Бодров Денис Алексеевич
Международная лаборатория физики конденсированного состояния
Профессиональные интересы
Должности
- Аспирант — Международная лаборатория физики конденсированного состояния
- Научный сотрудник — Московский институт электроники и математики им. А.Н. Тихонова, Международная лаборатория физики элементарных частиц
Био
- · Начал работать в НИУ ВШЭ в 2020 году.
- · Научно-педагогический стаж: 2 года.
Образование
- 2021 · Магистратура: Московский физико-технический институт (национальный исследовательский университет), специальность «Прикладные математика и физика», квалификация «Магистр»
- 2019 · Бакалавриат: Московский физико-технический институт (государственный университет), специальность «Прикладные математика и физика», квалификация «Бакалавр»
Опыт работы
- · 2021 - н.в.: март : младший научный сотрудник, лаборатория тяжелых кварков и лептонов ФИАН
- · 2020: сентябрь декабрь
- · 2020: : техник, физтех кластер академической и научной карьеры ЛФИ МФТИ
- · 2020 - н.в.: май : стажер-исследователь, международная лаборатория физики элементарных частиц МИЭМ ВШЭ
- · 2020: февраль май
- · 2020: : техник, физтех кластер академической и научной карьеры ЛФИ МФТИ
- · 2018: март декабрь
- · 2020: : техник, лаборатория физики высоких энергий МФТИ
Идентификаторы исследователя
- ResearcherID:
AAH-3024-2021
Публикации (110)
Two-particle angular correlations in e+e− collisions to hadronic final states in two reference coordinates at Belle
2023 · ARTICLE · en
We present the analysis of two-particle angular correlations using coordinate systems defined with the conventional beam axis and the event thrust axis. We propose the latter as a good representation for the correlation structure interpretation in the e(+)e(-) collision system. The e(+)e(-) collisions to hadronic final states at center-of-mass energies of vs = 10.52 GeV and 10.58 GeV are recorded by the Belle detector at KEKB. In this paper, results on the first dataset are supplementary to the previous Belle publication [1]. At the same time, the latter is the first two-particle correlation measurement at collision energy on the Y(4S) resonance and is sensitive to its decay products. Measurements are reported as a function of the charged-particle multiplicity. Finally, a qualitative understanding of the correlation structure is discussed using a combination of Monte Carlo simulations and experimental data.
Search for the decay Bs → π0π0 at Belle
2023 · ARTICLE · en
We report the results of the first search for the decay B0s→π0π0 using 121.4 fb−1 of data collected at the Υ(5S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider. We observe no signal and set a 90% confidence level upper limit of 7.7×10−6 on the B0s→π0π0 decay branching fraction.
Search for CP violation and measurement of branching fractions and decay asymmetry parameters for Lambda(+)(c) -> Lambda h(+) and Lambda(+)(c) -> Sigma(0)h(+) (h = K, pi)
2023 · ARTICLE · en
We report a study of Lambda(+)(c)-> Lambda h(+) and Lambda(+)(c)-> Sigma(0)h(+) (h = K, pi) decays based on a data sample of 980 fb(-1) collected with the Belle detector at the KEKB energy-asymmetric e(+)e(-) collider. The first results of direct CP asymmetry in two-body singly Cabibbo-suppressed (SCS) decays of charmed baryons are measured, A(CP)(dir)(Lambda(+)(c)-> Lambda K+) = +0.021 +/- 0.026 +/- 0.001 and A(CP)(dir)(Lambda(+)(c)-> Sigma K-0(+)) = +0.025 +/- 0.054 +/- 0.004. We also make the most precise measurement of the decay asymmetry parameters (alpha) for the four modes of interest and search for CP violation via the alpha-induced CP asymmetry (A(CP)(alpha)). We measure A(CP)(alpha)(Lambda(+)(c)-> Lambda K+) = -0.023 +/- 0.086 +/- 0.071 and A(CP)(alpha)(Lambda(+)(c)-> Sigma K-0(+)) = +0.08 +/- 0.35 +/- 0.14, which are the first A(CP)(alpha) results for SCS decays of charmed baryons. We search for Lambda-hyperon CP violation in Lambda(+)(c)-> Lambda(+)(c)-> (Lambda, Sigma(0))pi(+) and find A(CP)(alpha)(Lambda -> p pi(-)) = +0.013 +/- 0.007 +/- 0.011. This is the first time that hyperon CP violation has been measured via Cabibbo-favored charm decays. No evidence of baryon CP violation is found. We also obtain the most precise branching fractions for two SCS Lambda(c+) decays, B(Lambda(+)(c) -> Lambda K+) = (6.57 +/- 0.17 +/- 0.11 +/- 0.35) x 10(-4) and B(Lambda(+)(c) -> Sigma K-0(+)) = (3.58 +/- 0.19 +/- 0.06 +/- 0.19) x 10(-4). The first uncertainties are statistical and the second systematic, while the third uncertainties come from the uncertainties on the world average branching fractions of Lambda(+)(c)-> (Lambda, Sigma(0))pi(+).
Measurement of the Michel Parameters ξ′ , ξ′′ , η′′ , α′/A , and β′/A in the τ−→μ−ν¯μντ Decay at the Future Super Charm-Tau Factory
2023 · ARTICLE · en
A method for measuring all Michel parameters describing the daughter muon polarization in the tau(-) -> mu(-) (nu(mu)) over bar nu(tau) decay, i.e., xi', xi", eta", alpha'/A, and beta'/A, is discussed. The application of the method to the future Super Charm-Tau Factory experiment is considered. The statistical uncertainties expected by the full data statistics (10 ab(-1)) are estimated as sigma(xi') = 0.006, sigma(xi'') = 0.03, sigma(eta'') = 0.02, sigma(alpha'/A) = 0.014, and sigma(beta'/A) = 0.007. On their basis, upper limits on the coupling constants of interactions beyond the Standard Model are estimated. The New Physics scenario is considered, which can be reliably detected if the estimated accuracy of the xi' parameter measurement is achieved.
First observation of Λπ+ and Λπ− signals near the K N (I = 1) mass threshold in Λc+ → Λπ+π+π− decay
2023 · ARTICLE · en
Using the data sample of 980 fb-1 collected with the Belle detector operating at the KEKB asymmetric -energy e+e- collider, we present the results of an investigation of the Az+ and Az- invariant mass distributions looking for substructure in the decay A+c -> Az+z+z-. We find a significant signal in each mass distribution. When interpreted as resonances, we find for the Az+ (Az-) combination a mass of 1434.3 +/- 0.6(stat) +/- 0.9(syst) MeV=c2 [1438.5 +/- 0.9(stat) +/- 2.5(syst) MeV=c2], an intrinsic width of 11.5 +/- 2.8(stat) +/- 5.3(syst) MeV=c2 [33.0 +/- 7.5(stat) +/- 23.6(syst) MeV=c2] with a significance of 7.5u (6.2u). As these two signals are very close to the over bar KN threshold, we also investigate the possibility of a over bar KN cusp, and find that we cannot discriminate between these two interpretations due to the limited size of the data sample.
Study of e+e− → Σ0Σ0 and Σ+Σ− by Initial State Radiation Method at Belle
2023 · ARTICLE · en
The processes e+e−→Σ0Σ-bar0 and e+e−→Σ+Σ-bar− are studied using initial-state-radiation events in a sample of 980 fb−1 collected with the Belle detector at the KEKB asymmetric-energy e+e− collider. The cross sections from the mass threshold to 3 GeV/c2 and the effective form factors of Σ0 and Σ+ are measured. In the charmonium region, we observe the decays J/ψ→Σ0Σ-bar0 and J/ψ→Σ+Σ-bar− and determine the respective branching fractions.
First observation of B → D1(→ Dπ+π−)ℓ+νℓ and measurement of the B → D(*)πℓ+νℓ and B → D(*)π+π−ℓ+νℓ branching fractions with hadronic tagging at Belle
2023 · ARTICLE · en
We report measurements of the ratios of branching fractions for B→¯D(*)πℓ+νℓ and B→¯D(*)π+π−ℓ+νℓ relative to B→¯D∗ℓ+νℓ decays with ℓ=e, μ. These results are obtained from a data sample that contains 772×106B¯B pairs collected near the Υ(4S) resonance with the Belle detector at the KEKB asymmetric energy e+e− collider. Fully reconstructing both B mesons in the event, we obtain B(B0→¯D0π−ℓ+νℓ)B(B0→D*−ℓ+νℓ)=(7.23±0.36±0.14)%, B(B+→D−π+ℓ+νℓ)B(B+→¯D*0ℓ+νℓ)=(6.78±0.24±0.18)%, B(B0→¯D*0π−ℓ+νℓ)B(B0→D*−ℓ+νℓ)=(11.10±0.48±0.23)%, B(B+→D*−π+ℓ+νℓ)B(B+→¯D*0ℓ+νℓ)=(9.50±0.33±0.34)%, B(B0→D−π+π−ℓ+νℓ)B(B0→D*−ℓ+νℓ)=(2.91±0.37±0.26)%, B(B+→¯D0π+π−ℓ+νℓ)B(B+→¯D*0ℓ+νℓ)=(3.10±0.26±0.22)%, B(B0→D*−π+π−ℓ+νℓ)B(B0→D*−ℓ+νℓ)=(0.99±0.43±0.20)%, B(B+→¯D*0π+π−ℓ+νℓ)B(B+→¯D*0ℓ+νℓ)=(1.25±0.27±0.15)%, where the uncertainties are statistical and systematic, respectively. These are the most precise measurements of these branching fraction ratios to date. The invariant mass spectra of the Dπ, D∗π, and Dππ systems are studied, and the branching fraction products B(B0→D*−2ℓ+νℓ)×B(D*−2→¯D0π−)=(0.157±0.015±0.005)%, B(B+→¯D*00ℓ+νℓ)×B(¯D*00→D−π+)=(0.054±0.022±0.005)%, B(B+→¯D*02ℓ+νℓ)×B(¯D*02→D−π+)=(0.163±0.011±0.008)%, B(B0→D−1ℓ+νℓ)×B(D−1→¯D*0π−)=(0.306±0.050±0.029)%, B(B0→D'−1ℓ+νℓ)×B(D'−1→¯D*0π−)=(0.206±0.068±0.025)%, B(B0→D*−2ℓ+νℓ)×B(D*−2→¯D*0π−)=(0.051±0.040±0.010)%, B(B+→¯D01ℓ+νℓ)×B(¯D01→D*−π+)=(0.249±0.023±0.015)%, B(B+→¯D'01ℓ+νℓ)×B(¯D'01→D*−π+)=(0.138±0.036±0.009)%, B(B+→¯D*02ℓ+νℓ)×B(¯D*02→D*−π+)=(0.137±0.026±0.009)%, B(B0→D−1ℓ+νℓ)×B(D−1→D−π+π−)=(0.102±0.013±0.009)%, B(B+→¯D01ℓ+νℓ)×B(¯D01→¯D0π+π−)=(0.105±0.011±0.009)%, are extracted. This is the first observation of the decays B→¯D1ℓ+νℓ with D1→Dπ+π−.
Search for lepton-flavor-violating τ decays into a lepton and a vector meson using the full Belle data sample
2023 · ARTICLE · en
Charged-lepton-flavor-violation is predicted in several new physics scenarios. We update the analysis of tau lepton decays into a light charged lepton (l = e(+/-) or mu(+/-)) and a vector meson (V-0 = rho(0), phi, omega, K-*0, or (K) over bar (*0)) using 980 fb(-1) of data collected with the Belle detector at the KEKB collider. No significant excess of such signal events is observed, and thus 90% credibility level upper limits are set on the tau -> lV(0) branching fractions in the range of (1.7- 4.3) x 10(-8). These limits are improved by 30% on average from the previous results.
First measurement of the Michel parameter ξ' in the τ−→μ−νμντ decay at Belle
2023 · ARTICLE · en
We report the first measurement of the Michel parameter ξ′ in the τ−→μ−¯νμντ decay with a new method proposed just recently. The measurement is based on the reconstruction of the τ−→μ−¯νμντevents with subsequent muon decay in flight in the Belle central drift chamber. The analyzed data sample of 988 fb−1 collected by the Belle detector corresponds to approximately 912×106 τ+τ−pairs. We measure ξ′=0.22±0.94(stat)±0.42(syst), which is in agreement with the standard model prediction of ξ′=1. Statistical uncertainty dominates in this study, being a limiting factor, while systematic uncertainty is well under control. Our analysis proved the practicability of this promising method and its prospects for further precise measurement in future experiments.
Study of the muon decay-in-flight in the τ−→μ−νμντ decay to measure the Michel parameter ξ'
2023 · ARTICLE · en
We present the first measurement of the Michel parameter ξ′ in the τ−→μ−¯νμντ decay using the full data sample of 988 fb−1 collected by the Belle detector operating at the KEKB asymmetric energy e+e− collider. The method is based on the reconstruction of the μ−→e−¯νeνμ decay-in-flight in the Belle central drift chamber and relies on the correlation between muon spin and its daughter electron momentum. We study the main sources of the background that can imitate the signal decay, such as kaon and pion decays-in-flight and charged particle scattering on the detector material. Highly efficient methods of their suppression are developed and applied to select 165 signal-candidate events. We obtain ξ′=0.22±0.94±0.42 where the first uncertainty is statistical, and the second one is systematic. The result is in agreement with the Standard Model prediction of ξ′=1.
Курсы (1)
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Основы современной физики: атомная и ядерная физика
2021/2022 · Бакалавриат · рус