Properties Of Heavy Mesons Research Articles

Thermal modification of open heavy-flavor mesons from an effective hadronic theory

We have developed a self-consistent theoretical approach to study the modification of the properties of heavy mesons in hot mesonic matter which takes into account chiral and heavy-quark spin-flavor symmetries. The heavylight meson-meson unitarized scattering amplitudes in coupled channels incorporate thermal corrections by using the imaginary-time formalism, as well as the dressing of the heavy mesons with the self-energies. We report our results for the ground-state thermal spectral functions and the implications for the excited mesonic states generated dynamically in the heavy-light molecular model. We have applied these to the calculation of meson Euclidean correlators and transport coefficients for D mesons and summarize here our findings.

Properties of heavy mesons at finite temperature

We study the properties of heavy mesons using a unitarized approach in a hot pionic medium, based on an effective hadronic theory. The interaction between the heavy mesons and pseudoscalar Goldstone bosons is described by a chiral Lagrangian at next-to-leading order in the chiral expansion and leading order in the heavy-quark mass expansion so as to satisfy heavy-quark spin symmetry. The meson-meson scattering problem in coupled channels with finite-temperature corrections is solved in a self-consistent manner. Our results show that the masses of the ground-state charmed mesons D(0^-)D(0−) and D_s(1^-)Ds(1−) decrease in a pionic environment at T\neq 0T≠0 and they acquire a substantial width. As a consequence, the behaviour of excited mesonic states (D_{s0}^*(2317)^\pmDs0*(2317)± and D_0^*(2300)^{0,\pm}D0*(2300)0,±), generated dynamically in our heavy-light molecular model, is also modified at T\neq 0T≠0. The aim is to test our results against Lattice QCD calculations in the future.

Doubly heavy baryons, heavy quark-diquark symmetry, and nonrelativistic QCD

In the heavy quark limit, properties of heavy mesons and doubly heavy baryons are related by heavy quark-diquark symmetry. This problem is reanalyzed in the framework of Non-Relativistic QCD (NRQCD). We introduce a novel method for deriving Potential NRQCD (pNRQCD) Lagrangians for composite fields from vNRQCD, which contains quarks and antiquarks as explicit degrees of freedom and maintains manifest power counting in the velocity via a label formalism. A Hubbard-Stratonovich transformation is used to eliminate four quark interactions in vNRQCD and then quarks and antiquarks are integrated out to get effective Lagrangians for composite fields. This method is used to rederive Lagrangians for the Q\bar Q and QQ sectors of pNRQCD and give a correct derivation of the O(1/m_Q) prediction for the hyperfine splitting of doubly heavy baryons.

Effective field theory of heavy mesons

In this paper we present a detailed formulation for a recently proposed effective field theory to describe the nonperturbative QCD dynamics of heavy mesons. This effective theory incorporates with heavy quark symmetry (HQS) and the heavy quark effective theory (HQET). Heavy mesons in this theory are constructed as composite particles of a heavy quark bounded with the light degrees of freedom. The heavy meson properties in the heavy quark limit and the $1/m_Q$ corrections can then be explicitly evaluated from this effective theory. All the basic parameters of the HQET, namely, the heavy quark mass $m_Q$, the heavy meson residual mass $\overline{\Lambda}$, and the HQS breaking mass parameters $\lambda_1$ and $\lambda_2$, are consistently determined. $\lambda_1$ is found to be small due to a large cancellation between the heavy quark kinetic energy and the chromo-electric interaction between the heavy quark and light degrees of freedom. We also evaluate the Isgur-Wise function, the decay constant, and the axial-vector coupling constant of heavy mesons.

Semileptonic, radiative, and pionic decays of B,B* and D,D* mesons.

A relativistic constituent quark model (RQM) is used to calculate the form factors for the semileptonic decays B, D\ensuremath{\rightarrow}\ensuremath{\pi}(\ensuremath{\rho})l\ensuremath{\nu}, B\ensuremath{\rightarrow}D(${\mathit{D}}^{\mathrm{*}}$)l\ensuremath{\nu}, D\ensuremath{\rightarrow}K(${\mathit{K}}^{\mathrm{*}}$)l\ensuremath{\nu}, and the coupling constants for the radiative decays ${\mathit{B}}^{\mathrm{*}}$\ensuremath{\rightarrow}B\ensuremath{\gamma}, ${\mathit{D}}^{\mathrm{*}}$\ensuremath{\rightarrow}D\ensuremath{\gamma}. The quark model is combined with a soft pion theorem to derive the ${\mathit{B}}^{\mathrm{*}}$B\ensuremath{\pi} and ${\mathit{D}}^{\mathrm{*}}$D\ensuremath{\pi} coupling constants, which are used to calculate the rate for ${\mathit{D}}^{\mathrm{*}}$\ensuremath{\rightarrow}D\ensuremath{\pi}. The parameters of the model are fixed by exploiting the duality of the vector meson dominance (VMD) picture and the picture of constituent quarks. This approach, which requires only that the predictions of the VMD model and the RQM are consistent, enables a parameter free determination of heavy quark properties, and leads to a ${\mathit{q}}^{2}$ dependence of form factors which is different from the usual pole approximation. The predicted rates for D and ${\mathit{D}}^{\mathrm{*}}$ mesons agree with the data without exception. This positive result supports the conclusion that properties of heavy mesons can be analyzed consistently in this framework. \textcopyright{} 1996 The American Physical Society.

The interaction of fast K-mesons

Two events are described in which heavy mesons interact with nuclei in photographic emulsions, producing small stars and emerging themselves from the collisions. In one example, a relativistic singly charged particle enters the stack and produces a star with only three emergent charged particles, which have been identified as a hyperon, a π-meson and a K-meson respectively. The K-meson creates two stars before it comes to rest and decays with the emission of a slow μ-meson. In the other example, a K-meson enters the stack from outside and, after interacting, comes to rest within the emulsion and decays with the emission of a single lightly ionizing particle. Certain features of interest associated with the scattering properties of heavy mesons are discussed.