A Correction to this paper has been published: https://doi.org/10.1140/epjc/s10052-020-08739-5
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A Correction to this paper has been published: https://doi.org/10.1140/epjc/s10052-020-08739-5
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Measurements of the total and differential fiducial cross sections for the Z boson decaying into two neutrinos are presented at the LHC in proton-proton collisions at a center-of-mass energy of 13 TeV. The data were collected by the CMS... more
Measurements of the total and differential fiducial cross sections for the Z boson decaying into two neutrinos are presented at the LHC in proton-proton collisions at a center-of-mass energy of 13 TeV. The data were collected by the CMS detector in 2016 and correspond to an integrated luminosity of 35.9 fb−1. In these measurements, events are selected containing an imbalance in transverse momentum and one or more energetic jets. The fiducial differential cross section is measured as a function of the Z boson transverse momentum. The results are combined with a previous measurement of charged-lepton decays of the Z boson. The measured total fiducial cross section for events with Z boson transverse momentum greater than 200 GeV is $$ {3000}_{-170}^{+180} $$ 3000 − 170 + 180 fb.
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Measurements of the total and differential fiducial cross sections for the Z boson decaying into two neutrinos are presented at the LHC in proton-proton collisions at a center-of-mass energy of 13 TeV. The data were collected by the CMS... more
Measurements of the total and differential fiducial cross sections for the Z boson decaying into two neutrinos are presented at the LHC in proton-proton collisions at a center-of-mass energy of 13 TeV. The data were collected by the CMS detector in 2016 and correspond to an integrated luminosity of 35.9 fb−1. In these measurements, events are selected containing an imbalance in transverse momentum and one or more energetic jets. The fiducial differential cross section is measured as a function of the Z boson transverse momentum. The results are combined with a previous measurement of charged-lepton decays of the Z boson. The measured total fiducial cross section for events with Z boson transverse momentum greater than 200 GeV is $$ {3000}_{-170}^{+180} $$ 3000 − 170 + 180 fb.
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Abstract Droplets of quark-gluon plasma (QGP), an exotic state of strongly interacting quantum chromodynamics (QCD) matter, are routinely produced in heavy nuclei high-energy collisions. Although the experimental signatures marked a... more
Abstract Droplets of quark-gluon plasma (QGP), an exotic state of strongly interacting quantum chromodynamics (QCD) matter, are routinely produced in heavy nuclei high-energy collisions. Although the experimental signatures marked a paradigm shift away from expectations of a weakly coupled QGP, a challenge remains as to how the locally deconfined state with a lifetime of a few fm can be resolved. The only colored particle that decays mostly within the QGP is the top quark. Here we demonstrate, for the first time, that top quark decay products are identified, irrespective of whether interacting with the medium (bottom quarks) or not (leptonically decaying W bosons). Using 1.7±0.1 nb−1 of lead-lead (A = 208) collision data recorded by the CMS experiment at a nucleon-nucleon center-of-mass energy of 5.02 TeV, we report evidence of top quark pair ( t t ¯ ) production. Dilepton final states are selected, and the cross section ( σ t t ¯ ) is measured from a likelihood fit to a multivariate discriminator using lepton kinematic variables. The σ t t ¯ measurement is additionally performed considering the jets originating from the hadronization of bottom quarks, which improve the sensitivity to the t t ¯ signal process. After background subtraction and analysis corrections, the measured σ t t ¯ is 2.56 ± 0.82(tot) and 2.02 ± 0.69(tot)μb in the two cases, respectively, consistent with predictions from perturbative QCD.
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Abstract Droplets of quark-gluon plasma (QGP), an exotic state of strongly interacting quantum chromodynamics (QCD) matter, are routinely produced in heavy nuclei high-energy collisions. Although the experimental signatures marked a... more
Abstract Droplets of quark-gluon plasma (QGP), an exotic state of strongly interacting quantum chromodynamics (QCD) matter, are routinely produced in heavy nuclei high-energy collisions. Although the experimental signatures marked a paradigm shift away from expectations of a weakly coupled QGP, a challenge remains as to how the locally deconfined state with a lifetime of a few fm can be resolved. The only colored particle that decays mostly within the QGP is the top quark. Here we demonstrate, for the first time, that top quark decay products are identified, irrespective of whether interacting with the medium (bottom quarks) or not (leptonically decaying W bosons). Using 1.7±0.1 nb−1 of lead-lead (A = 208) collision data recorded by the CMS experiment at a nucleon-nucleon center-of-mass energy of 5.02 TeV, we report evidence of top quark pair ( t t ¯ ) production. Dilepton final states are selected, and the cross section ( σ t t ¯ ) is measured from a likelihood fit to a multivariate discriminator using lepton kinematic variables. The σ t t ¯ measurement is additionally performed considering the jets originating from the hadronization of bottom quarks, which improve the sensitivity to the t t ¯ signal process. After background subtraction and analysis corrections, the measured σ t t ¯ is 2.56 ± 0.82(tot) and 2.02 ± 0.69(tot)μb in the two cases, respectively, consistent with predictions from perturbative QCD.
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A search for a heavy Higgs boson in the mass range from 0.2 to 3.0 TeV, decaying to a pair of W bosons, is presented. The analysis is based on proton-proton collisions at $$ \sqrt{s} $$ s = 13 TeV recorded by the CMS experiment at the LHC... more
A search for a heavy Higgs boson in the mass range from 0.2 to 3.0 TeV, decaying to a pair of W bosons, is presented. The analysis is based on proton-proton collisions at $$ \sqrt{s} $$ s = 13 TeV recorded by the CMS experiment at the LHC in 2016, corresponding to an integrated luminosity of 35.9 fb−1. The W boson pair decays are reconstructed in the 2ℓ2ν and ℓν2q final states (with ℓ = e or μ). Both gluon fusion and vector boson fusion production of the signal are considered. Interference effects between the signal and background are also taken into account. The observed data are consistent with the standard model (SM) expectation. Combined upper limits at 95% confidence level on the product of the cross section and branching fraction exclude a heavy Higgs boson with SM-like couplings and decays up to 1870 GeV. Exclusion limits are also set in the context of a number of two-Higgs-doublet model formulations, further reducing the allowed parameter space for SM extensions.
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The average total energy as well as its hadronic and electromagnetic components are measured with the CMS detector at pseudorapidities $$-6.6<\eta <-5.2$$-6.6<η<-5.2 in proton-proton collisions at a centre-of-mass energy... more
The average total energy as well as its hadronic and electromagnetic components are measured with the CMS detector at pseudorapidities $$-6.6<\eta <-5.2$$-6.6<η<-5.2 in proton-proton collisions at a centre-of-mass energy $$\sqrt{s}=13\,\text {TeV} $$s=13TeV. The results are presented as a function of the charged particle multiplicity in the region $$|\eta |<2$$|η|<2. This measurement is sensitive to correlations induced by the underlying event structure over a very wide pseudorapidity region. The predictions of Monte Carlo event generators commonly used in collider experiments and ultra-high energy cosmic ray physics are compared to the data. All generators considered overestimate the fraction of energy going into hadrons.
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The mass of the top quark is measured using a sample of $${{\text {t}}\overline{{\text {t}}}}$$ t t ¯ events collected by the CMS detector using proton-proton collisions at $$\sqrt{s}=13$$ s = 13 $$\,\text {TeV}$$ TeV at the CERN LHC.... more
The mass of the top quark is measured using a sample of $${{\text {t}}\overline{{\text {t}}}}$$ t t ¯ events collected by the CMS detector using proton-proton collisions at $$\sqrt{s}=13$$ s = 13 $$\,\text {TeV}$$ TeV at the CERN LHC. Events are selected with one isolated muon or electron and at least four jets from data corresponding to an integrated luminosity of 35.9$$\,\text {fb}^{-1}$$ fb - 1 . For each event the mass is reconstructed from a kinematic fit of the decay products to a $${{\text {t}}\overline{{\text {t}}}}$$ t t ¯ hypothesis. Using the ideogram method, the top quark mass is determined simultaneously with an overall jet energy scale factor (JSF), constrained by the mass of the W boson in $${\text {q}} \overline{{\text {q}}} ^\prime $$ q q ¯ ′ decays. The measurement is calibrated on samples simulated at next-to-leading order matched to a leading-order parton shower. The top quark mass is found to be $$172.25 \pm 0.08\,\text {(stat+JSF)} \pm 0.62\,\text {(syst)} \,\t...
Research Interests: Physics, Quantum Physics, CMS, Kinematics, Calibration, and 3 moreExperimental results, DDC, and Higher order
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Research Interests: Physics, Nuclear Physics, Particle Physics, CMS, Large Hadron Collider, and 3 moreQuark, Muon, and Elsevier
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Research Interests: Mathematical Physics, Physics, Theoretical Physics, Nuclear Physics, Quantum Physics, and 15 moreParticle Physics, CMS, Charged Particle Optics, High Energy Physics, Large Hadron Collider, Multiplicity, Physical sciences, APS, Physical, American physical society, Kinetic Energy, NSD, Glauber, High energy, and Charged Particles
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A pulsed monoenergetic 7Li+ ion beam (lab. energy 10–40 eV) is scattered from a highly collimated (= 1.5°) H2 nozzle beam. The time-of-flight spectrum of the ions scattered in the forward laboratory direction shows both a fast peak... more
A pulsed monoenergetic 7Li+ ion beam (lab. energy 10–40 eV) is scattered from a highly collimated (= 1.5°) H2 nozzle beam. The time-of-flight spectrum of the ions scattered in the forward laboratory direction shows both a fast peak corresponding to forward center-of-mass scattering and a slow peak corresponding to wide-angle center-of-mass scattering. These peaks have been further resolved to show contributions from individual vibrational quantum transitions. From an analysis of the time-of flight spectra the differential inelastic cross sections for a wide range of angles and energies between 2 eV <Ecm < 9 eV have been determined. The spectra also contain information on rotational inelastic cross sections.
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The first LHC pp collisions at centre-of-mass energies of 0.9 and 2.36 TeV were recorded by the CMS detector in December 2009. The trajectories of charged particles produced in the collisions were reconstructed using the all-silicon... more
The first LHC pp collisions at centre-of-mass energies of 0.9 and 2.36 TeV were recorded by the CMS detector in December 2009. The trajectories of charged particles produced in the collisions were reconstructed using the all-silicon Tracker and their momenta were measured in the 3.8 T axial magnetic field. Results from the Tracker commissioning are presented including studies of timing, efficiency, signal-to-noise, resolution, and ionization energy. Reconstructed tracks are used to benchmark the ...
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A measurement of the underlying activity in scattering processes with p T scale in the GeV region is performed in proton–proton collisions at TeV, using data collected by the CMS experiment at the LHC. Charged particle production is... more
A measurement of the underlying activity in scattering processes with p T scale in the GeV region is performed in proton–proton collisions at TeV, using data collected by the CMS experiment at the LHC. Charged particle production is studied with reference to the direction of a leading object, either a charged particle or a set of charged particles forming a jet. Predictions of several QCD-inspired models as implemented in PYTHIA are compared, after full detector simulation, to the data. The models generally predict too little production ...