton mass ratio variations in the Galaxy. III. 0.6mm methanol lines toward SgrB2(N) and Orion-KL

In this paper, we show that methanol (CH3OH) torsional-rotational transitions, which have increased sensitivity to small variations of mu - the electron-to-proton mass ratio, are shifted relative to less sensitive transitions in the spectrum of the SgrB2(N) molecular cloud located at the Galactic center. At the same time, an identical set of methanol lines in the spectrum of the Orion-KL molecular cloud, located far from the center, shows no shifts. Interpreting this behavior of molecular frequencies in terms of Delta mu/mu = (mu_obs - mu_lab)/mu_lab leads to the following weighted mean values: = (-3.4 +/- 0.4)*10^(-7) for SgrB2 and = (-1.1 +/- 0.8)*10^(-7) for Orion-KL (indicated are the total +/-1sigma errors of the weighted means including both statistical and systematic uncertainties). A possible correlation between values measured in various molecular clouds of the Galactic disk and the distribution of dark matter along the Galactic radius is discussed, which may suggest a hypothetical modulation of the Higgs scalar field by dark matter, resulting in a change of mu.

astro-ph.GA↗

arXiv2025

Acetaldehyde as a molecule for testing variations of electron-to-proton mass ratio

We present the quantum-mechanical calculations of the dimensionless sensitivity coefficients Q to small changes in the fundamental physical constant mu = m_e/m_p - the electron-to-proton mass ratio - for a number of low-frequency (1-50 GHz) transitions of the acetaldehyde (CH3CHO) molecule. The calculations show that Q varies in the range from 0.62 to 3.61. An example of the practical use of the CH3CHO and CH3OH lines tracing the same regions in three molecular clouds, located at large galactocentric distances (D_GC ~ 8 kpc) is considered. This results in a limit on the mu variations of Delta mu/mu = (0.1 +/- 0.4)*10^(-7) which is in line with previously obtained most stringent upper limits on changes in mu based on other molecules and methods. The limit obtained restricts hypothetical violations of the Einstein principle of the local position invariance at the level of 4*10^(-8) in the Galactic disk at large galactocentric distances.

physics.atom-ph↗

arXiv2025

Indications of electron-to-proton mass ratio variations in the Galaxy. II. 3 mm methanol lines toward Sgr B2(N) and (M)

Differential measurements of the fundamental constant mu = m_e/m_p (the electron-to-proton mass ratio) for two sources near the Galactic Center - the Sgr B2(N) and B2(M) molecular clouds - suggest that mu is lower in these clouds than its laboratory value. Based on observations of methanol (CH3OH) emission lines in the 80-112 GHz range (data from the IRAM 30-m telescope), a weighted mean value (Delta mu/mu) = (mu_obs - mu_lab)/mu_lab = (-2.1 +/- 0.6)*10^(-7) (1 sigma) was obtained for Sgr B2(N) at the sample size n = 9. This value of (Delta mu/mu) has the same sign as the result of recent measurements of methanol lines in the higher frequency range of 542-543 GHz (data from the Herschel space telescope) for Sgr B2(N): (Delta mu/mu) = (-4.2 +/- 0.7)*10^(-7) (sample size n = 2).

astro-ph.GA↗

arXiv2025

Indication of the electron-to-proton mass ratio variation within the Galaxy

Near (~100 pc) and far (~8.7 kpc) relative to the Galactic center, the molecular clouds SgrB2(N) and Orion-KL exhibit different values of the fundamental physical constant mu=m_e/m_p - the electron-to-proton mass ratio. Measured frequency difference between the emission lines of methanol (CH3OH), - J_K_u - J_K_l = 6_3 - 5_2 A+ 542000.981 MHz, 6_3 - 5_2 A- 542081.936 MHz, and 8_0 - 7_-1 E 543076.194 MHz, - observed with the space observatory Herschel toward SgrB2(N) and Orion-KL corresponds to (Sgr-Ori): Delta mu/mu = (-3.7 +/- 0.5)*10^(-7) (1 sigma C.L.). At the same time, comparison of the same methanol lines in Orion-KL with laboratory frequencies shows no significant changes in mu (Ori-lab): Delta mu/mu = (-0.5 +/- 0. 6)*10^(-7), while a comparison between SgrB2(N) and laboratory lines indicates a lower value of mu near the Galactic center (Sgr-lab): Delta mu/mu = (-4.2 +/- 0.7)*10^(-7). The reduced value of mu in SgrB2(N) is not explained by known systematic effects and requires further investigation.

astro-ph.GA↗

arXiv2024

Spectroscopic Shifts in Deuterated Methanol Induced by Variation of me/mp

Numerical calculations of the sensitivity coefficients, Q_mu, of microwave molecular transitions in the ground torsion-rotation state of deuterated methanol (CH3OD, CD3OH, and CD3OD) to small variations in the fundamental physical constant mu = me/mp - the electron-to-proton mass ratio - are reported. Theoretical motivation for changes in mu comes from a variety of models beyond the Standard Model of particle physics which are invoked to explain the nature of dark matter and dark energy that dominate the Universe. The calculated values of Q_mu range from -300 to +73 and, thus, make deuterated methanol promising for searches for small space-time changes in mu. It is also shown that among the calculated sensitivity coefficients Q_mu using different Hamiltonians in the present and previous works, there are several pronounced outliers of unclear nature.

hep-ph↗

arXiv2024

Torsion-rotational transitions in methanol as a probe of fundamental physical constants -- electron and proton masses

We report on the using of torsion-rotational transitions in the CH3OH and (13)CH3OH molecules to evaluate possible variations of the physical constant mu=m_e/m_p - the electron-to-proton mass ratio - from spectral observations of emission lines detected in the microwave range towards the dense molecular cloud Orion-KL. An estimate of the upper limit on the relative changes in mu is obtained by two independent ways - with (13)CH3OH lines and with the combination of (13)CH3OH and CH3OH lines. The calculated upper limit Delta mu/mu < 1.1*10^{-8} (1 sigma) is in line with the most stringent constraints on the variability of fundamental physical constants established by other astrophysical methods.

astro-ph.GA↗

arXiv2023

Hyperfine structure of methanol lines at 25 GHz

High-dispersion (channel width 0.015 km s^-1) laboratory spectroscopy of the torsion-rotation lines J_2 - J_1 (J = 2 - 6) in the ground torsional state (vt = 0) of the E-type methanol demonstrates multicomponent hyperfine splitting patterns at 25 GHz. The observed patterns are compared with simulations of CH3OH emission lines based on ab initio quantum-mechanical models. A substantial disparity between the laboratory and simulated patterns is revealed. The observed morphology of the line shapes is not reproduced in the model profiles. The found inconsistency requires further refinement of the current quantum-mechanical models to fit the observed hyperfine splitting patterns at 25 GHz.

physics.atom-ph↗

arXiv2023

Methanol isotopologues as a probe for spatial and temporal variations of the electron-to-proton mass ratio

We present results on numerical calculations of the sensitivity coefficients, Qmu, of microwave molecular transitions in (13C)H3OH and CH3(18O)H to the hypothetical variation in the fundamental physical constant mu - the electron-to-proton mass ratio. The invariability of mu in time and space is one of the basic assumptions of the Standard Model of particle physics which can be tested at cosmological scales by means of astronomical observations in the Galaxy and external galaxies. Our calculations show that these two methanol isotopologues can be utilized for such tests since their microwave transitions from the frequency interval 1-100 GHz exhibit a large spread in Qmu values which span a range of -109 < Qmu < 78. We show that the thermal emission lines of (13C)H3OH observed in the star-forming region NGC6334I constrain the variability of mu at a level of 3x10^-8 (1σ), which is in line with the most stringent upper limits obtained previously from observations of methanol (CH3OH) and other molecules in the Galaxy.

astro-ph.GA↗