共查询到11条相似文献,搜索用时 5 毫秒
1.
The discovery of Ξcc++has inspired new interest in studying doubly heavy baryons.In this study,the weak decays of a doubly charmed baryon Bccto a light baryon B and a charm meson D*(either a pseudoscalar or a vector one)are calculated.Following our previous work,we calculate the short distance contributions under the factorization hypothesis,whereas the long distance contributions are modeled as the final state interactions,which are calculated with the one particle exchange model.We find that the Bcc→BD*decays'branching ratios are obviously larger,as they receive contributions of more polarization states.Among the decays that we investigate,the following have the largest branching fractions:BR(Ξcc++→∑+D*+)∈[0.46%,3.33%]estimated with τΞcc++=256 fs;BR(Ξcc+→AD*+)∈[0.38%,2.63%]and BR(Ξcc+→∑0D*+)∈[0.45%,3.16%]with τΞcc++=45 fs;and BR(Ωcc+→Ξ0D+)∈[0.27%,1.03%),BR(Ωcc+→∑0D*+)∈[0.07%,0.44%],and BR(Ωcc+→∑0D*+)∈[0.06%,0.45%] with τ_(Ωcc)+=75 fs.By comparing the decay widths of pure color commensurate channels with those of pure bow-tie ones we find that the bow-tie mechanism plays an important role in charm decays. 相似文献
2.
In this research, the hadronic decay of B 0 → J/φρ0 is analyzed by using the QCD factorization (QCDF) and final state interaction (FSI). The D +(*) D ?(*) for d $\bar d$ and D 0(*) $\bar D^{0(*)}$ for u $\bar u$ contributions via the exchange of charmed mesons are chosen for the intermediate states. These amplitudes are calculated by using QCDF and used in the absorptive part of the diagrams. The experimental branching ratio of B 0 → J/φρ0 decay is (2.7 ± 0.4) × 10?5 and our results according to the QCDF method and FSI are 0.87 × 10?5 and (0.057–4.18) × 10?5, respectively. 相似文献
3.
Using the photon spectrum of a high energy charged patton, we investigate the J/ψ production via the two photon interaction mechanism in ultra-peripheral pp collisions. It is shown that the contributions from the direct electromagnetic and the corresponding fragmentation processes are meaningful for the J/ψ productions in ultra-peripheral pp collisions at LHC energy. 相似文献
4.
《中国物理 C》2010,(4)
The decay channel ψ→π+π-J/ψ(J/ψ→γp) is studied using a sample of 1.06×108 ψ events collected by the BESIII experiment at BEPCII. A strong enhancement at threshold is observed in the p invariant mass spectrum. The enhancement can be fitted with an S-wave Breit-Wigner resonance function with a resulting peak mass of M =1861+6-13 (stat)+7-26 (syst) MeV/c2 and a narrow width that is Γ <38 MeV/c2 at the 90% confidence level. These results are consistent with published BESII results. These mass and width values... 相似文献
5.
LIU Xiang ZENG Xiao-Qiang DING Yi-Bing LI Xue-Qian SHENG Hong SHEN Peng-Nian 《中国物理C(英文版)》2006,30(1):1-12
Provided the enhancement in the pp spectrum in radiative decay J/ψ→γpp observed by the BES collaboration is due to an existence of a pp molecular state, we calculate its binding energy and lifetime in the linear σ model. Concretely, we consider a possibility that the enhancement is due to a pp resonance which is in either S-wave or P-wave structure and compare our results with the data. Moreover, pp can annihilate at s-channel which is absent in deuteron, thus by studying the total width of the pp bound state, we may gain more information about the linear σ model and some concerned issues 相似文献
6.
With the recent investigations of the g*g*-η(') transition form factor and η-η' mixing scheme, we present an updated study of the radiative decays J/ψ → η(')γ in perturbative QCD. The decays are taken as a test ground for the g*g*-η(') transition form factors and the η-η' mixing scheme. The form factors are found to be working for glunic η' production and the mixing angle is constrained to be φ=35.1°±0.8°. 相似文献
7.
The π^+π^ transition of heavy quarkonia in decay ψ(2S) →π^+π^-J/ψ is studied. With the BESII data on the decay ψ(2S) →π^+π^-J/ψ, we update the values of coupling constants (gi) and chromopolarizability (αψ(2s)J/ψ) in this process. 相似文献
8.
Properties of ground state and anomalous quantum fluctuations in one-dimensional polaron-soliton systems—the effects of electron-two-phonon interaction and non-adiabatic quantum correlations 下载免费PDF全文
Based on the Holstein model Hamiltonian of one-dimensional molecular crystals, by making use of the expansion approach of the correlated squeezed-coherent states of phonon instead of the two-phonon coherent state expansion scheme, the properties of the ground state and the anomalous quantum fluctuations are investigated in a strongly coupled electron-phonon system with special consideration of the electron-two-phonon interaction. The effective renormalization (αi) of the displacement of the squeezed phonons with the effect of the squeezed-coherent states of phonon and both the electron-displaced phonon and the polaron-squeezed phonon correlations have been combined to obtain the anomalous quantum fluctuations for the corrections of the coherent state. Due to these non-adiabatic correlations, the effective displacement parameter αi is larger than the ordinary parameter α (0) i . In comparison with the electron-one-phonon interaction (g) corrected as αig, we have found the electron-two-phonon interaction (g1) corrected as αi2 g1 is enhanced significantly. For this reason, the ground state energy (E(2) 0 ) contributed by the electron-two-phonon interaction is more negative than the single-phonon case (E(1) 0 ) and the soliton solution is more stable. At the same time, the effects of the electron-two-phonon interaction greatly increase the polaron energy and the quantum fluctuations. Furthermore, in a deeper level, we have considered the effect of the polaron-squeezed phonon correlation (f-correlation). Since this correlation parameter f > 1, this effect will strengthen the electron-one and two-phonon interactions by fαig and f2αi2 g1, respectively. The final results show that the ground state energy and the polaron energy will appear more negative further and the quantum fluctuations will gain further improvement. 相似文献
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10.
We propose one possible mechanism,i.e.,the vector meson (VV) rescattering effects,to interpret the near threshold narrow enhancement observed in J/ψ → γpp.The estimate indicates that these effects can give sizeable contributions to this channel,and a destructive interference between different rescattering amplitudes is required to reproduce the line shape of the data. 相似文献
11.
M. Ablikim 《中国物理C(英文版)》2010,34(4):421-426
The decay channel ψ′→π+π-J/ψ(J/ψ→γpp) is studied using a sample of 1.06×108 ψ′ events collected by the BESIII experiment at BEPCII. A strong enhancement at threshold is observed in the pp invariant mass spectrum. The enhancement can be fitted with an S-wave Breit-Wigner resonance function with a resulting peak mass of M=1861+6-13 (stat)+7-26 (syst) MeV/c2 and a narrow width that is Γ<38 MeV/c2 at the 90% confidence level. These results are consistent with published BESII results. These mass and width values do not match with well established mesons.
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