Персона: Данилов, Михаил Владимирович
Загружается...
Email Address
Birth Date
Научные группы
Организационные подразделения
Организационная единица
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.
Статус
Фамилия
Данилов
Имя
Михаил Владимирович
Имя
172 results
Результаты поиска
Теперь показываю 1 - 10 из 172
- ПубликацияТолько метаданныеSearch for a charged Higgs boson decaying into top and bottom quarks in events with electrons or muons in proton-proton collisions at √s = 13 TeV(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 search is presented for a charged Higgs boson heavier than the top quark, produced in association with a top quark, or with a top and a bottom quark, and decaying into a top-bottom quark-antiquark pair. The search is performed using proton-proton collision data collected by the CMS experiment at the LHC at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb−1. Events are selected by the presence of a single isolated charged lepton (electron or muon) or an opposite-sign dilepton (electron or muon) pair, categorized according to the jet multiplicity and the number of jets identified as originating from b quarks. Multivariate analysis techniques are used to enhance the discrimination between signal and background in each category. The data are compatible with the standard model, and 95% confidence level upper limits of 9.6–0.01 pb are set on the charged Higgs boson production cross section times branching fraction to a top-bottom quark-antiquark pair, for charged Higgs boson mass hypotheses ranging from 200 GeV to 3 TeV. The upper limits are interpreted in different minimal supersymmetric extensions of the standard model. [Figure not available: see fulltext.]
- ПубликацияТолько метаданныеMeasurements of production cross sections of WZ and same-sign WW boson pairs in association with two jets in proton-proton collisions at s=13TeV(2020) Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Chistov, R.; Danilov, M.; Oskin, A.; Parygin, P.; Rusinov, V.; Matveev, V.; Чистов, Руслан Николаевич; Данилов, Михаил Владимирович; Русинов, Владимир Юрьевич; Матвеев, Виктор Анатольевич© 2020 The AuthorMeasurements of production cross sections of WZ and same-sign WW boson pairs in association with two jets in proton-proton collisions at s=13TeV at the LHC are reported. The data sample corresponds to an integrated luminosity of 137fb−1, collected with the CMS detector during 2016–2018. The measurements are performed in the leptonic decay modes [Formula presented] and [Formula presented], where ℓ,ℓ′=e, [Formula presented]. Differential fiducial cross sections as functions of the invariant masses of the jet and charged lepton pairs, as well as of the leading-lepton transverse momentum, are measured for W±W± production and are consistent with the standard model predictions. The dependence of differential cross sections on the invariant mass of the jet pair is also measured for WZ production. An observation of electroweak production of WZ boson pairs is reported with an observed (expected) significance of 6.8 (5.3) standard deviations. Constraints are obtained on the structure of quartic vector boson interactions in the framework of effective field theory.
- ПубликацияТолько метаданныеSearch for long-lived particles using delayed photons in proton-proton collisions at s =13 TeV(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 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.A search for long-lived particles decaying to photons and weakly interacting particles, using proton-proton collision data at s=13 TeV collected by the CMS experiment in 2016-2017 is presented. The data set corresponds to an integrated luminosity of 77.4 fb-1. Results are interpreted in the context of supersymmetry with gauge-mediated supersymmetry breaking, where the neutralino is long-lived and decays to a photon and a gravitino. Limits are presented as a function of the neutralino proper decay length and mass. For neutralino proper decay lengths of 0.1, 1, 10, and 100 m, masses up to 320, 525, 360, and 215 GeV are excluded at 95% confidence level, respectively. We extend the previous best limits in the neutralino proper decay length by up to one order of magnitude, and in the neutralino mass by up to 100 GeV.
- ПубликацияОткрытый доступSearch for dark matter produced in association with a Higgs boson decaying to a pair of bottom quarks in proton–proton collisions at √s=13Te(2019) Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; Chistov, R.; Danilov, M.; Parygin, P.; Philippov, D.; Polikarpov, S.; Tarkovskii, E.; Matveev, V.; Dremin, I.; Чистов, Руслан Николаевич; Данилов, Михаил Владимирович; Поликарпов, Сергей Михайлович; Матвеев, Виктор Анатольевич© 2019, CERN for the benefit of the CMS collaboration. A search for dark matter produced in association with a Higgs boson decaying to a pair of bottom quarks is performed in proton–proton collisions at a center-of-mass energy of 13Te collected with the CMS detector at the LHC. The analyzed data sample corresponds to an integrated luminosity of 35.9fb-1. The signal is characterized by a large missing transverse momentum recoiling against a bottom quark–antiquark system that has a large Lorentz boost. The number of events observed in the data is consistent with the standard model background prediction. Results are interpreted in terms of limits both on parameters of the type-2 two-Higgs doublet model extended by an additional light pseudoscalar boson a (2HDM+a) and on parameters of a baryonic Z ′ simplified model. The 2HDM+a model is tested experimentally for the first time. For the baryonic Z ′ model, the presented results constitute the most stringent constraints to date.
- ПубликацияОткрытый доступObservation of triple J/psi meson production in proton-proton collisions(2023) Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Bychkova, O.; Chistov, R.; Danilov, M.; Oskin, A.; Parygin, P.; Polikarpov, S.; Matveev, V.; Чистов, Руслан Николаевич; Данилов, Михаил Владимирович; Поликарпов, Сергей Михайлович; Матвеев, Виктор АнатольевичProtons consist of three valence quarks, two up-quarks and one down-quark, held together by gluons and a sea of quark-antiquark pairs. Collectively, quarks and gluons are referred to as partons. In a proton-proton collision, typically only one parton of each proton undergoes a hard scattering - referred to as single-parton scattering - leaving the remainder of each proton only slightly disturbed. Here, we report the study of double- and triple-parton scatterings through the simultaneous production of three J/psi mesons, which consist of a charm quark-antiquark pair, in proton-proton collisions recorded with the CMS experiment at the Large Hadron Collider. We observed this process - reconstructed through the decays of J/psi mesons into pairs of oppositely charged muons - with a statistical significance above five standard deviations. We measured the inclusive fiducial cross-section to be 272(-104)(+141) (stat) +/- 17 (syst) fb, and compared it to theoretical expectations for triple-J/psi meson production in single-, double- and triple-parton scattering scenarios. Assuming factorization of multiple hard-scattering probabilities in terms of single-parton scattering cross-sections, double- and triple-parton scattering are the dominant contributions for the measured process.
- ПубликацияТолько метаданныеSearches for physics beyond the standard model with the MT 2 variable in hadronic final states with and without disappearing tracks in proton–proton collisions at √s=13Te(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© 2019, CERN for the benefit of the CMS collaboration.Two related searches for phenomena beyond the standard model (BSM) are performed using events with hadronic jets and significant transverse momentum imbalance. The results are based on a sample of proton–proton collisions at a center-of-mass energy of 13Te, collected by the CMS experiment at the LHC in 2016–2018 and corresponding to an integrated luminosity of 137fb-1. The first search is inclusive, based on signal regions defined by the hadronic energy in the event, the jet multiplicity, the number of jets identified as originating from bottom quarks, and the value of the kinematic variable MT 2 for events with at least two jets. For events with exactly one jet, the transverse momentum of the jet is used instead. The second search looks in addition for disappearing tracks produced by BSM long-lived charged particles that decay within the volume of the tracking detector. No excess event yield is observed above the predicted standard model background. This is used to constrain a range of BSM models that predict the following: the pair production of gluinos and squarks in the context of supersymmetry models conserving R-parity, with or without intermediate long-lived charginos produced in the decay chain; the resonant production of a colored scalar state decaying to a massive Dirac fermion and a quark; or the pair production of scalar and vector leptoquarks each decaying to a neutrino and a top, bottom, or light-flavor quark. In most of the cases, the results obtained are the most stringent constraints to date.
- ПубликацияТолько метаданныеUsing Z Boson Events to Study Parton-Medium Interactions in Pb-Pb Collisions(2022) Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Ambrogi, F.; 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 CERN. 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 1.7 nb-1 and 320 pb-1, respectively. Hadronic collision data with one reconstructed Z boson candidate with the transverse momentum pT>30 GeV/c are analyzed. The Z boson constrains the initial energy and direction of the associated parton. In heavy ion events, azimuthal angular distributions of charged hadrons with respect to the direction of a Z boson are sensitive to modifications of the in-medium parton shower and medium response. compared to reference data from pp interactions, the results for central Pb-Pb collisions indicate a modification of the angular correlations. The measurements of the fragmentation functions and pT spectra of charged particles in Z boson events, which are sensitive to medium modifications of the parton shower longitudinal structure, are also reported. Significant modifications in central Pb-Pb events compared to the pp reference data are also found for these observables.
- ПубликацияТолько метаданныеSearch for dark matter produced in association with a leptonically decaying Z boson in proton–proton collisions at √s=13Te(2021) Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Chistov, R.; Danilov, M.; Parygin, P.; Philippov, D.; Polikarpov, S.; Matveev, V.; Чистов, Руслан Николаевич; Данилов, Михаил Владимирович; Поликарпов, Сергей Михайлович; Матвеев, Виктор Анатольевич© 2020, CERN for the benefit of the CMS collaboration.A search for dark matter particles is performed using events with a Z boson candidate and large missing transverse momentum. The analysis is based on proton–proton collision data at a center-of-mass energy of 13Te, collected by the CMS experiment at the LHC in 2016–2018, corresponding to an integrated luminosity of 137fb-1. The search uses the decay channels Z → e e and Z → μ μ. No significant excess of events is observed over the background expected from the standard model. Limits are set on dark matter particle production in the context of simplified models with vector, axial-vector, scalar, and pseudoscalar mediators, as well as on a two-Higgs-doublet model with an additional pseudoscalar mediator. In addition, limits are provided for spin-dependent and spin-independent scattering cross sections and are compared to those from direct-detection experiments. The results are also interpreted in the context of models of invisible Higgs boson decays, unparticles, and large extra dimensions.
- ПубликацияТолько метаданныеMeasurement of the inclusive and differential t(t)over-bar gamma cross sections in the single-lepton channel and EFT interpretation at root s=13 TeV(2021) Tumasyan, A.; Adam, W.; Andrejkovic, J. W.; Bergauer, T.; Danilov, M.; Bychkova, O.; Chistov, R.; Parygin, P.; Polikarpov, S.; Matveev, V.; Данилов, Михаил Владимирович; Чистов, Руслан Николаевич; Поликарпов, Сергей Михайлович; Матвеев, Виктор АнатольевичThe production cross section of a top quark pair in association with a photon is measured in proton-proton collisions at a center-of-mass energy of 13 TeV. The data set, corresponding to an integrated luminosity of 137 fb(-1), was recorded by the CMS experiment during the 2016-2018 data taking of the LHC. The measurements are performed in a fiducial volume defined at the particle level. Events with an isolated, highly energetic lepton, at least three jets from the hadronization of quarks, among which at least one is b tagged, and one isolated photon are selected. The inclusive fiducial t (t) over bar'gamma cross section, for a photon with transverse momentum greater than 20 GeV and pseudorapidity vertical bar eta vertical bar< 1.4442, is measured to be 798 +/- 7(stat) +/- 48(syst) fb, in good agreement with the prediction from the standard model at next-to-leading order in quantum chromodynamics. The differential cross sections are also measured as a function of several kinematic observables and interpreted in the framework of the standard model effective field theory (EFT), leading to the most stringent direct limits to date on anomalous electromagnetic dipole moment interactions of the top quark and the photon.
- ПубликацияОткрытый доступMeasurement of the top quark Yukawa coupling from t(t)over-bar kinematic distributions in the lepton plus jets final state in proton-proton collisions at root s=13 TeV(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 МихайловичResults are presented for an extraction of the top quark Yukawa coupling from top quark-antiquark (t (t) over bar) kinematic distributions in the lepton plus jets final state in proton-proton collisions, based on data collected by the CMS experiment at the LHC at root s = 13 TeV, corresponding to an integrated luminosity of 35.8 fb(-1). Corrections from weak boson exchange, including Higgs bosons, between the top quarks can produce large distortions of differential distributions near the energy threshold of t (t) over bar production. Therefore, precise measurements of these distributions are sensitive to the Yukawa coupling. Top quark events are reconstructed with at least three jets in the final state, and a novel technique is introduced to reconstruct the t (t) over bar system for events with one missing jet. This technique enhances the experimental sensitivity in the low invariant mass region, M-t (t) over bar. The data yields in M-t (t) over bar, the rapidity difference vertical bar y(t) - y((t) over bar)vertical bar, and the number of reconstructed jets are compared with distributions representing different Yukawa couplings. These comparisons are used to measure the ratio of the top quark Yukawa coupling to its standard model predicted value to be 1.07(-0.43)(+0.34) with an upper limit of 1.67 at the 95% confidence level.