?
Физика элементарных частиц и атомного ядра
Chapters
Bocharnikov V., Derkach D., Ratnikov F., , in: Физика элементарных частиц и атомного ядра.: Pleiades Publishing, Ltd. (Плеадес Паблишинг, Лтд), 2023. Ch. 55 P. 995–999.
At present, new compact highly granular neutron detector is being developed for the BM@N experiment. This detector will be used to identify neutrons, to measure their energies using time-of-flight method, neutron yields and azimuthal flow of neutrons in heavy-ion collisions at beam energies up to 4A GeV. Application of machine learning techniques and preliminary results ...
Added: December 11, 2023
Language:
English
Ai X., An L., An S. et al., Nuclear Science and Techniques/Hewuli 2025 Vol. 36 Article 242
Electron–positron colliders operating in the GeV center-of-mass range, or tau-charm energy region, have been proved to enable competitive frontier research due to several unique features. With the progress of high-energy physics in the last two decades, a new-generation Tau-Charm factory, called the Super Tau-Charm Facility (STCF), has been actively promoted by the particle physics community ...
Added: December 5, 2025
Ratnikov F., Hushchyn M., Bocharnikov V. et al., Physical Review Letters 2025 Vol. 134 Article 081901
The Ξ0(−)𝑏→Ξ𝑐(3055)+(0)(→𝐷+(0)Λ)𝜋− decay chains are observed, and the spin-parity of Ξ𝑐(3055)+(0) baryons is determined for the first time. The measurement is performed using proton-proton collision data at a center-of-mass energy of √𝑠 =13 TeV, corresponding to an integrated luminosity of 5.4 fb−1, recorded by the LHCb experiment between 2016 and 2018. The spin-parity of the Ξ𝑐(3055)+(0) baryons is determined to be 3/2+ with a significance of more than 6.5𝜎 (3.5𝜎) ...
Added: December 4, 2025
Derkach D., Ratnikov F., Курбатов Е. О., Revista Mexicana de Fisica 2025 Vol. 71 No. 4 P. 041201
TheMulti-Purpose Detector (MPD) is one of the three experiments of the Nuclotron Ion Collider-fAcility (NICA) complex, which is currently under construction at the Joint Institute for Nuclear Research in Dubna. With collisions of heavy ions in the collider mode, the MPD will cover the energy range √sNN = 4 − 11 GeV to scan the ...
Added: December 4, 2025
Ratnikov F., Hushchyn M., Ryzhikov A. et al., Physical Review Letters 2025 Vol. 134 Article 061801
The branching fraction ratios of ¯𝐵0→𝐷+𝜏−¯𝜈𝜏 and ¯𝐵0→𝐷*+𝜏−¯𝜈𝜏 decays are measured with respect to their muonic counterparts, using a data sample corresponding to an integrated luminosity of 2.0 fb−1 collected by the LHCb experiment in proton-proton collisions at √𝑠 =13 TeV. The reconstructed final states are formed by combining 𝐷+ mesons with 𝜏−→𝜇−¯𝜈𝜇𝜈𝜏 candidates, where the 𝐷+ is reconstructed via the 𝐷+ →𝐾−𝜋+𝜋+ decay. The results are 𝑅(𝐷+)=0.249±0.043±0.047, 𝑅(𝐷*+)=0.402±0.081±0.085, where the first uncertainties are statistical and ...
Added: December 4, 2025
Ratnikov F., Bocharnikov V., Boldyrev A. et al., Journal of High Energy Physics 2025 Article 54
The first full amplitude analysis of B+ → ψ(2S)K+π+π− decays is performed using proton-proton collision data corresponding to an integrated luminosity of 9 fb−1 recorded with the LHCb detector. The rich K+π+π− spectrum is studied and the branching fractions of the resonant substructure associated with the prominent K1(1270)+ contribution are measured. The data cannot be described by conventional strange and charmonium resonances only. An ...
Added: December 4, 2025
Ratnikov F., Hushchyn M., Ryzhikov A. et al., Physical Review Letters 2025 Vol. 134 Article 031902
The first study of 𝐽/𝜓𝜙 production in diffractive processes in proton-proton collisions is presented. The study is based on an LHCb dataset recorded at center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5 fb−1. The data disfavor a nonresonant 𝐽/𝜓𝜙 production but are consistent with a resonant model including several resonant states observed previously only in 𝐵+→𝐽/𝜓𝜙𝐾+ decays. The 𝜒𝑐0(4500) state is observed ...
Added: December 4, 2025
Ratnikov F., Hushchyn M., Bocharnikov V. et al., Physical Review D - Particles, Fields, Gravitation and Cosmology 2025 Vol. 111 Article 012001
A measurement of the time-dependent ratio of the 𝐷0 →𝐾+𝜋− to ¯𝐷0→𝐾+𝜋− decay rates is reported. The analysis uses a sample of proton-proton collisions corresponding to an integrated luminosity of 6 fb−1 recorded by the LHCb experiment from 2015 through 2018 at a center-of-mass energy of 13 TeV. The 𝐷0 meson is required to originate from a 𝐷*(2010)+→𝐷0𝜋+ decay, such that its flavor at production is inferred from ...
Added: December 4, 2025
Derkach D., Bocharnikov V., Hushchyn M. et al., Physical Review Letters 2025 Vol. 134 Article 081901
The Ξ0(−)𝑏→Ξ𝑐(3055)+(0)(→𝐷+(0)Λ)𝜋− decay chains are observed, and the spin-parity of Ξ𝑐(3055)+(0) baryons is determined for the first time. The measurement is performed using proton-proton collision data at a center-of-mass energy of √𝑠 =13 TeV, corresponding to an integrated luminosity of 5.4 fb−1, recorded by the LHCb experiment between 2016 and 2018. The spin-parity of the Ξ𝑐(3055)+(0) baryons is determined to be 3/2+ with a significance of more than 6.5𝜎 (3.5𝜎) ...
Added: December 4, 2025
Ratnikov F., Bocharnikov V., Boldyrev A. et al., Physical Review Letters 2025 Vol. 134 Article 121803
Lepton flavor universality in rare 𝑏 →𝑠 transitions is tested for the first time using 𝐵0𝑠 meson decays. The measurements are performed using 𝑝𝑝 collision data collected by the LHCb experiment between 2011 and 2018, corresponding to a total integrated luminosity of 9 fb−1. Branching fraction ratios between the 𝐵0𝑠→𝜙𝑒+𝑒− and 𝐵0𝑠 →𝜙𝜇+𝜇− decays are measured in three regions of dilepton mass squared, 𝑞2, with 0.1<𝑞2<1.1, 1.1 <𝑞2 <6.0, and 15<𝑞2<19 GeV2/𝑐4. The results agree with ...
Added: December 4, 2025
Ratnikov F., Hushchyn M., Boldyrev A. et al., The European Physical Journal C - Particles and Fields 2025 Vol. 85 Article 562
This paper presents the first measurement of ψ(2S) and χc1(3872) meson production within fully reconstructed jets. Each quarkonium state (tag) is reconstructed via its decay to the J/ψ(→μ+μ−)π+π− final state in the forward region using proton-proton collision data collected by the LHCb experiment at the center-of-mass-energy of 13TeV in 2016, corresponding to an integrated luminosity of 1.64fb−1. The fragmentation function, presented as the ratio ...
Added: December 4, 2025
Ratnikov F., Ryzhikov A., Hushchyn M. et al., Science Bulletin 2025 Vol. 70 No. 9 P. 1432–1444
An amplitude analysis of the Ds1(2460)+→D+sπ+π− transition is performed simultaneously in B0→D−D+sπ+π−, B+→D¯0D+sπ+π−, and B0→D∗−D+sπ+π− decays. The study is based on a data sample of proton-proton collisions recorded with the LHCb detector at centre-of-mass energies of s√=7,8, and 13TeV, corresponding to a total integrated luminosity of 9fb−1. A clear double-peak structure is observed in the m(π+π−) spectrum of the Ds1(2460)+→D+sπ+π− decay. The data can be described either with a ...
Added: December 4, 2025
Ratnikov F., Ryzhikov A., Hushchyn M. et al., Physical Review Letters 2025 Vol. 134 Article 101801
The 𝐶𝑃 asymmetry and branching fraction of the Cabibbo-Kobayashi-Maskawa-suppressed decay 𝐵+ →𝐽/𝜓𝜋+ are precisely measured relative to the favored decay 𝐵+ →𝐽/𝜓𝐾+ using a sample of proton-proton collision data corresponding to an integrated luminosity of 5.4 fb−1 recorded at a center-of-mass energy of 13 TeV during 2016–2018. The results of the 𝐶𝑃 asymmetry difference and branching fraction ratio are Δ𝒜𝐶𝑃≡𝒜𝐶𝑃(𝐵+→𝐽/𝜓𝜋+)−𝒜𝐶𝑃(𝐵+→𝐽/𝜓𝐾+)=(1.29±0.49±0.08)×10−2, ℛ𝜋/𝐾≡[ℬ(𝐵+→𝐽/𝜓𝜋+)/ℬ(𝐵+→𝐽/𝜓𝐾+)]=(3.852±0.022±0.018)×10−2, where the first uncertainties are statistical and the second are ...
Added: December 4, 2025
Aaij R., Abdelmotteleb A. S., Abellan Beteta C. et al., Physical Review Letters 2025 Vol. 134 No. 10 Article 101901
An amplitude analysis of 𝐵−→𝐷−𝐷0𝐾0𝑆 decays is performed using proton-proton collision data, corresponding to an integrated luminosity of 9 fb−1, collected with the LHCb detector at center-of-mass energies of 7, 8, and 13 TeV. A resonant structure of spin-parity 0+ is observed in the 𝐷0𝐾0𝑆 invariant-mass spectrum with a significance of 5.3𝜎. The mass and width of the state, modeled with a Breit-Wigner line shape, ...
Added: December 4, 2025
Aaij R., Abdelmotteleb A. S., Abellan Beteta C. et al., Physical Review Letters 2025 Vol. 134 No. 18 Article 181803
The first test of lepton flavor universality between muons and electrons using 𝐵+→𝐾+𝜋+𝜋−ℓ+ℓ− (ℓ =𝑒, 𝜇) decays is presented. The measurement is performed with data from proton-proton collisions collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb−1. The ratio of branching fractions between 𝐵+→𝐾+𝜋+𝜋−𝑒+𝑒− and 𝐵+→𝐾+𝜋+𝜋−𝜇+𝜇− decays is measured in the dilepton invariant-mass-squared ...
Added: December 4, 2025
Ratnikov F., Bocharnikov V., Ryzhikov A. et al., Physical Review D - Particles, Fields, Gravitation and Cosmology 2025 Vol. 111 Article 092009
A study is presented of 𝐵+ →𝐾0S𝐾−𝜋+𝐾+ and 𝐵+ →𝐾0S𝐾+𝜋−𝐾+ decays based on the analysis of proton-proton collision data collected with the LHCb detector at center-of-mass energies of 7, 8 and 13 TeV, corresponding to an integrated luminosity of 9 fb−1. The 𝐾0S𝐾𝜋 invariant-mass distributions of both 𝐵+ decay modes show, in the 𝑚(𝐾0S𝐾𝜋) <1.85 GeV mass region, large activity which is resolved using an amplitude analysis. A simple model, where 𝐽𝑃𝐶 amplitudes are ...
Added: December 4, 2025
Ratnikov F., Hushchyn M., Bocharnikov V. et al., Journal of High Energy Physics 2025 Article 149
An analysis of the flavour oscillations of the charmed neutral meson is presented. The ratio of D0 → K+π− and D0 → K−π+ decay rates is measured as a function of the decay time of the D0 meson and compared with the charge-conjugated system to search for charge-parity violation. The meson flavour at production is double-tagged by the charges of the muon and pion in ...
Added: December 4, 2025
Ratnikov F., Bocharnikov V., Boldyrev A. et al., Physical Review D - Particles, Fields, Gravitation and Cosmology 2025 Vol. 111 Article L091102
The first measurement of the 𝐶𝑃 asymmetry of the decay rate (𝐴𝐶𝑃) and the 𝐶𝑃 average (Σ𝐴FB) and 𝐶𝑃 asymmetry (Δ𝐴FB) of the forward-backward asymmetry in the muon system of Λ+𝑐 →𝑝𝜇+𝜇− decays is reported. The measurement is performed using a data sample of proton-proton collisions, recorded by the LHCb experiment from 2016 to 2018 at a center-of-mass energy of 13 TeV, which corresponds to ...
Added: December 3, 2025
Ratnikov F., Boldyrev A., Hushchyn M. et al., Physical Review D - Particles, Fields, Gravitation and Cosmology 2025 Vol. 111 Article 092008
The branching fraction of the decay 𝐵+ →𝜓(2𝑆)𝜙(1020)𝐾+, relative to the topologically similar decay 𝐵+ →𝐽/𝜓𝜙(1020)𝐾+, is measured using proton-proton collision data collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb−1. The ratio is found to be 0.061 ±0.004 ±0.009, where the first uncertainty is statistical and the second systematic. Using the ...
Added: December 3, 2025
Aaij R., Abdelmotteleb A. S., Abellan Beteta C. et al., Nature 2025 Vol. 643 No. 8074 P. 1223–1228
The Standard Model of particle physics—the theory of particles and interactions at the smallest scale—predicts that matter and antimatter interact differently due to violation of the combined symmetry of charge conjugation (C) and parity (P). Charge conjugation transforms particles into their antimatter particles, whereas the parity transformation inverts spatial coordinates. This prediction applies to both ...
Added: December 3, 2025
Ratnikov F., Boldyrev A., Journal of High Energy Physics 2025 Vol. 2025 No. 6 Article 13
A search for the decay Bc→ χc1(3872)π+ is reported using proton-proton collision data collected with the LHCb detector between 2011 and 2018 at centre-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb−1. No significant signal is observed. Using the decay Bc→ ψ(2S)π+ as a normalisation channel, an upper limit for the ...
Added: December 3, 2025
Ratnikov F., Boldyrev A., Journal of High Energy Physics 2025 Article 69
An angular analysis of the decay Bs→ ϕe+e− is presented, using proton-proton collision data collected with the LHCb detector between 2011 and 2018 at centre-of-mass energies of 7, 8 and 13 TeV. The combined dataset corresponds to an integrated luminosity of 9 fb−1. Observables are determined by fitting time-integrated projections of the angular distribution in three ...
Added: December 3, 2025
Aaij R., Abdelmotteleb A. S., Abellan Beteta C. et al., Physical Review Letters 2025 Vol. 135 No. 5 Article 051801
The first observation of the Σ+ →𝑝𝜇+𝜇− decay is reported with high significance using proton-proton collision data, corresponding to an integrated luminosity of 5.4 fb−1, collected with the LHCb detector at a center-of-mass energy of 13 TeV. A yield of 237±16 Σ+→𝑝𝜇+𝜇− decays is obtained, where the uncertainty is statistical only. A branching fraction of (1.08±0.17)×10−8 is measured, where the uncertainty includes statistical and systematic sources. ...
Added: December 3, 2025
Aaij R., Abdelmotteleb A. S., Abellan Beteta C. et al., Journal of High Energy Physics 2025 Vol. 2025 No. 7 Article 121
A study of the charmless baryonic decays is presented, where denotes either a B0 or a meson. The analysis is based on proton-proton collision data collected by the LHCb experiment at centre-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb−1. The decay is observed for the first time, with a measured branching fraction of ...
Added: December 3, 2025
Aaij R., Abdelmotteleb A. S., Abellan Beteta C. et al., Journal of High Energy Physics 2025 Article 174
A study on the Bose-Einstein correlations for triplets of same-sign pions is presented. The analysis is performed using proton-proton collisions at a centre-of-mass energy of = 7 TeV, recorded by the LHCb experiment, corresponding to an integrated luminosity of 1.0 fb−1. For the first time, the results are interpreted in the core-halo model. The parameters of ...
Added: December 3, 2025