Using the most general form of the interpolating current of the baryons, the strong coupling constants of the light vector mesons with the octet baryons are calculated within the light cone QCD sum rules. The SU(3)_f symmetry breaking effects are taken into account in the calculations. It is shown that each of the electric and magnetic coupling constants can be described in terms of three universal functions. A detailed comparison of the results of this work on aforementioned couplings with the existing theoretical results is presented.
We show that energetically favored meson-baryon fluctuations present in the light-cone wave function of a transversely polarized proton can account for the left-right asymmetries measured in inclusive meson production processes.
This is a short review of the theory and phenomenology of baryon distribution amplitudes, including recent applications to the studies of nucleon form factors at intermediate momentum transfers using the light-cone sum rule approach.
The magnetic moments of heavy sextet $J^P = {1\over 2}^+$ baryons are calculated in framework of the light cone QCD sum rules method. Linearly independent relations among the magnetic moments of these baryons are obtained. The results for the magnetic moments of heavy baryons obtained in this work are compared with the predictions of the other approaches.
Octet baryon magnetic moments are calculated in framework of the light cone QCD sum rules. The analysis is carried for the general form of the interpolating currents for octet baryons. A comparison of our results on the magnetic moments of octet baryons with the predictions of other approaches and experimental data is presented.
The magnetic moments of heavy $Ξ_{Q}$ baryons containing a single charm or bottom quark are calculated in the framework of light cone QCD sum rules method. A comparison of our results with the predictions of the quark models is presented.
We present the application of the method of light-cone sum rules to the determination of baryonic form factors at intermediate momentum transfer. After reviewing the current status of this field we give some outlook on possible future projects.
We calculate the magnetic moments of decuplet baryons containing strange quarks within the framework of light cone QCD sum rules taking into account the SU(3) flavor symmetry breaking effects. It is obtained that magnetic moments of the neutral $\sso$ and $\xis0$ baryons are mainly determined by the SU(3) breaking terms. A comparison of our results on the magnetic moments of the decuplet baryons with the predictions of other approaches is presented.
We calculate the magnetic moments of Delta baryons within the framework of QCD sum rules. A comparison of our results on the magnetic moments of the Delta baryons with the predictions of different approaches is presented.
Using the most general form of the interpolating currents of heavy baryons, the magnetic moments of heavy baryons "Lambda_Q (Q=b,c)" are calculated in framework of the light cone QCD sum rules. A comparison of our results on magnetic moments with the existing theoretical results calculated in various other frameworks are presented.
We provide the definition of the complete set of light-cone distribution amplitudes (LCDAs) for the ground state heavy bottom baryons with the spin-parities J^P = 1/2^+ and J^P = 3/2^+ in the heavy quark limit. We present the renormalization effects on the twist-2 light-cone distribution amplitudes and use the QCD sum rules to compute the moments of twist-2, twist-3, and twist-4 LCDAs. Simple models for the heavy baryon distribution amplitudes are analyzed with account of their scale dependence.
Using the general form of the baryon currents, we calculate the meson-baryon coupling constants and the F/D ratio within the framework of light cone QCD sum rules in the SU(3) flavor symmetry limit. The dependence of the results on the Dirac structure and on the free parameter (b) appearing in the general baryon current is considered. Comparison of our results on F/D ratio with the existing results is presented.
We calculate the "pi Sigma Lambda" and "pi Sigma Sigma" coupling constants in light cone QCD sum rules for the structure "sigma_{alpha beta} gamma_5 p^alpha q^beta". A comparison of our results on these coupling constants with prediction of the SU(3) symmetry is presented.
The transition magnetic dipole and electric quadrupole moments of the radiative decays of the sextet heavy flavored spin 3/2 to the heavy spin 1/2 baryons are calculated within the light cone QCD sum rules approach. Using the obtained results, the decay rate for these transitions are also computed and compared with the existing predictions of the other approaches.
The semileptonic decays of heavy spin--1/2, $Ξ_{b(c)}$ and $Ξ'_{b(c)}$ baryons to the light spin-- 1/2, $Ξ$ and $Σ$ baryons are investigated in the framework of the light cone QCD sum rules. In particular, using the most general form of the interpolating currents for the heavy baryons as well as the distribution amplitudes of the $Ξ$ and $Σ$ baryons, we calculate all form factors entering the matrix elements of the corresponding effective Hamiltonians in full QCD. Having calculated the responsible form factors, we evaluate the decay rates and branching fractions of the related transitions.
The couplings of pions with heavy baryons g_2 (Σ^*, Σ) and g_3(Σ^*, Λ) are studied with light-cone QCD sum rules in the leading order of heavy quark effective theory. Both sum rules are stable. Our results are g_2=(1.56\pm 0.3), g_3=(0.94\pm 0.06).
The radiative decays of decuplet to octet baryons are analyzed within the light cone QCD sum rules framework.The electromagnetic transition form factors for these decays are calculated up to twist four accuracy for photon wave functions as well as including first order strange quark mass corrections. A comparison of our results with predictions of lattice theory and existing experimental data is presented.
The strong coupling constants of the $π$ and $K$ mesons with negative parity octet baryons are estimated within the light cone QCD sum rules. It is observed that all strong coupling constants, similar to the case for the positive parity baryons, can be described in terms of three invariant functions, where two of them correspond to the well known $F$ and $D$ couplings in the $SU(3)_f$ symmetry, and the third function describes the $SU(3)_f$ symmetry violating effects. We compare our predictions on the strong coupling constants of pseudoscalar mesons of negative parity baryons with those corres…
In this paper, we analyze the doubly heavy spin-3/2--spin-1/2 baryons and light meson vertices within the method of light-cone QCD sum rules. These vertices are parametrized in terms of one (three) coupling constant(s) for the pseudoscalar (vector) mesons. The said coupling constants are calculated for all possible transitions. The results presented here can serve to be useful information in experimental as well as theoretical studies of the properties of doubly heavy baryons.
Motivated by the results of the recent experimental discoveries for charm and bottom baryons, the masses and magnetic moments of the heavy baryons with $J^P=3/2^+$ containing a single heavy quark are studied within light cone QCD sum rules method. Our results on the masses of heavy baryons are in good agreement with predictions of other approaches, as well as with the existing experimental data.
Inspired by the results of recent experimental discoveries for charm and bottom baryons, the masses and magnetic moments of the heavy baryons with $J^P=3/2^+$ containing a single heavy quark are studied within light cone QCD sum rules method. Our results on the masses of heavy baryons are in good agreement with predictions of other approaches, as well as with the existing experimental values. Our predictions on the masses of the states, which are not yet discovered in the experiments, can be tested in the future experiments. A comparison of our results on the magnetic moments of these baryons …
We present an extensive study of the static properties of light exotic and non-exotic baryons, based on the formulation of chiral quark-soliton model in terms of light-cone wave functions. We discuss in particular vector, axial and tensor charges as well as an estimation of the electromagnetic moments for the baryon octet, decuplet and hypothetical antidecuplet. Contributions from Fock components up to the seven-quark sector are considered and appear to be sizeable, reflecting the importance of the pion cloud. All these observables are further decomposed into flavor, valence quark, sea quark a…
We present the light-cone QCD sum rules up to twist 6 for the electromagnetic form factors of the $Λ$ baryon. To estimate the magnetic moment of the baryon, the magnetic form factor is fitted by the dipole formula. The numerical value of our estimation is $μ_Λ=-(0.64\pm0.04)μ_N$, which is in accordance with the experimental data and the existing theoretical results. We find that it is twist 4 but not the leading twist distribution amplitudes that dominate the results.
The coupling constants of K and pi mesons with the octet baryons are studied in light cone QCD sum rules taking into account SU(3)f flavor symmetry breaking effects, but keeping the SU(2) isospin symmetry intact. It is shown that, in the SU(3)f flavor symmetry breaking case, all of the couplings can be written in terms of four universal functions instead of F and D couplings which exist in the SU(3)f symmetry case. A comparison of our results of kaon and pion-baryon couplings with existing theoretical and experimental results in the literature is performed.
Magnetic dipole moment form factor, $G_M^{(2)}(Q^2)$, describing the radial excitation of decuplet baryons to octet baryons electromagnetic transitions as well as the ratios, $R_{SM} = -\frac{1}{4 m_2^2} \sqrt{4 m_2^2 Q^2 + (m_2^2 - Q^2 -m_1^2)^2} \frac{G_C^{(2)}(Q^2)}{G_M^{(2)}(Q^2)}$ and $R_{EM} = -\frac{G_E^{(2)}(Q^2)}{G_M^{(2)}(Q^2)}$ are calculated in the framework of light-cone sum rules. We also estimate the degree of the violation of U-spin symmetry. The obtained results for the multipole form factors can be useful in searching the properties of radially excited baryon states.
Form factors of the weak $Ξ_c \to Ξ(Λ)$ transitions are calculated within the light cone QCD sum rules. The pollutions coming from the contribution of the negative parity $Ξ_c^*$ baryon is eliminated by considering the combinations of sum rules corresponding to the different Lorentz structures. Having obtained the form factors, the branching ratios of the $Ξ_c \to Ξ(Λ) \ell ν$ decays are also calculated, and our predictions are compared with the results of other approaches as well as the measurements done by BELLE and ALICE Collaborations.
The electric quadrupole and magnetic octupole moments of the light decuplet baryons are calculated in the framework of the light cone QCD sum rules. The obtained non-vanishing values for the electric quadrupole and magnetic octupole moments of these baryons show nonspherical charge distribution. The sign of electric quadrupole moment is positive for $Ω^-$, $Ξ^{*-}$, $Σ^{*-}$ and negative for $Σ^{*+}$, which correspond to the prolate and oblate charge distributions, respectively. A comparison of the obtained results with the predictions of non-covariant quark model which shows a good consistenc…
The Light-cone distribution amplitudes (LCDAs) of the $Σ^\pm$ baryons up to twist six are investigated on the basis of QCD conformal partial wave expansion approach. The calculations are carried out to the next-to-leading order of conformal spin accuracy. The nonperturbative parameters relevant to the LCDAs are determined in the framework of the QCD sum rule method. The explicit expressions of the LCDAs are given as the main results.
We derive QCD light-cone sum rules for the hadronic matrix elements of the heavy baryon transitions to nucleon. In the correlation functions the $Λ_c,Σ_c$ and $Λ_b$ -baryons are interpolated by three-quark currents and the nucleon distribution amplitudes are used. To eliminate the contributions of negative parity heavy baryons, we combine the sum rules obtained from different kinematical structures. The results are then less sensitive to the choice of the interpolating current. We predict the $Λ_{b}\to p$ form factor and calculate the widths of the $Λ_{b}\to p\ellν_l$ and $Λ_{b}\to p π$ decays…
The semileptonic $Ω_c^0 \rightarrow Ω^- l ν$ and non-leptonic $Ω_c^0 \to Ω^- π^+$, $Ω_c^0 \to Ω^- ρ^+$ decays of charmed $Ω_c$ baryon are studied within the light cone sum rules. The form factors responsible for $Ω_c \to Ω$ transitions are calculated using the distribution amplitudes of $Ω_c$ baryon. With the obtained form factors, the branching ratios of $Ω_c^0 \to Ω^- l^+ ν_l$, $Ω_c^0 \rightarrow Ω^- π^+$, and $Ω_c^0 \rightarrow Ω^- ρ^+$ decays are estimated. The results are compared with Belle data as well as the findings of the other approaches.
Taking into account the $SU(3)_f$ breaking effects, the strong coupling constants of the $π$, $K$ and $η$ mesons with decuplet baryons are calculated within light cone QCD sum rules method. It is shown that all coupling constants, even in the case of $SU(3)_f$ breaking, are described in terms of only one universal function. It is shown that for $Ξ^{\ast 0} \to Ξ^{\ast 0} η$ transition violation of $SU(3)_f$ symmetry is very large and for other channels when $SU(3)_f$ symmetry is violated, its maximum value constitutes $10%\div15%$.
Due to the very short life time of the $Δ$ baryons, a direct measurement on the electromagnetic moments of these systems is almost impossible in the experiment and can only be done indirectly. Although only for the magnetic dipole moments of $Δ^{++}$ and $Δ^{+}$ systems there are some experimental data, the theoretical, phenomenological and lattice calculations could play crucial role. In present work, the magnetic dipole ($μ_Δ$) , electric quadrupole ($Q_Δ$) and magnetic octupole ($O_Δ$) moments of these baryons are computed within the light cone QCD sum rules. The results are compared with t…
The improved light-cone distribution amplitudes (LCDAs) of the $Λ$ baryon are examined on the basis of the QCD conformal partial wave expansion approach. The calculations are carried out to the next-to-leading order of conformal spin accuracy with consideration of twist 6. The next leading order conformal expansion coefficients are related to the nonperturbative parameters defined by the local three quark operator matrix elements with different Lorentz structures with a covariant derivative. The nonperturbative parameters are determined with the QCD sum rule method. The explicit expressions of…
We study the electroweak properties of ground state octet baryons in a relativistic quark-spectator-diquark model, with light-front formalism applied to take relativistic effects into account. Our model provides a consistent picture of the electroweak properties of the ground state octet baryons in the low momentum transfer region. The Melosh-Wigner rotation is applied as the transformation relation between spinors in the instant form and front form. Numerical results are presented for the magnetic moments, weak transition charges and Sachs form factors. Our results are in good agreement with …
In this article, we calculate the strong coupling constants of the $ρNN$, $ρΣΣ$ and $ρΞΞ$ in the framework of the light-cone QCD sum rules approach. The strong coupling constants of the meson-baryon-baryon are the fundamental parameters in the one-boson exchange model which describes the baryon-baryon interactions successfully. The numerical values are in agreement with the existing calculations in part. The electric and magnetic $F/(F+D)$ ratios deviate from the prediction of the vector meson dominance theory, the SU(3) symmetry breaking effects are very large.
The electromagnetic form factors of the Xi baryons and the semileptonic decay process Xi_c->Xi e^+nu_e are investigated in the frame work of the light-cone QCD sum rule method with Ioffe-type interpolating currents. Our estimates on the magnetic moments are $mu_{Xi^0}=-(1.75\pm0.21) mu_N and mu_{Xi^-}=-(1.01\pm0.11)mu_N. The decay width of the semileptonic process is expected to be Gamma(Ξ_c\to Ξe^+ν_e)=(6.17^{+2.24}_{-2.48})\times10^{-14}GeV. The results make sure that the adoption of this type interpolating current improve the calculations of the magnetic form factors and give more reliable …
Using the calculated values of the strong coupling constants of the heavy sextet spin-3/2 baryons to sextet and antitriplet heavy spin-1/2 baryons with light mesons within the light cone QCD sum rules method, and vector meson dominance assumption, the radiative decay widths are calculated. These widths are compared with the "direct" radiative decay widths predicted in the framework of the light cone QCD sum rules.
Light cone QCD sum rules for the electromagnetic transition form factors among positive and negative parity octet baryons are derived. The unwanted contributions of the diagonal transitions among positive parity octet baryons are eliminated by combining the sum rules derived from different Lorentz structures. The $Q^2$ dependence for the transversal and longitudinal helicity amplitudes are studied.
Light-cone sum rules for the $Λ_b \to p, Λ$ transition form factors are derived from the correlation functions expanded by the twist of the distribution amplitudes of $Λ_b$ baryon. In terms of the $Λ_b$ three-quark distribution amplitudes models constrained by the QCD theory, we calculate the form factors at small momentum transfers and compare the results with that estimated in the conventional light-cone sum rules (LCSR) and perturbative QCD approaches. Our results indicate that the two different version of sum rules can lead to the consistent numbers of form factors responsible for $Λ_b \to…
The magnetic dipole moments of the spin-$\frac{1}{2}$ doubly heavy baryons are extracted in the framework of light-cone QCD sum rule. The electromagnetic properties of the doubly heavy baryons encodes important information of their internal structure. The results for the magnetic dipole moments of doubly heavy baryons acquired in this work are compared with the predictions of the other theoretical approaches.
We use distribution amplitudes of the light $Σ$ baryon and the most general form of the interpolating current for heavy $Σ_b$ baryon to investigate the semileptonic $Σ_b\rightarrow Σl^+l^-$ transition in light cone QCD sum rules. We calculate all twelve form factors responsible for this transition and use them to evaluate the branching ratio of the considered channel. The order of branching fraction shows that this channel can be detected at LHC.
We investigate the light-cone wave functions and leading-twist distribution amplitudes for the nucleon and $Δ$ baryon within the framework of the chiral quark-soliton model. The baryon wave function consists of the valence quark and vacuum wave functions. The vacuum wave functions generate all possible higher Fock states by expanding them. We find that it is essential to consider the five-quark component and relativistic corrections to evaluate the distribution amplitudes of the nucleon and $Δ$ isobar. Having taken into account them, we derive the distribution amplitudes. The results are in go…
In this study, the magnetic moments of the spin-1/2 triply-heavy baryons have been calculated using both light-cone QCD sum rules and Quark-diquark model. Theoretical investigations on magnetic moments of the triply-heavy baryons, are crucial as their results can help us better understand their internal structure and the dynamics of the QCD as the theory of the strong interaction. We compare the results extracted for the magnetic moment with the existing theoretical predictions. It is seen that the obtained magnetic moment values are quite compatible with the results in the literature.
We present the state-of-the-art of the light-cone sum rule approach to Baryon form factors. The essence of this approach is that soft Feynman contributions are calculated in terms of small transverse distance quantities using dispersion relations and duality. The form factors are thus expressed in terms of nucleon wave functions at small transverse separations, called distribution amplitudes, without any additional parameters. The distribution amplitudes, therefore, can be extracted from the comparison with the experimental data on form factors and compared to the results of lattice QCD simula…
In this work, we investigate the semi-leptonic weak decays of spin-1/2 doubly-heavy baryons $Ξ_{QQ^{\prime}}$ into spin-3/2 singly-heavy baryons $Σ_{Q^{\prime}}^*$ within light-cone sum rules. Using the parallel components of the light-cone distribution amplitudes of $Σ_{Q^{\prime}}^*$, the transition form factors for these decays are calculated both analytically and numerically. The numerical results for these semi-leptonic weak decays widths and branching ratios are also predicted, which are compared with the same predictions by other theoretical approaches in the literatures. These phenomen…
We analyze the weak decay of doubly-heavy baryon decays into anti-triplets $Λ_Q$ with light-cone sum rules. To calculate the decay form factors, both bottom and charmed anti-triplets $Λ_b$ and $Λ_c$ are described by the same set of leading twist light-cone distribution functions. With the obtained form factors, we perform a phenomenology study on the corresponding semi-leptonic decays. The decay widths are calculated and the branching ratios given in this work are expected to be tested by future experimental data, which will help us to understand the underlying dynamics in doubly-heavy baryon …
In this work we present a minimal parametrization of the light-cone distribution amplitudes of the baryon octet including higher twist contributions. Simultaneously we obtain the quark mass dependence of the amplitudes at leading one-loop accuracy by the use of three-flavor baryon chiral perturbation theory (BChPT), which automatically yields model-independent results for the leading $SU(3)$ flavor breaking effects. For that purpose we have constructed the nonlocal light-cone three-quark operators in terms of baryon octet and meson fields and have carried out a next-to-leading order BChPT calc…
The magnetic moment of the $Λ\to Σ^0$ transition between negative parity, baryons is calculated in framework of the QCD sum rules approach, using the general form of the interpolating currents. The pollution arising from the positive--to--positive, and positive to negative parity baryons are eliminated by constructing the sum rules for different Lorentz structures. Nonzero value of the considered magnetic moment can be attributed to the violation of the $SU(3)$ symmetry.
We present results of the first ab initio lattice QCD calculation of the normalization constants and first moments of the leading twist distribution amplitudes of the full baryon octet, corresponding to the small transverse distance limit of the associated S-wave light-cone wave functions. The P-wave (higher twist) normalization constants are evaluated as well. The calculation is done using $N_f=2+1$ flavors of dynamical (clover) fermions on lattices of different volumes and pion masses down to 222 MeV. Significant SU(3) flavor symmetry violation effects in the shape of the distribution amplit…
We present a systematic light-cone QCD sum rule study of the exclusive rare radiative decay $Λ_b\rightarrowΛγ$ and rare semileptonic decay $Λ_b\rightarrowΛl^+l^-$ within the framework of the standard model. Although some LCSR studies on these rare processes can be found in different literatures, it is necessary to reanalyze them systematically for the reason that either the baryonic distribution amplitudes are improved or different interpolating currents for the $Λ_b$ baryon may lead to quite different results. In addition, the rare process $Λ_b\rightarrowΛγ$ has not yet been analyzed by LCSR …
We construct parametrizations of light-cone distribution amplitudes (LCDAs) for B-mesons and Lambda_b-baryons that obey various theoretical constraints, and which are simple to use in factorization theorems relevant for phenomenological applications in heavy-flavour physics. In particular, we find the eigenfunctions of the Lange-Neubert renormalization kernel, which allow for a systematic implementation of renormalization-group evolution effects for both B-meson and Λ_b-baryon decays. We also present a new strategy to construct LCDA models from momentum-space projectors, which can be used to i…
The radiative decays of heavy baryons and lowest three doublets of heavy mesons are studied with the light cone QCD sum rules in the leading order of heavy quark effective theory.
The electromagnetic form factors of octet baryons are estimated within light cone QCD sum rules method, using the most general form of the interpolating current for baryons. A comparison of our predictions on the magnetic dipole and electric form factors with the results of other approaches is performed.
In this work, we calculate the transition form factors of $Λ_b$ decaying into $Λ_c$ within the framework of light-cone sum rules with the distribution amplitudes (DAs) of $Λ_b$-baryon. In the hadronic representation of the correlation function, we have isolated both the $Λ_c$ and the $Λ_c^*$ states so that the $Λ_b \rightarrow Λ_c$ form factors can be obtained without ambiguity. We investigate the P-type and A-type current to interpolate the light baryons for a comparison since the interpolation current for the baryon state is not unique. We also employ three parametrization models for DAs of …
For the heavy baryons $Ξ_c$ and $Ξ_b$ the coupling constants $g_{Ξ_cΞ_cπ}$ and $g_{Ξ_bΞ_bπ}$ are calculated in the framework of light cone QCD sum rules. The most general form of the interpolating field of $Ξ_Q$ is used in the calculation.
We study decay properties of the $P$-wave charmed baryons using the method of light-cone QCD sum rules, including the $S$-wave decays of the flavor $\mathbf{\bar 3}_F$ $P$-wave charmed baryons into ground-state charmed baryons accompanied by a pseudoscalar meson ($π$ or $K$) or a vector meson ($ρ$ or $K^*$), and the $S$-wave decays of the flavor $\mathbf{6}_F$ $P$-wave charmed baryons into ground-state charmed baryons accompanied by a pseudoscalar meson ($π$ or $K$). We study both two-body and three-body decays which are kinematically allowed. We find two mixing solutions from internal $ρ$- an…
We use the method of light-cone sum rules to study decay properties of $P$-wave bottom baryons belonging to the $SU(3)$ flavor $\mathbf{6}_F$ representation. In Ref.~\cite{Cui:2019dzj} we have studied their mass spectrum and pionic decays, and found that the $Σ_{b}(6097)$ and $Ξ_{b}(6227)$ can be well interpreted as $P$-wave bottom baryons of $J^P = 3/2^-$. In this paper we further study their decays into ground-state bottom baryons and vector mesons. We propose to search for a new state $Ξ_b({5/2}^-)$, that is the $J^P = 5/2^-$ partner state of the $Ξ_{b}(6227)$, in the $Ξ_b({5/2}^-) \to Ξ_b^…
