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Of all publications in the section: 97
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Article
Аушев Т. А., Mizuk R., Pakhlov P. et al. Physical Review D - Particles, Fields, Gravitation and Cosmology. 2018. Vol. 98. No. 11. P. 1-10.

We report measurements of the branching fractions of the decays Λc+→Σ+π-π+, Λc+→Σ0π+π0 and Λc+→Σ+π0π0 relative to the reference channel Λc+→pK-π+. The analysis is based on the full data sample collected at and near the (4S) resonance by the Belle detector at the KEKB asymmetric-energy e+e- collider, corresponding to an integrated luminosity of 711 fb-1. We measure B(Λc+→Σ+π-π+)/B(Λc+→pK-π+)=0.719±0.003±0.024, B(Λc+→Σ0π+π0)/B(Λc+→pK-π+)=0.575±0.005±0.036 and B(Λc+→Σ+π0π0)/B(Λc+→pK-π+)=0.247±0.006±0.019. The listed uncertainties are statistical and systematic, respectively. © 2018 authors. Published by the American Physical Society.

Added: Oct 28, 2020
Article
Khachatryan V., Ratnikov F. Physical Review D - Particles, Fields, Gravitation and Cosmology. 2016. Vol. 94. No. 5. P. 052006.

Measurements are reported of the normalized differential cross sections for top quark pair production with respect to four kinematic event variables: the missing transverse energy; the scalar sum of the jet transverse momentum (pT); the scalar sum of the pT of all objects in the event; and the pT of leptonically decaying W bosons from top quark decays. The data sample, collected using the CMS detector at the LHC, consists of 5.0  fb−1 of proton-proton collisions at s√=7  TeV and 19.7  fb−1at s√=8  TeV. Top quark pair events containing one electron or muon are selected. The results are presented after correcting for detector effects to allow direct comparison with theoretical predictions. No significant deviations from the predictions of several standard model event simulation generators are observed.

Added: Oct 21, 2016
Article
Khachatryan V., Ratnikov F. Physical Review D - Particles, Fields, Gravitation and Cosmology. 2016.

The cross section for pair production of top quarks (tt¯) with high transverse momenta is measured in pp collisions, collected with the CMS detector at the LHC with s√=8  TeV in data corresponding to an integrated luminosity of 19.7  fb−1. The measurement is performed using lepton+jets events, where one top quark decays semileptonically, while the second top quark decays to a hadronic final state. The hadronic decay is reconstructed as a single, large-radius jet, and identified as a top quark candidate using jet substructure techniques. The integrated cross section and the differential cross sections as a function of top quark pT and rapidity are measured at particle level within a fiducial region related to the detector-level requirements and at parton level. The particle-level integrated cross section is found to be σtt¯=0.499±0.035(stat+syst)±0.095(theo)±0.013(lumi)  pb for top quark pT>400  GeV. The parton-level measurement is σtt¯=1.44±0.10(stat+syst)±0.29(theo)±0.04(lumi)  pb. The integrated and differential cross section results are compared to predictions from several event generators.

Added: Oct 21, 2016
Article
Aaij R., Arzymatov K., Belavin V. et al. Physical Review D - Particles, Fields, Gravitation and Cosmology. 2020. Vol. 102. No. 11.

The relative branching fractions of B+→h+h'+h'− decays, where h(') is a pion or kaon, are measured. The analysis is performed with a data sample, collected with the LHCb detector, corresponding to an integrated luminosity of 3.0  fb−1 of pp collisions. The results obtained improve significantly on previous measurements of these quantities, and are important for the interpretation of Dalitz plot analyses of three-body charmless hadronic decays of B+ mesons.

Added: Sep 1, 2021
Article
Khachatryan V., Ratnikov F. Physical Review D - Particles, Fields, Gravitation and Cosmology. 2016. No. 9.
ABSTRACT

A novel technique for measuring the mass of the top quark that uses only the kinematic properties of its charged decay products is presented. Top quark pair events with final states with one or two charged leptons and hadronic jets are selected from the data set of 8 TeV proton-proton collisions, corresponding to an integrated luminosity of 19.7 fb−1. By reconstructing secondary vertices inside the selected jets and computing the invariant mass of the system formed by the secondary vertex and an isolated lepton, an observable is constructed that is sensitive to the top quark mass that is expected to be robust against the energy scale of hadronic jets. The main theoretical systematic uncertainties, concerning the modeling of the fragmentation and hadronization of b quarks and the reconstruction of secondary vertices from the decays of b hadrons, are studied. A top quark mass of 173.68±0.20(stat)+1.58−0.97(syst)  GeV is measured. The overall systematic uncertainty is dominated by the uncertainty in the b quark fragmentation and the modeling of kinematic properties of the top quark.

 

Added: Oct 21, 2016
Article
Аушев Т. А., Bondar A. Physical Review D - Particles, Fields, Gravitation and Cosmology. 2018. Vol. 97. No. 1. P. 1-17.
Added: Oct 28, 2020
Article
Аушев Т. А., Mizuk R., Pakhlov P. et al. Physical Review D - Particles, Fields, Gravitation and Cosmology. 2018. Vol. 97. No. 9. P. 1-10.

We report a measurement of time-dependent CP violation parameters in B0→KS0ηγ decays. The study is based on a data sample, containing 772×106BB pairs, that was collected at the (4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We obtain the CP violation parameters of S=-1.32±0.77(stat)±0.36(syst) and A=-0.48±0.41(stat)±0.07(syst) for the invariant mass of the KS0η system up to 2.1 GeV/c2. © 2018 authors. Published by the American Physical Society.

Added: Oct 28, 2020
Article
Аушев Т. А., Mizuk R., Pakhlova G. et al. Physical Review D - Particles, Fields, Gravitation and Cosmology. 2019. P. 1-7.

We report a measurement of time-dependent CP violation in B0→KS0π0π0 decays using a data sample of 772×106 BB pairs collected by the Belle experiment running at the ?(4S) resonance at the KEKB e+e- collider. This decay proceeds mainly via a b→sdd "penguin" amplitude. The results are sin2φ1eff=0.92-0.31+0.27 (stat.) ±0.11 (syst.) and A=0.28±0.21 (stat.) ±0.04 (syst.), which are the most precise measurements of CP violation in this decay mode to date. The value for the CP-violating parameter sin2φ1eff is consistent with that obtained using decay modes proceeding via a b→ccs "tree" amplitude.

Added: Jun 5, 2020
Article
K. Arzymatov, V. Belavin, A. Boldyrev et al. Physical Review D - Particles, Fields, Gravitation and Cosmology. 2020. Vol. 101. No. 7. P. 072004.

The element |Vcb| of the Cabibbo-Kobayashi-Maskawa matrix is measured using semileptonic B0s decays produced in proton-proton collision data collected with the LHCb detector at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb−1. Rates of B0sDsμ+νμ and B0sD∗−sμ+νμ decays are analyzed using hadronic form-factor parametrizations derived either by Caprini, Lellouch and Neubert (CLN) or by Boyd, Grinstein and Lebed (BGL). The measured values of |Vcb| are (41.4±0.6±0.9±1.2)×10−3 and (42.3±0.8±0.9±1.2)×10−3 in the CLN and BGL parametrization, respectively. The first uncertainty is statistical, the second systematic, and the third is due to the external inputs used in the measurement. These results are in agreement with those obtained from decays of B+ and B0 mesons. They are the first determinations of |Vcb| at a hadron-collider experiment and the first using B0s meson decays.

Added: Sep 16, 2020
Article
Аушев Т. А., Mizuk R., Pakhlov P. et al. Physical Review D - Particles, Fields, Gravitation and Cosmology. 2018. Vol. 98. No. 7. P. 1-17.

We report the measurement of γγ→ηc(1S),ηc(2S)→η′π+π- with η′ decays to γρ and ηπ+π- using 941 fb-1 of data collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. The ηc(1S) mass and width are measured to be M=[2984.6±0.7 (stat)±2.2 (syst)±0.3 (model)] MeV/c2 and Γ=[30.8-2.2+2.3 (stat)±2.5 (syst)±1.4 (model)] MeV, respectively. First observation of ηc(2S)→η′π+π- with a significance of 5.5σ including systematic error is obtained, and the ηc(2S) mass is measured to be M=[3635.1±3.7 (stat)±2.9 (syst)±0.4 (model)] MeV/c2. The products of the two-photon decay width and branching fraction (B) of decays to η′π+π- are determined to be ΓγγΓγγB=[65.4±2.6 (stat)±7.8 (syst)] eV for ηc(1S) and [5.6-1.1+1.2 (stat)±1.1 (syst)] eV for ηc(2S). The cross sections for γγ→η′π+π- and η′f2(1270) are measured for the first time. © 2018 authors. Published by the American Physical Society.

Added: Oct 28, 2020
Article
Аушев Т. А., Mizuk R., Pakhlova G. et al. Physical Review D - Particles, Fields, Gravitation and Cosmology. 2019. Vol. 99. No. 3. P. 1-9.

We study charmless hadronic decays of charged B mesons to the final states KS0KS0K± and KS0KS0π± using a 711 fb-1 data sample that contains 772×106 BB̄ pairs and was collected at the Ï (4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. For B±→KS0KS0K±, the measured branching fraction and direct CP asymmetry are [10.42±0.43(stat)±0.22(syst)]×10-6 and [+1.6±3.9(stat)±0.9(syst)]%, respectively. In the absence of a statistically significant signal for B±→KS0KS0π±, we obtain a 90% confidence-level upper limit on its branching fraction as 8.7×10-7. © 2019 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.

Added: Oct 28, 2020
Article
Аушев Т. А., Mizuk R., Pakhlov P. et al. Physical Review D - Particles, Fields, Gravitation and Cosmology. 2019. Vol. 99. No. 3. P. 1-13.

We report measurements of isospin asymmetry Δ0- and difference of direct CP asymmetries ΔACP between charged and neutral B→Xsγ decays. This analysis is based on the data sample containing 772×106BB̄ pairs that was collected with the Belle detector at the KEKB energy-asymmetric e+e- collider. Using a sum-of-exclusive technique with invariant Xs mass up to 2.8 GeV/c2, we obtain Δ0-=[-0.48±1.49(stat)±0.97(syst)±1.15(f+-/f00)]% and ΔACP=[+3.69±2.65(stat)±0.76(syst)]%, where the last uncertainty for Δ0- is due to the uncertainty on the production ratio of B+B- to B0B̄0 in Ï (4S) decays. The measured value of Δ0- is consistent with zero, allowing us to constrain the resolved photon contribution in the B→Xsγ, and improve the branching fraction prediction. The result for ΔACP is consistent with the prediction of the SM. We also measure the direct CP asymmetries for charged and neutral B→Xsγ decays. All the measurements are the most precise to date. © 2019 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 SCOAP 3 .

Added: Oct 28, 2020
Article
Аушев Т. А., Mizuk R., Pakhlov P. et al. Physical Review D - Particles, Fields, Gravitation and Cosmology. 2018. Vol. 97. No. 1. P. 1-10.

We present the measurement of the absolute branching fractions of B+→Xcc̄K+ and B+→D̄(∗)0π+ decays, using a data sample of 772×106 BB̄ pairs collected at the (4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. Here, Xcc̄ denotes ηc, J/ψ, χc0, χc1, ηc(2S), ψ(2S), ψ(3770), X(3872), and X(3915). We do not observe significant signals for X(3872) or X(3915) and set the 90% confidence level upper limits at B(B+→X(3872)K+)<2.6×10-4 and B(B+→X(3915)K+)<2.8×10-4. These represent the most stringent upper limit for B(B+→X(3872)K+) to date and the first limit for B(B+→X(3915)K+). The measured branching fractions for ηc and ηc(2S) are the most precise to date, B(B+→ηcK+)=(12.0±0.8±0.7)×10-4 and B(B+→ηc(2S)K+)=(4.8±1.1±0.3)×10-4, where the first and second uncertainties are statistical and systematic, respectively. © 2018 authors. Published by the American Physical Society.

Added: Oct 28, 2020
Article
Аушев Т. А., Mizuk R., Pakhlov P. et al. Physical Review D - Particles, Fields, Gravitation and Cosmology. 2019. Vol. 100. No. 11. P. 1-8.

Using the data sample of 711 fb−1 of Υ(4S) on-resonance data taken by the Belle detector at the KEKB asymmetric-energy electron-positron collider, we present the first measurements of branching fractions of the decays B−→Λ¯−cΞ′0c , B−→Λ¯−cΞc(2645)0 , and B−→Λ¯−cΞc(2790)0 . The signal yields for these decays are extracted from the recoil mass spectrum of the system recoiling against Λ¯−c baryons in selected B− candidates. The branching fraction of B−→Λ¯−cΞc(2790)0 is measured to be (1.1±0.4±0.2)×10−3 , where the first uncertainty is statistical and the second systematic. The 90\% credibility level upper limits on B(B−→Λ¯−cΞ′0c) and B(B−→Λ¯−cΞc(2645)0) are determined to be 6.5×10−4 and 7.9×10−4 , respectively.

Added: Jun 5, 2020
Article
Akhmedov E., Popov F., Kalinov D. Physical Review D - Particles, Fields, Gravitation and Cosmology. 2016. Vol. D93. No. 6. P. 064006.

We propose a way to distinguish compact stellar object, whose size is very close to its Schwarzschild radius, from the collapsing stars. Namely, we show that {\it massive} fields in the vicinity of a very compact stellar object have discrete energy levels. (These levels are different from the standard non-relativistic ones present in Coulomb type of potentials and from the quasinormal modes.) At the same time we show that there are no such discrete levels for massive fields in the vicinity of a collapsing star.

Added: Mar 11, 2016
Article
Arzymatov K., Belavin V., Borisyak M. et al. Physical Review D - Particles, Fields, Gravitation and Cosmology. 2021. P. 1-17.

Using a proton-proton collision data sample collected by the LHCb experiment, corresponding to an integrated luminosity of 8.5  fb−1, the observation of a new excited Ξ0b resonance decaying to the Ξ−bπ+final state is presented. The state, referred to as Ξb(6227)0, has a measured mass and natural width of m(Ξb(6227)0)=6227.1+1.4−1.5±0.5  MeV and Γ(Ξb(6227)0)=18.6+5.0−4.1±1.4  MeV, where the uncertainties are statistical and systematic. The production rate of the Ξb(6227)0 state relative to that of the Ξ−b baryon in the kinematic region 2<η<5 and pT<30  GeV is measured to be fΞb(6227)0fΞ−bB(Ξb(6227)0→Ξ−bπ+)=0.045±0.008±0.004, where B(Ξb(6227)0→Ξ−bπ+) is the branching fraction of the decay, and fΞb(6227)0 and fΞ−b represent fragmentation fractions. Improved measurements of the mass and natural width of the previously observed Ξb(6227)− state, along with the mass of the Ξ−b baryon, are also reported. Both measurements are significantly more precise than, and consistent with, previously reported values.

Added: Aug 31, 2021
Article
Аушев Т. А., Mizuk R., Pakhlov P. et al. Physical Review D - Particles, Fields, Gravitation and Cosmology. 2019. Vol. 99. No. 3. P. 1-9.

We report the study of B+→pΛ̄K+K- and B+→p̄ΛK+K+ decays using a 772×106 BB̄ pair data sample recorded on the Ï (4S) resonance with the Belle detector at KEKB. The following branching fractions are measured: B(B+→pΛ̄K+K-)=(4.10-0.43+0.45±0.50)×10-6, B(B+→p̄ΛK+K+)=(3.70-0.37+0.39±0.44)×10-6, B(ηc→pΛ̄K-+c.c.)=(2.83-0.34+0.36±0.35)×10-3 and B(B+→pΛ̄φ)=(7.95±2.09±0.77)×10-7, where c.c. denotes the corresponding charge-conjugation process. The intermediate resonance decays are excluded in the four-body decay measurements. We also find evidence for B(ηc→Λ(1520)Λ̄+c.c.)=(3.48±1.48±0.46)×10-3 and B(B+→Λ(1520)Λ̄K+)=(2.23±0.63±0.25)×10-6. No significant signals are found for J/ψ→Λ(1520)Λ̄+c.c. and B+→Λ̄(1520)ΛK+; we set the 90% confidence level upper limits on their decay branching fractions as <1.80×10-3 and <2.08×10-6, respectively.

Added: Jun 5, 2020
Article
Аушев Т. А., Pakhlova G., Mizuk R. et al. Physical Review D - Particles, Fields, Gravitation and Cosmology. 2018. Vol. 98. No. 9. P. 1-8.

Using data samples of 89.5 fb-1, 711.0 fb-1, and 121.4 fb-1 collected with the Belle detector at the KEKB asymmetric-energy e+e- collider at center-of-mass energies 10.52, 10.58, and 10.867 GeV, respectively, we study the exclusive reactions e+e-→γχcJ (J=0, 1, 2) and e+e-→γηc. A significant γχc1 signal is observed for the first time at s=10.58 GeV with a significance of 5.1σ including systematic uncertainties. No significant excesses for γχc0, γχc2, and γηc final states are found, and we set 90% credibility level upper limits on the Born cross sections (σB) at 10.52 GeV, 10.58 GeV, and 10.867 GeV. Together with cross sections measured by BESIII at lower center-of-mass energies, the energy dependency of σB(e+e-→γχc1) is obtained. © 2018 authors. Published by the American Physical Society.

Added: Oct 28, 2020
Article
Аушев Т. А., Mizuk R., Pakhlov P. et al. Physical Review D - Particles, Fields, Gravitation and Cosmology. 2018. Vol. 98. No. 9. P. 1-9.

We report searches for the processes e+e-→π+π-π0χbJ and e+e-→φχbJ (J=1, 2) based on data samples collected by the Belle experiment at the KEKB collider. We report the first observation of the process e+e-→(π+π-π0)non-ωχb1 and first evidence for e+e-→ωχbJ in the vicinity of the ?(11020) resonance, with center-of-mass energies from 10.96 to 11.05 GeV. The significances for (π+π-π0)non-ωχb1 and ωχbJ are greater than 5.3σ and 4.0σ, respectively. We also investigate the energy dependence of the e+e-→π+π-π0χbJ cross section, but we cannot determine whether the contributions are from the ?(10860) and ?(11020) resonances or nonresonant continuum processes. The signals for e+e-→φχbJ are not significant, and the upper limits of the Born cross sections at the 90% confidence level are 0.7 and 1.0 pb for e+e-→φχb1 and φχb2, respectively, for center-of-mass energies from 10.96 to 11.05 GeV. © 2018 authors. Published by the American Physical Society.

Added: Oct 28, 2020
Article
Аушев Т. А., Mizuk R., Pakhlov P. et al. Physical Review D - Particles, Fields, Gravitation and Cosmology. 2018. Vol. 97. No. 5. P. 1-6.

Using the entire Belle data sample of 980 fb-1 of e+e- collisions, we present the results of a study of excited Ωc charmed baryons in the decay mode Ξc+K-. We show confirmation of four of the five narrow states reported by the LHCb Collaboration: the Ωc(3000), Ωc(3050), Ωc(3066), and Ωc(3090). © 2018 authors.

Added: Oct 28, 2020
Article
Аушев Т. А., Mizuk R., Pakhlov P. et al. Physical Review D - Particles, Fields, Gravitation and Cosmology. 2019. Vol. 100. No. 7. P. 1-9.

We present the first measurements of branching fractions of rare tau-lepton decays, τ-→π-ντ+- (=e or μ), using a data sample corresponding to 562 fb-1 collected at a center-of-mass energy of 10.58 GeV with the Belle detector at the KEKB asymmetric-energy e+e- collider. The τ-→π-ντe+e- decay is observed for the first time with 7.0σ significance. The partial branching fraction determined by the structure-dependent mechanisms mediated by either a vector or an axial-vector current for the mass region Mπee>1.05 GeV/c2 is measured to be B(τ-→π-ντe+e-)[Mπ-e+e->1.05 GeV/c2]=(5.90±0.53±0.85±0.11)×10-6, where the first uncertainty is statistical, the second is systematic, and the third is due to model dependence. In the full phase space, due to the different detection efficiencies for the structure-dependent mechanisms mediated by axial-vector and vector currents, the branching fraction varies from BA(τ-→π-ντe+e-)=(1.46±0.13±0.21)×10-5 to BV(τ-→π-ντe+e-)=(3.01±0.27±0.43)×10-5, respectively. An upper limit is set on the branching fraction of the τ-→π-ντμ+μ- decay, B(τ-→π-ντμ+μ-)<1.14×10-5, at the 90% confidence level. © 2019 authors. Published by the American Physical Society.

Added: Oct 28, 2020