Approximate heavy-quark spin and flavor symmetry and chiral symmetry play an important role in our understanding of the nonperturbative regime of strong interactions. In this work, utilizing the unitarized chiral perturbation theory, we explore the consequences of these symmetries in the description of the interactions between the ground-state singly charmed (bottom) baryons and the pseudo-Nambu-Goldstone bosons. In particular, at leading order in the chiral expansion, by fixing the only parameter in the theory to reproduce the $Λ_b(5912)$ [$Λ_b^*(5920)$] or the $Λ_c(2595)$ [$Λ_c^*(2625)$], we predict a number of dynamically generated states, which are contrasted with those of other approaches and available experimental data. In anticipation of future lattice QCD simulations, we calculate the corresponding scattering lengths and compare them to the existing predictions from a $\mathcal{O}(p^3)$ chiral perturbation theory study. In addition, we estimate the effects of the next-to-leading-order potentials by adopting heavy-meson Lagrangians and fixing the relevant low-energy constants using either symmetry or naturalness arguments. It is shown that higher-order potentials play a relatively important role in many channels, indicating that further studies are needed once more experimental or lattice QCD data become available.
The magnetic moments, transition magnetic moments and the radiative decay widths of singly charmed baryons are calculated with $ {J^P = \frac{1}{2}}^+$ and $ {J^P = \frac{3}{2}}^+$ in the constitute quark model. Further, the strong decay rates for $ S $, $ P $ and $ D $ wave transitions are also presented. The singly charmed baryon masses used in the calculations were obtained from the hypercentral Constitute Quark Model (hCQM) without and with first order relativistic correction. Obtained results are compared with experimental observation as well as with the other theoretical predictions.
In the paper, we study the production of pentaquark $\bar{c}q qqq$ from singly bottom baryon. The tensor representations of pentaquark $\bar{c}q qqq$ are completed at first. Under the light quark symmetry analysis, we decompose the singly charmed pentaquarks into $6$, $15$ and $15'$ multiple states, and deduce the representations of these states. Then we construct the production Hamiltonian of the multiple states in proper order. For completeness, we systematically study the production channels of pentaquark states, including the possible production amplitudes and cross section relations betwe…
We study the masses of radial and orbital excited states of nonstrange singly charmed baryons in the framework of hypercentral Constituent Quark Model (hCQM). To obtain the mass spectra, the Coulomb plus screened potential is employed with the first order correction, which gives a relativistic effect of order $\cal{O}$$(1/m)$. The spin-spin, spin-orbit and tensor interactions are included (perturbatively as a spin dependent potential) in order to generate the splitting in mass spectra. We compare our computed mass spectra of nonstrange singly charmed baryons with the other theoretical predicti…
We provide an extensive study of the lifetimes of singly charmed baryons and mesons, within the heavy quark expansion with all known corrections included. A special attention is devoted to the choice of the charm mass and wavefunctions of heavy baryons. We give our predictions for lifetimes, lifetime ratios, and semileptonic branching ratios of singly charmed baryons. Our results accommodate the experimentally-favoured hierarchy of singly charmed baryon lifetimes \begin{eqnarray*} τ\left(Ξ_c^{0}\right) < τ\left(Λ_c^{+}\right)< τ\left(Ω_c^{0}\right) < τ\left(Ξ_c^{+}\right)\, \end{eqnarray*} in …
Excited states masses of the strange singly charmed baryons are calculated using the non-relativistic approach of hypercentral Constituent Quark Model (hCQM). The hyper-Coulomb plus screened potential is used as a confinement potential with the first order correction. The spin-spin, spin-orbit and spin-tensor interaction terms are included perturbatively. Our calculated masses are allowed to construct the Regge trajectories in both $(n_r, M^2)$ and $(J, M^2)$ planes. The mass spectra and the Regge trajectories study predict the spin-parity of $Ξ{_c(2970)^{+/0}}$, $Ξ{_c(3080)^{+/0}}$, $Ξ{_c(312…
Mass spectra of excited states of the singly charmed baryons are calculated using the hypercentral description of three body system. The baryon consist of a charm quark and light quarks (u, d and s) are studied in the framework of QCD motivated constituent quark model. The form of confinement potential is hyper coloumb plus power potential with potential index $ν$, varying from 0.5 to 2.0. The first order correction to the confinement potential is also incorporated in this approach. The radial as well as orbital excited state masses of $Σ_{c}^{++}, Σ_{c}^+, Σ_{c}^0, Ξ_c^+, Ξ_c^0, Λ_c^+, Ω_c^0$…
Recently, some singly bottom baryons have been established experimentally, but none of doubly or triply bottom baryons has been observed. Under the Regge phenomenology, the mass of a ground state unobserved doubly or triply bottom baryon is expressed as a function of masses of the well established light baryons and singly bottom baryons. Then, the values of Regge slopes and Regge intercepts for baryons containing one, two, or three bottom quarks are calculated. After that, masses of the orbitally excited singly, doubly, and triply bottom baryons are estimated. Our predictions may be useful for…
In this article, we perform a systematic study of the mass spectrum of the axial-vector hidden charmed and hidden bottom tetraquark states using the QCD sum rules, and identify the $Z^+(4430)$ as an axial-vector tetraquark state tentatively.
In this work, using the covariant light front approach with conventional vertex functions, we estimate the production rates of $D$-wave charmed/charmed-strange mesons via $B_{(s)}$ semileptonic decays. Due to these calculated considerable production rates, it is possible to experimentally search for $D$-wave charmed/charmed-strange mesons via the semileptonic decays, which may provide extra approach to explore $D$-wave charmed/charmed-strange mesons.
Recent experimental advances have reignited theoretical interests in heavy-flavor hadrons. In this work, we study the magnetic moments of the spin-1/2 singly charmed baryons up to the next-to-leading order in covariant baryon chiral perturbation theory with the extended-on-mass-shell renormalization scheme. The pertinent low energy constants $g_{1-4}$ are fixed with the help of the quark model and the heavy quark spin flavor symmetry, while the remaining $d_2$, $d_3$, $d_5$ and $d_6$ are determined by fitting to the lattice QCD pion-mass dependent data. We study the magnetic moments as a funct…
The implementation of the heavy quark spin symmetry in possible molecular states at the mixed bottom-charm threshold is somewhat different from that at the open charm or bottom thresholds. In particular it depends on two parameters describing separately the symmetry for the bottom and for charmed quarks. The corresponding spin structures of the $S$-wave molecular states of the meson pairs $B^{(*)} D^{(*)}$ are discussed as well as their consequences for properties of possible near-threshold resonances, analogs of the known charmonium-like and bottomonium-like $X$ and $Z$ states.
We estimate the strong coupling constants of charmed and bottom mesons $ D_{(s)}^* $, $ D_{(s)1} $, $ B_{(s)}^* $, and $ B_{(s)1} $ with light vector mesons $ ρ$, $ ω$, $ K^* $, and $ ϕ$ within the framework of light-cone QCD sum rules. We compare our estimations to the ones predicted by other approaches.
We report on the calculation of the CP-violating form factor $F_3$ and the corresponding electric dipole moment for charmed baryons in the spin-1/2 sector generated by the QCD $θ$-term. We work in the framework of covariant baryon chiral perturbation theory within the extended-on-mass-shell renormalization scheme up to next-to-leading order in the chiral expansion.
We investigate the possible deuteron-like molecules composed of a pair of charmed spin-$\frac{3}{2}$ baryons, or one charmed baryon and one charmed antibaryon within the one-boson-exchange (OBE) model. For the spin singlet and triplet systems, we consider the couple channel effect between systems with different orbital angular momentum. Most of the systems have binding solutions. The couple channel effect plays a significant role in the formation of some loosely bound states. The possible molecular states of $Ω_c^*Ω_c^*$ and $Ω_c^*\barΩ_c^*$ might be stable once produced.
In this article, the three point QCD sum rules is used to compute the strong coupling constants of vertices containing the strange bottomed ( charmed ) mesons with pion. The coupling constants are calculated, when both the bottom ( charm ) and pion states are off-shell. A comparison of the obtained results of coupling constants with the existing predictions is also made. Key words: strong coupling constant, meson, QCD sum rules, bottom, charm.
We present the ground and excited state spectra of singly, doubly and triply-charmed baryons by using dynamical lattice QCD. A large set of baryonic operators that respect the symmetries of the lattice and are obtained after subduction from their continuum analogues are utilized. These operators transform as irreducible representations of SU(3)$_F$ symmetry for flavour, SU(4) symmetry for Dirac spins of quarks and O(3) symmetry for orbital angular momenta. Using novel computational techniques correlation functions of these operators are generated and the variational method is exploited to extr…
Two body nonleptonic weak decays of bottom mesons to a pseudoscalar meson and an axial-vector meson involving charmed states are studied using the non-relativistic quark model. We calculate the branching ratios of these decays by employing the factorization hypothesis. Obtained results are in good agreement with the existing experimental data. We also calculated the branching ratios in the light of heavy quark symmetry constraints and compared with the exiting theoretical analyses.
Hadron masses are calculated in quenched lattice QCD with a fermion action of the D234 type on an anisotropic lattice. Hyperfine splittings for singly charmed baryons are found to be in agreement with expectations from the quark model and with a magnitude slightly larger than experimental values. Masses of doubly charmed baryons are also calculated and compared to a variety of model calculations. Hyperfine splittings in doubly charmed baryons are found to be slightly smaller than in singly charmed states.
The present work has been done on the baryons containing one, two, or three bottom quarks. In this article, the ground-state masses of $Ω_{b}^{-}$, $Ξ_{bb}^{0}$, $Ξ_{bb}^{-}$, $Ω_{bb}^{-}$, and $Ω_{bbb}^{*-}$ baryons are calculated within the framework of Regge phenomenology. Further, the values of Regge slopes and Regge intercepts for singly, doubly, and triply bottom baryons are estimated in both the ($J,M^{2}$) and ($n,M^{2}$) planes to calculate the excited-state masses of these baryons. Here our attempt is to assign a possible spin-parity to recently observed some singly bottom baryons an…
The mass spectrum of S and P-wave mesons containing a single heavy quark has been computed using quenched lattice nonrelativistic QCD. Numerical results have been obtained at first, second and third order in the heavy quark expansion, so convergence can be discussed. The computed spectrum of charmed and bottom mesons is compared to existing model calculations and experimental data.
We systematically derive the analytical expressions of the magnetic moments of the spin-$1\over 2$ singly charmed baryons to the next-to-next-to-leading order in the heavy baryon chiral perturbation theory (HBChPT). We discuss the analytical relations between the magnetic moments. We estimate the-low energy constants (LECs) in two scenarios. In the first scenario, we use the quark model and Lattice QCD simulation results as input. In the second scenario, the heavy quark symmetry is adopted to reduce the number of the independent LECs, which are then fitted using the data from the Lattice QCD s…
We enumerated ground and excited state masses of singly heavy bottom-strange baryons using the Hypercentral Constituent Quark Model (hCQM). The screening potential is used with color-Coulomb potential, as the confining potential. We determine the possible $J^P$ values to recently observed excited states like, $Ξ_b(6100)$, $Ξ_b(6227)$, $Ξ_b(6327)$, $Ξ_b(6333)$ and four $Ω_b(6316,6330,6340,6350)$ states. The Regge trajectories are plotted in $(J, M^2)$ plane to assign the $J^P$ values and quantum numbers to recently observed states. Using the calculated spectroscopic data, properties such as mag…
We investigate the electromagnetic transitions of the singly charmed baryons with spin 3/2, based on a pion mean-field approach, also known as the chiral quark-soliton model, taking into account the rotational $1/N_c$ corrections and the effects of flavor SU(3) symmetry breaking. We examine the valence- and sea-quark contributions to the electromagnetic transition form factors and find that the quadrupole form factors of the sea-quark contributions dominate over those of the valence-quark ones in the smaller $Q^2$ region, whereas the sea quarks only provide marginal contributions to the magnet…
Flavor $SU(3)$ symmetry is a powerful tool to analyze charmed baryon decays. In this work, we propose an approach to generate $SU(3)$ sum rules for the singly and doubly charmed baryon decays without writing the Wigner-Eckhart invariants explicitly. The $SU(3)$ sum rules are computed routinely in several master formulas. Hundreds of $SU(3)$ sum rules are found to serve as test of the flavor symmetry in the charmed baryon decays.
We calculate the branching ratio of a bottom hadron decaying into a charmed hadron and a charged $ρ$ meson within the QCD factorization approach. We consider the effect of the finite width correction of the $ρ$ meson. Our numerical calculation shows an obvious correction because of this effect. We find that the finite width effect of the $ρ$ meson reduces the branching ratios by about 9% to 11% for bottom meson decay channels: $B^+\to\bar{D^0}ρ^+$, $B^0\to D^-ρ^+$, and $B^0_s\to D^-_sρ^+$, and increases the branching ratio by about 10% for $Λ_b^0\toΛ_c^+ρ^-$.
The bottom-charmed meson spectrum is studied in this work via an effective version of the Coulomb gauge QCD Hamiltonian. The Tamm-Dancoff approximation is employed to estimate the energies of the low-lying and radial-excited $B_c$ states with quantum numbers $J^P = 0^{-}, 0^{+}, 1^{-}, 1^{+}, 2^{+}, 2^{-}$. In particular, we analyze the effects of incorporating an effective transverse hyperfine interaction and spin mixing. The Regge trajectories and hyperfine splitting of both $S$- and $P$-wave states are also examined. The numerical results are compared with available experimental data and th…
We present predictions for the inclusive productions of the D meson originating from bottom hadrons at the CERN LHC in the general-mass variable-flavour-number scheme at next-to-leading order. We present results using two methods to describe the transition for $b\rightarrow D$: a two-step transition $b\rightarrow B \rightarrow D$, based on the $b\rightarrow B$ fragmentation functions and the spectra for $B\rightarrow D$ as measured by CLEO and a one-step transition based on the fragmentation functions for $b\rightarrow D$. The results of both approaches are compared.
I review the recent proposal that there are new isotriplet heavy baryons with masses approximately 2380 MeV and 5760 MeV. This prediction follows from the application of heavy spin-flavor and light $SU(3)$ symmetries to the observed charmed and bottom baryon states. It also entails assumptions about the spin and parity quantum numbers of the observed states which are different than is commonly supposed. The discovery of such states would imply that the nonrelativistic constituent quark model is a poor predictor of heavy baryon spectroscopy. I update the analysis in light of new data which have…
Up to now, the excited charmed and bottom baryon states are still not well studied both experimentally and theoretically. In the present paper, we predict the mass of $Ω_b^*$, 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) and the one gluon exchange (OGE) hyperfine interaction models, respectively. Inserting the latest experimental data from the "Review of Particle Physics", we find that in the …
In this work, we study the mass spectrum of the $Ω_{ccc}$ and $Ω_{bbb}$ baryons up to the $N=2$ shell within a nonrelativistic constituent quark model (NRCQM). The model parameters are adopted from the determinations by fitting the charmonium and bottomonium spectra in our previous works. The masses of the $Ω_{ccc}$ and $Ω_{bbb}$ baryon states predicted in present work reasonably agree with the results obtained with the Lattice QCD calculations. Furthermore, to provide more knowledge of the $Ω_{ccc}$ and $Ω_{bbb}$ states, we evaluate their radiative decays with the available masses and wave fu…
The analysis of singly charmed hadrons has been extended to the case of doubly charmed baryons, $Ξ_{cc}^{++}$, $Ξ_{cc}^{+}$ and $Ω_{cc}^{+}$. Doubly charmed baryons are described as a system containing a heavy $cc$-diquark and a light quark, similarly as in a heavy-light meson. This leads to preasymptotic effects in semileptonic and nonleptonic decays which are essentially proportional to the meson wave function. Interplay between preasymptotic effects in semileptonic and/or nonleptonic decay rates leads to very clear predictions for semileptonic branching ratios and lifetimes of doubly charme…
We provide comprehensive investigations for the mass spectrum of exotic open-flavor charmed/bottom $sq\bar q\bar c$, $qq\bar q\bar c$, $sq\bar q\bar b$, $qq\bar q\bar b$ tetraquark states with various spin-parity assignments $J^P=0^+, 1^+, 2^+$ and $0^-, 1^-$ in the framework of QCD sum rules. In the diquark configuration, we construct the diquark-antidiquark interpolating tetraquark currents using the color-antisymmetric scalar and axial-vector diquark fields. The stable mass sum rules are established in reasonable parameter working ranges, which are used to give reliable mass predictions for…
We consider the decay of a polarized top quark into a stable $W^+$ boson and charmed-flavored (D) or bottom-flavored (B) hadrons, via $t(\uparrow)\rightarrow W^++D/B+X$. We study the angular distribution of the scaled-energy of B/D-hadrons at next-to-leading order (NLO) considering the contribution of bottom and gluon fragmentations into the heavy mesons B and D. To obtain the energy spectrum of B/D-hadrons we present our analytical expressions for the parton-level differential decay widths of $t(\uparrow)\rightarrow b+W^+(+g)$ at NLO. Comparison of our predictions with data at the LHC enable …
We calculate the spectrum of $B_c$ mesons using a non-relativistic quark potential model. Using the calculated wave functions, we compute the radiative widths of $B_c$ excited states. The strong decay widths are calculated in a modified $^3P_0$ model, assuming harmonic oscillator wave functions. The hadronic transition rates of $B_c$ mesons are calculated using the Kuang-Yan approach. These results are used to determine branching ratios of possible decay channels of several $B_c$ excited states. Calculated branching ratios are then combined with production cross section of $B_c$ states at the …
Singly-Cabibbo-suppressed decays of charmed particles governed by the quark subprocesses $c \to s u \bar s$ and $c \to d u \bar d$ are analyzed using a flavor-topology approach, based on a previous analysis of the Cabibbo-favored decays governed by $c \to s u \bar d$. Decays to $PP$ and $PV$, where $P$ is a pseudoscalar meson and $V$ is a vector meson, are considered. We include processes in which $η$ and $η'$ are produced.
As a continuation of our recent work on the electromagnetic properties of the doubly charmed $Ξ_{cc}$ baryon, we compute the charge radii and the magnetic moments of the singly charmed $Σ_c$, $Ω_c$ and the doubly charmed $Ω_{cc}$ baryons in 2+1 flavor Lattice QCD. In general, the charmed baryons are found to be compact as compared to the proton. The charm quark acts to decrease the size of the baryons to smaller values. We discuss the mechanism behind the dependence of the charge radii on the light valence- and sea-quark masses. The magnetic moments are found to be almost stable with respect t…
We compute the masses of the singly and doubly charmed baryons in full QCD using the relativistic Fermilab action for the charm quark. For the light quarks we use domain-wall fermions in the valence sector and improved Kogut-Susskind sea quarks. We use the low-lying charmonium spectrum to tune our heavy-quark action and as a guide to understanding the discretization errors associated with the heavy quark. Our results are in good agreement with experiment within our systematics. For the Ξ_{cc}, we find the isospin-averaged mass to be M_{Ξ_{cc}} = 3665 +/- 17 +/- 14 +0 -78 MeV; the three given u…
We develop a framework to study the exclusive two-body decays of bottomonium into two charmed mesons and apply it to study the decays of the C-even bottomonia. Using a sequence of effective field theories, we take advantage of the separation between the scales contributing to the decay processes, 2m_b >> m_c >> Λ_{QCD}. We prove that, at leading order in the EFT power counting, the decay rate factorizes into the convolution of two perturbative matching coefficients and three non-perturbative matrix elements, one for each hadron. We calculate the relations between the decay rate and non-perturb…
We propose to measure the decay asymmetry parameters in the hadronic weak decays of singly charmed baryons, such as $\ldc\to\ldπ^+,Σ^0π^+,p \bar K_0$, $Ξ_c^0\toΞ^-π^+$ and $Ω_c^0\toΩ^-π^+$. 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 $α_{\ldπ^+}$ for $\ldc\to\ldπ^+$, $α_{Σ^+π^0}$ for $\ldc\toΣ^+π^0$ and $α_{\usigπ^+}$ for $\ldc\to\usigπ^+$.
We give the explicit wave functions of the $qqqq\bar{q}$ components of the C=+1, J=1/2 charmed baryons, $Σ_{c}$, $Λ_{c}$ and $Ξ_{c}^{a}$, and calculate the magnetic moments by adding the 5q components contributions, and we also compute the magnetic moments of the $Σ_{b}$ and $Σ_{b}^{*}$ baryons. The influence of the additional light and strange $q\bar{q}$ pairs is investigated. It's obvious that the constituent quark masses of the charm and beauty quarks are much heavier than that of the light and strange quarks, consequently, the hidden flavor contributions to the baryons magnetic moments may…
The strong coupling constants, $g_{D_{s}DK_0^*}$, $g_{B_{s}BK_0^*}$, $g_{D^{\ast}_{s}D K}$, $g_{B^{\ast}_{s}BK}$, $g_{D^{\ast}_{s}D K_1}$ and $g_{B^{\ast}_{s}BK_1}$, where $K_0^*$, $K$ and $K_1$ are scalar, pseudoscalar and axial vector kaon mesons, respectively are calculated in the framework of three-point QCD sum rules. In particular, the correlation functions of the considered vertices when both $B(D)$ and $K_0^*(K)(K_1)$ mesons are off-shell are evaluated. In the case of $K_1$, which is either $K_1(1270)$ or $K_1(1400)$, the mixing between these two states are also taken into account. A c…
H1 Collaboration recently observed the charmed pentaquark. In this short note, we point out that the dominant production mechanism for pentaquark consisting of a heavy quark is heavy quark fragmentation. We obtain a crude estimate on the fragmentation probability for charm quark into Theta_c^0, based on the known fragmentation probabilities of charm quark into mesons and baryons: f(c-bar --> Theta_c^0) =~ (2-7) x 10^{-3}. Similarly, we also obtain the fragmentation probability for bottom quark into Theta_b^+: f(b-bar --> Theta_b^+) =~ (5-20) x 10^{-3}. We also estimate the prospect of observin…
The mass spectrum of charmed and bottom baryons has been computed on anisotropic lattices using quenched lattice nonrelativistic QCD. Masses are extracted by using mass splittings which are more accurate than masses obtained directly by using the nonrelativistic mass-energy relation. Of particular interest are the mass splittings between spin-1/2 and spin-3/2 heavy baryons, and we find that these color hyperfine effects are not suppressed in the baryon sector although they are known to be suppressed in the meson sector. Results are compared with those obtained in a previous NRQCD calculation a…
Motivated by the recent LHCb observation of $CP$ violation in charm, we study $CP$ violation in the charmed baryon decays. A simple method to search for the $CP$ violation relations in the flavor $SU(3)$ limit, which is associated with a complete interchange of $d$ and $s$ quarks, is proposed. With this method, hundreds of $CP$ violation sum rules in the doubly and singly charmed baryon decays can be found. As examples, the $CP$ violation sum rules in two-body charmed baryon decays are presented. Some of the $CP$ violation sum rules could help the experiment to find better observables. As bypr…
Changes in properties of heavy hadrons with a charm or a bottom quark are studied in nuclear matter. Effective masses (scalar potentials) for the hadrons are calculated using quark-meson coupling model. Our results also suggest that the heavy baryons containing a charm or a bottom quark will form charmed or bottom hypernuclei, which was first predicted in mid 70's. In addition a possibility of $B^-$-nuclear bound (atomic) states is briefly discussed.
Stimulated by recent progress made by the LHCb Collaboration in discoveries of new bottom baryons, e.g., the $Ξ_{b}(6227)^{-}$ and the $Σ_{b}(6097)^{\pm}$, we re-examine the orbitally excited spectrum of the charmed and bottom baryons using Regge approach in the heavy quark-diquark picture. The results indicate that the spin-averaged mass spectrum of the orbitally-excited charmed and bottom baryons can be described by a linear Regge relation, which is derived from the rotating QCD string model. By giving further mass-splitting analysis of spin-dependent interactions, we explain the baryons $Ξ_…
