Publications by authors named "Spanring M"

The structure of nucleons is multidimensional and depends on the transverse momenta, spatial geometry, and polarization of the constituent partons. Such a structure can be studied using high-energy photons produced in ultraperipheral heavy-ion collisions. The first measurement of the azimuthal angular correlations of exclusively produced events with two jets in photon-lead interactions at large momentum transfer is presented, a process that is considered to be sensitive to the underlying nuclear gluon polarization.

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The double differential cross sections of the Drell-Yan lepton pair (, dielectron or dimuon) production are measured as functions of the invariant mass , transverse momentum , and . The observable, derived from angular measurements of the leptons and highly correlated with , is used to probe the low- region in a complementary way. Dilepton masses up to 1 are investigated.

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Measurements of the associated production of a W boson and a charm ( ) quark in proton-proton collisions at a centre-of-mass energy of 8 are reported. The analysis uses a data sample corresponding to a total integrated luminosity of 19.7 collected by the CMS detector at the LHC.

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Multiparticle azimuthal correlations of prompt D^{0} mesons are measured in Pb-Pb collisions at a nucleon-nucleon center-of-mass energy of sqrt[s_{NN}]=5.02  TeV. For the first time, a four-particle cumulant method is used to extract the second Fourier coefficient of the azimuthal distribution (v_{2}) of D^{0} mesons as a function of event centrality and the D^{0} transverse momentum.

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A search for resonances decaying into a W boson and a radion, where the radion decays into two W bosons, is presented. The data analyzed correspond to an integrated luminosity of 138  fb^{-1} recorded in proton-proton collisions with the CMS detector at sqrt[s]=13  TeV. One isolated charged lepton is required, together with missing transverse momentum and one or two massive large-radius jets, containing the decay products of either two or one W bosons, respectively.

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Article Synopsis
  • A search for exclusive two-photon production via photon exchange in proton-proton collisions was conducted using data from the LHC in 2016, focusing on events with intact protons.
  • The analysis aimed to select events with a diphoton invariant mass above 350 GeV, ensuring both protons remained intact to minimize interference from strong interactions.
  • No events meeting the criteria were found, which allowed researchers to set new limits on two anomalous four-photon coupling parameters, revealing |ζ_{1}|<2.9×10^{-13} GeV^{-4} and |ζ_{2}|<6.0×10^{-13} GeV^{-4} at a 95% confidence level.
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A search for low-mass dilepton resonances in Higgs boson decays is conducted in the four-lepton final state. The decay is assumed to proceed via a pair of beyond the standard model particles, or one such particle and a boson. The search uses proton-proton collision data collected with the CMS detector at the CERN LHC, corresponding to an integrated luminosity of 137 , at a center-of-mass energy .

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The spectra measurements of charged hadrons produced in the shower of a parton originating in the same hard scattering with a leptonically decaying Z boson are reported in lead-lead nuclei (Pb-Pb) and proton-proton (pp) collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV. Both Pb-Pb and pp data sets are recorded by the CMS experiment at the LHC and correspond to an integrated luminosity of 1.

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A search for dark matter in the form of strongly interacting massive particles (SIMPs) using the CMS detector at the LHC is presented. The SIMPs would be produced in pairs that manifest themselves as pairs of jets without tracks. The energy fraction of jets carried by charged particles is used as a key discriminator to suppress efficiently the large multijet background, and the remaining background is estimated directly from data.

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The first evidence for X(3872) production in relativistic heavy ion collisions is reported. The X(3872) production is studied in lead-lead (Pb-Pb) collisions at a center-of-mass energy of sqrt[s_{NN}]=5.02  TeV per nucleon pair, using the decay chain X(3872)→J/ψπ^{+}π^{-}→μ^{+}μ^{-}π^{+}π^{-}.

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The first measurements of diboson production cross sections in proton-proton interactions at a center-of-mass energy of 5.02 TeV are reported. They are based on data collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 302  pb^{-1}.

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A combination of searches for top squark pair production using proton-proton collision data at a center-of-mass energy of 13 at the CERN LHC, corresponding to an integrated luminosity of 137 collected by the CMS experiment, is presented. Signatures with at least 2 jets and large missing transverse momentum are categorized into events with 0, 1, or 2 leptons. New results for regions of parameter space where the kinematical properties of top squark pair production and top quark pair production are very similar are presented.

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The measurement of the luminosity recorded by the CMS detector installed at LHC interaction point 5, using proton-proton collisions at in 2015 and 2016, is reported. The absolute luminosity scale is measured for individual bunch crossings using beam-separation scans (the van der Meer method), with a relative precision of 1.3 and 1.

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A search is presented for a heavy vector resonance decaying into a boson and the standard model Higgs boson, where the boson is identified through its leptonic decays to electrons, muons, or neutrinos, and the Higgs boson is identified through its hadronic decays. The search is performed in a Lorentz-boosted regime and is based on data collected from 2016 to 2018 at the CERN LHC, corresponding to an integrated luminosity of 137 . Upper limits are derived on the production of a narrow heavy resonance , and a mass below 3.

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A search for charged Higgs bosons produced in vector boson fusion processes and decaying into vector bosons, using proton-proton collisions at at the LHC, is reported. The data sample corresponds to an integrated luminosity of 137 collected with the CMS detector. Events are selected by requiring two or three electrons or muons, moderate missing transverse momentum, and two jets with a large rapidity separation and a large dijet mass.

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This paper presents new sets of parameters ("tunes") for the underlying-event model of the event generator. These parameters control the description of multiple-parton interactions (MPI) and colour reconnection in , and are obtained from a fit to minimum-bias data collected by the CMS experiment at , 7, and . The tunes are based on the NNPDF 3.

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Collinear (small-angle) and large-angle, as well as soft and hard radiations are investigated in three-jet and  + two-jet events collected in proton-proton collisions at the LHC. The normalized production cross sections are measured as a function of the ratio of transverse momenta of two jets and their angular separation. The measurements in the three-jet and  + two-jet events are based on data collected at a center-of-mass energy of 8 , corresponding to an integrated luminosity of 19.

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Results of the Model Unspecific Search in CMS (MUSiC), using proton-proton collision data recorded at the LHC at a centre-of-mass energy of 13 , corresponding to an integrated luminosity of 35.9 , are presented. The MUSiC analysis searches for anomalies that could be signatures of physics beyond the standard model.

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Production cross sections of the Higgs boson are measured in the ( ) decay channel. A data sample of proton-proton collisions at a center-of-mass energy of 13 , collected by the CMS detector at the LHC and corresponding to an integrated luminosity of 137 is used. The signal strength modifier , defined as the ratio of the Higgs boson production rate in the channel to the standard model (SM) expectation, is measured to be at a fixed value of .

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The rate for Higgs ( ) bosons production in association with either one ( ) or two ( ) top quarks is measured in final states containing multiple electrons, muons, or tau leptons decaying to hadrons and a neutrino, using proton-proton collisions recorded at a center-of-mass energy of by the CMS experiment. The analyzed data correspond to an integrated luminosity of 137 . The analysis is aimed at events that contain , , or decays and each of the top quark(s) decays either to lepton+jets or all-jet channels.

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The first measurement of the dependence of γγ→μ^{+}μ^{-} production on the multiplicity of neutrons emitted very close to the beam direction in ultraperipheral heavy ion collisions is reported. Data for lead-lead interactions at sqrt[s_{NN}]=5.02  TeV, with an integrated luminosity of approximately 1.

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The CMS experiment at the LHC has measured the differential cross sections of Z bosons decaying to pairs of leptons, as functions of transverse momentum and rapidity, in lead-lead collisions at a nucleon-nucleon center-of-mass energy of 5.02  TeV. The measured Z boson elliptic azimuthal anisotropy coefficient is compatible with zero, showing that Z bosons do not experience significant final-state interactions in the medium produced in the collision.

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A fiducial cross section for Wγ production in proton-proton collisions is measured at a center-of-mass energy of 13 TeV in 137  fb^{-1} of data collected using the CMS detector at the LHC. The W→eν and μν decay modes are used in a maximum-likelihood fit to the lepton-photon invariant mass distribution to extract the combined cross section. The measured cross section is compared with theoretical expectations at next-to-leading order in quantum chromodynamics.

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The Ξ_{b}^{-}π^{+}π^{-} invariant mass spectrum is investigated with an event sample of proton-proton collisions at sqrt[s]=13  TeV, collected by the CMS experiment at the LHC in 2016-2018 and corresponding to an integrated luminosity of 140  fb^{-1}. The ground state Ξ_{b}^{-} is reconstructed via its decays to J/ψΞ^{-} and J/ψΛK^{-}. A narrow resonance, labeled Ξ_{b}(6100)^{-}, is observed at a Ξ_{b}^{-}π^{+}π^{-} invariant mass of 6100.

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The production of Z boson pairs in proton-proton ( ) collisions, , where or , is studied at a center-of-mass energy of 13 with the CMS detector at the CERN LHC. The data sample corresponds to an integrated luminosity of 137 , collected during 2016-2018. The production cross section, , measured for events with two pairs of opposite-sign, same-flavor leptons produced in the mass region is consistent with standard model predictions.

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