Search for ψ(4S) → ηJ/ψ in B~±→ ηJ/ψK~± and e~+e~-→ ηJ/ψ processes

We search for the ψ(4S) state in the B~±→ηJ/ψK~± and e~+e~-→ηJ/ψ processes based on the Belle measurements with the assumed mass M =(4230±8) MeV/c~2 and width Γ =(38±12) MeV. No significant signal is observed in the ηJ/ψ mass spectra. The 90% confidence level upper limit on the product branching fraction B(B~±→ψ(4S)K~±)B(ψ(4S)→ηJ/ψ) 6.8×10~(-6) is obtained in the B~±→ηJ/ψK~± decays. By assuming the partial width of ψ(4S)→e~+e~-to be 0.63 ke V, a branching fraction limitB(ψ(4S)→ηJ/ψ) 1.3% is obtained at the 90%confidence level in e~+e~-→ηJ/ψ, which is consistent with the theoretical prediction.     

ηb decay into charmonium in association with cc pair

We calculate the inclusive decay rates of ηb into charmonium via double c~ pairs for S- and P-wave states ηc, J/ψ and XcJ within the framework of non-relativistic QCD （NRQCD） factorization at leading order in αs. Besides calculating the contributions of the color-singlet channels ηb → cc[2s＋1SL^（1）]＋cc, the effects of cc pair in the color-octet configurations are also considered. We find that ηb → cc[3S1^（8）] ＋cc make a small contribution to Br（ηb →J/ψ（ηc）＋cc）. While in the ηb →XcJ ＋cc case, the color octet contributions are significant, for they are of the same a 5 order as the color-singlet processes. We predict Br（ηb →J/ψ（ηc）＋cc） = 2.99（2.75） × 10^-5 Vc for S-wave states J/ψ and ηc, and Br（ηb → XcJ ＋cc） = （4.37, 3.40, 2.83） × 10^-5 （for J = 0,1, 2） for P-wave states XcJ. In the end, we also find Br（ηb → cccc） is almost saturated by ηb decay into charmonium in association with cc pair from the point of view of duality.     

B→（J/ψ,η_c）K decays in the perturbative QCD approach

In this paper,we calculated the B →（J/ψ,ηc） K decays in the perturbative QCD（pQCD） factorization approach with the inclusion of the partial next-to-leading order（NLO） contributions. With the inclusion of the significant enhancement from the NLO vertex corrections,the NLO pQCD predictions for the branching ratios agree with the data within 2σ errors：Br（B0 → J/ψK0） = 5.2-＋32..58×10-4,Br（B＋ → J/ψK＋） = 5.6-＋32..79×10-4,Br（B0 →ηcK0） = 5.5-＋22..30 × 10-4,Br（B＋ →ηcK＋） = 5.9-＋22..51 × 10-4.     

Charmonium spectroscopy and decay at CLEO-c

We report recent results on charmonium spectroscopy and decay from the CLEO-c experiment at the Cornell electrompositron storage ring accelerator, CESR. Most of the results are based on the analysis of 54 pb-1 of luminosity collected at the ψ（2S） resonance, corresponding to 27 M ψ（2S） decays. We concentrate on radiative decays of ψ（2S） and J/ψ, on two-body mesonic decay of XcJ, on hadronic decay of the he, and on higher multipoles in the two-photon cascade ψ（2S）→γχcJ, XcJ→γJ/ψ.     

J/ψ Inclusive Photon Spectrum at BESⅢ

With a 15M J/ψ inclusive Monte Carlo sample, the absolute branching fraction of J/ψ→γη′ from the J/ψ inclusive photon spectrum is measured to be Br（J/ψ→γη′）= （4.68 ± 0.08± 0.27） × 10-3, which is in good agreement with the input value. The J/ψ→γfJ（2220） is also searched for using the same sample. Under our assumptions, the statistical significanees of J/ψ→γfJ（2220） are larger than 7σ.     

Semileptonic decays B_c■(η_c,J/ψ)l■_l in the “PQCD+Lattice” approach

We study the semileptonic decaysBc-→(ηc,J/ψ)l-■lusing the PQCD factorization approach with the newly defined distribution amplitudes of the B c meson and a new kind of parametrization for extrapolating the form factors which takes into account the recent lattice QCD results.We find the following main results:(a)the PQCD predictions of the branching ratios of theBc→(ηc,J/ψ)l■decays are smaller by about 5%-16%when the lattice results are taken into account in the extrapolation of the relevant form factors;(b)the PQCD predictions of the ratio Rηc,RJ/ψand of the longitudinal polarization PτareRηc=0.34±0.01,RJ/ψ=0.28±0.01,Pτ(ηc)=0.37±0.01and Pτ(J/ψ)=-0.55±0.01;and(c)after including the lattice results,the theoretical predictions slightly change:Rηc=0.31±0.01,RJ/ψ=0.27±0.01,Pτ(ηc)=0.36±0.01andPτ(J/ψ)=-0.53±0.01.The theoretical predictions of RJ/ψagree with the measurements within the errors.The other predictions could be tested by the LHCb experiment in the near future.     

ηb decay into charmonium in association with c(c) pair

We calculate the inclusive decay rates of ηb into charmonium via double cc pairs for S- and P-wave states ηc, J/ψ and χcJ within the framework of non-relativistic QCD (NRQCD) factorization at leading order in αs. Besides calculating the contributions of the color-singlet channels ηb→c(c)[2S+1Sl(1)]+c(c), the effects of c(c) pair in the color-octet configurations are also considered. We find that ηb→c(c)[3S1(8)]+c(c) make a small contribution to Br(ηb→J/ψ(ηc)+c(c)). While in ther ηb→χcJ+c(c) case, the color octet contributions are significant, for they are of the same αs4vc5 order as the color-singlet processes. We predict Br(ηb → J/ψ(ηc)+c(c)) = 2.99(2.75) × 10-5 for S-vrave states J/ψ and ηc, and Br(ηb→χcJ +c(c))= (4.37,3.40,2.83)×10-5 (for J = 0,1,2) for P-wave states χcJ. In the end, we also find Br(ηb → c(c)c(c)) is almost saturated by ηb decay into charmonium in association with cc pair from the point of view of duality.     

η_b decay into charmonium in association with c pair

We calculate the inclusive decay rates of ηb into charmonium via double c pairs for S-and P-wave states ηc,J/ψ and χcJ within the framework of non-relativistic QCD(NRQCD) factorization at leading order in αs.Besides calculating the contributions of the color-singlet channels ηb→c[2S+1SL(1)]+c,the effects of c pair in the color-octet configurations are also considered.We find that ηb→c[3S1(8)]+c make a small contribution to Br(ηb→J/ψ(ηc)+c).While in the ηb→χcJ+c case,the color octet contributions are significant,for they are of the same αs4vc5 order as the color-singlet processes.We predict Br(ηb→J/ψ(ηc)+c)=2.99(2.75)×10-5 for S-wave states J/ψ and ηc,and Br(ηb→χcJ+c)=(4.37,3.40,2.83)×10-5(for J =0,1,2) for P-wave states χcJ.In the end,we also find Br(ηb→ cc) is almost saturated by ηb decay into charmonium in association with c pair from the point of view of duality.     

NLO QCD corrections to η_c+h_c(1P)/ψ_(1,2)(1D) production at B-factories

We calculate the next-to-leading order(NLO) quantum chromodynamics(QCD) corrections to double charmonium production processes e+e-→γ*→ηc+hc(1P)/ψ1,2(1D) within the non-relativistic QCD(NRQCD)factorization framework. We find that the corrections to ηc+hc(1P) production are positive, while those to ηc+ψ1,2(1D)are negative. Unlike the J/ψ+ηc case, all the corrections here are not large. Uncertainties in the renormalization scale, quark mass and running energy of center-of-mass are discussed, and the scale dependence of these processes is found to be greatly reduced with the NLO QCD corrections.     

B→ Ds^（＊）η（′） Decays in Perturbative QCD

In this paper, we calculate the branching ratios for B^＋→ Ds^＋η, B^＋→ Ds^＋η′, B^＋→ Ds^（→）η and B^＋ → Ds^＋η′ decays by employing the perturbative QCD （pQCD） factorization approach. Under the two kinds of η - η′ mixing schemes, the quark-flavor mixing scheme and the singlet-octet mixing scheme, we find that the calculated branching ratios agree well with the currently available experimental upper limits. We also consider the so called ＂fDs puzzle＂, by using two groups of parameters about the Ds^（→） meson decay constants, that are fDs = 241 MeV, fDs^→ = 272 MeV and fDs = 274 MeV, fDs^→ = 312 MeV, to calculate the branching ratios for the considered decays. We find that the results change 30%by using these two different kinds of paramters.     

A Proposal on the Search for the Hybrid with I^G（J^PC）=1^—（1—＋）in the Process J／ψ→ρωππ at Upgraded BEPC／BES

We give the moment expressions for the boson resonances X with spin-parity JXPXC=0 ,1- ,1 and 2 posibly produced in the process J/ψ→ρX,X→b1(1235)π,b1→ωπ in terms of the generalized moment analysis method .The resonance with JXPXC=1- can e distingguished from other resonances by means of these moments exceptfor some rather special cases.The suggestion that the search for the hybrid with IG(JPC)=1-(1- ) can be performed in the decay channl J/ψ→ρωππat upgraded BEPC/BES is presented.     

J/ψ Inclusive Photon Spectrum at BESIII

With a 15M J/ψ inclusive Monte Carlo sample, the absolute branching fraction of J/ψ→γ\η' from the J/ψ inclusive photon spectrum is measured to be Br(J/ψ→γ\η')=(4.68±0.08±0.27)×10^-3, which is in good agreement with the input value. The J/ψ→γf_J(2220) is also searched for using the same sample. Under our assumptions, the statistical significances of J/ψ→γf_J(2220) are larger than 7\σ.     

Evidence for resonant structures in e＋e-→π＋π-hc

Abstract： The cross sections of e＋e-→π＋π-hc at center-of-mass energies from 3.90 to 4.42 GeV were measured by the BESIII and the CLEO-c experiments. Resonant structures are evident in the e＋e-→π＋π-hc line shape. The fit to the line shape results in a narrow structure at a mass of （4216±18） MeV/c2 and a width of （39±2） MeV, and a possible wide structure of mass （4293±9） MeV/c2 and width （222=k67） MeV. Here, the errors are combined statistical and systematic errors. This may indicate that the Y（4260） state observed in e＋e-→π＋π-J/ψ has a fine structure in it.     

Observation of a p mass threshold enhancement in ψ′→π+π-J/ψ(J/ψ→γp) decay

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...     

Pseudoscalar mixing in J/ψ and ψ（2S）decay

Based on the branching fractions of J/ψ（ψ（2S））→ VP from different collaborations, pseudoscalar mixing is extensively discussed with a well established phenomenological model. The mixing angle is determined to be -14° by fitting to the new world average if only quark content is considered. After taking into account the gluonic content in η and η＇ simultaneously, the investigation shows that η favors only consisting of light quarks, while the gluonic content of η＇ is Z2η＇, = 0.30±0.24.     

Analysis of the coupling constants ga0ηπ0 and ga0η＇ π0 with light-cone QCD sum rules

In this article, we take the point of view that the light scalar meson a0（980） is a conventional qqstate, and calculate the coupling constants ga0ηπ0 and ga0ηπ0 with the light-cone QCD sum rules. The central value of the coupling constant ga0ηπ0 is consistent with that extracted from the radiative decay φ（1020） → a0（980）γ→ηπ0γ. The central value and lower bound of the decay width Γa0→ηπ0 =127＋8448 MeV are compatible with the experimental data of the total decay width Γa0（980） = （50-100） MeV from the Particle Data Group with a very model dependent estimation （the decay width can be much larger）, while the upper bound is too large. We give a possible explanation for the discrepancy between the theoretical calculation and experimental data.     

Analysis of Infrared Divergence in OZI-Forbidden Decays of Orthoquarkonia

It is interesting to investigate the OZI-forbidden decays of orthoquarkoknium, J/ψ→γπ^0（γη,γη′）, J/ψ→π^＋π^-（π^0π^0）. At first glance, there is infrared divergence in the above processes. In this work, to clear the mist we use the factorization method with the light cone wavefunction of the final state light meson. We prove straightforwardly that the infrared divergence can be eliminated completely.     

Helicity Amplitude Analysis of ηc Decays into Hyperon-Antihyperon Pairst

The helicity amplitudes for the processes of e^＋e^- →J/ψ→γηc→γYY（Y： hyperon） are presented, together with the joint angular distributions for ηc decays into ∧∧,∑^0 ∑^0, and [1]-[1]＋. The sensitivities to measure the hyperon decay parameters in these decays are evaluated based on the helicity amplitudes. The prospects to test the Bell inequality in experiment using the decay of ηc→∧∧ are discussed.     

Hadron molecules

We discuss a possible interpretation of the open charm mesons D＊s0 （2317）,D s1 （2460） and the hidden charm mesons X（3872）,Y（3940） and Y（4140） as hadron molecules.Using a phenomenological Lagrangian approach we review the strong and radiative decays of the D＊ s0 （2317） and D s1 （2460） states.The X（3872） is assumed to consist dominantly of molecular hadronic components with an additional small admixture of a charmonium configuration.Determing the radiative （γJ/ψ and γψ（2s）） and strong （J/ψ2π and J/ψ3π） decay modes we show that the present experimental observation is consistent with the molecular structure assumption of the X（3872）.Finally,we give evidence for molecular interpretations of the Y（3940） and Y（4140） related to the observed strong decay modes J/ψ＋ω or J/ψ＋φ,respectively.     

J/ψ inclusive production in χbJ（nP） decays

We study J/ψ inclusive production in the decays of P-wave bottomonium χbJ（1P,2P） for J=0,1,2. Within the framework of the non-relativistic QCD（NRQCD） factorization method we calculate the contri-butions coming from four relevant processes including one color-singlet process and three color-octet ones,which are b（3PJ,1） → c（3S1,8） ＋ c ＋,b（3S1,8） → c（3S1,1） ＋ g ＋ g,b（3S1,8） → c（3S1,1） ＋ c ＋ and b（3S1,8） → c（3S1,8） ＋g. Our calculation shows that the color-octet processes,especially the gluon fragmen-tation one,contribute the most in the decays of χb0 and χb1. However,the J/ψ production in the χb2 decay is dominated by the color-singlet process. Furthermore,the gluon fragmentation process gives a δ function in the energy fraction distribution of J/ψ,which can be considered to be another characteristic for its identification. From our estimation the branching ratio for these processes is about 10-4-10-5,which indicates that J/ψ inclusive production is detectable at B-factories. Studying these processes would help us to gain a deeper understanding of the color-octet mechanism.