Search for resonances in the mass spectrum of muon pairs produced in association with b quark jets in proton-proton collisions at √s = 8 and 13 TeV

Abstract

A search for resonances in the mass range 12–70 GeV produced in association with a b quark jet and a second jet, and decaying to a muon pair, is reported. The analysis is based on data from proton-proton collisions at center-of-mass energies of 8 and 13 TeV, collected with the CMS detector at the LHC and corresponding to integrated luminosities of 19.7 and 35.9 fb⁻¹, respectively. The search is carried out in two mutually exclusive event categories. Events in the first category are required to have a b quark jet in the central region (|η| ≤ 2.4) and at least one jet in the forward region (|η| > 2.4). Events in the second category are required to have two jets in the central region, at least one of which is identified as a b quark jet, no jets in the forward region, and low missing transverse momentum. An excess of events above the background near a dimuon mass of 28 GeV is observed in the 8 TeV data, corresponding to local significances of 4.2 and 2.9 standard deviations for the first and second event categories, respectively. A similar analysis conducted with the 13 TeV data results in a mild excess over the background in the first event category corresponding to a local significance of 2.0 standard deviations, while the second category results in a 1.4 standard deviation deficit. The fiducial cross section measurements and 95% confidence level upper limits on those for a resonance consistent with the 8 TeV excess are provided at both collision energies.

Description
Keywords
Beyond Standard Model, Hadron-Hadron scattering (experiments), Higgs physics
Citation
Sirunyan, A. M., Tumasyan, A., Adam, W., Ambrogi, F., Asilar, E., Bergauer, T., Brandstetter, J., Dragicevic, M., Erö, J., Escalante Del Valle, A., Flechl, M., Frühwirth, R., Ghete, V. M., Hrubec, J., Jeitler, M., Krammer, N., Krätschmer, I., Liko, D., … Woods, N. (2018). Search for resonances in the mass spectrum of muon pairs produced in association with b quark jets in proton-proton collisions at $ \sqrt{s}=8 $ and 13 TeV. In Journal of High Energy Physics (Vol. 2018, Issue 11). Springer Science and Business Media LLC. https://doi.org/10.1007/jhep11(2018)161