Персона: Чадеева, Марина Валентиновна
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Институт ядерной физики и технологий
Цель ИЯФиТ и стратегия развития - создание и развитие научно-образовательного центра мирового уровня в области ядерной физики и технологий, радиационного материаловедения, физики элементарных частиц, астрофизики и космофизики.
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Марина Валентиновна
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- ПубликацияОткрытый доступSearch for invisible decays of a Higgs boson produced through vector boson fusion in proton-proton collisions at s=13TeV(2019) Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Chadeeva, M.; Parygin, P.; Philippov, D.; Polikarpov, S.; Popova, E.; Rusinov, V.; Dremin, I.; Matveev, V.; Чадеева, Марина Валентиновна; Поликарпов, Сергей Михайлович; Русинов, Владимир Юрьевич; Матвеев, Виктор Анатольевич© 2019 The Author(s) A search for invisible decays of a Higgs boson is performed using proton-proton collision data collected with the CMS detector at the LHC in 2016 at a center-of-mass energy s=13TeV, corresponding to an integrated luminosity of 35.9fb −1 . The search targets the production of a Higgs boson via vector boson fusion. The data are found to be in agreement with the background contributions from standard model processes. An observed (expected) upper limit of 0.33 (0.25), at 95% confidence level, is placed on the branching fraction of the Higgs boson decay to invisible particles, assuming standard model production rates and a Higgs boson mass of 125.09 GeV. Results from a combination of this analysis and other direct searches for invisible decays of the Higgs boson, performed using data collected at s=7, 8, and 13 TeV, are presented. An observed (expected) upper limit of 0.19 (0.15), at 95% confidence level, is set on the branching fraction of invisible decays of the Higgs boson. The combined limit represents the most stringent bound on the invisible branching fraction of the Higgs boson reported to date. This result is also interpreted in the context of Higgs-portal dark matter models, in which upper bounds are placed on the spin-independent dark-matter-nucleon scattering cross section.
- ПубликацияОткрытый доступSearch for supersymmetric partners of electrons and muons in proton–proton collisions at s=13TeV(2019) Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Chadeeva, M.; Parygin, P.; Philippov, D.; Polikarpov, S.; Popova, E.; Rusinov, V.; Matveev, V.; Dremin, I.; Чадеева, Марина Валентиновна; Поликарпов, Сергей Михайлович; Русинов, Владимир Юрьевич; Матвеев, Виктор Анатольевич© 2019 The Author(s) A search for direct production of the supersymmetric (SUSY) partners of electrons or muons is presented in final states with two opposite-charge, same-flavour leptons (electrons and muons), no jets, and large missing transverse momentum. The data sample corresponds to an integrated luminosity of 35.9 fb−1 of proton–proton collisions at s=13TeV, collected with the CMS detector at the LHC in 2016. The search uses the MT2 variable, which generalises the transverse mass for systems with two invisible objects and provides a discrimination against standard model backgrounds containing W bosons. The observed yields are consistent with the expectations from the standard model. The search is interpreted in the context of simplified SUSY models and probes slepton masses up to approximately 290, 400, and 450 GeV, assuming right-handed only, left-handed only, and both right- and left-handed sleptons (mass degenerate selectrons and smuons), and a massless lightest supersymmetric particle. Limits are also set on selectrons and smuons separately. These limits show an improvement on the existing limits of approximately 150 GeV.
- ПубликацияОткрытый доступMeasurements with silicon photomultipliers of dose-rate effects in the radiation damage of plastic scintillator tiles in the CMS hadron endcap calorimeter(2020) Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Chadeeva, M.; Chistov, R.; Danilov, M.; Parygin, P.; Philippov, D.; Polikarpov, S.; Popova, E.; Rusinov, V.; Tarkovskii, E.; Matveev, V.; Чадеева, Марина Валентиновна; Чистов, Руслан Николаевич; Данилов, Михаил Владимирович; Поликарпов, Сергей Михайлович; Русинов, Владимир Юрьевич; Матвеев, Виктор Анатольевич© 2020 CERN for the benefit of the CMS collaboration..Measurements are presented of the reduction of signal output due to radiation damage for two types of plastic scintillator tiles used in the hadron endcap (HE) calorimeter of the CMS detector. The tiles were exposed to particles produced in proton-proton (pp) collisions at the CERN LHC with a center-of-mass energy of 13 TeV, corresponding to a delivered luminosity of 50 fb-1. The measurements are based on readout channels of the HE that were instrumented with silicon photomultipliers, and are derived using data from several sources: A laser calibration system, a movable radioactive source, as well as hadrons and muons produced in pp collisions. Results from several irradiation campaigns using 60Co sources are also discussed. The damage is presented as a function of dose rate. Within the range of these measurements, for a fixed dose the damage increases with decreasing dose rate.
- ПубликацияОткрытый доступIdentification of heavy, energetic, hadronically decaying particles using machine-learning techniques(2020) Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Bychkova, O.; Chadeeva, M.; Parygin, P.; Popova, E.; Rusinov, V.; Matveev, V.; Чадеева, Марина Валентиновна; Русинов, Владимир Юрьевич; Матвеев, Виктор Анатольевич© 2020 CERN for the benefit of the CMS collaboration..Machine-learning (ML) techniques are explored to identify and classify hadronic decays of highly Lorentz-boosted W/Z/Higgs bosons and top quarks. Techniques without ML have also been evaluated and are included for comparison. The identification performances of a variety of algorithms are characterized in simulated events and directly compared with data. The algorithms are validated using proton-proton collision data at s = 13TeV, corresponding to an integrated luminosity of 35.9 fb-1. Systematic uncertainties are assessed by comparing the results obtained using simulation and collision data. The new techniques studied in this paper provide significant performance improvements over non-ML techniques, reducing the background rate by up to an order of magnitude at the same signal efficiency.
- ПубликацияОткрытый доступSearch for low-mass resonances decaying into bottom quark-antiquark pairs in proton-proton collisions at s =13 TeV(2019) Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Matveev, V.; Chadeeva, M.; Parygin, P.; Philippov, D.; Polikarpov, S.; Popova, E.; Rusinov, V.; Dremin, I.; Матвеев, Виктор Анатольевич; Чадеева, Марина Валентиновна; Поликарпов, Сергей Михайлович; Русинов, Владимир Юрьевич© 2019 CERN, for the CMS Collaboration. Published by the American Physical Society under the terms of the »https://creativecommons.org/licenses/by/4.0/» Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3. A search for narrow, low-mass, scalar, and pseudoscalar resonances decaying to bottom quark-antiquark pairs is presented. The search is based on events recorded in s=13 TeV proton-proton collisions with the CMS detector at the LHC, collected in 2016, and corresponding to an integrated luminosity of 35.9 fb-1. The search selects events in which the resonance would be produced with high transverse momentum because of the presence of initial- or final-state radiation. In such events, the decay products of the resonance would be reconstructed as a single large-radius jet with high mass and two-prong substructure. A potential signal would be identified as a narrow excess in the jet invariant mass spectrum. No evidence for such a resonance is observed within the mass range from 50 to 350 GeV, and upper limits at 95% confidence level are set on the product of the cross section and branching fraction to a bottom quark-antiquark pair. These constitute the first constraints from the LHC on exotic bottom quark-antiquark resonances with masses below 325 GeV.
- ПубликацияТолько метаданныеMeasurement of the Z boson differential production cross section using its invisible decay mode (Z → νν¯) in proton-proton collisions at √s = 13 TeV(2021) Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Matveev, V.; Bychkova, O.; Chadeeva, M.; Philippov, D.; Popova, E.; Rusinov, V.; Матвеев, Виктор Анатольевич; Чадеева, Марина Валентиновна; Русинов, Владимир Юрьевич© 2021, The Author(s).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 fb. [Figure not available: see fulltext.]
- ПубликацияТолько метаданныеMeasurement of anisotropic flow in XeXe collisions at 5.44 TeV with the CMS experiment(2019) Stojanovic, M.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Matveev, V.; Chadeeva, M.; Parygin, P.; Philippov, D.; Polikarpov, S.; Popova, E.; Rusinov, V.; Azarkin, M.; Dremin, I.; Kirakosyan, M.; Матвеев, Виктор Анатольевич; Чадеева, Марина Валентиновна; Поликарпов, Сергей Михайлович; Русинов, Владимир ЮрьевичNew measurements of anisotropic flow in XeXe collisions at a center-of-mass energy of 5.44 TeV per nucleon pair, collected by the CMS experiment at the LHC, are presented. The v(2), v(3) and v(4) Fourier coefficients of the anisotropic azimuthal distribution are obtained employing three different analysis techniques: two-particle correlations, the scalar product method, and multiparticle cumulants, which have different sensitivities to non-flow and flow fluctuation effects. The results are shown as a function of transverse momentum (P-T) for various centrality selections, and compared with corresponding results from PbPb collisions. These new measurements in a smaller nucleus-nucleus system than PbPb provide additional insights into the system-size dependence of the collective flow induced by the dominant collision geometry and its fluctuations. In particular, these results, compared to theoretical predictions and Monte Carlo generators, will provide important details on the system size dependence of the medium response in heavy ion collisions. They also offer a unique opportunity to study the onset of flow from small to large systems.
- ПубликацияТолько метаданныеMeasurement of the Wγ Production Cross Section in Proton-Proton Collisions at s =13 TeV and Constraints on Effective Field Theory Coefficients(2021) Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Matveev, V.; Bychkova, O.; Chadeeva, M.; Oskin, A.; Popova, E.; Zhemchugov, E.; Матвеев, Виктор Анатольевич; Чадеева, Марина Валентиновна© 2021 CERN. CERN, for the CMS Collaboration.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. In addition, 95% confidence level intervals are reported for anomalous triple-gauge couplings within the framework of effective field theory.
- ПубликацияТолько метаданныеSearch for chargino-neutralino production in events with Higgs and W bosons using 137 fb −1 of proton-proton collisions at √s = 13 TeV(2021) Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Matveev, V.; Chadeeva, M.; Oskin, A.; Parygin, P.; Popova, E.; Rusinov, V.; Матвеев, Виктор Анатольевич; Чадеева, Марина Валентиновна; Русинов, Владимир Юрьевич© 2021, The Author(s).A search for electroweak production of supersymmetric (SUSY) particles in final states with one lepton, a Higgs boson decaying to a pair of bottom quarks, and large missing transverse momentum is presented. The search uses data from proton-proton collisions at a center-of-mass energy of 13 TeV collected using the CMS detector at the LHC, corresponding to an integrated luminosity of 137 fb−1. The observed yields are consistent with backgrounds expected from the standard model. The results are interpreted in the context of a simplified SUSY model of chargino-neutralino production, with the chargino decaying to a W boson and the lightest SUSY particle (LSP) and the neutralino decaying to a Higgs boson and the LSP. Charginos and neutralinos with masses up to 820 GeV are excluded at 95% confidence level when the LSP mass is small, and LSPs with mass up to 350 GeV are excluded when the masses of the chargino and neutralino are approximately 700 GeV. [Figure not available: see fulltext.].
- ПубликацияТолько метаданныеMeasurements of angular distance and momentum ratio distributions in three-jet and Z + two-jet final states in pp collisions(2021) Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Matveev, V.; Bychkova, O.; Chadeeva, M.; Philippov, D.; Popova, E.; Rusinov, V.; Матвеев, Виктор Анатольевич; Чадеева, Марина Валентиновна; Русинов, Владимир Юрьевич© 2021, The Author(s).Collinear (small-angle) and large-angle, as well as soft and hard radiations are investigated in three-jet and Z + 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 Z + two-jet events are based on data collected at a center-of-mass energy of 8TeV, corresponding to an integrated luminosity of 19.8fb-1. The Z + two-jet events are reconstructed in the dimuon decay channel of the Z boson. The three-jet measurement is extended to include s=13TeV data corresponding to an integrated luminosity of 2.3fb-1. The results are compared to predictions from event generators that include parton showers, multiple parton interactions, and hadronization. The collinear and soft regions are in general well described by parton showers, whereas the regions of large angular separation are often best described by calculations using higher-order matrix elements.