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Деркач Денис Александрович

Факультет компьютерных наук

Профиль на hse.ru ↗ тел.: 27266
Публикаций
226
Языков
3
Наград
6
Конференций
0
Профиль Публикации (226) Курсы (9)

Профессиональные интересы

физика высоких энергийанализ данных

Должности

  • Заведующий лабораторией — Факультет компьютерных наук, Институт искусственного интеллекта и цифровых наук, Научно-учебная лаборатория методов анализа больших данных
  • Доцент — Факультет компьютерных наук, Департамент больших данных и информационного поиска
  • Научный руководитель образовательной программы — Умные устройства: аппаратная разработка

Био

  • · Начал работать в НИУ ВШЭ в 2015 году.
  • · Научно-педагогический стаж: 7 лет.

Образование

  • 2010 · PhD: Университет Париж XI
  • 2007 · Магистратура: Санкт-Петербургский государственный университет, специальность «Физика», квалификация «Магистр»
  • 2004 · Бакалавриат: Санкт-Петербургский государственный университет, специальность «Физика», квалификация «Бакалавр»

Опыт работы

  • · 2017: н. в

Награды и поощрения

  • · Медаль "Признание - 10 лет успешной работы" НИУ ВШЭ (сентябрь 2025)
  • · Благодарность первого проректора НИУ ВШЭ (август 2024)
  • · Благодарность НИУ ВШЭ (май 2024)
  • · Почетная грамота Министерства науки и высшего образования Российской Федерации (ноябрь 2022)
  • · Благодарность первого проректора НИУ ВШЭ (август 2022)
  • · Благодарность Факультета компьютерных наук НИУ ВШЭ (август 2018)

Гранты и проекты

  • — · на соискание учёной степени кандидата наук

Идентификаторы исследователя

Публикации (226)

Measurement of the prompt-production cross-section ratio σ(χc2)/σ(χc1) in pPb collisions at sNN=8.16 TeV

2021 · ARTICLE · en

This article reports the first measurement of prompt χc1 and χc2 charmonium production in nuclear collisions at Large Hadron Collider energies. The cross-section ratio σ(χc2)/σ(χc1) is measured in pPb collisions at sNN=8.16 TeV, collected with the LHCb experiment. The χc1,2 states are reconstructed via their decay to a J/ψ meson, subsequently decaying into a pair of oppositely charged muons, and a photon, which is reconstructed in the calorimeter or via its conversion in the detector material. The cross-section ratio is consistent with unity in the two considered rapidity regions. Comparison with a corresponding cross-section ratio previously measured by the LHCb Collaboration in pp collisions suggests that χc1 and χc2 states are similarly affected by nuclear effects occurring in pPb collisions.

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Measurement of CP Violation in the Decay B+→K+π0

2021 · ARTICLE · en

A measurement of CP violation in the decay B+→K+π0 is reported using data corresponding to an integrated luminosity of 5.4 fb−1 collected with the LHCb experiment at a center-of-mass energy of √s=13 TeV. The CP asymmetry is measured to be 0.025±0.015±0.006±0.003, where the uncertainties are statistical, systematic, and due to an external input. This is the most precise measurement of this quantity. It confirms and significantly enhances the observed anomalous difference between the direct CP asymmetries of the B0→K+π− and B+→K+π0 decays, known as the Kπ puzzle.

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Observation of the 𝐵0𝑠 → D*±D∓ decay

2021 · ARTICLE · en

A search for the Bs0 → D*±D∓ decay is performed using proton-proton collision data at centre-of-mass energies of 7, 8 and 13 TeV collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb−1. The decay is observed with a high significance and its branching fraction relative to the B0 → D*±D∓ decay is measured to be B(Bs0→D∗±D∓)/(B0→D∗±D∓)=0.137±0.017±0.002±0.006, where the first uncertainty is statistical, the second systematic and the third is due to the uncertainty on the ratio of the Bs0 and B0 hadronisation fractions.

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Evidence of a J/ψΛ structure and observation of excited Ξ− states in the Ξ−b→J/ψΛK− decay

2021 · ARTICLE · en

First evidence of a structure in the J/ψΛ invariant mass distribution is obtained from an amplitude analysis of Ξb-→J/ψΛK- decays. The observed structure is consistent with being due to a charmonium pentaquark with strangeness with a significance of 3.1σ including systematic uncertainties and look-elsewhere effect. Its mass and width are determined to be 4458.8±2.9-1.1+4.7MeV and 17.3±6.5-5.7+8.0MeV, respectively, where the quoted uncertainties are statistical and systematic. The structure is also consistent with being due to two resonances. In addition, the narrow excited Ξ- states, Ξ1690- and Ξ1820-, are seen for the first time in a Ξb- decay, and their masses and widths are measured with improved precision. The analysis is performed using pp collision data corresponding to a total integrated luminosity of 9 fb-1, collected with the LHCb experiment at centre-of-mass energies of 7, 8 and 13 TeV.

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Measurement of CP observables in B±→D(∗)K± and B±→D(∗)π± decays using two-body D final states

2021 · ARTICLE · en

Measurements of CP observables in B± → D(*)K± and B± → D(*)π± decays are presented, where D(∗) indicates a neutral D or D∗ meson that is an admixture of meson and anti-meson states. Decays of the D(∗) meson to the Dπ0 and Dγ final states are partially reconstructed without inclusion of the neutral pion or photon. Decays of the D meson are reconstructed in the K±π∓, K+K−, and π+π− final states. The analysis uses a sample of charged B mesons produced in proton-proton collisions and collected with the LHCb experiment, corresponding to integrated luminosities of 2.0, 1.0, and 5.7 fb−1 taken at centre-of-mass energies of 7, 8, and 13 TeV, respectively. The measurements of partially reconstructed B± → D(*)K± and B± → D(∗)π± with D → K∓π± decays are the first of their kind, and a first observation of the B± → (Dπ0)D∗π± decay is made with a significance of 6.1 standard deviations. All CP observables are measured with world-best precision, and in combination with other LHCb results will provide strong constraints on the CKM angle γ.

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Observation of CP violation in two-body B0(s)-meson decays to charged pions and kaons

2021 · ARTICLE · en

The time-dependent CP asymmetries of B0 → π+π− and B0s → K+K− decays are measured using a data sample of pp collisions corresponding to an integrated luminosity of 1.9 fb−1, collected with the LHCb detector at a centre-of-mass energy of 13 TeV. The results are Cππ=−0.311±0.045±0.015, Sππ=−0.706±0.042±0.013, CKK=0.123±0.034±0.015, SKK=0.164±0.034±0.014, AΔΓKK=−0.83±0.05±0.09, where the first uncertainties are statistical and the second systematic. The same data sample is used to measure the time-integrated CP asymmetries of B0 → K + π− and B0s → K−π+ decays and the results are AB0CP=−0.0824±0.0033±0.0033, AB0sCP=0.236±0.013±0.011. All results are consistent with earlier measurements. A combination of LHCb measurements provides the first observation of time-dependent CP violation in B0s decays.

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First observation of the decay B0s→K−μ+νμ and measurement of |Vub|/|Vcb|

2021 · ARTICLE · en

The first observation of the suppressed semileptonic B0s→K−μ+νμ decay is reported. Using a data sample recorded in pp collisions in 2012 with the LHCb detector, corresponding to an integrated luminosity of 2 fb−1, the branching fraction B(B0s→K−μ+νμ) is measured to be [1.06±0.05(stat)±0.08(syst)]×10−4, where the first uncertainty is statistical and the second one represents the combined systematic uncertainties. The decay B0s→D−sμ+νμ, where D−s is reconstructed in the final state K+K−π−, is used as a normalization channel to minimize the experimental systematic uncertainty. Theoretical calculations on the form factors of the B0s→K− and B0s→D−s transitions are employed to determine the ratio of the Cabibbo-Kobayashi-Maskawa matrix elements |Vub|/|Vcb| at low and high B0s→K− momentum transfer.

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Observation of the decay Λ0b → χc1pπ−

2021 · ARTICLE · en

The Cabibbo-suppressed decay Λ0b → χc1pπ− is observed for the first time us- ing data from proton-proton collisions corresponding to an integrated luminosity of 6 fb−1, collected with the LHCb detector at a centre-of-mass energy of 13 TeV. Evidence for the Λ0b → χc2pπ− decay is also found. Using the Λ0b → χc1pK− decay as normalisation channel, the ratios of branching fractions are measured to be... where the first uncertainty is statistical, the second is systematic and the third is due to the uncertainties in the branching fractions of χc1,2 → J/ψγ decays.

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Observation of New Resonances Decaying to J=ψK+ and J=ψφ

2021 · ARTICLE · en

The first observation of exotic states with a new quark content cc ̄us ̄ decaying to the J=ψKþ final state is reported with high significance from an amplitude analysis of the Bþ → J=ψφKþ decay. The analysis is carried out using proton-proton collision data corresponding to a total integrated luminosity of 9 fb−1 collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV. The most significant state, Z ð4000Þþ, has a mass of 4003  6þ4 MeV, a width of 131  15 26 MeV, and spin parity cs −14 JP 1⁄4 1þ, where the quoted uncertainties are statistical and systematic, respectively. A new 1þ Xð4685Þ state decaying to the J=ψφ final state is also observed with high significance. In addition, the four previously reported J=ψφ states are confirmed and two more exotic states, Zcsð4220Þþ and Xð4630Þ, are observed with significance exceeding 5 standard deviations.

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Angular Analysis of the B+→K*+μ+μ− Decay

2021 · ARTICLE · en

We present an angular analysis of the Bþ → Kþð→ K0SπþÞμþμ− decay using 9 fb−1 of pp collision data collected with the LHCb experiment. For the first time, the full set of CP-averaged angular observables is measured in intervals of the dimuon invariant mass squared. Local deviations from standard model predictions are observed, similar to those in previous LHCb analyses of the isospin-partner B0 → K0μþμ− decay. The global tension is dependent on which effective couplings are considered and on the choice of theory nuisance parameters.

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Курсы (9)