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.

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.

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.

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.

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.

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.

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.

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.

Radiative decays D*(s)→ D(s)γ in covariant confined quark model

Radiative decays D((s))*→D((s))γare revisited in light of new experimental data from the BaBar and BESⅢCollaborations.The radiative couplings gD*Dγencoding nonperturbative QCD effects are calculated in the framework of the covariant confined quark model developed by us.We compare our results with other theoretical studies and experimental data.The couplings(in GeV-1)|g(D*+D+γ)|=0.45(9)and|g(D*0D0γ)|=1.72(34)calculated in our model agree with the corresponding experimental data|g(D*+D+γ)|=0.47(7)and|g(D*0D0γ)|=1.77(16).The most interesting case is the decay Ds*→Dsγ,for which a recent prediction based on light-cone sum rules at next-to-leading order|gDs*Dsγ|=0.60(19)deviates from the first(and only to date)lattice QCD result|gDs*Dsγ|=0.11(2)at nearly3σ.Our calculation yields|gDs*Dsγ|=0.29(6),which falls somehow between the two mentioned results,although it is larger than those predicted in other studies using quark models or QCD sum rules.

Charm hadronic decays and quantum correlations at CLEO-c

Several recent CLEO-c results on hadronic decays of charm mesons are reviewed. Topics include measurements of precision branching fractions for exclusive modes, investigations of inclusive rates, and analyses of Dalitz plots. In addition, the quantum correlations of the DD pairs produced at the ψ（3770） are exploited to measure phase information that is of current interest for both D and B physics.

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.

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.

Charmed andϕmeson decay constants from 2+1-flavor lattice QCD

On a lattice with 2+1-flavor dynamical domain-wall fermions at the physical pion mass,we calculate the decay constants of D_s^(*) , D^(*) ,and φ .The lattice size is 48^3×96 ,which corresponds to a spatial extension of -5.5 fm,with a lattice spacing of a\approx a≈0.114 fm.For the valence light,strange,and charm quarks,we use overlap fermions at several mass points close to their physical values.Our results at the physical point are f_(D)=213(5) MeV, f_(D)_(s)=249(7) MeV, f_(D)^(*)=234(6) MeV, f_(D)_(s)^(*)=274(7) MeV,and f_(D)_(s)=241(9) MeV.The couplings of D^(*) and D_s^(*) to the tensor current( f_(V)^(T) )can be derived from ratios f_(D)^(*)^T/f_(D)^(*)=0.91(4) and f_(D)_(s)^(*)^T/f_(D)_(s)^(*)=0.92(4) ,respectively,which are the first lattice quantum chromodynamics(QCD)results.We also obtain ratios f_(D)^(*)/f_(D)=1.10(3) and f_(D)_(s)^(*)/f_(D)_(s)=1.10(4) ,which reflect the size of heavy quark symmetry breaking in charmed mesons.Ratios f_(D)_(s)/f_(D)=1.16(3) and f_(D)_(s)^(*)/f_(D)^(*)=1.17(3) can be taken as a measure of SU(3)flavor symmetry breaking.

Study of charmonium(-like) states via ISR at Belle

The cross sections for e^＋e^- →π^＋ π^-J/ψ, π^＋π^-ψ（2S）, K^＋K^-J/ψ, DD1D^0D1-π^＋ ＋c.c., D^＊D＋c.c., and D^＊D^＊ are measured using data sample collected on or near the T（4S） resonance with the Belle detector at KEKB. A peak near 4.25 GeV/c^2, corresponding to the so called Y（4260）, is observed in π^＋π^-J/ψ final state. In addition, there is another cluster of events at around 4.05 GeV/c^2. Two resonant structures are observed in the π^＋π^-ψ（2S） invariant mass distribution, one at 4361±9±9 MeV/c^2 with a width of 74±15±10 MeV/c2, and another at 4664 ±11±5 MeV/c2 with a width of 48±15±3 MeV/c^2. The rich structures observed in all these final states indicate that our understanding of the vector charmonium states above the open charm threshold is still poor, let alone the other possible dynamics such as charmonium hybrids or final state re-scattering and so on.

Dynamics of strong and radiative decays of D_s-mesons in the hadrogenesis conjecture

The positive parity scalar D ＊ s0 （2317） and axial-vector D ＊ s1 （2460） charmed strange mesons are generated by coupled-channel dynamics through the s-wave scattering of Goldstone bosons off the pseudoscalar and vector D（D s ）-meson ground states.The specific masses of these states are obtained as a consequence of the attraction arising from the Weinberg-Tomozawa interaction in the chiral Lagrangian.Chiral corrections to order Q 2 χ are calculated and found to be small.The D ＊ s0 （2317） and D ＊ s1 （2460） mesons decay either strongly into the isospin-violating π 0 D s and π 0 D ？ s channels or electromagnetically.We show that the π 0-η and （K^ 0 D ^＋-K^ ＋ D^ 0 ） mixings act constructively to generate strong widths of the order of 140 keV and emphasize the sensitivity of this value to the KD component of the states.The one-loop contribution to the radiative decay amplitudes of scalar and axial-vector states is calculated using the electromagnetic Lagrangian to chiral order Q 2 χ .We show the importance of taking into account processes involving light vector mesons explicitly in the dynamics of electromagnetic decays.The radiative width are sensitive to both η D s and KD components,hence providing information complementary to the strong widths on the positive parity D s-meson structure.

Study of excited D_s mesons

The spectrum of D s mesons is systematically studied in a semi-classic mass loaded flux tube model.D s in D-wave multiplets is predicted to have lower masses in comparison with most theoretical predictions.D sJ （2632） ＋,D s1 （2700） ±,D sJ （2860） ＋ and D sJ （3040） ＋ are interpreted in the constituent quark model.

Investigations on the charmless decays of Y(4260)

Apart from the charmful decay channels of Y（4260）, the charmless decay channels of Y（4260） also provide us a good platform to study the nature and the decay mechanism of Y（4260）. In this paper, we propose to probe the structure of Y（4260） through the charmless decays Y（4260）→VP via intermediate D1D＋c.c. meson loops, where V and P stand for light vector and pseudoscalar mesons, respectively. Under the molecule ansatz of Y（4260）, the predicted total branching ratio BRVP for all Y（4260） → VP processes are about（0.34＋0.32-0.23）% to（0.75＋0.72-0.52）% with the cutoff parameter α=2–3. Numerical results show that the intermediate D1D＋c.c. meson loops may be a possible transition mechanism in the Y（4260） → VP decays. These predicted branching ratios are the same order to that of Y（4260）→Z＋c（3900）π-, which may be an evidence of D1 D molecule and can be examined by the forthcoming BESdata in the near future.

B_((s))→D^(∗∗)_((s))form factors in HQEFT and model independent analysis of relevant semileptonic decays with NP effects

The form factors of B(s)decays into P-wave excited charmed mesons(including D∗0(2300),D1(2430),D1(2420),D∗2(2460)and their strange counterparts,denoted generically as D∗∗(s))are systematically calculated via QCD sum rules in the framework of heavy quark effective field theory(HQEFT).We consider contributions up to the next leading order of heavy quark expansion and give all the relevant form factors,including the scalar and tensor ones only relevant for possible new physics effects.The expressions for the form factors in terms of several universal wave functions are derived via heavy quark expansion.These universal functions can be evaluated through QCD sum rules.Then,the numerical results of the form factors are presented.With the form factors given here,a model independent analysis of relevant semileptonic decays B(s)→D∗∗(s)lν¯l is performed,including the contributions from possible new physics effects.Our predictions for the differential decay widths,branching fractions,and ratios of branching fractions R(D∗∗(s))may be tested in more precise experiments in the future.

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.

Hadron spectroscopy from B-factories

We review the recent experimental results on hadron spectroscopy from B-factories focusing on the exotic charmonium-like states.Among them we discuss the X（3872）,Y（3940）,Z（4430） ＋,Z（4050） ＋,Z（4250） ＋ and Y（4140） states found in B-meson decays,the X（3940） and X（4160） states produced in double charmonium production,the Y（4260）,Y（4325）,Y（4660） and X（4630） states produced with initial-state radiation in e ＋ eannihilation and the X（3915）,Y（4350） states observed in two-photon collisions.