Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userCoupling constants calculation of charmed meson with kaon from QCD sum rules
267
0
0.0
(
0
)
Authors
M.R. Seyedhabashy
Ask ChatGPT about the research
No Arabic abstract
In this research, the strong coupling constants of the $D^*D_s^*K$, $D_1D_{s1}K$, $D^*D_sK$ and $D_1D_{s0}^*K$ vertices are evaluated, using the three-point QCD sum rules. In order to calculate the coupling constant of each vertex, either the kaon or the charmed meson is considered as the off-shell particle. The basic $g$ parameter, in the heavy quark effective theory, is related to the coupling constants of $D^*D_s^*K$ and $D^*D_sK$. Our obtained value for $g$ parameter is $0.24pm 0.09$, which is in good agreement with the lower limits of the other existing predictions.
rate research
Read More
The external-field QCD Sum Rules method is used to evaluate the coupling constants of the light-isoscalar scalar meson (``sigma or epsilon) to the Lambda, Sigma, and Xi baryons. It is shown that these coupling constants as calculated from QCD Sum Rules are consistent with SU(3)-flavor relations, which leads to a determination of the F/(F+D) ratio of the scalar octet assuming ideal mixing: we find alpha_s equiv F/(F+D)=0.55. The coupling constants with SU(3) breaking effects are also discussed.
Using general baryon interpolating fields $J_B$ for $B= N, Xi, Sigma, $ without derivative, we study QCD sum rules for meson-baryon couplings and their dependence on Dirac structures for the two-point correlation function with a meson $iint d^4x e^{iqx} bra 0|{rm T}[J_B(x)bar{J}_B(0)] |{cal M}(p)ket$. Three distinct Dirac structures are compared: $igamma_5$, $igamma_5fslash{p}$, and $gamma_5sigma_{mu u}q^mu p^ u$ structures. From the dependence of the OPE on general baryon interpolating fields, we propose criteria for choosing an appropriate Dirac structure for the coupling sum rules. The $gamma_5sigma_{mu u}q^mu p^ u$ sum rules satisfy the criteria while the $igamma_5$ sum rules beyond the chiral limit do not. For the $igamma_5fslash{p}$ sum rules, the large continuum contributions prohibit reliable prediction for the couplings. Thus, the $gamma_5sigma_{mu u}q^mu p^ u$ structure seems pertinent for realistic predictions. In the SU(3) limit, we identify the OPE terms responsible for the $F/D$ ratio. We then study the dependence of the ratio on the baryon interpolating fields. We conclude the ratio $F/D sim 0.6-0.8$ for appropriate choice of the interpolating fields.
Finite energy QCD sum rules with Legendre polynomial integration kernels are used to determine the heavy meson decay constant $f_{B_c}$, and revisit $f_B$ and $f_{B_s}$. Results exhibit excellent stability in a wide range of values of the integration radius in the complex squared energy plane, and of the order of the Legendre polynomial. Results are $f_{B_c} = 528 pm 19$ MeV, $f_B = 186 pm 14$ MeV, and $f_{B_s} = 222 pm 12$ MeV.
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 use QCD Laplace sum-rules to explore mixing between conventional mesons and hybrids in the heavy quarkonium vector $J^{PC}!=!1^{--}$ channel. Our cross-correlator includes perturbation theory and contributions proportional to the four-dimensional and six-dimensional gluon condensates. We input experimentally determined charmonium and bottomonium hadron masses into both single and multi-resonance models in order to test them for conventional meson and hybrid components. In the charmonium sector we find evidence for meson-hybrid mixing in the $J/psi$ and a $approx4.3$ GeV resonance. In the bottomonium sector, we find that the $Upsilon(1S)$, $Upsilon(2S)$, $Upsilon(3S)$, and $Upsilon(4S)$ all exhibit mixing.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
