Scintillation Tiles Production for the nT2 Telescope Upgrade of the TOTEM Experiment

The measurement of the total proton-proton cross-section using the luminosity independent method and the ρ parameter at the maximal collision energy of 13.6 TeV or more in Run 3 at CERNs Large Hadron Collider (LHC) requires an upgrade of the existing TOTEM T2 telescopes, which is called the new T2 (nT2). The specifications for nT2 is to provide inelastic event counting with maximal efficiency for data taking in special runs. The nT2 telescope consists of four quarters with each of them having 4 planes of plastic scintillators distributed in circular geometrical shape around the beam pipe on both sides of the CMS experiment and, at a distance of 15 m from the interaction point. The development of the concept was done in cooperation with CERN with the mass-production carried out at HIP. The results of its characterization at the PS and SPS at with muons/pions will be shown.Peer reviewe

A Study of a Quartz Bar Detector in the Forward Region of the CMS Experiment at LHC

In high rapidity regions of experiments at colliders (e.g. Large Hadron Collider LHC), along the direction of the interacting beams, the conditions are particularly challenging and the detectors need to have excellent time resolution, spatial resolution, high-rate capability and radiation resistance. Among various detector schemes proposed for these applications, combinations of Cherenkov radiators (quartz, sapphire, etc.) with fast photodetectors (e.g. Micro Channel Plate PMT (MCP PMT), Silicon PM (SiPM)) have been studied. Quartz-based calorimeters are already employed at CMS (Compact Muon Solenoid) experiment in the forward direction. Quartz bar array detectors were initially proposed as timing elements for the CT-PPS (CMS-TOTEM Precise Proton Spectrometer) project. We report here on the performance of one of these QUARTIC (QUARtz TIming Cherenkov) detectors, which was installed in 2018 (as test prototype) in the CMS Forward Zone near the CMS beam pipe

Erratum to: Search for dark matter and unparticles in events with a Z boson and missing transverse momentum in proton-proton collisions at s=13\sqrt{s}=13 TeV

A search for dark matter and unparticle production at the LHC has been performed using events containing two charged leptons (electrons or muons), consistent with the decay of a Z boson, and large missing transverse momentum. This study is based on data collected with the CMS detector in 2015, corresponding to an integrated luminosity of 2.3 inverse femtobarns of proton-proton collisions at the LHC, at a center-of-mass energy of 13 TeV. No excess over the standard model expectation is observed. Compared to previous searches in this topology, which exclusively relied on effective field theories, the results are interpreted in terms of a simplified model of dark matter production for both vector and axial vector couplings between a mediator and dark matter particles. The first study of this class of models using CMS data at $\sqrt{s}=13$ TeV is presented. Additionally, effective field theories of dark matter and unparticle production are used to interpret the data

A search for Higgs boson pair production in the bbtautau final state in proton-proton collisions at sqrt(s) = 8 TeV

Results are presented from a search for production of Higgs boson pairs (HH) where one boson decays to a pair of b quarks and the other to a tau lepton pair. This work is based on proton-proton collision data collected by the CMS experiment at sqrt(s) = 8 TeV, corresponding to an integrated luminosity of 18.3 inverse femtobarns. Resonant and non-resonant modes of HH production have been probed and no significant excess relative to the background-only hypotheses has been found in either mode. Upper limits on cross sections of the two HH production modes have been set. The results have been combined with previously published searches at sqrt(s) = 8 TeV, in decay modes to two photons and two b quarks, as well as to four b quarks, which also show no evidence for a signal. Limits from the combination have been set on resonant HH production by an unknown particle X in the mass range m[X] = 300 GeV to m[X] = 1000 GeV. For resonant production of spin 0 (spin 2) particles, the observed 95% CL upper limit is 1.13 pb (1.09 pb) at m[X] = 300 GeV and to 21 fb (18 fb) at m[X] = 1000 GeV. For non-resonant HH production, a limit of 43 times the rate predicted by the standard model has been set

Study of jet quenching with Z+jet correlations in PbPb and pp collisions at sNN\sqrt{s_{NN}} = 5.02 TeV

The production of jets in association with Z bosons, reconstructed via the mu+mu- and e+e- decay channels, is studied in pp and, for the first time, in PbPb collisions. Both data samples were collected by the CMS experiment at the LHC, at a center-of-mass energy of 5.02 TeV. The PbPb collisions were analyzed in the 0-30% centrality range. The back-to-back azimuthal alignment was studied in both pp and PbPb collisions for Z bosons with transverse momentum ptz > 60 GeV/c and a recoiling jet with ptj > 30 GeV/c. The pt imbalance, xjz= ptj/ptz, as well as the average number of jet partners per Z, rjz, were studied in intervals of ptz, in both pp and PbPb collisions. The rjz is found to be smaller in PbPb than in pp collisions, which suggests that in PbPb collisions a larger fraction of partons, associated with the Z bosons, lose energy and fall below the 30 GeV/c ptj threshold

Search for electroweak production of a vector-like quark decaying to a top quark and a Higgs boson using boosted topologies in fully hadronic final states

A search is performed for electroweak production of a vector-like top quark partner T of charge 2/3 in association with a standard model top or bottom quark, using 2.3 inverse femtobarns of proton-proton collision data at $\sqrt{s} =$ 13 TeV collected by the CMS experiment at the CERN LHC. The search targets T quarks decaying to a top quark and a Higgs boson in fully hadronic final states. For a T quark with mass above 1 TeV the daughter top quark and Higgs boson are highly Lorentz-boosted and can each appear as a single hadronic jet. Jet substructure and b tagging techniques are used to identify the top quark and Higgs boson jets, and to suppress the standard model backgrounds. An excess of events is searched for in the T quark candidate mass distribution in the data, which is found to be consistent with the expected backgrounds. Upper limits at 95% confidence level are set on the product of the single T quark production cross sections and the branching fraction $B(T \to tH)$, and these vary between 0.31 and 0.93 pb for T quark masses in the range 1000-1800 GeV. This is the first search for single electroweak production of a vector-like T quark in fully hadronic final states

Searches for pair production for third-generation squarks in sqrt(s)=13 TeV pp collisions

Searches are presented for direct production of top or bottom squark pairs in proton-proton collisions at the CERN LHC. Two searches, based on complementary techniques, are performed in all-jet final states that are characterized by a significant imbalance in transverse momentum. An additional search requires the presence of a charged lepton isolated from other activity in the event. The data were collected in 2015 at a centre-of-mass energy of 13 TeV with the CMS detector and correspond to an integrated luminosity of 2.3 inverse femtobarns. No statistically significant excess of events is found beyond the expected contribution from standard model processes. Exclusion limits are set in the context of simplified models of top or bottom squark pair production. Models with top and bottom squark masses up to 830 and 890 GeV, respectively, are probed for light neutralinos. For models with top squark masses of 675 GeV, neutralino masses up to 260 GeV are excluded at 95% confidence level

Search for massive resonances decaying into WW, WZ or ZZ bosons in proton-proton collisions at s=\sqrt{s} = 13 TeV

A search is presented for new massive resonances decaying to WW, WZ or ZZ bosons in $\ell \nu q\overline{q}$ and $q\overline{q}q\overline{q}$ final states. Results are based on data corresponding to an integrated luminosity of 2.3-2.7 fb$^{−1}$ recorded in proton-proton collisions at $\sqrt{s}=13$ TeV with the CMS detector at the LHC. Decays of spin-1 and spin-2 resonances into two vector bosons are sought in the mass range 0.6-4.0 TeV. No significant excess over the standard model background is observed. Combining the results of the $\ell \nu q\overline{q}$ and $q\overline{q}q\overline{q}$ final states, cross section and mass exclusion limits are set for models that predict heavy spin-1 and spin-2 resonances. This is the first search for a narrow-width spin-2 resonance at $\sqrt{s}=13$ TeV