Search for the Higgs Boson Decaying to Two Muons in Proton-Proton Collisions at $\sqrt{s}=13\mathrm{TeV}$

A search for the Higgs boson decaying to two oppositely charged muons is presented using data recorded by the CMS experiment at the CERN LHC in 2016 at a center-of-mass energy $\sqrt{s}=13\mathrm{TeV}$, corresponding to an integrated luminosity of $35.9{\mathrm{fb}}^{-1}$. Data are found to be compatible with the predicted background. For a Higgs boson with a mass of 125.09 GeV, the 95% confidence level observed (background-only expected) upper limit on the production cross section times the branching fraction to a pair of muons is found to be 3.0 (2.5) times the standard model expectation. In combination with data recorded at center-of-mass energies $\sqrt{s}=7$ and 8 TeV, the background-only expected upper limit improves to 2.2 times the standard model value with a standard model expected significance of 1.0 standard deviation. The corresponding observed upper limit is 2.9 with an observed significance of 0.9 standard deviation. This corresponds to an observed upper limit on the standard model Higgs boson branching fraction to muons of $6.4\times {10}^{-4}$ and to an observed signal strength of $1.0\pm 1.0(\mathrm{stat})\pm 0.1(\mathrm{syst})$.

Figure 1

The transformed BDT output distributions in data (solid points) and MC simulation (histograms). The stacked solid histograms represent the background processes, while the stacked dashed histograms represent the signal. In the legend, V denotes the vector bosons $W$ and $Z$, and TTX indicates the top quark pair production in association with a vector boson V or another top quark pair. The vertical lines denote the BDT response intervals indicated in Table 1.

Figure 2

Data and weighted sum of signal-plus-background fits to each category. Events are weighted according to the expected ratio of signal to signal plus background in the category to which they belong. The solid blue line represents the expectation from the SM Higgs boson multiplied by a factor of 10. The lower panel shows the difference between the data and the background component of the fit.

Figure 3

The 95% C.L. upper limit on the signal strength modifier $\mu$ in the region around the Higgs boson mass for the combination of the 7, 8, and 13 TeV data sets together with the expected limit obtained in the background-only hypothesis (dashed black line) and in the signal-plus-background hypothesis (dashed red line) for the SM Higgs boson with $m_H=125\mathrm{GeV}$.