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CMS-HIG-14-042 ; CERN-PH-EP-2015-075
Combined measurement of the Higgs boson mass in pp collisions at $\sqrt{s}$ = 7 and 8 TeV with the ATLAS and CMS experiments
Phys. Rev. Lett. 114 (2015) 191803
Abstract: A measurement of the Higgs boson mass is presented based on the combined data samples of the ATLAS and CMS experiments at the CERN LHC in the $H \rightarrow \gamma\gamma$ and $H \rightarrow ZZ\rightarrow 4\ell$ decay channels. The results are obtained from a simultaneous fit to the reconstructed invariant mass peaks in the two channels and for the two experiments. The measured masses from the individual channels and the two experiments are found to be consistent among themselves. The combined measured mass of the Higgs boson is $m_{H}$ = 125.09 $\pm$ 0.21 (stat.) $\pm$ 0.11(syst.) GeV.
Summary CMS Publications
Cover

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Cover of Physical Review Letters Volume 114, Number 19, published 15 May 2015. The present article was chosen as PRL Editor's Suggestion.

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Table of Content of Physical Review Letters Volume 114, Number 19, published 15 May 2015. The present article was chosen as PRL Editor's Suggestion.

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Picture prepared for the cover of PRL, without text.

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Pictures prepared for the cover of PRL, with text.
PRL Editor's Suggestion, Featured in Physics

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(not an ATLAS nor CMS figure) Figure from ``Viewpoint: A More Precise Higgs Boson Mass'', by Chris Quigg, FERMILAB (USA) and ENS (Paris, France). Values of the top quark and W boson masses measured in experiments (green) and inferred from calculations (blue). The inner and outer ellipses represent 68% and 95% confidence levels, respectively, for the measured and inferred values. Within current experimental and theoretical uncertainties, the two ways of determining the top quark and W boson masses agree. A more precise value of the Higgs mass would narrow the width of the blue ellipses, whereas improved measurements of the top quark and W boson masses would shrink the green ellipses, making for a more incisive test for new physics. (Note, the calculations assume the Higgs mass has a central value of 125.14 GeV, which differs insignificantly from the new measurement by ATLAS and CMS, but does not affect the width of the blue ellipses.)
Summary
In summary, a combined measurement of the Higgs boson mass is performed in the $ H \to \gamma \gamma $ and $ H \to ZZ \to 4\ell $ channels using the LHC Run 1 data sets of the ATLAS and CMS experiments, with minimal reliance on the assumption that the Higgs boson behaves as predicted by the SM.
The result is
$ m_H =$ 125.09 $\pm$ 0.24  GeV = 125.09 $\pm$ 0.21 (stat) $\pm$ 0.11 (syst)  GeV,

where the total uncertainty is dominated by the statistical term, with the systematic uncertainty dominated by effects related to the photon, electron, and muon energy or momentum scales and resolutions. Compatibility tests are performed to ascertain whether the measurements are consistent with each other, both between the different decay channels and between the two experiments. All tests on the combined results indicate consistency of the different measurements within 1$ \sigma $, while the four Higgs boson mass measurements in the two channels of the two experiments agree within 2$ \sigma $. The combined measurement of the Higgs boson mass improves upon the results from the individual experiments and is the most precise measurement to date of this fundamental parameter of the newly discovered particle.
Compact Muon Solenoid
LHC, CERN