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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)

Constraints on the CKM angle γ from B± → Dh± decays using D → h±h′∓π0 final states

2022 · ARTICLE · en

A data sample collected with the LHCb detector corresponding to an integrated luminosity of 9 fb−1 is used to measure eleven CP violation observables in B± → Dh± decays, where h is either a kaon or a pion. The neutral D meson decay is reconstructed in the three-body final states: K±π∓π0; π+π−π0; K+K−π0 and the suppressed π±K∓π0 combination. The mode where a large CP asymmetry is expected, B± → [π±K∓π0]DK±, is observed with a significance greater than seven standard deviations. The ratio of the partial width of this mode relative to that of the favoured mode, B± → [K±π∓π0]DK±, is RADS(K) = (1.27 ± 0.16 ± 0.02) × 10−2. Evidence for a large CP asymmetry is also seen: AADS(K) = −0.38 ± 0.12 ± 0.02. Constraints on the CKM angle γ are calculated from the eleven reported observables.

DOI ↗ PDF ↗

Identification of charm jets at LHCb

2022 · ARTICLE · en

The identification of charm jets is achieved at LHCb for data collected in 2015–2018 using a method based on the properties of displaced vertices reconstructed and matched with jets. The performance of this method is determined using a dijet calibration dataset recorded by the LHCb detector and selected such that the jets are unbiased in quantities used in the tagging algorithm. The charm-tagging efficiency is reported as a function of the transverse momentum of the jet. The measured efficiencies are compared to those obtained from simulation and found to be in good agreement.

DOI ↗ PDF ↗

Observation of Λ0b → D+pπ−π− and Λ0b → D*+pπ−π− decays

2022 · ARTICLE · en

The multihadron decays Λ0bΛb0 → D+pπ−π− and Λ0bΛb0 → D*+pπ−π− are observed in data corresponding to an integrated luminosity of 3 fb−1, collected in proton-proton collisions at centre-of-mass energies of 7 and 8 TeV by the LHCb detector. Using the decay Λ0bΛb0 → Λ+cΛc+π+π−π− as a normalisation channel, the ratio of branching fractions is measured to be B(Λ0b→D+pπ−π−)B(Λ0b→Λ0cπ+π−π−)×B(D+→K−π+π+)B(Λ0c→pK−π−)=(5.35±0.21±0.16)%,B(Λb0→D+pπ−π−)B(Λb0→Λc0π+π−π−)×B(D+→K−π+π+)B(Λc0→pK−π−)=(5.35±0.21±0.16)%, where the first uncertainty is statistical and the second systematic. The ratio of branching fractions for the Λ0bΛb0 → D*+pπ−π− and Λ0bΛb0 → D+pπ−π− decays is found to be B(Λ0b→D∗+pπ−π−)B(Λ0b→D+pπ−π−)×(B(D∗+→D+π0)+B(D∗+→D+γ))=(61.3±4.3±4.0)%.

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First Measurement of the Z → μ + μ − Angular Coefficients in the Forward Region of pp Collisions at √s = 13 TeV

2022 · ARTICLE · en

The first study of the angular distribution of μþμ− pairs produced in the forward rapidity region via the Drell-Yan reaction pp → γ=Z þ X → lþl− þ X is presented, using data collected with the LHCb detector at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.1 fb−1. The coefficients of the five leading terms in the angular distribution are determined as a function of the dimuon transverse momentum and rapidity. The results are compared to various theoretical predictions of the Z-boson production mechanism and can also be used to probe transverse-momentum-dependent parton distributions within the proton.

DOI ↗ PDF ↗

Measurement of the charm mixing parameter y − yKπ using two-body D0 meson decays

2022 · ARTICLE · en

A measurement of the ratios of the effective decay widths of D0 → π−πþ and D0 → K−Kþ decays over that of D0 → K−πþ decays is performed with the LHCb experiment using proton–proton collisions at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 6 fb−1. These observables give access to the charm mixing parameters yππ − yKπ and yKK − yKπ , and are measured as CP CP yππ CP −yKπ CP 1⁄4ð6.570.530.16Þ×10−3, yKK −yKπ 1⁄4ð7.080.300.14Þ×10−3, where the first CP CP CP CP uncertainties are statistical and the second systematic. The combination of the two measurements is y −yKπ 1⁄4ð6.960.260.13Þ×10−3, which is four times more precise than the previous world average.

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Centrality determination in heavy-ion collisions with the LHCb detector

2022 · ARTICLE · en

The centrality of heavy-ion collisions is directly related to the created medium in these interactions. A procedure to determine the centrality of collisions with the LHCb detector is implemented for lead-lead collisions at √sNN = 5 TeV and lead-neon fixed-target collisions at √sNN = 69 GeV. The energy deposits in the electromagnetic calorimeter are used to determine and define the centrality classes. The correspondence between the number of participants and the centrality for the lead-lead collisions is in good agreement with the correspondence found in other experiments, and the centrality measurements for the lead-neon collisions presented here are performed for the first time in fixed-target collisions at the LHC.

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Test of lepton universality in beauty-quark decays

2022 · ARTICLE · en

The standard model of particle physics currently provides our best description of fundamental particles and their interactions. The theory predicts that the different charged leptons, the electron, muon and tau, have identical electroweak interaction strengths. Previous measurements have shown that a wide range of particle decays are consistent with this principle of lepton universality. This article presents evidence for the breaking of lepton universality in beauty-quark decays, with a significance of 3.1 standard deviations, based on proton–proton collision data collected with the LHCb detector at CERN’s Large Hadron Collider. The measurements are of processes in which a beauty meson transforms into a strange meson with the emission of either an electron and a positron, or a muon and an antimuon. If confirmed by future measurements, this violation of lepton universality would imply physics beyond the standard model, such as a new fundamental interaction between quarks and leptons.

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Analysis of Neutral B-Meson Decays into Two Muons

2022 · ARTICLE · en

Branching fraction and effective lifetime measurements of the rare decay B0s→μ+μ− and searches for the decays B0→μ+μ− and B0s→μ+μ−γare reported using proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7 TeV, 8 TeV and 13 TeV, corresponding to a luminosity of 9 fb−1. The branching fraction Br(B0s→μ+μ−)=(3.09+0.46+0.15−0.43−0.11)×10−9 and the effective lifetime τ(B0s→μ+μ−)=(2.07±0.29±0.03) are measured, where the first uncertainty is statistical and the second systematic. No significant signal for B0→μ+μ− and B0s→μ+μ−γ decays is found and upper limits Br(B0→μ+μ−)4.9GeV/c2. The results are in agreement with the Standard Model expectations.

DOI ↗ PDF ↗

Measurement of the B0s→μ+μ− decay properties and search for the B0→μ+μ− and B0s→μ+μ−γ decays

2022 · ARTICLE · en

An improved measurement of the decay B0s→μ+μ− and searches for the decays B0→μ+μ− and B0s→μ+μ−γ are performed at the LHCb experiment using data collected in proton-proton collisions at s√=7, 8and 13 TeV, corresponding to integrated luminosities of 1, 2 and 6 fb−1, respectively. The B0s→μ+μ− branching fraction and effective lifetime are measured to be Br(B0s→μ+μ−)=(3.09+0.46+0.15−0.43−0.11)×10−9 and τ(B0s→μ+μ−)=(2.07±0.29±0.03) ps, respectively, where the uncertainties include both statistical and systematic contributions. No significant signal for B0→μ+μ− and B0s→μ+μ−γ decays is found and the upper limits Br(B0→μ+μ−)4.9 GeV/c2. Additionally, the ratio between the B0→μ+μ− and B0s→μ+μ− branching fractions is measured to be Rμ+μ−

DOI ↗

Search for the radiative Ξ−b→Ξ−γ decay

2022 · ARTICLE · en

The first search for the rare radiative decay Ξ−𝑏→Ξ−γ is performed using data collected by the LHCb experiment in proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.4 fb−1. The Ξ−𝑏→ Ξ−J/ψ channel is used as normalization. No Ξ−𝑏→Ξ−γ signal is found and an upper limit of Br(Ξ−𝑏 → Ξ−γ) 1.3 × 10−4 at 95% confidence level is obtained.

DOI ↗

Курсы (9)