Chiral shifts in heavy-light mesons

Physical Review D, 2008

The mass shifts of the P -wave D s and B s mesons due to coupling to DK, D * K and BK, B * K channels are studied using the chiral quark-pion Lagrangian without fitting parameters. The strong mass shifts down ∼ 140 MeV and ∼ 100 MeV for D * s (0 + ) and D s (1 + ′ ) and ∼ 100 MeV for B * s (0 + ) and B s (1 + ′ ) are calculated. Two factors are essential for large mass shifts: strong coupling of the 0 + and 1 + ′ states to the S-wave decay channel, containing a Nambu-Goldstone meson, and the chiral flip transitions due to the bispinor structure of both heavy-light mesons. The masses M (B * s (0 + )) = 5695(10) MeV and M (B s (1 + ′ )) = 5730(15) MeV,very close to M (B(0 + ))

In the framework of the coupled channel model the mass shifts of the P -wave excitations of D s and B s mesons have been calculated. The corresponding coupling to DK and BK channels is provided by the effective chiral Lagrangian which is deduced from QCD and does not contain fitting parameters. The strong mass shifts down for 0 + and 1 + ′ states have been obtained, while 1 + ′′ and 2 + states remain almost at rest. Two factors are essential for large mass shifts: strong coupling of the 0 + and 1 + ′ states to the S-wave decay channel, containing a Nambu-Goldstone meson, and the chiral flip transitions due to the bispinor structure of both heavy-light mesons. The masses M (B * s (0 + )) = 5710 MeV and M (B s (1 + ′ )) = 5730(15) MeV are predicted. Experimental limit on the width Γ(D s1 (2536)) < 2.3 MeV puts strong restrictions on admittable mixing angle between the 1 + and 1 +

2002

Recently we have proposed a new level-classification scheme of hadrons with a manifestly covariant framework. In this scheme the requirement of chiral symmetry on the light quark leads to a prediction of existence of new type of scalars XB, XD and axial-vectors XB * , XD * as the chiral partners of ground state pseudoscalar B, D and vector B * , D * mesons, respectively. They belong to "relativistic S-wave states," and are discriminated from the conventional P -wave mesons with jq = 1/2 appearing in the heavy quark effective theory. In this talk we examine the properties of these chiral mesons: The mass-splittings between the respective chiral partners are predicted to be equal, and the decay widths of one pion emission of XB, XD, XB * and XD * are to take the same value due to both chiral and heavy quark symmetries. Some experimental indications for existence of XB and XD * are also given, which are consistent with the above prediction. * ) Here the normalization of states |B(0) ≡ a † B(0) |0 , etc. are used, where [a B(p) , a † B(p ′ ) ] = δ (3) (p − p ′ ).

Physical Review D, 1992

Progress of Theoretical Physics, 2007

We succeed in reproducing the = 1 B mesons B 1 (5720), B * 2 (5745), and B * s2 (5839) that were recently reported by D0 and CDF, using our semi-relativistic quark potential model, which also succeeds in predicting the mass spectra of the narrow D sJ , as well as broad D * 0 (0 + ) and D 1 (1 + ) particles observed a couple of years ago. The mass of higher excited states ( = 1, 2) of B and B s mesons, which have not yet been observed, is also predicted to first order in p/m b with the internal quark momentum p and the b quark mass m b . We find that the corresponding B sJ are below the BK/B * K threshold and should have narrow decay widths, contrary to most other predictions. Also, already established states ( = 0 and = 1) of D, D s , B, and B s heavy mesons are simultaneously reproduced in good agreement with experimental data, within one percent accuracy. To calculate these D/D s and B/B s heavy mesons, we use different values of the strong coupling, α c s and α b s , respectively. * )

Proceedings of XV International Conference on Hadron Spectroscopy — PoS(Hadron 2013), 2014

Il Nuovo Cimento A, 1967

We consider here a model for strong interactions which involve P-wave pseudoscalar mesons. IIadrons are regarded as being composed of quarks according to the usual assignment~ of the fractionally-charged quark model (1), and the basic interaction co~sidered is a quark-quark-meson coup]ing whose static limit has the form

Physics Letters B, 1994

We compute the strong coupling constant g P * P π , with P and P * respectively pseudoscalar and vector heavy mesons by using the QCD sum rules approach. Our computation is based on the evaluation of the time ordered product of currents between the vacuum and the soft pion state. The so-called parasitic terms are taken into account and give a contribution to the sum rule of the same order of the lowest lying state, while higher dimension non perturbative terms have small numerical effects. The infinite heavy quark mass limit is also examined.

Journal of Mathematical Sciences, 2000

We compare two QCD-inspired quark models with four-fermion interaction, without and with the remnant coupling to low-energy gluons, in the regime of dynamical chiral symmetry breaking (DCSB). The first one, the Nambu-Jona-Lasinio (NJL) model ensures the factorization of scalar and pseudoscalar meson poles in correlators, the well-known Nambu relation between the scalar meson mass and the dynamical quark mass, m σ = 2m dyn , and the residual chiral symmetry in coupling constants characteristic for the linear σ-model. The second one, the Gauged NJL model, happens to be qualitatively different from the NJL model, namely, the Nambu relation is not valid and the factorization of light meson poles does not entail the residual chiral symmetry, i.e. it does not result in a linear σ-model. The more complicated DCSB pattern in the GNJL model is fully explained in terms of excited meson states with the same quantum numbers. The asymptotic restrictions on parameters of scalar and pseudoscalar meson states are derived from the requirement of chiral symmetry restoration at high energies.

Journal of Physics G: Nuclear and Particle Physics, 2012

We reanalyze the decay constants of s-wave and p-wave mesons and D, B → M form factors, where M represents a pseudoscalar meson, a vector meson, a scalar meson, or an axial vector meson within a covariant light-front quark model. The parameter β for wave-functions of most of s-wave mesons and of a few axial-vector mesons are fixed with latest experimental information, wherever available or using the lattice calculations. The treatment of masses and mixing angles for strange axial vector mesons is improved for the purpose. We extend our analysis to determine the form factors appearing in the transition of D s , B s → M transitions, and to the isoscalar final state mesons. Numerical results of the form factors for transitions between a heavy pseudoscalar meson and an s-wave or p-wave light meson and their momentum dependence are presented in detail. Further, their sensitivity to uncertainties of β parameters of the initial as well as the final mesons is investigated. Some experimental measurements of the charmed and bottom meson decays are employed to compare the decay constants and transition form factors obtained in this and other works. ′(′′) 1 + p 2 , where p ′(′′) 1 and p 2 are the momenta of the off-shell