100,820 research outputs found
Holographic heavy-light mesons from non-Abelian DBI
In the context of gauge/gravity duals with flavor, we examine heavy-light
mesons which involve a heavy and a light quark. For this purpose we embed two
D7 brane probes at different positions into the gravity background. We
establish the non-Abelian Dirac-Born-Infeld (DBI) action for these probes, in
which the U(2) matrix describing the embedding is diagonal. The fluctuations of
the brane probes correspond to the mesons. In particular, the off-diagonal
elements of the U(2) fluctuation matrix correspond to the heavy-light mesons,
while the diagonal elements correspond to the light-light and heavy-heavy
mesons, respectively. The heavy-light mesons scale differently with the 't
Hooft coupling than the mesons involving quarks of equal mass. The model
describes both scalar and vector mesons. For different dilaton-deformed gravity
backgrounds, we also calculate the Wilson loop energy, and compare with the
meson masses.Comment: 21 pages, 7 figure
Scalar mesons in the Nambu--Jona-Lasinio model with 't Hooft interaction
We calculate the mass spectra of the pseudoscalar and scalar meson nonets in
the Nambu--Jona-Lasinio model with the 't Hooft interaction. We obtain
satisfactory result for the pseudoscalar mesons. For the scalar mesons, the 't
Hooft interaction somewhat increases the values of the masses. However, it is
not sufficient to explain the whole scalar mass spectrum. The situation could
be improved for the and mesons through mixing with the glueball
state. For the description of the masses of and \kstar mesons, it is
necessary to involve the other models. The strong decay widths of the scalar
mesons are described.Comment: LaTeX text, 8 page
Tetramixing of vector and pseudoscalar mesons: A source of intrinsic quarks
The tetramixing of pseudoscalar mesons --- and
vector mesons --- are studied in the light-cone
constituent quark model, and such mixing of four mesons provides a natural
source for the intrinsic charm components of light mesons. By mixing
with the light mesons, the charmonium states and could decay
into light mesons more naturally, without introducing gluons or a virtual
photon as intermediate states. Thus, the introduction of light quark components
into is helpful to reproduce the new experimental data of
decays. The mixing matrices and the behaviors of the transition form
factors are also calculated and compared with experimental data.Comment: 20 pages, 10 figures. Version for publication in PR
Heavy Scalar, Vector and Axial-Vector Mesons in Hot and Dense Nuclear Medium
In this work we shall investigate the mass modifications of scalar mesons
,vector mesons
and axial-vector mesons at finite density and
temperature of the nuclear medium. The above mesons are modified in the nuclear
medium through themodification of quark and gluon condensates. We shall find
the medium modification of quark and gluon condensates within chiral SU(3)
model through the medium modification of scalar-isoscalar fields and
at finite density and temperature. These medium modified quark and
gluon condensates will further be used through QCD sum rules for the evaluation
of in-medium properties of above mentioned scalar, vector and axial vector
mesons. We shall also discuss the effects of density and temperature of the
nuclear medium on the scattering lengths of above scalar, vector and
axial-vector mesons. The study of the medium modifications of above mesons may
be helpful for understanding their production rates in heavy-ion collision
experiments. The results of present investigations of medium modifications of
scalar, vector and axial-vector mesons at finite density and temperature can be
verified in the Compressed Baryonic Matter (CBM) experiment of FAIR facility at
GSI, Germany.Comment: 35 pages, 11 figure
A relativistic chiral quark model for pseudoscalar emission from heavy mesons
The amplitudes for one-pion mediated transitions between heavy meson excited
states are obtained in the framework of the relativistic chiral quark model.
The effective coupling constants to pions and the decay widths of excited heavy
mesons with l<=2 for non-radially excited, and the l=0 radially excited mesons
are presented for both charmed and beauty mesons. We also discuss the allowed
decays of strange excited heavy mesons by emission of a K-meson.Comment: 20 pages, revte
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