112 research outputs found
Property of cn - nbar cbar System in U(12)-Scheme and X(3872),Y(3940)
The properties of four quark cn - nbar cbar states are investigated as cn
di-quark and nbar cbar di-antiquark system in U(12)-classification scheme of
hadrons. We consider the negative-parity di-quark and di-antiquark in ground
states, and the properties of X(3872) and Y(3940) are consistent, respectively,
with those of the JPC=1++ and 2++ states from these negative-parity di-quark
and di-antiquark. Their narrow-widths are explained from an orthogonality of
spinor wave functions. The properties of ground-state cs - sbar cbar system are
also predicted in this scheme.Comment: 8pages, proceedings of HADRON'05, CBPF, Rio de Janeiro, August 200
Property of Chiral Scalar and Axial-Vector Mesons in Heavy-Light Quark Systems
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 X_B, X_D and axial-vectors X_B^*,X_D^* 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 j_q=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 X_B, X_D, X_B^* and X_D^* are to take the same
value due to both chiral and heavy quark symmetries. Some experimental
indications for existence of X_B and X_D^* are also given, which are consistent
with the above prediction.Comment: proc. of "Hadron '01," Protvino, Russia, Aug, 2001. 5 pages, uses
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Covariant Classification Scheme of Hadrons
Starting from the multi-local Klein-Gordon equations with Lorentz-scalar
squared-mass operator we give a covariant quark representation of the general
composite mesons and baryons with definite Lorentz transformation property. The
mass spectra satisfy the approximate symmetry under the tilde U(4)
transformation group, including the chiral transformation as a subgroup,
concerning the spinor freedom of light constituent quarks, and this symmetry
predicts the existence of new type of chiral mesons and baryons out of the
conventional framework in non-relativistic quark model: For example, for light
qqbar systems, the scalar sigma- and axial-vector a_1-nonets, and for
heavy-light Qqbar and qQbar systems the scalar and axial-vector mesons are
predicted to exist as relativistic S-wave states besides the ordinary P-wave
state mesons. The existence of two ``exotic'' 1^-+ meson nonets is predicted as
the relativistic P-wave states in qqbar systems. For light quark baryons the
extra 56 with positive parity and the extra 70 with negative parity of the
static SU(6) are predicted to exist as the ground state chiral particles.Comment: proc. of "Hadron '01," Protvino, Russia, Aug, 2001. 10 pages, uses
ptptex.st
Scalar Mesons and Chiral States
The essential points and physical backgrounds of the covariant
level-classification scheme, based on U(12)SF * O(3,1)L, are reviewed: This
scheme is extended from the non-relativistic SU(6)SF * O(3)L scheme by
introducing the new SU(2)-spin (rho-spin) degree of freedom, which is necessary
for covariant description of composite hadrons. Our scheme predicts the
existence of new type of chiral mesons and baryons (Chiralons) out of the
conventional SU(6)SF * O(3)L scheme. The sigma nonet is a typical example of
chiralons to be assigned to the q qbar relativistic S-wave state. The new
narrow mesons Ds(2317)/Ds(2463) are naturally assigned as the ground-state
scalar and axial-vector chiralons in the c sbar system.Comment: 5 pages, proc of Hadron 200
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