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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)

Search for long-lived particles decaying to e±μ∓ν

2021 · ARTICLE · en

Long-lived particles decaying to e±μ∓νe±μ∓ν, with masses between 7 and 5050 GeV/c22 and lifetimes between 2 and 5050 ps, are searched for by looking at displaced vertices containing electrons and muons of opposite charges. The search is performed using 5.45.4 fb−1−1 of pppp collisions collected with the LHCb detector at a centre-of-mass energy of s√=13s=13 TeV. Three mechanisms of production of long-lived particles are considered: the direct pair production from quark interactions, the pair production from the decay of a Standard-Model-like Higgs boson with a mass of 125125 GeV/c22, and the charged current production from an on-shell WW boson with an additional lepton. No evidence of these long-lived states is obtained and upper limits on the production cross-section times branching fraction are set on the different production modes.

DOI ↗ PDF ↗

Search for the rare decay B0→J/ψϕ

2021 · ARTICLE · en

A search for the rare decay B0 → J/ψφ is performed using pp collision data collected with the LHCb detector at centre-of-mass energies of 7, 8 and 13 TeV, corresponding to an integrated luminosity of 9 fb−1. No significant signal of the decay is observed and an upper limit of 1.1 × 10−7 at 90% confidence level is set on the branching fraction.

DOI ↗ PDF ↗

Observation of the Λ0b→Λ+cK+K−π− decay

2021 · ARTICLE · en

The Λ0b→Λ+cK+K−π−Λb0→Λc+K+K−π− decay is observed for the first time using a data sample of proton-proton collisions at centre-of-mass energies of s√=7s=7 and 8 TeVTeV collected by the LHCbLHCb detector, corresponding to an integrated luminosity of 3fb−13fb−1. The ratio of branching fractions between the Λ0b→Λ+cK+K−π−Λb0→Λc+K+K−π− and the Λ0b→Λ+cD−sΛb0→Λc+Ds− decays is measured to be B(Λ0b→Λ+cK+K−π−)B(Λ0b→Λ+cD−s)=(9.26±0.29±0.46±0.26)×10−2,B(Λb0→Λc+K+K−π−)B(Λb0→Λc+Ds−)=(9.26±0.29±0.46±0.26)×10−2, where the first uncertainty is statistical, the second systematic and the third is due to the knowledge of the D−s→K+K−π−Ds−→K+K−π− branching fraction. No structure on the invariant mass distribution of the Λ+cK+Λc+K+ system is found, consistent with no open-charm pentaquark signature.

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Search for heavy neutral leptons in W+ → μ+μ± jet decays

2021 · ARTICLE · en

A search is performed for heavy neutrinos in the decay of a W boson into two muons and a jet. The data set corresponds to an integrated luminosity of approximately 3.0 fb−1 of proton–proton collision data at centre-of-mass energies of 7 and 8 TeV collected with the LHCb experiment. Both same-sign and opposite-sign muons in the final state are considered. Data are found to be consistent with the expected background. Upper limits on the coupling of a heavy neutrino with the Standard Model neutrino are set at 95% confidence level in the heavy-neutrino mass range from 5 to 50 GeV/c2. These are of the order of 10−3 for lepton-number-conserving decays and of the order of 10−4 for lepton-number-violating heavy-neutrino decays.

DOI ↗

Measurement of the CKM angle γ and B0s−B0s¯¯¯¯¯¯ mixing frequency with B0s→D∓sh±π±π∓ decays

2021 · ARTICLE · en

The CKM angle γγ is measured for the first time from mixing-induced CPCP violation between B0s→D∓sK±π±π∓Bs0→Ds∓K±π±π∓ and B¯0s→D±sK∓π∓π±B¯s0→Ds±K∓π∓π± decays reconstructed in proton-proton collision data corresponding to an integrated luminosity of 9 fb−1fb−1 recorded with the LHCb detector. A time-dependent amplitude analysis is performed to extract the CPCP-violating weak phase γ−2βsγ−2βs and, subsequently, γγ by taking the B0sBs0-B¯0sB¯s0 mixing phase βsβs as an external input. The measurement yields γ=(44±12)∘γ=(44±12)∘ modulo 180∘180∘, where statistical and systematic uncertainties are combined. An alternative model-independent measurement, integrating over the five-dimensional phase space of the decay, yields γ=(44+20−13)∘γ=(44−13+20)∘ modulo 180∘180∘. Moreover, the B0sBs0-B¯0sB¯s0 oscillation frequency is measured from the flavour-specific control channel B0s→D−sπ+π+π−Bs0→Ds−π+π+π− to be Δms=(17.757±0.007(stat.)±0.008(syst.))ps−1Δms=(17.757±0.007(stat.)±0.008(syst.))ps−1, consistent with and more precise than the current world-average value.

DOI ↗ PDF ↗

Study of B0s → J/ψπ+π−K+K− decays

2021 · ARTICLE · en

The decays B0s → J/ψπ+π−K+K− are studied using a data set corresponding to an integrated luminosity of 9fb−1, collected with the LHCb detector in proton-proton collisions at centre-of-mass energies of 7, 8 and 13 TeV. The decays B0s → J/ψK∗0K∗0 and B0s → χc1(3872)K+K−, where the K+K− pair does not originate from a φ meson, are ob- served for the first time. Precise measurements of the ratios of branching fractions between intermediate χc1(3872)φ, J/ψK∗0K∗0, ψ(2S)φ and χc1(3872)K+K− states are reported.

DOI ↗

Observation of a new excited D+s meson in B0 to D−D+K+π− decays

2021 · ARTICLE · en

Using pppp collision data corresponding to an integrated luminosity of 5.4fb−15.4fb−1 collected with the LHCb detector at a center-of-mass energy of 13TeV13TeV, the B0→D−D+K+π−B0→D−D+K+π− decay is studied. A new excited D+sDs+ meson is observed decaying into the D+K+π−D+K+π− final state with large statistical significance. The pole mass and width, and the spin-parity of the new state are measured with an amplitude analysis to be mR=2591±6±7MeVmR=2591±6±7MeV, ΓR=89±16±12MeVΓR=89±16±12MeV and JP=0−JP=0−, where the first uncertainty is statistical and the second systematic. Fit fractions for all components in the amplitude analysis are also reported. The new resonance, denoted as Ds0(2590)+Ds0(2590)+, is a strong candidate to be the Ds(21S0)+Ds(21S0)+ state, the radial excitation of the pseudoscalar ground-state D+sDs+ meson.

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Searches for 25 rare and forbidden decays of D+ and 𝐷+𝑠, Ds+ mesons

2021 · ARTICLE · en

A search is performed for rare and forbidden charm decays of the form D+ → h±l+l(′)∓, where h± is a pion or kaon and l(′)± is an electron or muon. The (s) measurements are performed using proton-proton collision data, corresponding to an inte- grated luminosity of 1.6fb−1, collected by the LHCb experiment in 2016. No evidence is observed for the 25 decay modes that are investigated and 90 % confidence level limits on the branching fractions are set between 1.4 × 10−8 and 6.4 × 10−6. In most cases, these results represent an improvement on existing limits by one to two orders of magnitude.

DOI ↗

Observation of new excited 𝐵0𝑠 states

2021 · ARTICLE · en

A structure is observed in the B± K ∓ mass spec- trum in a sample of proton–proton collisions at centre-of- mass energies of 7, 8, and 13 TeV, collected with the LHCb detector and corresponding to a total integrated luminosity of 9 fb−1. The structure is interpreted as the result of overlapping excited B0 states. With high significance, a two-peak ss hypothesis provides a better description of the data than a single resonance.

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Observation of a new Ξ0b state

2021 · ARTICLE · en

Using a proton-proton collision data sample collected by the LHCb experiment, corresponding to an integrated luminosity of 8.5 fb−1, the observation of a new excited Ξ0b resonance decaying to the Ξ−bπ+final state is presented. The state, referred to as Ξb(6227)0, has a measured mass and natural width of m(Ξb(6227)0)=6227.1+1.4−1.5±0.5 MeV and Γ(Ξb(6227)0)=18.6+5.0−4.1±1.4 MeV, where the uncertainties are statistical and systematic. The production rate of the Ξb(6227)0 state relative to that of the Ξ−b baryon in the kinematic region 2

DOI ↗

Курсы (9)