In the framework of the factorization approach we calculate the branching fractions of 100 two-body nonleptonic decay channels in total,including 44 channels of the charm meson decays and 56 channels of the bottom mes...In the framework of the factorization approach we calculate the branching fractions of 100 two-body nonleptonic decay channels in total,including 44 channels of the charm meson decays and 56 channels of the bottom meson decays.For charm meson decays,we test and confirm the previous observation that taking the limit for the number of colors N→∞significantly improves theoretical predictions.For bottom meson decays,the penguin contributions are included in addition.As an essential input,we employ the weak decay form factors obtained in the framework of the relativistic quark model based on the quasi-potential approach.These form factors have well been tested by calculating observables in the semileptonic D and B meson decays and confronting obtained results with experimental data.In general,the predictions for the nonleptonic decay branching fractions are acceptable.However,for a quantitative calculation it is necessary to account for a more subtle effects of the final-state interaction.展开更多
In this paper we propose a dispersive method to describe two-body scattering with unitarity imposed. This approach is applied to elastic ππ scattering. The amplitudes keep single-channel unitarity and describe the e...In this paper we propose a dispersive method to describe two-body scattering with unitarity imposed. This approach is applied to elastic ππ scattering. The amplitudes keep single-channel unitarity and describe the experimental data well, and the low-energy amplitudes are consistent with that of chiral perturbation theory. The pole locations of the σ, f0(980), ρ(770) and f2(1270) and their couplings to ππ are obtained. A virtual state appearing in the isospin-two S-wave is confirmed. The correlations between the left(and right) hand cut and the poles are discussed. Our results show that the poles are more sensitive to the right hand cut rather than the left hand cut. The proposed method could be used to study other two-body scattering processes.展开更多
We discuss possible implications of exotic stringy instantons for baryon-violating signatures in future colliders. In particular, we discuss high-energy quark collisions and A- transitions. In principle, the A-A proce...We discuss possible implications of exotic stringy instantons for baryon-violating signatures in future colliders. In particular, we discuss high-energy quark collisions and A- transitions. In principle, the A-A process can be probed by high-luminosity electron-positron colliders. However, we find that an extremely high luminosity is needed in order to provide a （somewhat） stringent bound compared to the current data on NN→ππ,KK. On the other hand, （exotic） instanton-induced six-quark interactions can be tested in near future high-energy colliders beyond LHC, at energies around 20-100 TeV. The Super proton-proton Collider （SppC） would be capable of such measurement given the proposed energy level of 50-90 TeV. Comparison with other channels is made. In particular, we show the compatibility of our model with neutron-antineutron and NN→ππ, KK bounds.展开更多
We study the rare decaysΛb→Λl+l−(l=e,μ,τ)in the Bethe-Salpeter equation approach.We find that the branching ratio is Br(Λb→Λμ^+μ^−)×10^6=1.051∼1.098 in our model.This result agrees with the experimenta...We study the rare decaysΛb→Λl+l−(l=e,μ,τ)in the Bethe-Salpeter equation approach.We find that the branching ratio is Br(Λb→Λμ^+μ^−)×10^6=1.051∼1.098 in our model.This result agrees with the experimental data well.In the same parametric region,we find that the branching ratio is Br(Λb→Λe^+e^−(τ^+τ^−))×10^6=0.252∼0.392(0.286∼0.489).展开更多
基金supported by Joint Large Scale Scientific Facility Funds of the National Natural Science Foundation of China(NSFC)and Chinese Academy of Sciences(CAS)(U1932110,NSFC(11805059,11805012,11675051,12322502),and 12335002)Fundamental Research Funds for the central Universities+3 种基金supported by Deutsche Forschungsgemeinschaft(DFG)(TRR110)NSFC through funds provided to the Sino-German CRC 110“Symmetries and the Emergence of Structure in QCD”(11621131001)supported in part by VolkswagenStiftung(93562)by the CAS President’s International Fellowship Initiative(PIFI)(2018DM0034)。
基金support from the National Natural Science Foundation of China (NSFC) under Project Nos.11805012 and 12275023.
文摘In the framework of the factorization approach we calculate the branching fractions of 100 two-body nonleptonic decay channels in total,including 44 channels of the charm meson decays and 56 channels of the bottom meson decays.For charm meson decays,we test and confirm the previous observation that taking the limit for the number of colors N→∞significantly improves theoretical predictions.For bottom meson decays,the penguin contributions are included in addition.As an essential input,we employ the weak decay form factors obtained in the framework of the relativistic quark model based on the quasi-potential approach.These form factors have well been tested by calculating observables in the semileptonic D and B meson decays and confronting obtained results with experimental data.In general,the predictions for the nonleptonic decay branching fractions are acceptable.However,for a quantitative calculation it is necessary to account for a more subtle effects of the final-state interaction.
基金Supported by National Natural Science Foundation of China uder Grant Nos.11805059,11805012,11805037Fundamental Research Funds for the Central Universities+6 种基金the Joint Large Scale Scientific Facility Funds of the NSFCChinese Academy of Sciences(CAS)under Grant No.U1832121Shanghai Pujiang Program under Grant No.18PJ1401000Open Research Program of Large Research Infrastructures(2017)CAS,the DFG(SFB/TR 110,“Symmetries and the Emergence of Structure in QCD”)the Chinese Academy of Sciences(CAS) President’s International Fellowship Initiative(PIFI)under Grant No.2018DM0034Volkswagen Stiftung under Grant No.93562
文摘In this paper we propose a dispersive method to describe two-body scattering with unitarity imposed. This approach is applied to elastic ππ scattering. The amplitudes keep single-channel unitarity and describe the experimental data well, and the low-energy amplitudes are consistent with that of chiral perturbation theory. The pole locations of the σ, f0(980), ρ(770) and f2(1270) and their couplings to ππ are obtained. A virtual state appearing in the isospin-two S-wave is confirmed. The correlations between the left(and right) hand cut and the poles are discussed. Our results show that the poles are more sensitive to the right hand cut rather than the left hand cut. The proposed method could be used to study other two-body scattering processes.
基金supported in part by the MIUR research grant “Theoretical Astroparticle Physics” PRIN 2012CPPYP7partly supported by the DFG and the NSFC through funds provided to the Sino-German CRC 110 “Symmetries and the Emergence of Structure in QCD”+2 种基金MOST,Taiwan,(104-2112-M-001-022)from April 2017Supported by MEPhI Academic Excellence Project(contract 02.03.21.0005,27.08.2013)supported by the Ministry of Education and Science of Russian Federation,project 3.472.2014/K and grant RFBR 14-22-03048
文摘We discuss possible implications of exotic stringy instantons for baryon-violating signatures in future colliders. In particular, we discuss high-energy quark collisions and A- transitions. In principle, the A-A process can be probed by high-luminosity electron-positron colliders. However, we find that an extremely high luminosity is needed in order to provide a （somewhat） stringent bound compared to the current data on NN→ππ,KK. On the other hand, （exotic） instanton-induced six-quark interactions can be tested in near future high-energy colliders beyond LHC, at energies around 20-100 TeV. The Super proton-proton Collider （SppC） would be capable of such measurement given the proposed energy level of 50-90 TeV. Comparison with other channels is made. In particular, we show the compatibility of our model with neutron-antineutron and NN→ππ, KK bounds.
基金Supported by National Natural Science Foundation of China(11775024,11575023,11905117,11847052,11805012,11947001)。
文摘We study the rare decaysΛb→Λl+l−(l=e,μ,τ)in the Bethe-Salpeter equation approach.We find that the branching ratio is Br(Λb→Λμ^+μ^−)×10^6=1.051∼1.098 in our model.This result agrees with the experimental data well.In the same parametric region,we find that the branching ratio is Br(Λb→Λe^+e^−(τ^+τ^−))×10^6=0.252∼0.392(0.286∼0.489).
