Properties ofQQ¯mesons in nonrelativistic QCD formalism

Abstract

The decay rates of QQ mesons (Q ε c, b) are studied in the NRQCD formalism in terms of their short distance and long distance coefficients. The long distance coefficients are obtained through phenomenological potential model description of the mesons. The model parameters that reproduces the mass spectrum of the cc, bb and cb mesons are employed to study the decay widths of these mesons. We extract the mass spectrum as well as the reproduces the respective radial wave functions from the different potential models as well as from non-relativistic phenomenological quark antiquark potential of the type V (r) = − αc r + Ar ν , with ν varying from 0.5 to 2. The spin hyperfine and spin-orbit interactions are employed to obtain the masses of the pseudoscalar and vector mesons. The decay constants with QCD corrections are computed in this model as well as in the case of other potential models for comparison. The digamma and dileptonic decays of cc, and bb mesons are investigated using some of the known potential models without and with radiative corrections up to the lowest order. These decay width are also computed within the NRQCD formalism up to O(v 4 ) by making uses of the respective spectroscopic parameters of the models. Our theoretical predictions of the decays of the cc, and bb mesons and the results obtained from some of the other potential schemes are compared with the experimental values. The partial widths and life time of the B c meson are also computed using the model parameters and are found to be in good accordance with the experimental values.pacs 12.39Jh, 12.40Yx, 13.20.Gd, 13.20Fc, 13.25.Hw,14.40.Nd

Masses of di-mesonic molecular states

“…The spin dependent interaction potential added separately and the radial wave function for the ground state of the system are assumed as [8,9,[17][18][19][20] …”

“…where k mol is the residual strength like running coupling constant and C is the effective color screening parameter of the confined gluon [17][18][19][20]. One boson exchange interaction potential (OBEP) [21] is used based on the assumption that molecular like structure of multiquark system is being deuterium like structure of nucleon [13].…”

Spectroscopic properties of the B meson

“…As the interaction potential assumed here does not contain the spin dependent part, Eq (9) gives the spin averaged masses of the system. The calculated spin averaged mass of the ground state is matched with the experimental spin-averaged mass using the equation [15] …”

“…Using this value of V 0 we calculate S , P, and D wave spin-averaged masses of B mesons which are listed in Table 1. For the comparison for the nJ state, we compute the spin-averaged or the center of weight mass from the respective theoretical values as [15] …”

D meson spectroscopy and their decay properties using Martin potential in a relativistic Dirac formalism

“…For better predictions of the decay widths, many models have incorporated additional contributions such as radiative and higher order QCD corrections [13,[23][24][25][26][27]. Thus, in this paper we make an attempt to study properties like the mass spectrum, decay constants and other decay properties of the D meson based on a relativistic Dirac formalism.…”