95 research outputs found
Possible Molecular States of System and Y(4140)
The interpretation of Y(4140) as a molecule is studied
dynamically in the one boson exchange approach, where , and
exchange are included. Ten allowed states with
low spin parity are considered, we find that the , ,
, and configurations are most
tightly bound. We suggest the most favorable quantum numbers are
for Y(4140) as a molecule, however,
and can not be excluded. We propose to search for the
and partners in the and final
states, which is an important test of the molecular hypothesis of Y(4140) and
the reasonability of our model. The molecule is
deeply bound, experimental search in the channel at Tevatron
and LHC is suggested.Comment: 13 pages,2 figure
and
Recently Babar Collaboration reported a new state
and Belle Collaboration observed . We investigate the strong
decays of the excited states using the model. After
comparing the theoretical decay widths and decay patterns with the available
experimental data, we tend to conclude: (1) is probably the
state although the
assignment is not completely excluded; (2) seems unlikely to be
the and candidate; (3)
as either a or state is
consistent with the experimental data; (4) experimental search of
in the channels , , and
will be crucial to distinguish the above two possibilities.Comment: 18 pages, 7 figures, 2 tables. Some discussions added. The final
version to appear at EPJ
The newly observed open-charm states in quark model
Comparing the measured properties of the newly observed open-charm states
D(2550), D(2600), D(2750), D(2760), D_{s1}(2710), D_{sJ}(2860), and
D_{sJ}(3040) with our predicted spectroscopy and strong decays in a constituent
quark model, we find that: (1) the D(2\,^1S_0) assignment to D(2550) remains
open for its too broad width determined by experiment; (2) the D(2600) and
can be identified as the 2\,^3S_1-1\,^3D_1 mixtures; (3) if
the D(2760) and D(2750) are indeed the same resonance, they would be the
D(1\,^3D_3); otherwise, they could be assigned as the D(1\,^3D_3) and
, respectively; (4) the could be either the
's partner or the D_s(1\,^3D_3); and (5) both the
and interpretations for the seem likely. The
and radiative decays of these sates are also studied. Further
experimental efforts are needed to test the present quarkonium assignments for
these new open-charm states.Comment: 26 pages,7 figures, journal versio
Special relativity constraints on the effective constituent theory of hybrids
We consider a simplified constituent model for relativistic
strong-interaction decays of hybrid mesons. The model is constructed using
rules of renormalization group procedure for effective particles in light-front
quantum field theory, which enables us to introduce low-energy phenomenological
parameters. Boost covariance is kinematical and special relativity constraints
are reduced to the requirements of rotational symmetry. For a hybrid meson
decaying into two mesons through dissociation of a constituent gluon into a
quark-anti-quark pair, the simplified constituent model leads to a rotationally
symmetric decay amplitude if the hybrid meson state is made of a constituent
gluon and a quark-anti-quark pair of size several times smaller than the
distance between the gluon and the pair, as if the pair originated from one
gluon in a gluonium state in the same effective theory.Comment: 11 pages, 5 figure
Interplay of quark and meson degrees of freedom in a near-threshold resonance
We investigate the interplay of quark and meson degrees of freedom in a
physical state representing a near-threshold resonance for the case of a single
continuum channel. We demonstrate that such a near-threshold resonance may
possess quite peculiar properties if both quark and meson dynamics generate
weakly coupled near-threshold poles in the S-matrix. In particular, the
scattering t-matrix may possess zeros in this case. We also discuss possible
implications for production reactions as well as studies within lattice QCD.Comment: LaTeX2e, 11 pages, minor typo corrections, to appear in Eur.Phys.J.
Charmonium states in QCD-inspired quark potential model using Gaussian expansion method
We investigate the mass spectrum and electromagnetic processes of charmonium
system with the nonperturbative treatment for the spin-dependent potentials,
comparing the pure scalar and scalar-vector mixing linear confining potentials.
It is revealed that the scalar-vector mixing confinement would be important for
reproducing the mass spectrum and decay widths, and therein the vector
component is predicted to be around 22%. With the state wave functions obtained
via the full-potential Hamiltonian, the long-standing discrepancy in M1
radiative transitions of and are alleviated
spontaneously. This work also intends to provide an inspection and suggestion
for the possible among the copious higher charmonium-like states.
Particularly, the newly observed X(4160) and X(4350) are found in the
charmonium family mass spectrum as MeV and MeV, which strongly favor the assignments
respectively. The corresponding radiative transitions, leptonic and two-photon
decay widths have been also predicted theoretically for the further
experimental search.Comment: 16 pages,3 figure
Semileptonic B decays into even parity charmed mesons
By using a constituent quark model we compute the form factors relevant to
semileptonic transitions of B mesons into low-lying p-wave charmed mesons. We
evaluate the q^2 dependence of these form factors and compare them with other
model calculations. The Isgur-Wise functions tau(1/2) and tau(3/2) are also
obtained in the heavy quark limit of our results.Comment: 11 pages, 2 figure
Dissociation cross sections of ground-state and excited charmonia with light mesons in the quark model
We present numerical results for the dissociation cross sections of
ground-state, orbitally- and radially-excited charmonia in collisions with
light mesons. Our results are derived using the nonrelativistic quark model, so
all parameters are determined by fits to the experimental meson spectrum.
Examples of dissociation into both exclusive and inclusive final states are
considered. The dissociation cross sections of several C=(+) charmonia may be
of considerable importance for the study of heavy ion collisions, since these
states are expected to be produced more copiously than the J/psi. The relative
importance of the productions of ground-state and orbitally-excited charmed
mesons in a pion-charmonium collision is demonstrated through the -dependent charmonium dissociation cross sections.Comment: 9 pages, 8 figure
The open-charm radiative and pionic decays of molecular charmonium Y(4274)
In this work, we investigate the decay widths and the line shapes of the
open-charm radiative and pionic decays of Y(4274) with the
molecular charmonium assignment. Our calculation
indicates that the decay widths of and
can reach up to 0.05 keV and 0.75 keV,
respectively. In addition, the result of the line shape of the photon spectrum
of shows that there exists a very sharp
peak near the large end point of photon energy. The line shape of the pion
spectrum of is similar to that of the pion
spectrum of , where we also find a very
sharp peak near the large end point of pion energy. According to our
calculation, we suggest further experiments to carry out the search for the
open-charm radiative and pionic decays of Y(4274).Comment: 7 pages, 6 figures, 1 table. Published versio
Light meson mass dependence of the positive parity heavy-strange mesons
We calculate the masses of the resonances D_{s0}^*(2317) and D_{s1}(2460) as
well as their bottom partners as bound states of a kaon and a D^*- and
B^*-meson, respectively, in unitarized chiral perturbation theory at
next-to-leading order. After fixing the parameters in the D_{s0}^*(2317)
channel, the calculated mass for the D_{s1}(2460) is found in excellent
agreement with experiment. The masses for the analogous states with a bottom
quark are predicted to be M_{B^*_{s0}}=(5696\pm 40) MeV and M_{B_{s1}}=(5742\pm
40) MeV in reasonable agreement with previous analyses. In particular, we
predict M_{B_{s1}}-M_{B_{s0}^*}=46\pm 1 MeV. We also explore the dependence of
the states on the pion and kaon masses. We argue that the kaon mass dependence
of a kaonic bound state should be almost linear with slope about unity. Such a
dependence is specific to the assumed molecular nature of the states. We
suggest to extract the kaon mass dependence of these states from lattice QCD
calculations.Comment: 10 page
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