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)
Measurement of the branching fraction of Λc+→pω decay at Belle
2021 · ARTICLE · en
Using 980.6 /fb of data collected with the Belle detector operating at the KEKB asymmetric-energy e+e- collider, we present a measurement of the branching fraction of the singly Cabibbo-suppressed decay Λс+ → pω. A clear Λс+ signal is observed for Λс+ → pω with a statistical significance of 9.1 standard deviations, and we measure the ratio of branching fractions B(Λс+ → pω)/B(Λс+ → pK-π+)=(1.32±0.12(stat)±0.10(syst))×10-2, from which we infer the branching fraction B(Λс+ → pω)=(8.27±0.75(stat)±0.62(syst)±0.42(ref))×10-4. The first quoted uncertainty is statistical, the second systematic, and the third from the reference mode Λс+ → pK-π+.
Search for the dark photon in B0→A′A′, A′→e+e−, μ+μ−, and π+π− decays at Belle
2021 · ARTICLE · en
We present a search for the dark photon A′ in the B0 → A′A′ decays, where A′ subsequently decays to e+e−, μ+μ−, and π+π−. The search is performed by analyzing 772 × 106 BB events collected by the Belle detector at the KEKB e+e− energy- asymmetric collider at the Υ(4S) resonance. No signal is found in the dark photon mass range0.01GeV/c2≤mA′ ≤2.62GeV/c2,andwesetupperlimitsofthebranchingfraction of B0 → A′A′ at the 90% confidence level. The products of branching fractions, B(B0 → A′A′) × B(A′ → e+e−)2 and B(B0 → A′A′) × B(A′ → μ+μ−)2, have limits of the order of 10−8 depending on the A′ mass. Furthermore, considering A′ decay rate to each pair of charged particles, the upper limits of B(B0 → A′A′) are of the order of 10−8–10−5. From the upper limits of B(B0 → A′A′), we obtain the Higgs portal coupling for each assumed dark photon and dark Higgs mass. The Higgs portal couplings are of the order of 10−2–10−1 atmh′ ≃mB0 ±40MeV/c2 and10−1–1atmh′ ≃mB0 ±3GeV/c2.
Measurement of the branching fraction of the decay B+→π+π−l+νl in fully reconstructed events at Belle
2021 · ARTICLE · en
We present an analysis of the exclusive B+→π+π−ℓ+νℓ decay, where ℓ represents an electron or a muon, with the assumption of charge-conjugation symmetry and lepton universality. The study exploits the full Υ(4S) data sample collected by the Belle detector, corresponding to 711 fb−1 of integrated luminosity. Events are selected by fully reconstructing one B meson in hadronic decay modes, subsequently determining the properties of the other B meson. We extract the signal yields using a binned maximum-likelihood fit to the missing-mass squared distribution in bins of the invariant mass of the two pions or the momentum transfer squared. We measure a total branching fraction of B(B+→π+π−ℓ+νℓ)=[22.7+1.9−1.6(stat)±3.5(syst)]×10−5, where the uncertainties are statistical and systematic, respectively. This result is the first reported measurement of this decay.
Measurement of branching fractions and CP asymmetries for D+s→K+(η,π0) and D+s→π+(η,π0)decays at Belle
2021 · ARTICLE · en
We report measurements of the branching fractions and CP asymmetries for Dþs → Kþη, Dþs → Kþπ0, þþ þþ0 and Ds → π η decays, and the branching fraction for Ds → π π . Our results are based on a data sample corresponding to an integrated luminosity of 921 fb−1 collected by the Belle detector at the KEKB eþe− asymmetric-energy collider. Our measurements of CP asymmetries in these decays are the most precise to date; no evidence for CP violation is found.
First determination of the spin and parity of the charmed-strange baryon Ξc(2970)+
2021 · 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=1/2over 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.
Measurement of the energy dependence of the e+e−→B¯¯¯¯B, B¯¯¯¯B∗ and B∗¯¯¯¯B∗ exclusive cross sections
2021 · ARTICLE · en
We report the first measurement of the exclusive cross sections e+e− → 𝐵𝐵⎯⎯⎯⎯BB¯, e+e− → 𝐵𝐵⎯⎯⎯⎯∗BB¯∗, and e+e− → 𝐵∗𝐵⎯⎯⎯⎯∗B∗B¯∗ in the energy range from 10.63 GeV to 11.02 GeV. The B mesons are fully reconstructed in a large number of hadronic final states and the three channels are identified using a beam-constrained-mass variable. The shapes of the exclusive cross sections show oscillatory behavior with several maxima and minima. The results are obtained using data collected by the Belle experiment at the KEKB asymmetric-energy e+e− collider.
Measurements of branching fractions and asymmetry parameters of Ξ0c → ΛK ̄ ∗0, Ξ0c → Σ0K ̄ ∗0, and Ξ0c → Σ+K∗− decays at Belle
2021 · ARTICLE · en
Using a data sample of 980 fb−1 collected with the Belle detector at the KEKB asymmetric-energy e+e− collider, we study the processes of Ξ0c→ΛK¯∗0, Ξ0c→Σ0K¯∗0, and Ξ0c→Σ+K∗− for the first time. The relative branching ratios to the normalization mode of Ξ0c→Ξ−π+ are measured to be {\cal B}(\Xi^0_c\to \Lambda\bar K^{*0})/{\cal B}(\xic\to \Xi^-\pi^+)=0.18\pm0.02({\rm stat.})\pm0.01({\rm syst.}), {\cal B}(\Xi^0_c\to \Sigma^0\bar K^{*0})/{\cal B}(\xic\to \Xi^-\pi^+)=0.69\pm0.03({\rm stat.})\pm0.03({\rm syst.}), {\cal B}(\Xi^0_c\to \Sigma^+K^{*-})/{\cal B}(\xic\to \Xi^-\pi^+)=0.34\pm0.06({\rm stat.})\pm0.02({\rm syst.}), where the uncertainties are statistical and systematic, respectively. We obtain %measure the branching fractions of Ξ0c→ΛK¯∗0, Ξ0c→Σ0K¯∗0, and Ξ0c→Σ+K∗− to be (Ξ0c→ΛK¯∗0)=(3.3±0.3(stat.)±0.2(syst.)±1.0(ref.))×10−3, (Ξ0c→Σ0K¯∗0)=(12.4±0.5(stat.)±0.5(syst.)±3.6(ref.))×10−3, (Ξ0c→Σ+K∗−)=(6.1±1.0(stat.)±0.4(syst.)±1.8(ref.))×10−3, where the uncertainties are statistical, systematic, and from ${\cal B}(\xic \to \Xi^-\pi^+)$, respectively. The asymmetry parameters α(Ξ0c→ΛK¯∗0) and α(Ξ0c→Σ+K∗−) are 0.15±0.22(stat.)±0.04(syst.) and −0.52±0.30(stat.)±0.02(syst.), respectively, where the uncertainties are statistical followed by systematic.
Search for B0s→η′Xs¯¯¯s at Belle using a semi-inclusive method
2021 · ARTICLE · en
We report the first search for the penguin-dominated process B0s→η′Xss¯ using a semi-inclusive method. A 121.4 fb−1 integrated luminosity Υ(5S)data set collected by the Belle experiment, at the KEKB asymmetric-energy e+e− collider, is used. We observe no statistically significant signal and including all uncertainties, we set a 90\% confidence level upper limit on the partial branching fraction at 1.4 × 10−3 for M(Xss¯) ≤ 2.4 GeV/c2.
Measurements of partial branching fractions of inclusive B→Xul+νl decays with hadronic tagging
2021 · ARTICLE · en
We present measurements of partial branching fractions of inclusive semileptonic B→Xuℓ+νℓdecays using the full Belle dataset of 711 fb−1 of integrated luminosity at the Υ(4S) resonance and for ℓ=e, μ. Inclusive semileptonic B→Xuℓ+νℓ decays are Cabibbo-Kobayashi-Maskawa (CKM) suppressed and measurements are complicated by the large background from CKM favored B→Xcℓ+νℓ transitions, which have a similar signature. Using machine learning techniques, we reduce this and other backgrounds effectively, while retaining access to a large fraction of the B→Xuℓ+νℓ phase space and high signal efficiency. We measure partial branching fractions in three phase-space regions covering about 31% to 86% of the accessible B→Xuℓ+νℓ phase space. The most inclusive measurement corresponds to the phase space with lepton energies of EBℓ>1 GeV, and we obtain ΔB(B→Xuℓ+νℓ)=(1.59±0.07±0.16)×10−3 from a two-dimensional fit of the hadronic mass spectrum and the four-momentum-transfer squared distribution, with the uncertainties denoting the statistical and systematic error. We find |Vub|=(4.10±0.09±0.22±0.15)×10−3 from an average of four calculations for the partial decay rate with the third uncertainty denoting the average theory error. This value is higher but compatible with the determination from exclusive semileptonic decays within 1.3 standard deviations. In addition, we report charmless inclusive partial branching fractions separately for B+ and B0 mesons as well as for electron and muon final states. No isospin breaking or lepton flavor universality violating effects are observed.
Search for the ηc2(1D) in e+e−→γηc2(1D) at √s near 10.6 GeV at Belle
2021 · ARTICLE · en
For the first time we search for the eta(c2) (1D) in e(+) e(-) -> gamma eta(c2)(1D) at root s = 10.52, 10.58, and 10.867 GeV with data samples of 89.5 fb(-1), 711 fb(-1), and 121.4 fb(-1), respectively, accumulated with the Belle detector at the KEKB asymmetric energy electron-positron collider. No significant eta(c20) (1D) signal is observed in the mass range between 3.8 and 3.88 GeV/c(2). The upper limit at 90% confidence level on the product of the Born cross section for e(+)e(-) -> gamma eta(c2) (1D) and branching fraction for eta c2(1D) -> gamma h(c) (1P) is determined to be so e(+)e(-)-> gamma c(2) (1D)gamma B eta(c2()1D)-> gamma h(c) (1P))
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