Combined CDF and D0 Search for Standard Model Higgs Boson Production with up to 10.0 fb-1 of Data

TL;DR

This paper combines results from CDF and D0 to search for the Standard Model Higgs boson at the Fermilab Tevatron, setting exclusion limits and observing a modest excess around 120 GeV/c^2.

Contribution

It provides the most comprehensive Tevatron Higgs search by integrating additional data and channels, improving sensitivity over previous combinations.

Findings

Excluded Higgs mass ranges: 100-106 GeV/c^2 and 147-179 GeV/c^2.

Observed excess at 120 GeV/c^2 with 2.2 sigma global significance.

Limits are close to the Standard Model predictions at certain masses.

Abstract

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.