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.

Doubly charmed dibaryon states

In this work,we study the doubly charmed dibaryon states with the qqqqcc(q=u,d,s)configuration.The mass spectra of doubly charmed dibaryon states are obtained systematically within the chromomagnetic interaction model.In addition to the mass spectrum analysis,we illustrate their two-body strong decay behaviours.Our results suggest that there may be narrow states or even stable states that cannot decay through the strong interaction.We hope that our results will provide valuable information for further experimental searches for doubly charmed dibaryon states.

Possible molecular states from interactions of charmed strange baryons

In this study,we investigate possible molecular states composed of two charmed strange baryons from theΞ_(c)^((′,∗))Ξ_(c)^((′,∗))interaction and their hidden-charm hidden-strange partners from theΞ_(c)^((′,∗))Ξ¯_(c)^((′,∗))interaction.With the aid of heavy quark chiral effective Lagrangians,the interactions of charmed strange baryons are described with light meson exchanges.The potential kernels are constructed and inserted into the quasipotential Bethe–Salpeter equation.The bound states are produced from most interactions considered,which suggests that strong attractions exist widely between the charmed strange baryons.Experimental search for these types of molecular states is suggested in future high-precision measurements.

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.

Search for the doubly charmed baryon Ω_(cc)^(+)

A search for the doubly charmed baryon ?cc+ with the decay mode c Ω_(cc)^(+)→ Ξc+K-π+ is performed using proton-proton collision data at a centre-of-mass energy of 13 TeV collected by the LHCb experiment from 2016 to 2018, corresponding to an integrated luminosity of 5.4 fb-1. No significant signal is observed within the invariant mass range of 3.6 to 4.0 GeV/c2. Upper limits are set on the ratio R of the production cross-section times the total branching fraction of the Ω_(cc)^(+)→ Ξc+K-π+ decay with respect to the Ξcc++→ Λc+K-π+π+ decay. Upper limits at 95% credibility level for R in the range 0.005 to 0.11 are obtained for diferent hypotheses on the ?cc+ mass and lifetime in the rapidity range from 2.0 to 4.5 and transverse momentum range from 4 to 15 GeV/c.

Search for the doubly charmed baryon ■

A search for the doubly charmed baryon ■^+cc is performed through its decay to theΛ^+c K^-π^+ final state,using proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7,8 and 13 TeV.The data correspond to a total integrated luminosity of 9 fb^-1.No significant signal is observed in the mass range from 3.4 to 3.8 GeV/c^2.Upper limits are set at 95%credibility level on the ratio of the ■^+cc production cross-section times the branching fraction to that ofΛ^+c and ■^++cc baryons.The limits are determined as functions of the ■^+cc mass for different lifetime hypotheses,in the rapidity range from 2.0 to 4.5 and the transverse momentum range from 4 to 15 GeV/c.

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.

Charmed baryons circa 2015

This is essentially an update of Ref. [1] [H. Y. Cheng, Int. J. Mod. Phys. A 24 （Suppl. 1）, 593 （2009）], a review of charmed baryon physics around 2007. Topics covered in this review include the spectroscopy, strong decays, lifetimes, nonleptonic and semileptonic weak decays, and electromagnetic decays of charmed baryons.

CHARMED BARYONS(C=+1)∧_c^+=udc,∑_c^(++)=uuc,∑_c^+=udc,∑_c^0=ddc,≡_c^+=usc,≡_c^0=dsc,Ω_c^0=ssc

CHARMED BARYONS Revised March 2012 by C.G. Wohl （LBNL）. There are 17 known charmed baryons, and four other candidates not well enough established to be promoted to the Summary Tables.＊ Fig. l（a） shows the mass spectrum,

Discovery potentials of doubly charmed baryons

The existence of doubly heavy flavor baryons has not been well established experimentally so far. In this Letter we systematically investigate the weak decays of the doubly charmed baryons, Ξ;and Ξ;, which should be helpful for experimental searches for these particles. The long-distance contributions are first studied in the doubly heavy baryon decays, and found to be significantly enhanced. Comparing all the processes, Ξ;→Λ;K;π;π;andΞ;π;are the most favorable decay modes for experiments to search for doubly heavy baryons.

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.

Charmed hadrons in nuclear medium

We study the properties of charmed hadrons in dense matter within a coupled-channel approach which accounts for Pauli blocking effects and meson self-energies in a self-consistent manner.We analyze the behaviour in this dense environment of dynamically-generated baryonic resonances as well as the open-charm meson spectral functions.We discuss the implications of the in-medium properties of open-charm mesons on the D s0 （2317） and the predicted X（3700） scalar resonances.

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.

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.

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.

Spectra of charmed and bottom baryons with hyperfine interaction

Up to now, the excited charmed and bottom baryon states have still not been well studied experimentally or theoretically. In this paper, we predict the mass of Ωb, the only L=0 baryon state which has not been observed, to be 6069.2 MeV. The spectra of charmed and bottom baryons with the orbital angular momentum L= 1 are studied in two popular constituent quark models, the Goldstone boson exchange （GBE） model and the one gluon exchange （OGE） hyperfine interaction model. Inserting the latest experimental data from the ＂Review of Particle Physics＂, we find that in the GBE model, there exist some multiplets （∑c（b）, ≡c（b） and Ωc（b）） in which the total spin of the three quarks in their lowest energy states is 3/2, but in the OGE model there is no such phenomenon. This is the most important difference between the GBE and OGE models. These results can be tested in the near future. We suggest more efforts to study the excited charmed and bottom baryons both theoretically and experimentally, not only for the abundance of baryon spectra, but also for determining which hyperfine interaction model best describes nature.

Charmed baryon decay asymmetry in e^＋e^- annihilation

We propose to measure the decay asymmetry parameters in the hadronic weak decays of singly charmed baryons, such as Λc^＋ →Λπ^＋, Σ^0π^＋, pK0, Ξ0c →Ξ-π＋and Ω^0c →Ω^-π^＋. The joint angular formulae for these processes are presented, and are used to extract the asymmetry parameters in e^＋e^-annihilation data. Base on the currentΛ＋c data set collected at BESIII, we estimate the experimental sensitivities to measure the parameters αΛπ＋forΛ＋c →Λπ＋, αΣ＋π0for Λc^＋ →Σ＋π^0 and αΣ0π＋for Λc^＋ →Σ^0π^＋.

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.

Charmed baryon resonances with heavy-quark symmetry

We study charmed baryon resonances that are generated dynamically from a coupled-channel unitary approach that implements heavy-quark symmetry. Some states can already be identified with experimental observations, such as Ac（2595）, Ac（2660）, Ec（2902） or Ac（2941）, while others need a compilation of more experimental data as well as an extension of the model to include higher order contributions. We also compare our model to previous SU（4） schemes.