Search for long-lived charged particles in proton-proton collisions at $\sqrt{s}=13\mathrm{TeV}$

Results are presented of a search for heavy stable charged particles produced in proton-proton collisions at $\sqrt{s}=13\mathrm{TeV}$ using a data sample corresponding to an integrated luminosity of $2.5{\mathrm{fb}}^{-1}$ collected in 2015 with the CMS detector at the CERN LHC. The search is conducted using signatures of anomalously high energy deposits in the silicon tracker and long time-of-flight measurements by the muon system. The data are consistent with the expected background, and upper limits are set on the cross sections for production of long-lived gluinos, top squarks, tau sleptons, and leptonlike long-lived fermions. These upper limits are equivalently expressed as lower limits on the masses of new states; the limits for gluinos, ranging up to 1610 GeV, are the most stringent to date. Limits on the cross sections for direct pair production of long-lived tau sleptons are also determined.

Figure 1

Distribution of the $dE/dx$ estimator, $I_h$ (see Sec. 3a), versus particle momentum for tracks in the 13 TeV data, and for simulation of HSCP for singly or multiply charged particles with masses of 400 and 1000 GeV. The vertical scale shows the density of entries for data only.

Figure 2

Observed and predicted mass spectra for loose selection candidates in the tracker-only (top) and tracker+TOF (bottom) analyses. The expected distributions for representative signals are shown as histograms.

Figure 3

Observed and predicted mass spectra for candidates passing the final selection in the tracker-only (top) and tracker+TOF (bottom) analyses. The expected distributions for representative signals are shown as histograms.

Figure 4

Results of the HSCP search as the cross section upper limits at 95% CL for various signal models for the tracker-only analysis (top) and tracker+TOF analysis (bottom) at $\sqrt{s}=13\mathrm{TeV}$. In the legend, “CS” stands for charge-suppressed interaction model.