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 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 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.
- 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 доступMeasurements of the pp WZ inclusive and differential production cross sections and constraints on charged anomalous triple gauge couplings at s=13 TeV(2019) Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Matveev, V.; Parygin, P.; Philippov, D.; Polikarpov, S.; Dremin, I.; Chadeeva, M.; Popova, E.; Rusinov, V.; Матвеев, Виктор Анатольевич; Поликарпов, Сергей Михайлович; Чадеева, Марина Валентиновна; Русинов, Владимир ЮрьевичThe WZ production cross section is measured in proton-proton collisions at a centre-of-mass energy = 13 TeV using data collected with the CMS detector, corresponding to an integrated luminosity of 35.9 fb(-1). The inclusive cross section is measured to be sigma(tot)(ppWZ)=48.0) pb, resulting in a total uncertainty of -2.78/+2.98 pb. Fiducial cross section and ratios of charge-dependent cross section measurements are provided. Differential cross section measurements are also presented with respect to three variables: the Z boson transverse momentum p(T), the leading jet p(T), and the M(WZ) variable, defined as the invariant mass of the system composed of the three leptons and the missing transverse momentum. Differential measurements with respect to the W boson p(T), separated by charge, are also shown. Results are consistent with standard model predictions, favouring next-to-next-to-leading-order predictions over those at next-to-leading order. Constraints on anomalous triple gauge couplings are derived via a binned maximum likelihood fit to the M(WZ) variable.
- ПубликацияОткрытый доступSearch for resonant production of second-generation sleptons with same-sign dimuon events 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, CERN for the benefit of the CMS collaboration. A search is presented for resonant production of second-generation sleptons (μ~ L , ν~ μ ) via the R-parity-violating coupling λ211′ to quarks, in events with two same-sign muons and at least two jets in the final state. The smuon (muon sneutrino) is expected to decay into a muon and a neutralino (chargino), which will then decay into a second muon and at least two jets. The analysis is based on the 2016 data set of proton-proton collisions at s=13TeV recorded with the CMS detector at the LHC, corresponding to an integrated luminosity of 35.9fb-1. No significant deviation is observed with respect to standard model expectations. Upper limits on cross sections, ranging from 0.24 to 730fb, are derived in the context of two simplified models representing the dominant signal contributions leading to a same-sign muon pair. The cross section limits are translated into coupling limits for a modified constrained minimal supersymmetric model with λ211′ as the only nonzero R-parity violating coupling. The results significantly extend restrictions of the parameter space compared with previous searches for similar models.
- 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 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 pair-produced three-jet resonances 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 has been performed for pair-produced resonances decaying into three jets. The proton-proton collision data used for this analysis were collected with the CMS detector in 2016 at a center-of-mass energy of 13 TeV and correspond to an integrated luminosity of 35.9 fb-1. The mass range from 200 to 2000 GeV is explored in four separate mass regions. The observations show agreement with standard model expectations. The results are interpreted within the framework of R-parity violating SUSY, where pair-produced gluinos decay to a six quark final state. Gluino masses below 1500 GeV are excluded at 95% confidence level. An analysis based on data with multijet events reconstructed at the trigger level extends the reach to masses as low as 200 GeV. Improved analysis techniques have led to enhanced sensitivity, allowing the most stringent limits to date to be set on gluino pair production.
- ПубликацияОткрытый доступSearch for an L μ − L τ gauge boson using Z → 4μ events in proton-proton collisions at s=13 TeV(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 a narrow Z ′ gauge boson with a mass between 5 and 70 GeV resulting from an L μ −L τ U(1) local gauge symmetry is reported. Theories that predict such a particle have been proposed as an explanation of various experimental discrepancies, including the lack of a dark matter signal in direct-detection experiments, tension in the measurement of the anomalous magnetic moment of the muon, and reports of possible lepton flavor universality violation in B meson decays. A data sample of proton-proton collisions at a center-of-mass energy of 13 TeV is used, corresponding to an integrated luminosity of 77.3 fb −1 recorded in 2016 and 2017 by the CMS detector at the LHC. Events containing four muons with an invariant mass near the standard model Z boson mass are analyzed, and the selection is further optimized to be sensitive to the events that may contain Z→Z ′ μμ→4μ decays. The event yields are consistent with the standard model predictions. Upper limits of 10 −8 –10 −7 at 95% confidence level are set on the product of branching fractions B(Z→Z ′ μμ)B(Z ′ →μμ), depending on the Z ′ mass, which excludes a Z ′ boson coupling strength to muons above 0.004–0.3. These are the first dedicated limits on L μ −L τ models at the LHC and result in a significant increase in the excluded model parameter space. The results of this search may also be used to constrain the coupling strength of any light Z ′ gauge boson to muons.
- ПубликацияОткрытый доступCombination of Searches for Higgs Boson Pair Production in Proton-Proton Collisions at root 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 ЮрьевичThis Letter describes a search for Higgs boson pair production using the combined results from four final states: bb gamma gamma, bb tau tau, bbbb, and bbVV, where V represents a W or Z boson. The search is performed using data collected in 2016 by the CMS experiment from LHC proton-proton collisions at root s = 13 TeV, corresponding to an integrated luminosity of 35.9 fb(-1). Limits are set on the Higgs boson pair production cross section. A 95% confidence level observed (expected) upper limit on the non-resonant production cross section is set at 22.2 (12.8) times the standard model value. A search for narrow resonances decaying to Higgs boson pairs is also performed in the mass range 250-3000 GeV. No evidence for a signal is observed, and upper limits are set on the resonance production cross section.