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)
Evidence for a vector charmoniumlike state in e+e- → Ds+ Ds2∗ (2573)-+ c. c.
2020 · ARTICLE · en
We report the measurement of e+e-→Ds+Ds2∗(2573)-+c.c. via initial-state radiation using a data sample of an integrated luminosity of 921.9 fb-1 collected with the Belle detector at the γ(4S) and nearby. We find evidence for an enhancement with a 3.4σ significance in the invariant mass of Ds+Ds2∗(2573)-+c.c. The measured mass and width are (4619.8-8.0+8.9(stat.)±2.3(syst.)) MeV/c2 and (47.0-14.8+31.3(stat.)±4.6(syst.)) MeV, respectively. The mass, width, and quantum numbers of this enhancement are consistent with the charmoniumlike state at 4626 MeV/c2 recently reported by Belle in e+e-→Ds+Ds1(2536)-+c.c. The product of the e+e-→Ds+Ds2∗(2573)-+c.c. cross section and the branching fraction of Ds2∗(2573)-→D¯0K- is measured from Ds+Ds2∗(2573)- threshold to 5.6 GeV. © 2020 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.
First search for the ηc2(1D) in B decays at Belle
2020 · ARTICLE · en
The first dedicated search for the ηc2(1D) is carried out using the decays B+→ ηc2(1D)K+, B0 → ηc2(1D)KS0, B0→ ηc2(1D)π−K+, and B+→ ηc2(1D)π+KS0 with ηc2(1D) → hcγ. No significant signal is found. For the ηc2(1D) mass range between 3795 and 3845 MeV/c2, the branching-fraction upper limits are determined to be ℬ(B+→ ηc2(1D)K+) × ℬ(ηc2(1D) → hcγ)
Measurement of the integrated luminosity of the Phase 2 data of the Belle II experiment
2020 · ARTICLE · en
From April to July 2018, a data sample at the peak energy of the γ(4S) resonance was collected with the Belle II detector at the SuperKEKB electron-positron collider. This is the first data sample of the Belle II experiment. Using Bhabha and digamma events, we measure the integrated luminosity of the data sample to be (496.3 ± 0.3 ± 3.0) pb-1, where the first uncertainty is statistical and the second is systematic. This work provides a basis for future luminosity measurements at Belle II. © 2019 Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Sciences and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.
Study of B →p p ππ
2020 · ARTICLE · en
Using a data sample of 772×106 BB pairs collected on the Ï'(4S) resonance with the Belle detector at the KEKB asymmetric energy e+e-collider, we report the observation of B0→ppπ+π- A nd the first observation of B+→ppπ+π0. We measure a decay branching fraction of (0.83±0.17±0.17)×10-6 in B0→ppπ+π-for Mπ+π-
Observation of the Radiative Decays of ψ (1S) to χc1
2020 · ARTICLE · en
We report the first observation of the radiative decay of the ψ(1S) into a charmonium state. The significance of the observed signal of ψ(1S)→γχc1 is 6.3 standard deviations including systematics. The branching fraction is calculated to be B[ψ(1S)→γχc1]=[4.7-1.8+2.4(stat)-0.5+0.4(sys)×10-5]. We also searched for ψ(1S) radiative decays into χc0,2 and ηc(1S,2S), and set upper limits on their branching fractions. These results are obtained from a 24.9 fb-1 data sample collected with the Belle detector at the KEKB asymmetric-energy e+e- collider at a center-of-mass energy equal to the ψ(2S) mass using ψ(1S) tagging by the ψ(2S)→ψ(1S)π+π- transitions. © 2020 authors. Published by the American Physical Society.
Search for an Invisibly Decaying Z′ Boson at Belle II in e+e- →μ+μ- (e±μ) Plus Missing Energy Final States
2020 · ARTICLE · en
Theories beyond the standard model often predict the existence of an additional neutral boson, the Z′. Using data collected by the Belle II experiment during 2018 at the SuperKEKB collider, we perform the first searches for the invisible decay of a Z′ in the process e+e-→μ+μ-Z′ and of a lepton-flavor-violating Z′ in e+e-→e±μZ′. We do not find any excess of events and set 90% credibility level upper limits on the cross sections of these processes. We translate the former, in the framework of an Lμ-Lτ theory, into upper limits on the Z′ coupling constant at the level of 5×10-2-1 for MZ′≤6 GeV/c2. © 2020 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/" Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3.
Measurement of R (D) and R (D∗) with a Semileptonic Tagging Method
2020 · ARTICLE · en
The experimental results on the ratios of branching fractions R(D)=B(B→Dτ-ντ)/B(B→Dℓ-νℓ) and R(D∗)=B(B→D∗τ-ντ)/B(B→D∗ℓ-νℓ), where ℓ denotes an electron or a muon, show a long-standing discrepancy with the standard model predictions, and might hint at a violation of lepton flavor universality. We report a new simultaneous measurement of R(D) and R(D∗), based on a data sample containing 772×106 BB events recorded at the ϒ(4S) resonance with the Belle detector at the KEKB e+e- collider. In this analysis the tag-side B meson is reconstructed in a semileptonic decay mode and the signal-side τ is reconstructed in a purely leptonic decay. The measured values are R(D)=0.307±0.037±0.016 and R(D∗)=0.283±0.018±0.014, where the first uncertainties are statistical and the second are systematic. These results are in agreement with the standard model predictions within 0.2, 1.1, and 0.8 standard deviations for R(D), R(D∗), and their combination, respectively. This work constitutes the most precise measurements of R(D) and R(D∗) performed to date as well as the first result for R(D) based on a semileptonic tagging method. © 2020 authors.
Study of Electromagnetic Decays of Orbitally Excited Ξc Baryons
2020 · ARTICLE · en
Using 980 fb−1 of data collected with the Belle detector operating at the KEKB asymmetric-energy e^+e^- collider, we report a study of the electromagnetic decays of excited {charmed baryons} Ξc(2790) and Ξc(2815). A clear signal (8.6 standard deviations) is observed for Ξc(2815)0→Ξ0cγ, and we measure: B[Ξc(2815)0→Ξ0cγ]/B[Ξc(2815)0→Ξc(2645)+π−→Ξ0cπ+π−]=0.41±0.05±0.03. We also present evidence (3.8 standard deviations) for the similar decay of the Ξc(2790)0 and measure: B[Ξc(2790)0→Ξ0cγ]/B[Ξc(2790)0→Ξ′+cπ−→Ξ+cγπ−]=0.13±0.03±0.02. The first quoted uncertainties are statistical and the second systematic. We find no hint of the analogous decays of the Ξc(2815)+ and Ξc(2790)+ baryons and set upper limits at the 90% confidence level of: B[Ξc(2815)+→Ξ+cγ]/B[Ξc(2815)+→Ξc(2645)0π+→Ξ+cπ−π+]B[Ξc(2790)+→Ξ+cγ]/B[Ξc(2790)+→Ξ′0cπ+→Ξ0cγπ+] Approximate values of the partial widths of the decays are extracted, which can be used to discriminate between models of the underlying quark structure of these excited states.
Measurement of Branching Fractions of Λ+c→ηΛπ+, ηΣ0π+, Λ(1670)π+, and ηΣ(1385)+
2020 в печати · ARTICLE · en
We report branching fraction measurements of four decay modes of the Λ+c baryon, each of which includes an η meson and a Λ baryon in the final state, and all of which are measured relative to the Λ+c→pK−pi+ decay mode. The results are based on a 980 fb−1 data sample collected by the Belle detector at the KEKB asymmetric-energy e+e− collider. Two decays, ηΣ0π+ and Λ(1670)π+, are observed for the first time, while the measurements of the other decay modes, Λ+c→ηΛπ+ and ηΣ(1385)+, are more precise than those made previously. We obtain B(Λ+c→ηΛπ+)/B(Λ+c→pK−π+) = 0.293±0.003±0.014, B(Λ+c→ηΣ0π+)/B(Λ+c→pK−π+) = 0.120±0.006±0.006, B(Λ+c→Λ(1670)π+)×B(Λ(1670)→ηΛ)/B(Λ+c→pK−π+) = (5.54±0.29±0.73)×10−2, and B(Λ+c→ηΣ(1385)+)/B(Λ+c→pK−π+) = 0.192±0.006±0.016. The mass and width of the Λ(1670) are also precisely determined to be 1674.3±0.8±4.9 MeV/c2 and 36.1±2.4±4.8 MeV, respectively, where the uncertainties are statistical and systematic, respectively.
First Determination of the Spin and Parity of a Charmed-Strange Baryon, Ξc(2970)+
2020 в печати · ARTICLE · en
We report results from a study of the spin and parity of Ξc(2970)+ using a 980 fb−1 data sample collected by the Belle detector at the KEKB asymmetric-energy e+e− collider. The decay angle distributions in the chain Ξc(2970)+→Ξc(2645)0π+→Ξ+cπ−π+ are analyzed to determine the spin of this charmed-strange baryon. The angular distributions strongly favor the Ξc(2970)+ spin J=1/2 over 3/2 or 5/2, under an assumption that the lowest partial wave dominates in the decay. We also measure the ratio of Ξc(2970)+ decay branching fractions R=B[Ξc(2970)+→Ξc(2645)0π+]/B[Ξc(2970)+→Ξ′0cπ+]=1.67±0.29(stat.)+0.15−0.09(syst.)±0.25(IS), where the last uncertainty is due to possible isospin-symmetry-breaking effects. This R value favors the spin-parity JP=1/2+ with the spin of the light-quark degrees of freedom sl=0. This is the first determination of the spin and parity of a charmed-strange baryon.
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