Пахлова Галина Владимировна
Московский институт электроники и математики им. А.Н. Тихонова
Профессиональные интересы
Должности
- Ведущий научный сотрудник — Московский институт электроники и математики им. А.Н. Тихонова, Международная лаборатория физики элементарных частиц
Био
- · Начала работать в НИУ ВШЭ в 2020 году.
- · Научно-педагогический стаж: 4 года.
Образование
- 2011 · Доктор физико-математических наук: Высшая аттестационная комиссия Республика Болгария
- 1994 · Кандидат физико-математических наук: Институт теоретической и экспериментальной физики
- 1984 · Специалитет: Московский инженерно-физический институт, специальность «Экспериментальная ядерная физика», квалификация «Инженер-физик»
Идентификаторы исследователя
- ORCID:
0000-0001-7518-3022 - ResearcherID:
C-5378-2014 - SPIN РИНЦ:
1406-3272 - Google Scholar: https://scholar.google.com/citations?view_op=list_works&hl=en&user=fFiMLk0AAAAJ&gmla=AJsN-F7mn-IyCnEj_Ug1RmF450uvfNhIP59Uxymi_BKjMGYOUB8KunCrnueLqUiIeo_gIyW4wBX8b-M5m79_triQ4PcDP35zFxATkp5JZ_5okKDfZW6pyWs
- Scopus AuthorID:
35234620700
Публикации (189)
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.
Search for the double-charmonium state with ηc J/ψ at Belle
2023 · ARTICLE · en
We measure the cross section of e+e− → ηcJ/ψ at the Υ(nS)(n = 1–5) on-resonance and 10.52 GeV off-resonance energy points using the full data sample collected by the Belle detector with an integrated luminosity of 955 fb−1. We also search for double charmonium production in e+e− → ηcJ/ψ via initial state radiation near the ηcJ/ψ threshold. No evident signal of the double charmonium state is found, but evidence for the e+e− → ηcJ/ψ process is found with a statistical significance greater than 3.3σ near the ηcJ/ψ threshold. The average cross section near the threshold is measured and upper limits of cross sections are set for other regions.
Measurement of the e+e−→B0sB¯0sX cross section in the energy range from 10.63 to 11.02 GeV using inclusive D±s and D0 production
2023 · ARTICLE · en
We report the first measurement of the inclusive e+e−→bb¯→D±sX and e+e−→bb¯→D0/D¯0X cross sections in the energy range from 10.63 to 11.02. Based on these results, we determine σ(e+e−→B0sB¯0sX) and σ(e+e−→BB¯X) in the same energy range. We measure the fraction of B0s events at Υ(10860) to be fs=(22.0+2.0−2.1)%. We determine also the ratio of the B0s inclusive branching fractions B(B0s→D0/D¯0X)/B(B0s→D±sX)=0.416±0.018±0.092. The results are obtained using the data collected with the Belle detector at the KEKB asymmetric-energy e+e− collider.
First Simultaneous Determination of Inclusive and Exclusive |Vub|
2023 · ARTICLE · en
The first simultaneous determination of the absolute value of the Cabibbo-Kobayashi-Maskawa matrix element Vub using inclusive and exclusive decays is performed with the full Belle data set at the Υ(4S) resonance, corresponding to an integrated luminosity of 711 fb−1. We analyze collision events in which one B meson is fully reconstructed in hadronic modes. This allows for the reconstruction of the hadronic Xu system of the semileptonic b→uℓν¯ℓ decay. We separate exclusive B→πℓν¯ℓ decays from other inclusive B→Xuℓν¯ℓ and backgrounds with a two-dimensional fit, that utilizes the number of charged pions in the Xu system and the four-momentum transfer q2 between the B and Xu system. Combining our measurement with information from lattice QCD and QCD calculations of the inclusive partial rate as well as external experimental information on the shape of the B→πℓν¯ℓ form factor, we determine ∣∣Vexcl.ub∣∣=(3.78±0.23±0.16±0.14)×10−3 and ∣∣Vincl.ub∣∣=(3.88±0.20±0.31±0.09)×10−3, respectively, with the uncertainties being the statistical error, systematic errors, and theory errors. The ratio of ∣∣Vexcl.ub∣∣/∣∣Vincl.ub∣∣=0.97±0.12 is compatible with unity.
Search for the Lepton Flavor Violating Decays B+ → K+τ±ℓ∓ (ℓ=e,μ) at Belle
2023 · ARTICLE · en
We present a search for the lepton-flavour-violating decays B+→K+τ±ℓ∓, with ℓ=(e,μ), using the full data sample of 772×106 BB¯¯¯¯ pairs recorded by the Belle detector at the KEKB asymmetric-energy e+e− collider. We use events in which one B meson is fully reconstructed in a hadronic decay mode. We find no evidence for B±→K±τℓ decays and set upper limits on their branching fractions at the 90% confidence level in the (1-3)×10−5 range. The obtained limits are the world's best results.
Search for Bs0 → ℓ∓τ± with the Semi-leptonic Tagging Method at Belle
2023 · ARTICLE · en
We present a search for the lepton-flavor-violating decays B0s→ℓ∓τ±, where ℓ=e,μ, using the full data sample of 121 fb−1 collected at the Υ(5S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider. We use B0sB¯¯¯¯0s events in which one B0s meson is reconstructed in a semileptonic decay mode and the other in the signal mode. We find no evidence for B0s→ℓ∓τ± decays and set upper limits on their branching fractions at 90% confidence level as B(B0s→e∓τ±)
Study of the lineshape of X(3872) using B decays to D0D*0K
2023 · ARTICLE · en
We present a study of the X(3872) lineshape in the decay B→X(3872)K→D0¯D*0K using a data sample of 772×106 B¯B pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider. The peak near the threshold in the D0¯D*0 invariant mass spectrum is fitted using a relativistic Breit-Wigner lineshape. We determine the mass and width parameters to be mBW=3873.71+0.56−0.50(stat)±0.13(syst) MeV/c2 and ΓBW=5.2+2.2−1.5(stat)±0.4(syst) MeV, respectively. The branching fraction is found to be B(B+→X(3872)K+)×B(X(3872)→D0¯D*0)=(0.97+0.21−0.18(stat)±0.10(syst))×10−4. The signal from B0 decays is observed for the first time with 5.2σ significance, and the ratio of branching fractions between charged and neutral B decays is measured to be B(B0→X(3872)K0)/B(B+→X(3872)K+)=1.34+0.47−0.40(stat)+0.10−0.12(syst). The peak is also studied using a Flatté lineshape. We determine the lower limit on the D¯D∗ coupling constant g to be 0.075 at 95% credibility in the parameter region where the ratio of g to the mass difference from the D0¯D*0 threshold is equal to −15.11 GeV−1, as measured by LHCb.
First measurement of the Q2 distribution of X(3915) single-tag two-photon production
2023 · ARTICLE · en
We report the first measurement of the Q2 distribution of X(3915) produced by single-tag two-photon interactions. The decay mode used is X(3915)→J/ψω. The covered Q2 region is from 1.5 (GeV/c)2 to 10.0 (GeV/c)2. We observe 7.9±3.1(stat.)±1.5(syst.) events, where we expect 4.1±0.7 events based on the Q2=0 result from the no-tag two-photon process, extrapolated to higher Q2 region using the cc¯ model of Schuler, Berends, and van Gulik. The shape of the distribution is also consistent with this model; we note that statistical uncertainties are large.
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