Abstract
A search is presented for additional neutral Higgs bosons in the τ τ final state in proton-proton collisions at the LHC. The search is performed in the context of the minimal supersymmetric extension of the standard model (MSSM), using the data collected with the CMS detector in 2016 at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb−1. To enhance the sensitivity to neutral MSSM Higgs bosons, the search includes production of the Higgs boson in association with b quarks. No significant deviation above the expected background is observed. Model-independent limits at 95% confidence level (CL) are set on the product of the branching fraction for the decay into τ leptons and the cross section for the production via gluon fusion or in association with b quarks. These limits range from 18 pb at 90 GeV to 3.5 fb at 3.2 TeV for gluon fusion and from 15 pb (at 90 GeV) to 2.5 fb (at 3.2 TeV) for production in association with b quarks, assuming a narrow width resonance. In the mhhod + scenario these limits translate into a 95% CL exclusion of tan β > 6 for neutral Higgs boson masses below 250 GeV, where tan β is the ratio of the vacuum expectation values of the neutral components of the two Higgs doublets. The 95% CL exclusion contour reaches 1.6 TeV for tan β = 60.
Highlights
The CMS detectorThe central feature of the CMS apparatus is a superconducting solenoid of 6 m internal diameter, providing a magnetic field of 3.8 T
Background processH → τ τ (SM) Z → ττ Z→Diboson+single t tt Misidentification eμ eτh μτh τhτh MC MC MC MC MC† MC† MC† MC†→ τh Jet → τh MC MC MC MCFF FF FF τ / → τh Jet → τh τ / → τh Jet → τh FF FF FF MC† MC† MC† MC† with jets (W+jets)Jet → τh MC FF FF FFquantum chromodynamics (QCD) multijet productionCR FF FF FF signal purity supplementary samples are generated with up to four outgoing partons in the hard interaction
This can be attributed to three main factors: the choice of single lepton triggers in the eτh and μτh final states together with the higher instantaneous luminosity leads to the need for higher pT thresholds at the trigger level and reduced signal acceptance; the change of the discriminating variable from the estimate of the fully reconstructed τ τ mass to mtTot provides more sensitivity for high masses, but slightly less sensitivity for lower masses; and the prediction of the kinematic distributions of the signal at next-toleading order (NLO) precision reveals a generally softer pT spectrum for the gluon fusion production mode, which dominates for low values of tan β
Summary
The central feature of the CMS apparatus is a superconducting solenoid of 6 m internal diameter, providing a magnetic field of 3.8 T. The silicon tracker measures charged particles within the pseudorapidity range |η| < 2.5. It consists of 1440 silicon pixel and 15 148 silicon strip detector modules. Matching muons to tracks measured in the silicon tracker results in a relative pT resolution for muons with 20 < pT < 100 GeV of 1.3 to 2.0% in the barrel and better than 6% in the endcaps. In the barrel section of the ECAL, an energy resolution of about 1% is achieved for unconverted or late-converting photons in the tens of GeV energy range. The first level, composed of custom hardware processors, uses information from the calorimeters and muon detectors to select events at a rate of around 100 kHz within a time interval of less than 4 μs. A more detailed description of the CMS detector, together with a definition of the coordinate system used and the relevant kinematic variables, can be found in ref. [38]
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