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 共查询到20条相似文献,搜索用时 78 毫秒
1.
王志刚 《中国物理快报》2008,25(11):3908-3911
We calculate the masses and decay constants of the P-wave strange-bottomed mesons Bs0 and Bs1 with the QCD sum rules, and observe that the central values of the masses Bs0 and Bs1 are smaller than the corresponding BK and B^*K thresholds respectively, the strong decays Bs0→ BK and Bs1→B^*K are kinematically forbidden. They can decay through the isospin violation processes Bs0→ Bsη → Bsπ^0 and Bs1 → Bs^*η → Bs^*π^0 .The bottomed mesons Bs0 and Bs1, just like their charmed cousins Ds0(2317) and Ds1(2460), may be very narrow.  相似文献   

2.
In the qq quark model, the states π2(1670) and η2(1645) are assigned as the I1D2 meson nonet. The partner of state η2(1645) needs further confirmation in the experiments. We employ the meson-meson mixing and the Regge trajectory methods to calculate the mass of the partner of state η2 (1645) to be 1879.8 MeV and 1863 ± 24 MeV respectively. We also calculate the strong decay width in the 3po decay model. These predictions can be compared with experiments in the future.  相似文献   

3.
冯学超  冯军兰 《中国物理》2007,16(11):3297-3299
In the qq quark model, the states π(1300), η(1295) and η(1475) are assigned as the 2^1S0 meson nonet. The mass of the isodoublet remains interesting and needs further confirmation in experiments. This paper employs the phenomenological trajectory on the (N, M^2)-plot and meson meson mixing methods to calculate the mass of this state, the calculated results are 1341 MeV and 1311.58 ± 59 MeV respectively. These predictions can be compared with experiments in the future.[第一段]  相似文献   

4.
B^0(Bs)→γvv decays are useful to determining the decay constants fB(fBs) and B(Bs) meson wave function. Using the B meson wave function determined in hadronic B(Bs) decays, we study the uncertainties due to the types of B meson wave functions. We find that the branching ratios are sensitive to the type of wave functions and input parameters, but the energy spectrum is independent. The predicted branching ratios are (0.45-1.04)×10^-9 and (2.14-3.27)×10^-8 for B^0 and Bs decay, respectively.  相似文献   

5.
The photo-excitation and Auger decay processes of inner-shell double vacancy states 1s2s2p^6(1,3^S)3s3p of neutral neon atoms have been studied theoretically. Multi-configuration Dirac-Fock (MCDF) calculations have been carried out, with electron correlation effects taken into consideration. The relaxation of core and excited orbitals and configuration interaction are found to be crucial to creating the double vacancy states by single photo-absorption. The predominant decay paths for the double vacancy states turn out to be of the LLM Auger decay to 1s 2s^22p^53s(3p), KLL Auger decay to 1s^22s2p^43s3p, and KLM Auger decay to 1s^22p^63s(3p). They lead to further Auger decay, creating the neon ions of multiple charge states. For both double and single vacancy states the spectator type of Auger process is dominated in all the Auger decay processes. Theoretical Anger electron spectra are presented for further investigations, experimental and theoretical.  相似文献   

6.
刘翔 《中国物理 C》2010,34(9):1405-1407
In my talk,we present the dynamical study of Y(4140) and Y(3930) under the D*s D*s and D* D* molecular assignments respectively.The importance to theoretically and experimentally study their open-charm decay,hidden-charm decay,radiative decay and double-photon decay is proposed combing with the theoretical calculation of the decay behavior of Y(4140) and Y(3930).According to the recent new experimental progress made by Belle,we further indicate the reasonability of molecular explanation to Y(4140).Another event cluster around 4270 MeV in the J/ψφ invariant mass spectrum of B → KJ/ψφ can provide us more hints to reveal the creation mechanism of molecular structure in B meson decay,which will be helpful to clarify the underlying structure of Y(4140) and Y(3930).  相似文献   

7.
We study the CP-averaged branching fractions and the CP-violating asymmetries in the pure annihilation decays ofB _s~0→a_0~+a _0~-andB _d~0→K_0~(*+)K_0~(*-),where a_0[K_0~*]denotes the scalar a_0(980) and a_0(1450)[K_0~*(800)(ork)and K_0~*(1430)],with the perturbative QCD factorization approach under the assumption of two-quark structure for the a_0and K_0~*states.The numerical results show that the branching ratios of theB _d~0→K_0~(*+)K_0~(*-)decays are in the order of 10~(-6),while the decay rates of theB_s~0→a_0~+a _0~-modes are in the order of 10~(-5).In light of the measured modes with the same quark components in the pseudoscalar sector,namely,B _d~0→K~+K~-and B_s~0→p p~(+-),the predictions for the considered decay modes in this work are expected to be measured at the Large Hadron Collider beauty and/or Belle-Ⅱ experiments in the (near) future.Meanwhile,it is of great interest to find that the twist-3 distribution amplitudes φ~S and φ~T with inclusion of the Gegenbauer polynomials for the scalar a_0(1450) and K_0~*(1430)states in scenario2 contribute slightly to the branching ratios while significantly to the CP violations in the B_d~0→K_0~*(14 30)~+K_0*(14 30)~-and B_s~0→a_0(1450)~+a_0(1450)~-decays,which indicates that,compared to the asymptotic φ~Sand φ~T,these Gegenbauer polynomials could change the strong phases evidently in these pure annihilation decay channels.These predictions await for the future confirmation experimentally,which could further provide useful information to help explore the inner structure of the scalars and shed light on the annihilation decay mechanism.  相似文献   

8.
The decay widths of Υ(nS)→d~*(2380)+X with n=1,2,3 are studied in a phenomenological way. With the help of crossing symmetry, the decay widths are obtained by investigating the imaginary part of the forward scattering amplitudes between d~* and Υ(nS). The wave functions of d~* and deuteron obtained in previous studies are used for calculating the amplitude. The interaction between d~*(d) and Υ is governed by the quark-meson interaction, where the coupling constant is determined by fitting the observed widths of Υ(nS)→d+X. The numerical results show that the decay widths of Υ(nS)→d~*+X are about 2-10 times smaller than that of d+X. The calculated momentum of d~* is in the range 0.3-0.8 GeV. Therefore, it is very likely that one can find d~*(2380) in these semi-inclusive decay processes.  相似文献   

9.
This work studies the systematic reduced transition probabilities B(E2)↓, intrinsic quadrupole moments and deformation parameters of Pd isotopes with even neutrons from N =62 to 66. The downward reduced transition probabilities B(E2)↓from gamma transition 8^+to 6^+, 6^+ to 4^+, 4^+ to 2^+ and 2^+ to 0+states of even-even108 112Pd isotopes were calculated by the Interacting Boson Model(IBM-1) and compared with the available previous experimental results. The ratio of the excitation energies of the first 4+and the first 2+excited states, R4/2, is also studied for the classification of symmetry of these nuclei. Furthermore we have studied systematically the transition rate R = B(E2: L+ →(L 2)+)/B(E2 : 2+ →0+) of some of the low-lying quadrupole collective states in comparison with the available experimental data. The associated quadrupole moments and deformation parameters have been calculated. The results of this calculation are in good agreement with the corresponding available experimental data. The108 112Pd isotopes show the O(6) symmetry.  相似文献   

10.
张晓燕  杨传路  高峰  任廷琦 《中国物理》2006,15(9):1981-1986
The multi-reference configuration interaction method and aug-cc-pvqz (AVQZ) have been used to calculate potential energy curves (PECs) of the singlet and triplet states of the riu and rig symmetry of B2++. All of the four states (^l∏u, ^1∏g, ^3∏u and ^3∏g) are found to be metastable states, though the potential well of ^3∏u symmetry is very shallow. Based on the PECs, the analytical potential energy functions (APEFs) of these states have been fitted using the least square fitting method and two models of function. The spectroscopic parameters of each state are also calculated, and are compared with other investigations in the literature. The credibility and veracity of the two functions are evaluated. Some ideas to improve the fitting accuracy are presented. Also the vibrational levels for each state are predicted by solving the SchrSdinger equation of nuclear motion.  相似文献   

11.
In the framework of the heavy quark effective theory,the leading order Isgur-Wise functions relevant to semileptonic decays of the orbitally P-wave excited B s meson states B**s,including the newly found narrow B s1(5830) and B**s2(5840) states,into the(D s1(2536),D*s2(2573)) doublet are calculated from QCD sum rules.With these universal form factors,the decay rates and branching ratios are also estimated.  相似文献   

12.
A Gaussian wave function is used for detailed study of the mass spectra of the B and BS mesons using a Cornell potential incorporated with a O(1/m) correction in the potential energy term and expansion of the kinetic energy term up to O p~(10) for relativistic correction of the Hamiltonian.The predicted excited states for the B and B_s mesons are in very good agreement with results obtained by experiment.We assign B_2(5747) and B_(s2()5840) as the 1~3P~2 state,B1(5721) and Bs1(5830) as the 1P_1 state,B0(5732) as the 1~3P_0 state,B_(s1)(5850) as the 1~P 1 state and B(5970) as the 2~3S_1 state.We investigate the Regge trajectories in the(J,M~2) and(nr,M~2) planes with their corresponding parameters.The branching ratios for leptonic and radiative-leptonic decays are estimated for the B and BS mesons.Our results are in good agreement with experimental observations as well as outcomes of other theoretical models.  相似文献   

13.
In this work, we tentatively assign the charmed mesons D J(2580), D*J(2650), D J(2740), D*J(2760),D J(3000) and D*J(3000) observed by the LHCb collaboration according to their spin, parity and masses, then systematically study their strong decays to ground state charmed mesons plus pseudoscalar mesons with the3P0 decay model. Based on these studies, we assign the D*J(2760) as the 1D5/23-state, the D*J(3000) as the 1F5/22+or 1F7/24+state, the D J(3000) as the 1F7/23+or 2P1/21+state in the D meson family. As a byproduct, we also study the strong decays of the states 2P1/20+, 2P3/22+, 3S1/21-, 3S1/20-etc, which will be valuable in searching for the partners of these D mesons.  相似文献   

14.
We study the contributions of intermediate bottomonium-like Zb states and the bottom meson loops in the heavy quark spin flip transitionsγ(4 S)→hb(1 P,2 P)π+π-.Depending on the constructive or destructive interferences between the Zb-exchange and the bottom meson loops mechanisms,we predict two possible branching ratios for each process:BRγ(4 S)→hb(1 P)π+π-≈(1.20.40.8×10^-6)or(0.5-0.20.5×10^-6),and BRγ(4 S)→(2 P)π+π-≈(7.1-1.1+1.7×10^-10)or(2.4-0.10.2×10^-10)).The contribution of the bottom meson loops is found to be considerably larger than that of the Zbexchange in the T(4 S)→hb(1 P)ππtransitions,while its decay rates are not comparable to those of heavy quark spin conservedγ(4 S)→γ(1 S,2 S)ππprocesses.We also predict the contribution of the charm meson loops in the branch fractions ofΨ(3 S,4 S)→hc(1 P)ππ.  相似文献   

15.
In this article, we assign the higher charm mesons D1*(2680), D3*(2760) and D2*(3000) to be the 2S 1-, 1D 3- and 1F 2+ states, respectively, and study the two-body strong decays to the ground state charm mesons and light pseudoscalar mesons with the heavy meson effective theory. We obtain the ratios among the strong decays, which can be confronted to the experimental data in the future and shed light on the nature of those higher charm mesons.  相似文献   

16.
In this article, we assign the higher charm mesons D1_*(2680), D3_*(2760) and D2_*(3000) to be the 2S 1~-, 1D3~- and 1F 2~+ states, respectively, and study the two-body strong decays to the ground state charm mesons and light pseudoscalar mesons with the heavy meson effective theory. We obtain the ratios among the strong decays, which can be confronted to the experimental data in the future and shed light on the nature of those higher charm mesons.  相似文献   

17.
In my talk,we present the dynamical study of Y(4140)and Y(3930)under the D*s(D)*s and D*(D)*molecular assignments respectively.The importance to theoretically and experimentally study their open-charm decay,hidden-charm decay,radiative decay and double-photon decay is proposed combing with the theoretical calculation of the decay behavior of Y(4140)and Y(3930).According to the recent new experimental progress made by Belle,we further indicate the reasonability of molecular explanation to Y(4140).Another event cluster around 4270 MeV in the J/ψφ invariant mass spectrum of B → KJ/ψφ can provide us more hints to reveal the creation mechanism of molecular structure in B meson decay,which will be helpful to clarify the underlying structure of Y(4140)and Y(3930).  相似文献   

18.
Based on the assumption that Ds1 (2536) and Ds2 (2573) belong to T doublet (1+,2+),we calculate the semileptonic decays of Bs to Ds1(2536) and Ds2(2573) in terms of the Constituent Quark Meson (CQM)model.For Bs→Ds1(2536)+l(v) and Bs→Ds2(2573)+l(v),the order of magnitude of the obtained branching ratios is 10-3.Our numerical results of the semileptonic decays of Bs to Ds1(2536) and Ds2(2573) are large,which implies that two semileptonic decays should be seen in future experiments.  相似文献   

19.
孙献平  刘子东 《光学学报》1990,10(5):06-412
本文报道使用蒸汽泡和两光子两步激发方法,测量原子激发态敏化荧光I_(3/2)~1和直接荧光I_(3/2)~2其与温度的关系,得到与基态(5~2S_(1/2)铷原子碰撞产生的铷7~2D_(5/2)→7~2D_(3/2)和7~2D_(3/2)→7~2D_(5/2)精细结构转移截面分别为:σ_(fs)=4.7×10~(-13)cm~2、σ_(fs)~’=7.0×10~(-13)cm~2;碰撞转移出7~2D双态的转移截面σ_(tr)(5/2)=0.62×10~(-13)cm~2.由计算的7~2D态几何截面σ_(geom)能够相对很好地描述σ_(fs)和σ_(fs)~’的数量级.  相似文献   

20.
Within the heavy quark limit and the hierarchy approximation Λqcd << Md << Mb,we analyze the B→DOD-O and Bs→ DOD-O decays,which occur purely via annihilation type diagrams.As a rough estimate,we calculate their branching ratios and CP asymmetries in the perturbative QCD (PQCD) approach.The branching ratio of B→ DOD-O is about 3.8×10-5 that is just below the latest experimental upper limit.The branching ratio of Bs→ DOD-O is about 6.8 × 10-4,which could be measured in LHC-b.From the calculation,it is found that this branching ratio is not sensitive to the weak phase angle γ.In these two decay modes,there exist CP asymmetries because of the interference between weak and strong interaction.However,these asymmetries are too small to be measured easily.  相似文献   

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