b-Physics measurements at the Tevatron: m and Delta m
  We present experimental results on b-hadron mass measurements and b-meson oscillations based on integrated luminosity of 250 to 450 pb-1 of proton-antiproton collisions at c.m. energy = 1.98 TeV by the CDF and D0 collaborations at the Tevatron. The masses of b-hadrons have been measured precisely by the CDF collaboration in decays containing a J/psi . A blind search of the decay mode Bc to J/psi pi resulted in a peak of 18.9 +/- 5.4 candidates at a mass value of 6287.0 +/- 4.5 +/- 1.1 MeV/c2. A new limit has been set to the decay B_d,s to mu+ mu-. Both the CDF and D0 collaborations are in the position to put a limit on the frequency of the Bs oscillations. D0 reports Delta m_s > 5.0 ps-1. 
S. D'Auria (for the CDF collaboration, D0 collaboration)