No Arabic abstract
Charm spectroscopy has studied under a string model. Charmed baryons are composed of diquark and charm quark which are connected by a constant tension. In a diquark picture, the quantum numbers $J^P$ of confirmed baryons are well assigned. We give energy predictions for the first and second orbital excitations. We see some correspondences with the experimental data. Meanwhile, we have obtained diquark masses in the background of charm quark which satisfy a splitting relation based on spin-spin interaction.
We present a comparative study of the charmed baryon$-$nucleon interaction based on different theoretical approaches. For this purpose, we make use of i) a constituent quark model tuned in the light-flavor baryon$-$baryon interaction and the hadron spectra, ii) existing results in the literature based both on hadronic and quark-level descriptions, iii) (2+1)-flavor lattice QCD results of the HAL QCD Collaboration at unphysical pion masses and their effective field theory extrapolation to the physical pion mass. There is a general qualitative agreement among the different available approaches to the charmed baryon$-$nucleon interaction. Different from hadronic models based on one-boson exchange potentials, quark$-$model based results point to soft interactions without two-body bound states. They also support a negligible channel coupling, due either to tensor forces or to transitions between different physical channels, $Lambda_c N - Sigma_c N$. Short-range gluon and quark-exchange dynamics generate a slightly larger repulsion in the $^1S_0$ than in the $^3S_1$ $Lambda_c N$ partial wave. A similar asymmetry between the attraction in the two $S$ waves of the $Lambda_c N$ interaction also appears in hadronic approaches. A comparative detailed study of Pauli suppressed partial waves, as the $^1S_0 (I=1/2)$ and $^3S_1 (I=3/2)$ $Sigma_c N$ channels, would help to disentangle the short-range dynamics of two-baryon systems containing heavy flavors. The possible existence of charmed hypernuclei is discussed.
This is an update of the two articles [H.Y. Cheng, Int. J. Mod. Phys. A {bf 24} (Suppl. 1), 593 (2009); Front. Phys. {bf 10}, 101406 (2015)] in which charmed baryon physics around 2007 and 2015, respectively, were reviewed. In this review we emphasize the experimental progress and the theoretical development since 2015.
We propose to measure the decay asymmetry parameters in the hadronic weak decays of singly charmed baryons, such as $ldctoldpi^+,Sigma^0pi^+,p bar K_0$, $Xi_c^0toXi^-pi^+$ and $Omega_c^0toOmega^-pi^+$. The joint angular formulae for these processes are presented, and are used to extract the asymmetry parameters in $ee$ annihilation data. Base on the current $ldc$ data set collected at BESIII, we estimate the experimental sensitivities to measure the parameters $alpha_{ldpi^+}$ for $ldctoldpi^+$, $alpha_{Sigma^+pi^0}$ for $ldctoSigma^+pi^0$ and $alpha_{usigpi^+}$ for $ldctousigpi^+$.
We consider the string breaking phenomenon within effective string models which purport to mimic QCD with two light flavors, with a special attention to baryon modes. We make some estimates of the string breaking distances at zero and non-zero baryon chemical potentials. Our estimates point towards the enhancement of baryon production in strong decays of heavy mesons in dense baryonic matter. We also suggest that the enhanced production of $Lambda_c^+$ baryons in PbPb collisions is mainly due to larger values of chemical potential.
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 $Lambda_c(2595)$, $Lambda_c(2660)$, $Sigma_c(2902)$ or $Lambda_c(2941)$, 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.