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Пахлов Павел Николаевич

Московский институт электроники и математики им. А.Н. Тихонова

Профиль на hse.ru ↗ тел.: 00000
Публикаций
126
Языков
2
Наград
3
Конференций
2
Профиль Публикации (126) Курсы (2)

Профессиональные интересы

физика элементарных частиц

Должности

  • Ведущий научный сотрудник — Московский институт электроники и математики им. А.Н. Тихонова, Международная лаборатория физики элементарных частиц
  • Профессор — Московский институт электроники и математики им. А.Н. Тихонова, Департамент электронной инженерии

Био

  • · Начал работать в НИУ ВШЭ в 2020 году.
  • · Научно-педагогический стаж: 8 лет.

Образование

  • 2008 · Доктор физико-математических наук: Высшая аттестационная комиссия Республика Болгария
  • 1990 · Специалитет: Московский физико-технический институт, специальность «Прикладная математика и физика», квалификация «Инженер-физик»

Опыт работы

  • · 2000 - н.в.: профессор кафедры физики элемнтарных частиц МФТИ
  • · 2009 - н.в.: профессор кафедры экспериментальной ядерной физики и космофизики МИФИ
  • · 2020 - н.в.: профессор кафедры дискретной математики МИЭМ ВШЭ

Награды и поощрения

  • · Надбавка за публикацию в журнале из Списка А (и приравненном к нему научном издании) (2025–2026, 2024–2025, 2023–2024)
  • · Надбавка за публикацию в международном рецензируемом научном издании (2021–2022)
  • · Лучший преподаватель — 2021–2022

Гранты и проекты

  • — · на соискание учёной степени кандидата наук

Конференции (2)

Показать все
  • · 2024: The 2024 International Workshop on Future Tau Charm Facilities (Хефей). Доклад: On possibility to measure all Michel parameters at SCTF
  • · 2020: 5th International Conference on Particle Physics and Astrophysics (Москва). Доклад: Recent experimental results in B physics

Идентификаторы исследователя

Публикации (126)

Measurement of the B+/B0 production ratio in e+e− collisions at the ϒ(4S) resonance using B → J/ψ(ℓℓ)K decays at Belle

2023 · ARTICLE · en

We measure the ratio of branching fractions for the gamma(4S) decays to B+/B- and B-0(B) over barB(0) using B+ -> J/psi(ll)K+ and B-0 -> J/psi(ll)K-0 samples, where J/psi(ll) stands for J/psi -> l(+)l(-) (l = e or mu), with 711 fb(-1) of data collected at the gamma(4S) resonance with the Belle detector. We find the decay rate ratio of gamma(4S) -> B-0(B) over barB(0) over gamma(4S) -> B-0(B) over barB(0) to be 1.065 +/- 0.012 +/- 0.019 +/- 0.047, which is the most precise measurement to date. The first and second uncertainties are statistical and systematic, respectively, and the third uncertainty is due to the assumption of isospin symmetry in B -> J/psi(ll)K.

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Measurement of the branching fraction and search for CP violation in D0 → KS0KS0π+π− decays at Belle

2023 · ARTICLE · en

We measure the branching fraction for the Cabibbo-suppressed decay D0 -> K0SK0S pi+pi- and search for CP violation via a measurement of the CP asymmetry ACP as well as the T-odd triple-product asymmetry aTCP. We use 922 fb-1 of data recorded by the Belle experiment, which ran at the KEKB asymmetric-energy e+e- collider. The branching fraction is measured relative to the Cabibbo-favored normalization channel D0 -> K0S pi+pi-; the result is B(D0 -> K0SK0S pi+pi-)=[4.79 +/- 0.08(stat)+/- 0.10(syst)+/- 0.31(norm)]x10-4, where the first uncertainty is statistical, the second is systematic, and the third is from uncertainty in the normalization channel. We also measure ACP=[-2.51 +/- 1.44(stat)+0.11-0.10(syst)]%, and aTCP=[-1.95 +/- 1.42(stat)+0.14-0.12(syst)]%. These results show no evidence of CP violation.

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Search for X(3872)→π+π−π0 at Belle

2023 · ARTICLE · en

We present a search for the decay X(3872)-> pi(+)pi(-) pi(0) in the (772 +/- 11 ) 10(6) gamma (4S) -> B B-bar data sample collected at the Belle detector, where the X(3872) thorn is produced in B +/- -> (KX)-X-+/-(3872) and B-0 -> (KSX)-X-0(3872) decays. We do not observe a signal, and set 90% credible upper limits for two different models of the decay processes: if the decay products are distributed uniformly in phase space, B(X(3872) -> pi(+)pi(-)pi(0) ) (0) pair in the process X(3872) -> D-0 over bar (D) over bar (0) thorn c:c: -> D-0 (D) over bar (0)pi(0) -> pi(+)pi(-) pi(0), B(X(3872) -> pi(+) pi(-) pi(0) )

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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.

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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.

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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.

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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.

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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−.

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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.

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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.

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Курсы (2)