From the rate of hydrogen ionization and the gamma ray flux , we derived the spectrum of relativistic and subrelativistic cosmic rays ( CRs ) nearby and inside the molecular cloud Sgr B2 near the Galactic Center ( GC ) .
We studied two cases of CR propagation in molecular clouds : free propagation and scattering of particles by magnetic fluctuations excited by the neutral gas turbulence .
We showed that in the latter case CR propagation inside the cloud can be described as diffusion with the coefficient \sim 3 \times 10 ^ { 27 } cm ^ { 2 } s ^ { -1 } .
For the case of hydrogen ionization by subrelativistic protons , we showed that their spectrum outside the cloud is quite hard with the spectral index \delta > -1 .
The energy density of subrelativistic protons ( > 50 eV cm ^ { -3 } ) is one order of magnitude higher than that of relativistic CRs .
These protons generate the 6.4 keV emission from Sgr B2 , which was about 30 % of the flux observed by Suzaku in 2013 .
Future observations for the period after 2013 may discover the background flux generated by subrelativistic CRs in Sgr B2 .
Alternatively hydrogen ionization of the molecular gas in Sgr B2 may be caused by high energy electrons .
We showed that the spectrum of electron bremsstrahlung is harder than the observed continuum from Sgr B2 , and in principle this X-ray component provided by electrons could be seen from the INTEGRAL data as a stationary high energy excess above the observed spectrum E _ { x } ^ { -2 } .