We revisit the calculation of the strong couplings $D^*Dπ$ and $B^*Bπ$ from the QCD light-cone sum rules using the pion light-cone distribution amplitudes. The accuracy of the correlation function, calculated from the operator product expansion near the light-cone, is upgraded by taking into account the gluon radiative corrections to the twist-3 terms. The double spectral density of the correlation function, including the twist-2, 3 terms at ${\cal O} (α_s)$ and the twist-4 LO terms, is presented in an analytical form for the first time. This form allows us to use various versions of the quark-hadron duality regions in the double dispersion relation underlying the sum rules. We predict $g_{D^*Dπ}=14.1^{+1.3}_{-1.2}$ and $g_{B^*Bπ}=30.0^{+2.6}_{-2.4}$ when the decay constants of heavy mesons entering the light-cone sum rule are taken from lattice QCD results. We compare our results with the experimental value for the charmed meson coupling and with the lattice QCD calculations.
The B --> pi ell nu weak decay form factors are calculated via light-cone sum rules within the framework of the heavy quark effective theory. We calculate the leading and the relevant sub-leading universal form factors. Our results are matched to the known soft pion limit. We also address the large pion energy limit of our sum rule results. Our results are compared with that of other approaches.
We present the first direct calculation on the gravitational form factors (GFFs) of the $N \rightarrow Δ$ transition using an analytic method, the QCD light-cone sum rules. The matrix element of the quark part of the energy momentum tensor current sandwiched between the nucleon and $Δ$ states are parameterized in terms of five independent conserved and four independent non-conserved GFFs, for calculation of which we use the distribution amplitudes (DAs) of the on-shell nucleon expanded in terms of functions with different twists. We present the results for two sets of light-cone input paramete…
We calculate the leading-twist O(alphas^2 beta0) corrections to the B to pi transition form factor f+(0) in light-cone sum rules. We find that, as expected, there is a cancellation between the O(alphas^2 beta0) corrections to fB f+(0) and the large corresponding corrections to fB, calculated in QCD sum rules. This suggests the insensitivity of the form factors calculated in the light-cone sum rules approach to this source of radiative corrections. We further obtain an improved determination of the CKM matrix element |V(ub)|, using latest results from BaBar and Belle for f+(0)|V(ub)|.
The coupling constant of f0-->omega-gamma decay is calculated using 3-point sum rule and light cone QCD sum rules. We investigate the results within the two-models which depend on mixing angle.
We calculate the vector and axial-vector form factors of $B_{u,d,s}$ decays into P-wave axial-vector mesons in the light-cone sum rule approach. For the sum rule results, we have included corrections of order $m_A/m_b$, where $m_A$ is the mass of the axial-vector meson $A$. The results are relevant to the light-cone distribution amplitudes of the axial-vector mesons. It is important to note that, owing to the $G$-parity, the chiral-even two-parton light-cone distribution amplitudes of the $^3P_1$ ($^1P_1$) mesons are symmetric (antisymmetric) under the exchange of quark and anti-quark momentum…
We study the form factors for a heavy meson into the S-wave $Kπ/ππ$ system with an invariant mass below 1~GeV. The mesonic final state interactions are described in terms of the scalar form factors, which are obtained from unitarized chiral perturbation theory. Employing generalized light-cone distribution amplitudes, we compute the heavy-to-light transition using light-cone sum rules. Our approach simultaneously respects constraints from analyticity and unitarity, and also takes advantage of the power expansion in the $1/m_b$ and the strong coupling constant.
The Burkhardt-Cottingham (BC) sum rule connects the twist-3 light-cone parton distribution function (PDF) $g_{T}(x)$ to the twist-2 helicity PDF $g_{1}(x)$. The chiral-odd counterpart of the BC sum rule relates the twist-3 light-cone PDF $h_{L}(x)$ to the twist-2 transversity PDF $h_{1}(x)$. These BC-type sum rules can also be derived for the corresponding quasi-PDFs. We perform a perturbative check of the BC-type sum rules in the quark target model and the Yukawa model, by going beyond the ultra-violet (UV) divergent terms. We employ dimensional regularization (DR) and cut-off schemes to regu…
The coupling constant of g_phi-pion-gamma decay is calculated using light cone QCD sum rules. A comparison of our result with the ones existing in the literature is presented.
We investigate the a0-omega-gamma vertex and estimate the coupling constant in the framework of the light cone QCD sum rules. We compare our result with the value of the coupling constant was calculated in the QCD sum rules.
We compare the predictions for the form factors f_+^{D->pi,K}(0) from QCD sum rules on the light-cone with recent experimental results. We find f_+^{D->pi}(0) = 0.63\pm 0.11, f_+^{D->K}(0) = 0.75\pm 0.12 and f_+^{D->pi}(0)/f_+^{D->K}(0)= 0.84\pm 0.04 in very good agreement with experiment. Although the uncertainties of the form factors themselves are larger than the current experimental errors and difficult to reduce, their ratio is determined much more accurately and with an accuracy that matches that of experiment.
We argue that soft non-factorisable terms give a significant contribution to the baryon form factors at intermediate momentum transfers and set up a framework for the calculation of such terms in the light-cone sum rule approach. Among them, contributions of three-quark states with different helicity structure compared to the leading twist prove to be the most important. The leading-order sum rules are derived and confronted with the experimental data.
We calculate the W-exchange contribution to the $Ξ_{cc}^{++}\toΞ_{c}^{+(\prime)}π^{+}$ decay using light-cone sum rules. The two-particle light-cone distribution amplitudes of the pion are used as non-perturbative input for the sum rules calculation, and the perturbative kernel is calculated at the leading order. We obtain the corresponding decay branching fractions by combining our W-exchange amplitudes with the factorizable amplitudes given by various theoretical methods from the literature. It is shown that with the factorizable amplitudes from heavy quark effective theory, we obtain the br…
In this article, we use the light-cone QCD sum rules to relate the $Λ_b$ baryon light-cone distribution amplitudes to the Isgur-Wise function $ξ(ω)$ of the $Λ_b \to Λ_c$ transition, and obtain a simple relation. The numerical value of the Isgur-Wise function $ξ(ω)$ is consistent with the prediction of the QCD sum rules.
We calculate the form factors V, A_1, A_2 and A_0 appearing in the (D -> phi) transition in light cone QCD sum rule method. We compare our results on these form factors with the current experimental results and existing theoretical calculations.
The axial N-> Delta(1232) transition form factors are calculated within the light cone QCD sum rules method. A comparison of our results with predictions of lattice theory and quark model calculations is pre- sented.
We investigate the $ωσγ$-vertex and estimate the coupling constant g$_{ωσγ}$ in the framework of the light cone QCD sum rules. We compare our result with the values of this coupling constant deduced from a phenomenological analysis of $ω\toππγ$ decays.
The radiative $Δ\to γN$ transition is examined at the real photon point $Q^2=0$ using the framework of light-cone QCD sum rules. In particular, we determine the sum rules for the transition form factors $G_M(0)$ and $R_{EM}$ up to twist 4.
The strong coupling constants g_{K LAMBDA N} and g_{K SIGMA N} for the structure (sigma_{mu,nu} gamma_5) are calculated within light cone QCD sum rules. A comparison of our results on these couplings with predictions from traditional QCD sum rules is presented.
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.
A short introduction is given to the method of light-cone sum rules, their theoretical background and main modifications. The discussion is concentrated but not restricted to the applications to heavy quark decays.
We outline the developed approach within the light-cone sum rules at the leading order for calculation of the gravitational form factors related to the nucleon valence quark combinations. The predictions for the gravitational form factor $D(t)$ ($D$-term contributions) have been presented.
Semileptonic decay processes of $Ξ_c \to Ξ\ellν_\ell$ are studied by light-cone QCD sum rules in this paper. The six form factors of $Ξ_c \to Ξ$ semileptonic transition matrix elements are calculated by this method with the light-cone distribution amplitudes of $Ξ$ baryon up to twist six. With the six form factors, the absolute branching ratios of $Ξ_c^0 \to Ξ^- \ell^+ ν_\ell$ and $Ξ_c^+ \to Ξ^0 \ell^+ ν_\ell$ are calculated by the helicity amplitudes formalism of semileptonic differential decay widths. The ratios of absolute branching ratios of electron and muon final states processes give th…
The tensor form factors of $B$ into p--wave axial vector meson transition are calculated within light cone QCD sum rules method. The parametrizations of the tensor form factors based on the series expansion are presented.
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 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 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.
Using the recent results for the two-parton light-cone distribution amplitudes of the tensor meson, we calculate the form factors for the decays of $B_{u,d,s}$ into the light $J^{PC}=2^{++}$ tensor mesons via the vector/axial-vector/tensor current with the light-cone sum rules. We also obtain the $q^2$-dependence of the form factors.
We calculate the transition formfactors for the B -> K l(+) l(-) decay in the framework of the light cone QCD sum rules. The invariant dilepton mass distribution and the final lepton longitudinal polarization asymmetry are investigated. The comparison analysis of our results with traditional sum rules method predictions on the formfactors is performed.
We have analyzed the $B\to π$ and $B_{s}\to K$ semileptonic form factors and $B\to Vγ(V=K^*,ρ,ω)$ processes in the light-cone QCD sum rules. In order to enhance the predictivity and reliability of numerical results the chiral-current correlator is employed and the twist-3 light-cone wavefunction can be effectively eliminated from the sum rules.
The magnetic and quadrupole moments of the light-vector and axial-vector mesons are calculated in the light cone QCD sum rules. Our results for the static properties of these mesons are compared with the predictions of lattice QCD as well as other approaches existing in the literature.
Recently, LHCb Collaboration announced the discovery of radial excitations of $D_s$ and $B_s$ mesons. In present work, we calculate the most promising strong and electromagnetic decay widths of radially excited $D_s(2S)$ and $B_s(2S)$ mesons within the light cone QCD sum rules method.
We investigate the $a_0K^+K^-$-vertex in the framework of light cone QCD sum rules. We estimate the coupling constant g$_{a_0K^+K^-}$ which is an essential ingredient in the analysis of physical processes involving $a_0(980)$ meson. Our result is somewhat larger than the previous determinations of this coupling constant.
New sum rules for $B\to π,K $ and $B\to ρ,K^*$ form factors are derived from the correlation functions expanded near the light-cone in terms of B-meson distribution amplitudes. The contributions of quark-antiquark and quark-antiquark-gluon components in the B meson are taken into account. Models for the B-meson three-particle distribution amplitudes are suggested, based on QCD sum rules in HQET. Employing the new light-cone sum rules we calculate the form factors at small momentum transfers, including $SU(3)_{fl}$ violation effects. The results agree with the predictions of the conventional li…
Using light-cone sum rule techniques, we estimate the form factors which parametrise the hadronic matrix elements that are relevant for semi-leptonic three-body proton decays. The obtained form factors allow us to determine the differential rate for the decay of a proton ($p$) into a positron ($e^+$), a neutral pion ($π^0$) and a graviton ($G$), which is the leading proton decay channel in the effective theory of gravitons and Standard Model particles (GRSMEFT). The sensitivity of existing and next-generation neutrino experiments in detecting the $p \to e^+ π^0 G$ signature is studied and the …
Using the general form of the (Sigma^0) and (Lambda) currents, the (Sigma^0-Lambda) transition magnetic moment is calculated in framework of the light cone QCD sum rules. A comparison of our result on this quantity with the existing theoretical results and experimental data is presented.
We suggest a new approach for calculating heavy-to-light form factors. The method is based on light cone sum rules (LCSR) and covers the whole kinematical range of momentum transfer. The derivation of the new sum rule uses a suitable combination of double and single dispersion integrals. As an example we give numerical results for the form factor f^+ for the B -> pion transition.
In this article, we study the $B \to K^*_2(1430)$, $a_2(1320)$, $f_2(1270)$ form-factors with the light-cone QCD sum rules, where the $B$-meson light-cone distribution amplitudes are used. In calculations, we observe that the line-shapes of the $B$-meson light-cone distribution amplitude $ϕ_+(ω)$ have significant impacts on the values of the form-factors, and expect to obtain severe constraints on the parameters of the $B$-meson light-cone distribution amplitudes from the experimental data in the future.
Strong decay constants of the heavy tensor to heavy pseudoscalar (vector) and light pseudoscalar mesons are estimated within the light cone QCD sum rules. It is obtained that the values of these coupling constants are very strongly dependent on the choice of the Lorentz structure. Moreover, using these strong coupling constants the corresponding decay widths are calculated.
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).
Using the most general form of the interpolating currents, the coupling constants $g_{Σ_bΣ_bπ}$ and $g_{Σ_cΣ_cπ}$ are calculated within the light cone QCD sum rules approach. It is found that $g_{{Σ_{c}Σ_{c}π}}=-8.0\pm1.7$ and $g_{{Σ_{b}Σ_{b}π}}=-11.0\pm2.1$.
In this work, we analyze the semileptonic decay processes of $Λ_b \to Λ_c$ in the light-cone sum rule approach. In order to calculate the form factors of the $Λ_b$ baryon transition matrix element, we use the light-cone distribution amplitudes of $Λ_b$ obtained from the QCD sum rule in the heavy quark effective field theory framework. With the calculation of the six form factors of the $Λ_b \to Λ_c$ transition matrix element, the differential decay widths of $Λ_b^0 \to Λ_c^+ \ell^- \overlineν_\ell (\ell = e, ~μ, ~τ)$ and their absolute branching fractions are obtained. Additionally, the ratio …
We describe the construction of light-cone sum rules (LCSRs) for exclusive $B$-meson decays into light energetic hadrons from correlation functions within soft-collinear effective theory (SCET). As an example, we consider the SCET sum rule for the $B \to π$ transition form factor at large recoil, including radiative corrections from hard-collinear loop diagrams at first order in the strong coupling constant.
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.
In this article, we calculate the strong coupling constant $g_{ΔNπ}$ and study the strong decay $Δ^{++} \to pπ$ with the light-cone QCD sum rules. The numerical value of the strong coupling constant $g_{ΔNπ}$ is consistent with the experimental data. The small discrepancy maybe due to failure to take into account the perturbative $\mathcal {O}(α_s)$ corrections.
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.
Light-cone sum rules have proved to be very useful in calculating hadronic matrix elements for exclusive processes. I present recent applications of this method to the pion electromagnetic form factor and to the form factors of $γ^* ρ\to π$ and $γ^*γ\to π^0$ transitions.
We examine the radiative $Δ\to γN$ transition at the real photon point $Q^2=0$ using the framework of light-cone QCD sum rules. In particular, the sum rules for the transition form factors $G_M(0)$ and $R_{EM}$ are determined up to twist 4. The result for $G_M(0)$ agrees with experiment within 10% accuracy. The agreement for $R_{EM}$ is also reasonable. In addition, we derive new light-cone sum rules for the magnetic moments of nucleons, with a complete account of twist-4 corrections based on a recent reanalysis of photon distribution amplitudes.
We complete the set of QCD light-cone sum rules for $B\to ππ$ transition form factors, deriving a new sum rule for the timelike-helicity form factor $F_t$ in terms of dipion distribution amplitudes. This sum rule, in the leading twist-2 approximation, is directly related to the pion vector form factor. Employing a relation between $F_t$ and other $B\to ππ$ form factors we obtain also the longitudinal-helicity form factor $F_0$. In this way, all four (axial-)vector $B\to ππ$ form factors are predicted from light-cone sum rules with dipion distribution amplitudes. These results are valid for sma…
The introduction of an explicit negative radial excitation contribution in the hadronic side of the light cone QCD sum rule (LCSR) of Belyaev, Braun, Khodjamirian and Ruckl, can explain the large experimental value of g(D*Dpi), recently measured by CLEO. At the same time, it considerably improves the stability of the sum rule when varying the Borel parameter.
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.
