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Quasi-two-body decays B → ηc(1S, 2S) [ρ(770), ρ(1450), ρ(1700) →] ππ in the perturbative QCD approach

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arXiv 2017年

作者： Li, Ya Ma, Ai-Jun Rui, Zhou Xiao, Zhen-Jun Department of Physics Institute of Theoretical Physics Nanjing Normal University Nanjing Jiangsu210023 China College of Sciences North China University of Science and Technology Tangshan063009 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing Jiangsu210023 China

In this paper, we calculated the branching ratios of the quasi-two-body decays B → ηc(1S, 2S) [ρ(770), ρ(1450), ρ(1700) →]ππ by employing the perturbative QCD (PQCD) approach. The contributions from the P -wave resonances ρ(770), ρ(1450) and ρ(1700) were taken into account. The two-pion distribution amplitude ΦPππ is parameterized by the vector current time-like form factor Fπ to study the considered decay modes. We found that (a) the PQCD predictions for the branching ratios of the considered quasi-two-body decays are in the order of 10−7 ∼ 10−6, while the two-body decay rates B(B → ηc(1S, 2S)(ρ(1450), ρ(1700))) are extracted from those for the corresponding quasi-two-body decays;(b) the whole pattern of the pion form factor-squared |Fπ|2 measured by the BABAR Collaboration could be understood based on our theoretical results;(c) the general expectation based on the similarity between B → ηcππ and B → J/ψππ decays are confirmed: R2(ηc) ≈ 0.45 is consistent with the measured R2(J/ψ) ≈ 0.56 ± 0.09 within errors;and (d) new ratios R3(ηc(1S)) and R4(ηc(2S)) among the branching ratios of the considered decay modes are defined and could be tested by future experiments. Copyright © 2017, The Authors. All rights reserved.

关键词： Hadrons

Anatomy of Bs → P V decays and effects of next-to-leading order contributions in the perturbative QCD factorization approach

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arXiv 2017年

作者： Yan, Da-Cheng Yang, Ping Liu, Xin Xiao, Zhen-Jun Department of Physics Institute of Theoretical Physics Nanjing Normal University Nanjing Jiangsu210023 China School of Physics and Electronic Engineering Jiangsu Normal University Xuzhou221116 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing Jiangsu210023 China

In this paper, we will make systematic calculations for the branching ratios and the CP-violating asymmetries of the twenty one B¯s0 → P V decays by employing the perturbative QCD (PQCD) factorization approach. Besides the full leading-order (LO) contributions, all currently known next-to-leading order (NLO) contributions are taken into account. We found numerically that: (a) the NLO contributions can provide ∼ 40% enhancement to the LO PQCD predictions for B(B¯s0 → K0K¯ ∗0) and B(B¯s0 → K±K∗), or a ∼ 37% reduction to B(B¯s0 → π−K∗+);and we confirmed that the inclusion of the known NLO contributions can improve significantly the agreement between the theory and those currently available experimental measurements;(b) the total effects on the PQCD predictions for the relevant B → P transition form factors after the inclusion of the NLO twist-2 and twist-3 contributions is generally small in magnitude: less than 10% enhancement respect to the leading order result;(c) for the "tree" dominated decay B¯s0 → K+ρ− and the "color-suppressed-tree" decay B¯s0 → π0K∗0, the big difference between the PQCD predictions for their branching ratios are induced by different topological structure and by interference effects among the decay amplitude AT,C and AP: constructive for the first decay but destructive for the second one;and (d) for B¯s0 → V (η, η′) decays, the complex pattern of the PQCD predictions for their branching ratios can be understood by rather different topological structures and the interference effects between the decay amplitude A(V ηq) and A(V ηs) due to the η − η′ mixing. Copyright © 2017, The Authors. All rights reserved.

关键词： Forecasting

Anatomy of Bs → V V decays and effects of next-to-leading order contributions in the perturbative QCD factorization approach

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arXiv 2018年

作者： Yan, Da-Cheng Liu, Xin Xiao, Zhen-Jun Department of Physics Institute of Theoretical Physics Nanjing Normal University Nanjing Jiangsu210023 China School of Physics and Electronic Engineering Jiangsu Normal University Xuzhou221116 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing Jiangsu210023 China

By employing the perturbative QCD (PQCD) factorization approach, we calculated the branching ratios, CP-violating asymmetries, the longitudinal and transverse polarization fractions and other physical observables of the thirteen charmless hadronic B¯s0 → V V decays with the inclusion of all currently known next-to-leading order (NLO) contributions. We focused on the examination of the effects of all those currently known NLO contributions and found that: (a) for the measured decays B¯s0 → φφ, K∗0φ, K¯ ∗0K∗0 and ρ0φ, the NLO contributions can provide ∼ 20% to ∼ 40% enhancements to the leading order (LO) PQCD predictions of their CP-averaged branching ratios, and consequently the agreement between the PQCD predictions and the measured values are improved effectively after the inclusion of the NLO contributions;(b) for the measured decays, the NLO corrections to the LO PQCD predictions for (fL, f) and (φk, φ) are generally small in size, but the weak penguin annihilation contributions play an important role in understanding the data about their decay rates, fL and f;(c) the NLO PQCD predictions for above mentioned physical observables do agree with the measured ones and the theoretical predictions from the QCDF, SCET and FAT approaches;(d) for other considered Bs0 → V V decays, the NLO PQCD predictions for their decay rates and other physical observables are also basically consistent with the theoretical predictions from other popular approaches, future precision measurements could help us to test or examine these predictions. Copyright © 2018, The Authors. All rights reserved.

关键词： Forecasting

Resonance contributions from χc0 in the charmless three-body hadronic B meson decays

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arXiv 2023年

作者： Zhang, Ya-Lan Wang, Chao Lin, Yi Xiao, Zhen-Jun Faculty of Mathematics and Physics Huaiyin Institute of Technology Jiangsu Huaian223200 China Department of Physics Institute of Theoretical Physics Nanjing Normal University Jiangsu Nanjing210023 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Jiangsu Nanjing210023 China

Within the framework of perturbative QCD factorization, we investigate the nonfactorizable contributions to these factorization-forbidden Quasi-two-body decays B(s) → hχc0 → hπ+π−(K+K−) with h = π,K. We compare our predicted branching ratios for the B(s) → Kχc0 → Kπ+π−(K+K−) decay with available experiment data as well as predictions by other theoretical studies. The branching ratios of these decays are consistent with data and other theoretical predictions. In the Cabibbo-suppressed decays B(s) → hχc0 → hπ+π−(K+K−) with h = K¯0,π, however, the values of the branching ratios are the order of 10−7 and 10−8. The ratio Rχc0 between the decay B+ → π+χc0 → π+π+π− and B+ → K+χc0 → K+π+π− and the distribution of branching ratios for different decay modes in invariant mass are considered in this work. © 2023, CC BY.

关键词： Factorization

Hidden-charm tetraquarks with strangeness in the chiral quark model

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Physical Review D 2021年第9期104卷 094035-094035页

作者： Gang Yang Jialun Ping Jorge Segovia Department of Physics Zhejiang Normal University Jinhua 321004 China Department of Physics and Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing 210023 People’s Republic of China Departamento de Sistemas Físicos Químicos y Naturales Universidad Pablo de Olavide E-41013 Sevilla Spain

The hidden-charm tetraquarks with strangeness, cc¯sq¯ (q=u, d), in JP=0+, 1+, and 2+ are systematically investigated in the framework of real- and complex-scaling range of a chiral quark model, whose parameters have been fixed in advance describing hadron, hadron-hadron, and multiquark phenomenology. Each tetraquark configuration, compatible with the quantum numbers studied, is taken into account; this includes meson-meson, diquark-antidiquark, and K-type arrangements of quarks with all possible color wave functions in the four-body sector. Among the different numerical techniques to solve the Schrödinger-like four-body bound state equation, we use a variational method in which the trial wave function is expanded in complex-range Gaussian basis functions, which is characterized by its simplicity and flexibility. This theoretical framework has already been used to study different kinds of multiquark systems, such as the hidden-charm pentaquarks Pc+ and doubly charmed tetraquarks Tcc+. The recently reported Zcs states by the BESIII and LHCb Collaborations could be associated, in our investigation, with either compact tetraquark or hadronic molecular resonance configurations. However, it is fair to recognize that our complex poles survive when either the (cc¯)(sq¯) or (cq¯)(sc¯) configuration is preserved, but most of them get diluted when both are considered at the same time, indicating that such states seem to be very unstable. Finally, we mention that similar types of structures are also found in the mass range between 3.8 and 4.6 GeV.

关键词： Many-body techniques Quantum chromodynamics Quark model Strong interaction

Perturbative QCD factorization of ργ⋆→ρ

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Physical Review D 2016年第3期93卷 036002-036002页

作者： Ya-lan Zhang Shan Cheng Jun Hua Zhen-Jun Xiao Department of Physics and Institute of Theoretical Physics Nanjing Normal University Nanjing Jiangsu 210023 People’s Republic of China Theoretische Elementarteilchenphysik Naturwissenschaftlich Technische Fakultät Universiät Siegen 57068 Siegen Germany Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing 210023 People’s Republic of China

In this paper we first demonstrate step by step that the factorization hypothesis is valid at the next-to-leading order (NLO) for the exclusive process ργ⋆→ρ by employing the collinear factorization approach, and then extend this proof to the case of the kT factorization by taking into account the transversal momentum of the light external quark (antiquark) lines in the ρ meson. At the NLO level, we then show that the soft divergences from different subdiagrams will cancel each other in the quark level, while the remaining collinear divergences can be absorbed into the NLO meson wave functions. The full NLO amplitudes can therefore be factorized as the convolution of the NLO wave functions Φρ(1) and the infrared-finite leading order (LO) hard kernels GX,IJ,kl0 in the kT factorization. We also write down the polarized NLO ρ meson wave functions in the form of nonlocal hadron matrix elements with the gauge factor integral path deviating from the light cone. These NLO ρ meson wave functions can be used to calculate the NLO hard corrections to some relevant exclusive processes, such as B→ρ transition.

关键词： Perturbative QCD Scattering amplitudes Mesons

The next-to-leading order corrections to B →-transition in the kTfactorization

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arXiv 2018年

作者： Hua, Jun Zhang, Ya-Lan Xiao, Zhen-Jun Department of Physics Institute of Theoretical Physics Nanjing Normal University Nanjing Jiangsu210023 China Department of Faculty of Mathematics and Physics Huaiyin Institute of Technology Huaian Jiangsu223001 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing210023 China

In this paper, we investigate the factorization hypothesis step by step for the exclusive process B → ρ at next-to-leading order (NLO) with the collinear factorization approach, and then we extend our results to the kTfactorization frame. We show that the soft divergence from the specific NLO diagrams will cancel each other at the quark level, while the remaining collinear divergence can be absorbed into the NLO wave functions. The full NLO amplitudes can be factorized into two parts: The NLO B and ρ meson wave functions containing the collinear divergence and the leading order (LO) finite hard kernels. We give the general form of the nonlocal hadron matrix for the NLO B and ρ meson wave functions and all results of factorization for different twists' combinations. Copyright © 2018, The Authors. All rights reserved.

关键词： Factorization

Anatomy of Bs → P P decays and effects of the next-to-leading order contributions in the perturbative QCD approach

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arXiv 2019年

By employing the perturbative QCD (PQCD) factorization approach, we made a systematic investigation for the CP-averaged branching ratios and the CP-violating asymmetries of the thirteen B¯s0 → P P decays (here P = (π, K, η, η′)) with the inclusion of all currently known next-to-leading order (NLO) contributions, and compared our results with the measured values or the theoretical predictions from other different approaches. We focused on the examination of the effects of the NLO contributions and found the following points: (a) for B¯s0 → (K0K¯ 0, K+K−, η′η′, π−K+) decays, the NLO contributions can provide a (40 − 150)% enhancement or a 20% reduction to the corresponding leading order (LO) PQCD predictions for their decay rates and result in a much better agreement between the PQCD predictions and the experimental measurements;(b) for the pure annihilation decay B¯s0 → π+π−, the PQCD prediction still remain consistent with the data after the inclusion of the small NLO reduction;(c) the PQCD predictions for the ratio (fs/fd) · B(Bs0 → π+π−)/B(B0 → K+π−) and (fs/fd) · B(Bs0 → π+K−)/B(B0 → K+π−) become agree very well with the measured ones after the inclusion of a 40% NLO reduction;(d) for B¯s0 → K+K− and B¯s0 → π−K+ decays, the NLO PQCD predictions for their CP-violating asymmetries do agree very well with the measured values in both the sign and the magnitude;and (e) for all B¯s0 → P P decays, we also compared our results with those obtained in the QCD factorization approach and soft-collinear effective theory and discussed their similarities and differences. Copyright © 2019, The Authors. All rights reserved.

关键词： Forecasting

Bottomoniumlike tetraquarks in a chiral quark model

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Physical Review D 2022年第1期106卷 014021-014021页

The low-lying bottomoniumlike tetraquarks bb¯qq¯ (q=u, d, s) with spin-parity JP=0+, 1+, and 2+, and isospin I=0, 1, or 12, are systematically investigated within the theoretical framework of real- and complex-scaling range of a chiral quark model, which has already been successfully applied in analysis of several multiquark systems. A complete four-body S-wave function, which includes meson-meson, diquark-antidiquark and K-type arrangements of quarks, along with all possible color configurations are considered. In the bb¯qq¯ (q=u, d) tetraquark system, we found resonance states of B(*)B¯(*), ϒω, ϒρ, and ηbρ nature with all possible I(JP) quantum numbers. Their masses are generally located in the energy range 11.0–11.3 GeV and their widths are less than 10 MeV. In addition, extremely narrow resonances, with two-meson strong decay widths less than 1.5 MeV, are obtained in both bb¯us¯ and bb¯ss¯ tetraquark systems. Particularly, four radial excitations of ϒK* and ηbK* are found at ∼11.1 GeV in JP=0+, 1+, and 2+ channels of bb¯us¯ system. One ϒ(1S)ϕ(2S) resonance state is obtained at 11.28 GeV in the JP=1+ sector.

关键词： Quantum chromodynamics Quark model Strong interaction