Differential measurements of the fundamental constant \(\mu = {{m}_{e}}{\text{/}}{{m}_{p}}\) (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 \(\langle \Delta \mu {\text{/}}\mu \rangle \) \( \equiv \) \(\langle ({{\mu }_{{{\text{obs}}}}} - {{\mu }_{{{\text{lab}}}}}){\text{/}}{{\mu }_{{{\text{lab}}}}}\rangle = ( - 2.1 \pm 0.6) \times {{10}^{{ - 7}}}\) ( \(1\sigma \) ) was obtained for Sgr B2(N) at the sample size \(n = 9\) . This value of \(\Delta \mu {\text{/}}\mu \) 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): \(\langle \Delta \mu {\text{/}}\mu \rangle = ( - 4.2 \pm 0.7) \times {{10}^{{ - 7}}}\) (sample size \(n = 2\) ).
