Персона: Данилов, Михаил Владимирович
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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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Михаил Владимирович
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172 results
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- ПубликацияТолько метаданныеMeasurements of the Electroweak Diboson Production Cross Sections in Proton-Proton Collisions at s =5.02 TeV Using Leptonic Decays(2021) Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Matveev, V.; Chistov, R.; Danilov, M.; Oskin, A.; Parygin, P.; Polikarpov, S.; Матвеев, Виктор Анатольевич; Чистов, Руслан Николаевич; Данилов, Михаил Владимирович; Поликарпов, Сергей Михайлович© 2021 CERN.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. Events with two, three, or four charged light leptons (electrons or muons) in the final state are analyzed. The WW, WZ, and ZZ total cross sections are measured as σWW=37.0-5.2+5.5(stat)-2.6+2.7(syst) pb, σWZ=6.4-2.1+2.5(stat)-0.3+0.5(syst) pb, and σZZ=5.3-2.1+2.5(stat)-0.4+0.5(syst) pb. All measurements are in good agreement with theoretical calculations at combined next-to-next-to-leading order quantum chromodynamics and next-to-leading order electroweak accuracy.
- ПубликацияТолько метаданныеEvidence for Higgs boson decay to a pair of muons(2021) Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Matveev, V.; Chistov, R.; Danilov, M.; Oskin, A.; Parygin, P.; Polikarpov, S.; Матвеев, Виктор Анатольевич; Чистов, Руслан Николаевич; Данилов, Михаил Владимирович; Поликарпов, Сергей Михайлович© 2021, The Author(s).Evidence for Higgs boson decay to a pair of muons is presented. This result combines searches in four exclusive categories targeting the production of the Higgs boson via gluon fusion, via vector boson fusion, in association with a vector boson, and in association with a top quark-antiquark pair. The analysis is performed using proton-proton collision data at s = 13 TeV, corresponding to an integrated luminosity of 137 fb−1, recorded by the CMS experiment at the CERN LHC. An excess of events over the back- ground expectation is observed in data with a significance of 3.0 standard deviations, where the expectation for the standard model (SM) Higgs boson with mass of 125.38 GeV is 2.5. The combination of this result with that from data recorded at s = 7 and 8 TeV, corresponding to integrated luminosities of 5.1 and 19.7 fb−1, respectively, increases both the expected and observed significances by 1%. The measured signal strength, relative to the SM prediction, is 1.19−0.39+0.40(stat)−0.14+0.15(syst). This result constitutes the first evidence for the decay of the Higgs boson to second generation fermions and is the most precise measurement of the Higgs boson coupling to muons reported to date. [Figure not available: see fulltext.].
- ПубликацияТолько метаданныеMeasurements of (tt)over-barH Production and the CP Structure of the Yukawa Interaction between the Higgs Boson and Top Quark in the Diphoton Decay Channel(2020) Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Bychkova, O.; Chistov, R.; Danilov, M.; Philippov, D.; Polikarpov, S.; Matveev, V.; Чистов, Руслан Николаевич; Данилов, Михаил Владимирович; Поликарпов, Сергей Михайлович; Матвеев, Виктор АнатольевичThe first observation of the (tt) over barH process in a single Higgs boson decay channel with the full reconstruction of the final state (H -> gamma gamma) is presented, with a significance of 6.6 standard deviations (sigma). The CP structure of Higgs boson couplings to fermions is measured, resulting in an exclusion of the pure CP-odd structure of the top Yukawa coupling at 3.2 sigma. The measurements are based on a sample of protonproton collisions at a center-of-mass energy root s = 13 TeV collected by the CMS detector at the LHC, corresponding to an integrated luminosity of 137 fb(-1). The cross section times branching fraction of the (tt) over barH process is measured to be sigma B-(tt) over barH(gamma gamma) = 1.56(-0.32)(+0.34) th, which is compatible with the standard model prediction of 1.13(-0.11)(+0.08) fb. The fractional contribution of the CP-odd component is measured to be f(CP)(Hu) = 0.00 +/- 0.33.
- ПубликацияТолько метаданныеObservation of the Production of Three Massive Gauge Bosons at root s=13 TeV(2020) Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Chistov, R.; Danilov, M.; Polikarpov, S.; Matveev, V.; Parygin, P.; Oskin, A.; Чистов, Руслан Николаевич; Данилов, Михаил Владимирович; Поликарпов, Сергей Михайлович; Матвеев, Виктор АнатольевичThe first observation is reported of the combined production of three massive gauge bosons (VVV with V = W, Z) in proton-proton collisions at a center-of-mass energy of 13 TeV. The analysis is based on a data sample recorded by the CMS experiment at the CERN LHC corresponding to an integrated luminosity of 137 fb(-1). The searches for individualWWW, WWZ, WZZ, and ZZZ production are performed in final states with three, four, five, and six leptons (electrons or muons), or with two same-sign leptons plus one or two jets. The observed (expected) significance of the combinedVVV production signal is 5.7 (5.9) standard deviations and the corresponding measured cross section relative to the standard model prediction is 1.02(-0.23)(+0.26). The significances of the individual WWW and WWZ production are 3.3 and 3.4 standard deviations, respectively. Measured production cross sections for the individual triboson processes are also reported.
- ПубликацияТолько метаданныеSearch for pair production of first-generation scalar leptoquarks at root s=13 TeV(2019) Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Matveev, V.; Chistov, R.; Danilov, M.; Parygin, P.; Philippov, D.; Polikarpov, S.; Tarkovskii, E.; Dremin, I.; Матвеев, Виктор Анатольевич; Чистов, Руслан Николаевич; Данилов, Михаил Владимирович; Поликарпов, Сергей МихайловичA search for the pair production of first-generation scalar leptoquarks is performed using proton-proton collision data recorded at 13 TeV center-of-mass energy with the CMS detector at the LHC. The data correspond to an integrated luminosity of 35.9 fb(-1). The leptoquarks are assumed to decay promptly to a quark and either an electron or a neutrino, with branching fractions beta and 1 - beta, respectively. The search targets the decay final states comprising two electrons, or one electron and large missing transverse momentum, along with two quarks that are detected as hadronic jets. First-generation scalar leptoquarks with masses below 1435 (1270) GeVare excluded for beta = 1.0(0.5). These are the most stringent limits on the mass of first-generation scalar leptoquarks to date. The data are also interpreted to set exclusion limits in the context of an R-parity violating supersymmetric model, predicting promptly decaying top squarks with a similar dielectron final state.
- ПубликацияТолько метаданныеSearch for low-mass dilepton resonances in Higgs boson decays to four-lepton final states in proton–proton collisions at √s=13TeV(2022) Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Matveev, V.; Chistov, R.; Danilov, M.; Oskin, A.; Parygin, P.; Polikarpov, S.; Матвеев, Виктор Анатольевич; Чистов, Руслан Николаевич; Данилов, Михаил Владимирович; Поликарпов, Сергей Михайлович© 2022, The Author(s).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 Z boson. The search uses proton–proton collision data collected with the CMS detector at the CERN LHC, corresponding to an integrated luminosity of 137fb-1, at a center-of-mass energy s=13TeV. No significant deviation from the standard model expectation is observed. Upper limits at 95% confidence level are set on model-independent Higgs boson decay branching fractions. Additionally, limits on dark photon and axion-like particle production, based on two specific models, are reported.
- ПубликацияТолько метаданныеEvidence for X(3872) in Pb-Pb Collisions and Studies of its Prompt Production at sNN =5.02 TeV(2022) Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Matveev, V.; Bychkova, O.; Chistov, R.; Danilov, M.; Polikarpov, S.; Tarkovskii, E.; Матвеев, Виктор Анатольевич; Чистов, Руслан Николаевич; Данилов, Михаил Владимирович; Поликарпов, Сергей Михайлович© 2022 CERN. 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 sNN=5.02 TeV per nucleon pair, using the decay chain X(3872)→J/ψπ+π-→μ+μ-π+π-. The data were recorded with the CMS detector in 2018 and correspond to an integrated luminosity of 1.7 nb-1. The measurement is performed in the rapidity and transverse momentum ranges |y|<1.6 and 15
- ПубликацияТолько метаданныеMeasurement of differential cross sections for Z bosons produced in association with charm jets in pp collisions at √s = 13 TeV(2021) Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Matveev, V.; Chistov, R.; Danilov, M.; Oskin, A.; Parygin, P.; Polikarpov, S.; Матвеев, Виктор Анатольевич; Чистов, Руслан Николаевич; Данилов, Михаил Владимирович; Поликарпов, Сергей Михайлович© 2021, The Author(s).Measurements are presented of differential cross sections for the production of Z bosons in association with at least one jet initiated by a charm quark in pp collisions at s = 13 TeV. The data recorded by the CMS experiment at the LHC correspond to an integrated luminosity of 35.9 fb−1. The final states contain a pair of electrons or muons that are the decay products of a Z boson, and a jet consistent with being initiated by a charm quark produced in the hard interaction. Differential cross sections as a function of the transverse momentum pT of the Z boson and pT of the charm jet are compared with predictions from Monte Carlo event generators. The inclusive production cross section 405.4 ± 5.6 (stat) ± 24.3 (exp) ± 3.7 (theo) pb, is measured in a fiducial region requiring both leptons to have pseudorapidity |η| < 2.4 and pT> 10 GeV, at least one lepton with pT> 26 GeV, and a mass of the pair in the range 71–111 GeV, while the charm jet is required to have pT> 30 GeV and |η| < 2.4. These are the first measurements of these cross sections in proton-proton collisions at 13 TeV. [Figure not available: see fulltext.]
- ПубликацияТолько метаданныеSearch for supersymmetry in proton-proton collisions at 13 TeV in final states with jets and missing transverse momentum(2019) Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Matveev, V.; Bychkova, O.; Chistov, R.; Danilov, M.; Polikarpov, S.; Tarkovskii, E.; Матвеев, Виктор Анатольевич; Чистов, Руслан Николаевич; Данилов, Михаил Владимирович; Поликарпов, Сергей Михайлович© 2019, The Author(s).Results are reported from a search for supersymmetric particles in the final state with multiple jets and large missing transverse momentum. The search uses a sample of proton-proton collisions at s = 13 TeV collected with the CMS detector in 2016–2018, corresponding to an integrated luminosity of 137 fb−1, representing essentially the full LHC Run 2 data sample. The analysis is performed in a four-dimensional search region defined in terms of the number of jets, the number of tagged bottom quark jets, the scalar sum of jet transverse momenta, and the magnitude of the vector sum of jet transverse momenta. No significant excess in the event yield is observed relative to the expected background contributions from standard model processes. Limits on the pair production of gluinos and squarks are obtained in the framework of simplified models for supersymmetric particle production and decay processes. Assuming the lightest supersymmetric particle to be a neutralino, lower limits on the gluino mass as large as 2000 to 2310 GeV are obtained at 95% confidence level, while lower limits on the squark mass as large as 1190 to 1630 GeV are obtained, depending on the production scenario. [Figure not available: see fulltext.].
- ПубликацияТолько метаданныеA search for the standard model Higgs boson decaying to charm quarks(2020) Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Matveev, V.; Bychkova, O.; Chistov, R.; Danilov, M.; Polikarpov, S.; Tarkovskii, E.; Матвеев, Виктор Анатольевич; Чистов, Руслан Николаевич; Данилов, Михаил Владимирович; Поликарпов, Сергей Михайлович© 2020, The Author(s).A direct search for the standard model Higgs boson, H, produced in association with a vector boson, V (W or Z), and decaying to a charm quark pair is presented. The search uses a data set of proton-proton collisions corresponding to an integrated luminosity of 35.9 fb−1, collected by the CMS experiment at the LHC in 2016, at a centre-of-mass energy of 13 TeV. The search is carried out in mutually exclusive channels targeting specific decays of the vector bosons: W → ℓν, Z → ℓℓ, and Z → νν, where ℓ is an electron or a muon. To fully exploit the topology of the H boson decay, two strategies are followed. In the first one, targeting lower vector boson transverse momentum, the H boson candidate is reconstructed via two resolved jets arising from the two charm quarks from the H boson decay. A second strategy identifies the case where the two charm quark jets from the H boson decay merge to form a single jet, which generally only occurs when the vector boson has higher transverse momentum. Both strategies make use of novel methods for charm jet identification, while jet substructure techniques are also exploited to suppress the background in the merged-jet topology. The two analyses are combined to yield a 95% confidence level observed (expected) upper limit on the cross section σ(VH)ℬ(H→cc¯) of 4.5 (2.4−0.7+1.0) pb, corresponding to 70 (37) times the standard model prediction. [Figure not available: see fulltext.]