Abstract
A search is presented for pair production of the standard model Higgs boson using data from proton-proton collisions at a centre-of-mass energy of 13 TeV, collected by the CMS experiment at the CERN LHC in 2016, and corresponding to an integrated luminosity of 35.9 fb−1. The final state consists of two b quark-antiquark pairs. The search is conducted in the region of phase space where one pair is highly Lorentz-boosted and is reconstructed as a single large-area jet, and the other pair is resolved and is reconstructed using two b-tagged jets. The results are obtained by combining this analysis with another from CMS looking for events with two large jets. Limits are set on the product of the cross sections and branching fractions for narrow bulk gravitons and radions in warped extradimensional models having a mass in the range 750-3000 GeV. The resulting observed and expected upper limits on the non-resonant Higgs boson pair production cross section correspond to 179 and 114 times the standard model value, respectively, at 95% confidence level. The existence of anomalous Higgs boson couplings is also investigated and limits are set on the non-resonant Higgs boson pair production cross sections for representative coupling values.
Highlights
Background estimationThe multijet background estimation technique for the semi-resolved analysis is the same as that for the fully-merged analysis [39]
The search is conducted in the region of phase space where one pair is highly Lorentz-boosted and is reconstructed as a single large-area jet, and the other pair is resolved and is reconstructed using two b-tagged jets
Additional statistical uncertainties on the background shape and yield in the signal region result from the finite statistics of the multijets samples in the antitag region and are evaluated using the Barlow-Beeston Lite method [82, 83]. These uncertainties are small as compared with the uncertainty on the Rp/f ratio, and are uncorrelated from bin to bin. This analysis extends the search for a resonance X decaying to HH → bbbb with two boosted H jets [39] to cover the semi-resolved topology involving one boosted H jet and σ(pp → X) B (X → HH → bbbb) [fb]
Summary
The CMS detector with its coordinate system and the relevant kinematic variables is described in ref. [42]. The first level (L1), composed of custom hardware processors, uses information from the calorimeters and muon detectors to select events at a rate of around 100 kHz. The second level, known as the high-level trigger (HLT), consists of a farm of processors running a version of the full event reconstruction software optimized for fast processing, and reduces the event rate to around 1 kHz before data storage. The energy of each charged hadron is determined from a combination of its momentum measured in the tracker and the matching ECAL and HCAL energy deposits, corrected for zero-suppression effects and for the response function of the calorimeters to hadronic showers. To mitigate the effect of pileup on the AK4 jet momentum, tracks identified as originating from pileup vertices are discarded in the clustering, and an offset correction [47, 48] is applied for remaining contributions from neutral particles. The matching efficiency is 100% in the selected event sample
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
