Non-extensive statistical distributions of charmed meson production in Pb-Pb and pp(p)collisions

The mid-rapidity transverse momentum spectra of charmed mesons in Pb–Pb and pp(p)collisions are analyzed using the Tsallis–Pareto distribution derived from non-extensive statistics.We provide uniform descriptions of both small and large systems over a wide range of collision energies and hadron transverse momenta.By establishing the relationship between the event multiplicity and Tsallis parameters,we observe that there is a signifi-cant linear relationship between the thermal temperature and Tsallis q parameter in Pb–Pb collisions at √sNN=2.76 TeV and 5.02 TeV.Further,the slope of the T–(q-1)parameter plot is positively correlated with the hadron mass.In addition,charmed mesons have a higher thermal temperature than light hadrons at the same q-1,indicat-ing that the charm flavor requires a higher temperature to reach the same degree of non-extensivity as light flavors in heavy-ion collisions.The same fit is applied to the trans-verse momentum spectra of charmed mesons in pp(p)collisions over a large energy range using the Tsallis–Pareto distribution.It is found that the thermal temperature increases with system energy,whereas the q parameter becomes saturated at the pp(p)limit,q-1=0.142±0.010.In addition,the results of most peripheral Pb–Pb collisions are found to approach the pp(p)limit,which suggests that more peripheral heavy-ion collisions are less affected by the medium and more similar to pp(p)collisions.

RATIO OF CHARMED BARYON TO MESON IN e^(+)e^(-) ANNIHILATION

A method to determine the value of the ratio of charmed baryon to meson in e^(+)e^(-) annihilation is investigated.Using the data of CLEO,HRS and MARK Ⅱ groups,we obtain f≡B_(c)/M_(c)=0.21±0.05,0.24±0.08 and 0.33±0.05,for √s=5.2,10.55 and 29GeV,respectively.

Charmed Meson Production in Deep Inelastic e+A Scattering at Small_(-x)

Based on the nuclear effects considered in the Glauber-Gribov approach,charmed meson production inhigh energy deep inelastic e+A scattering is investigated in the color dipole formalism.Using the Peterson fragmentationfunction and the KLR-AdS/CFT color dipole model,which reasonably well describes the HERA data for the inclusivestructure functions at small Bjorken-x,we present the predictive results for the D-meson transverse spectra at EIC andLHeC energies.The theoretical results indicate that the x-independence phenomena at very small-x predicted by theKLR-AdS/CFT model are not seen in our calculation.

BOTTOM,CHARMED MESONS(B=C=±1)B_c^+=c,B_c^-=cb,similarly for B_c~*'s

I（JP） = 0（0-）I, J, P need confirmation.Quantum numbers shown are quark-model predictions.

Lepton mass correction in partial wave analyses of charmed meson semi-leptonic decays

We derive a parameterization formula for the partial wave analyses of charmed meson semi-leptonic decays while considering the effects of lepton mass.Because the proposed super-tau-charm factory will reach a significantly enhanced luminosity and BESIII is collecting newψ(3770)→DD data,our results will help improve the measurement precision of future partial wave analyses of charmed meson semi-muonic decays.

Estimating the production rates of D-wave charmed mesons via the semileptonic decays of bottom mesons

Using the covariant light-front approach with conventional vertex functions, we estimate the production rates of D-wave charmed/charmed-strange mesons via the B_((s)) semileptonic decays. As the calculated production rates are significant, it seems possible to experimentally search for D-wave charmed/charmed-strange mesons via semileptonic decays, which may provide an additional approach for exploring D-wave charmed/charmed-strange mesons.

CALCULATION OF THE YIELDS OF VARIOUS CHARMED MESONS IN e^+e^- ANNIHILATIONS

The yields of the charmed mesons in e^+e^- annihilations have been calculated in virtue of the quark production rule and quark combination rule proposed in Ref. [1]. The results are in agreement with the experimental data, which shows that the mechanism for e^+e^- annihilation into hardons is successful.

π-J/ψ correlation and elliptic flow parameter v_2 of charmed mesons at RHIC energy

We study the correlation between the trigger π and the associated J/ψ on near and away sides in Au＋Au collisions at sNN^（1/2） = 200 GeV. In the region of trigger momentum pt 〉 4 GeV/c, the π spectrum is composed of thermal-shower and shower-shower recombinations in the frame work of the recombination model. We consider the azimuthal anisotropy in the quenched hard parton distribution and then calculate the elliptic flow parameter v2 of charmed mesons （J/ψ, D0 and Ds） for different centralities.

Radiative decays of charmed mesons in a modified relativistic quark model

In this study, we perform systematic estimations of the radiative decays of the charmed mesons in a modified relativistic quark model. Our estimations indicate that the branching ratios of the processes of D^(0)_(2)(1^(3)P_(2)) →D^(0)(1^(3)S_(1)) γ , D_3^0(1D_3) o D^(0)_(2)(1^(3)P_(2)) γ , D^(0)_(2)(2D_2^) o D_1^(0)(2P_1) γ , D_3^0(2^3D_3) o D^(0)_(2)(2^3P_(2)) γ , and D^(\ast 0)(1^(3)S_(1)) o D^0(1^1S_0) γ are of the order of 10^(-2) , which are sizable to be detected experimentally. Moreover, the branching ratios of some channels, for example, D_1^0(1P_1) o D(1^1S_0)^0 γ , D^0(3^1S_0) o D_1^( 0)(2P^_(1)) γ , and D^0(3^3S_(1)) o D^(0)_(2)(2^3P_(2)) γ , are estimated to be of the order of 10^(-3) , which may be accessible with the accumulation of data in future experiments.

Strong Decays of Charm Mesons D_1~*(2680), D_3~*(2760), D_2~*(3000)

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.

Open charm mesons and charmonia in magnetized strange hadronic matter

We investigate the in-medium masses of open charm mesons(D(D^(0),D^(+)),■(■^(0),D^(-)),D_(s)(D_(s)^(+),D_(s)^(-)))and charmonium states(J/ψ,ψ(3686),ψ(3770),χ_(c0),χ_(c2)) in strongly magnetized isospin asymmetric strange hadronic matter using a chiral effective model.In the presence of a magnetic field,the number and scalar densities of charged baryons have contributions from Landau energy levels.The mass modifications of open charm mesons result from their interactions with nucleons,hyperons,and the scalar fields(the non-strange field σ,strange field C and isovector field δ) in the presence of a magnetic field.The mass modifications of the charmonium states result from the modification of gluon condensates in a medium simulated by the variation in the dilaton field(χ) in the chiral effective model.The effects of finite quark masses are also incorporated in the trace of the energy-momentum tensor in quantum chromodynamics to investigate the mass shifts of charmonium states.The in-medium masses of open charm mesons and charmonia are observed to decrease with an increase in baryon density.The charged D^(+),D^(-),Z_(s)^(+),and D_(s)^(-)mesons have additional positive mass shifts due to Landau quantization in the presence of a magnetic field.The effects of the strangeness fraction are observed to be more dominant for ■ mesons compared with D mesons.The mass shifts of charmonia are observed to be larger in hyperonic media compared with nuclear media when the effect of the finite quark mass term is neglected.These medium mass modifications can have observable consequences on the production of the open charm mesons and charmonia in high-energy asymmetric heavy-ion collision experiments.

Excited state mass spectra, decay properties and Regge trajectories of charm and charm-strange mesons

The framework of a phenomenological quark-antiquark potential（Coulomb plus linear confinement）model with a Gaussian wave function is used for detailed study of masses of the ground, orbitally and radially excited states of heavy-light Qq^-,（Q=c,q=u/d,s） mesons. We incorporate a O（1/m） correction to the potential energy term and relativistic corrections to the kinetic energy term of the Hamiltonian. The spin-hyperfine, spin-orbit and tensor interactions incorporating the effect of mixing are employed to obtain the pseudoscalar, vector, radially and orbitally excited state meson masses. The Regge trajectories in the（J,M^2） and（nr,M^2） planes for heavy-light mesons are investigated with their corresponding parameters. Leptonic and radiative leptonic decay widths and corresponding branching ratios are computed. The mixing parameters are also estimated. Our predictions are in good agreement with experimental results as well as lattice and other theoretical models.

Possible heavy molecular states composed of a pair of excited charm-strange mesons

The P-wave charm-strange mesons Ds0（2317） and Ds1（2460） lie below the DK and D＊K threshold respectively. They are extremely narrow because their strong decays violate the isospin symmetry. We study the possible heavy molecular states composed of a pair of excited charm strange mesons. As a byproduct, we also present the numerical results for the bottonium-like analogue.

矢量粲-底介子质量谱在雷吉唯象学中的研究

在雷吉(Regge)唯象学中,本文利用雷吉轨迹结合Regge斜率和截距关系式,首先计算了基态矢量粲-底介子B*c的质量,然后计算了矢量底偶素和粲偶素的雷吉斜率比值,最后计算了激发态矢量粲-底介子cb珋(2S,3S,4S)的质量。本文的预言与其它方法得到的结果很好的符合,这些预言可以对我们探索未被发现的粲-底矢量cb珋介子态提供帮助。

BESⅢ上粲介子半轻衰变D_s^+→K^(0)e^+ν_e和D_s^+→K^(*0)e^+ν_e的蒙特卡罗研究

通过分析在质心系能量s^(1/2)=4.18GeV处产生的蒙特卡罗样本,模拟测量了奇异粲介子D_s^+半轻衰变过程D_s^+→K^(0)e^+ν_e和D_s^+→K^(*0)e^+ν_e的绝对分支比。通过蒙特卡罗模拟,预期了BESⅢ实验对这2个半轻衰变分支比的测量精度。研究表明,如果BESⅢ实验在质心系能量s^(1/2)=4.18GeV采集3.2fb^(-1)的实验数据,D_s^+→K^(0)e^+ν_e和D_s^+→K^(*0)e^+ν_e衰变分支比的测量精度能够达到11.2%与12.5%。

S波自旋单态底夸克偶素衰变到粲夸克对

对S波自旋单态底夸克偶素衰变到粲夸克对进行了研究,同时还研究了S波自旋单态和自旋三重态底夸克偶素衰变到D介子对。利用BaBar实验组测量得到的自旋三重态底夸克偶素衰变到D介子分支比的数据,发现自旋三重态底夸克偶素的色八重态矩阵元远小于理论预言,理论预言要比实验上限大20倍以上;得到S波自旋单态底夸克偶素衰变到粲夸克对的分支比的理论预言,可以进行实验测量从而研究色八重态矩阵元;得到S波自旋单态底夸克偶素衰变到D介子对的分支比的理论预言,与其他理论预言差异较大。这些预言可以通过BelleⅡ的实验进行验证,从而得到更多强子化的信息。

Possible hadronic molecular states composed of S-wave heavy-light mesons

We perform a systematical study of possible molecular states composed of the S wave heavy light mesons,where the S–D mixing and η-η＇ mixing are explicitly included.Our calculation indicates that the observed X（3872） could be a loosely shallow molecular state composed of D＊＋ h.c,while neither Z_c（3900）/Z_c（4020） nor Z_b（10610）/Z_b（10650） is supported to be a molecule.Some observed possible molecular states are predicted,which could be searched for by further experimental measurements.

BESⅢ粲物理（英文）

分析BESIII探测器在质心系能量3.773和4.599GeV采集的2.93和~0.567fb-1数据,报道了衰变常数fD^+和D介子半轻子衰变的形状因子,D^+→K^0_Sπ^+π~0的Dalitz图分析,D→K^0_S/Lπ^+π-和K-π^+强相差,D^0D^0混合参数yCP的测量;2体强子衰变D^0(^+)→ωπ~0(^+),稀有衰变D^0→γγ和D^+→K(π)±ee^+的寻找以及Λ^+c→Λe^+νe和12个强子衰变绝对分支比的测量.

Experimental sensitivity on searching for CP violation at BES-Ⅲ

The CP violation in the D system is predicted to be an unobserved level in the Standard Model. In this paper, we describe the method of searching for CP violation decay processes with the coherently produced D^0D^0 mesons from the ψ（3770） decay. The CP violation decay processes can be searched for at the BES-Ⅲ experiment. The experimental sensitivity for searching for the CP violation can reach about a 10^-4 level with a ψ（3770） data sample of about 20 fb^-1.

Decay properties of D and D_s mesons in coulomb plus power potential (CPP_ν)

The decay properties of the D and D s mesons are computed in a nonrelativistic phenomenological quark-antiquark potential of the type V （r） =-4 /3 α s /r＋ Ar ν with different choices of ν.Numerical method to solve the Schrdinger equation has been used to obtain the spectroscopy of qQ mesons.The numerically obtained radial solutions are employed to obtain the decay constant and leptonic decay widths.It has been observed that predictions of the ground state masses and the decay widths are consistent with other model predictions as well as with the known experimental values.