  We combine results from CDF and D0 on direct searches for the standard model
(SM) Higgs boson (H) in ppbar collisions at the Fermilab Tevatron at
sqrt(s)=1.96 TeV. Compared to the previous Tevatron Higgs boson search
combination more data have been added, additional channels have been
incorporated, and some previously used channels have been reanalyzed to gain
sensitivity. With up to 10 fb-1 of luminosity analyzed, the 95% C.L. median
expected upper limits on Higgs boson production are factors of 0.94, 1.10, and
0.49 times the values of the SM cross section for Higgs bosons of mass m_H=115
GeV/c^2, 125 GeV/c^2,and 165 GeV/c^2, respectively. We exclude, at the 95%
C.L., two regions: 100<m_H<106 GeV/c^2, and 147<m_H<179 GeV/c^2. We expect to
exclude the regions 100<m_H<119 GeV/c^2 and 141<m_H<184 GeV/c^2. There is an
excess of data events with respect to the background estimation in the mass
range 115<m_H<135 GeV/c^2 which causes our limits to not be as stringent as
expected. At m_H=120 GeV/c^2, the p-value for a background fluctuation to
produce this excess is ~3.5 x 10^{-3}, corresponding to a local significance of
2.7 standard deviations. The global significance for such an excess anywhere in
the full mass range is approximately 2.2 standard deviations. We also combine
separately searches for H->bbbar and H->W+W-, and find that the excess is
concentrated in the H->bbbar channel, although the results in the H->W+W-
channel are also consistent with the possible presence of a low-mass Higgs
boson.
