11 research outputs found
Does the enhancement observed in contain two -wave higher charmonia?
Solved is a new puzzle raised by the observation of an enhancement structure
Z(3930) in . If categorizing Z(3930) as
suggested by Belle and BaBar, we must explain why
dominantly decaying into is missing in the
invariant mass spectrum. In this work, we propose that the Z(3930)
enhancement structure may contain two -wave higher charmonia
{} and . We show that this assumption is
supported by our analysis of the invariant mass spectrum and
distribution of . This observation
would not only provide valuable information of two P-wave higher charmonia
and , but also serve as the crucial test of our
novel proposal to the observed enhancement structure Z(3930), especially at the
forthcoming BelleII and the approved SuperB.Comment: 5 pages, 2 tables, 3 figures. More contents and discussions adde
Comment on Possibility of Deeply Bound Hadronic Molecules from Single Pion Exchange
We demonstrate that in calculation, where unitarity constraints are properly imposed, the deeply bound hadronic molecules recently proposed by Close and Downum do not exist
Heavy Meson Description with a Screened Potential
We perform a quark model calculation of the and spectra
from a screened funnel potential form suggested by unquenched lattice
calculations. A connection between the lattice screening parameter and an
effective gluon mass directly derived from QCD is established. Spin-spin energy
splittings, leptonic widths and radiative decays are also examined providing a
test for the description of the states.Comment: 17 pages, no figures, to appear in Phys. Rev.
Radiative decays with light scalar mesons and singlet-octet mixing in ChPT
We study different types of radiative decays involving f0(980) and a0(980)
mesons within a unified ChPT-based approach at one-loop level. Light scalar
resonances which are seen in pi pi, pi eta, K K-bar channels of phi(1020)
radiative decays and in J/psi decays are responsible for key questions of
low-energy dynamics in the strong interaction sector, and decays phi(1020) ->
gamma a0(980), phi(1020) -> gamma f0(980), a0(980) -> gamma gamma, f0(980) ->
gamma gamma are of interest for current experimental programs in Juelich,
Frascati and Novosibirsk. From theoretical point of view it is important to
verify whether light scalar mesons are members of some flavor octet or nonet.
We find a value of mixing angle dictated by consistency with experiment and
coupling structures of ChPT Lagrangian. Decay widths f0(980)/a0(980) -> gamma
rho(770)/omega(782), which are not studied experimentally yet, are predicted.
We also obtain several relations between widths, which hold independently of
coupling constants and represent a fingerprint of the model.Comment: 18 pages, 8 figures; misprints in text and tables corrected,
discussion extended, references added; version accepted for publication in
Eur.Phys.J.
Phenomenology of Pc(4380)+, Pc(4450)+ and related states
The and states recently discovered at LHCb have
masses close to several relevant thresholds, which suggests they can be
described in terms of meson-baryon degrees of freedom. This article explores
the phenomenology of these states, and their possible partners, from this point
of view. Competing models can be distinguished by the masses of the neutral
partners which have yet to be observed, and the existence or otherwise of
further partners with different isospin, spin, and parity. Future experimental
studies in different decay channels can also discriminate among models, using
selection rules and algebraic relations among decays. Among the several
possible meson-baryon pairs which could be important, one implies that the
states are mixtures of isospins 1/2 and 3/2, with characteristic signatures in
production and decay. A previous experimental study of a Cabibbo-suppressed
decay showed no evidence for the states, and further analysis is required to
establish the significance of this non-observation. Several intriguing
similarities suggest that is related to the meson.Comment: 16 pages, 1 figure. Journal version (some very minor changes from
arXiv v1
Accuracy of Auxiliary Field Approach for Baryons
We provide a check of the accuracy of the auxiliary field formalism used to
derive the Effective Hamiltonian for baryons in the Field Correlator Method. To
this end we compare the solutions for the Effective Hamiltonian with those
obtained from the solution of the Salpeter equation. Comparing these results
gives a first estimate of the systematic uncertainty due to the use of the
auxiliary field formalism for baryons.Comment: 6 pages, 2 tables; published versio
Measurement of Masses and Widths of Excited Charm Mesons and Evidence for Broad States
Using data from the FOCUS experiment we analyze the and
invariant mass distributions. We measure the mass M_{D_2^{*0}} =
(2464.5 \pm 1.1 \pm 1.9) \mev and width \Gamma_{D_2^{*0}} = (38.7 \pm 5.3 \pm
2.9) \mev, and the mass M_{D_2^{*+}} = (2467.6 \pm 1.5 \pm 0.76)
\mev and width \Gamma_{D_2^{*+}} = (34.1 \pm 6.5 \pm 4.2) \mev. We find
evidence for broad structures over background in both the neutral and charged
final state. If each is interpreted as evidence for a single L=1,
excited charm meson resonance, the masses and widths are M_{1/2}^0 =(2407 \pm
21 \pm 35) \mev, \Gamma_{1/2}^0 = (240 \pm 55 \pm 59) \mev, and M_{1/2}^+ =
(2403 \pm 14 \pm 35) \mev \Gamma_{1/2}^+ = (283 \pm 24 \pm 34) \mev,
respectively.Comment: 15 pages, 4 figures. Submitted to Phys. Lett. B. Added preprint
number
Coulomb gauge approach to (qqg)over-bar hybrid mesons
An effective Coulomb gauge Hamiltonian, H-eff, is used to calculate the light ( u (u) over barg), strange ( s (s) over barg) and charmed (c (c) over barg) hybrid meson spectra. For the same two parameter H-eff providing glueball masses consistent with lattice results and a good description of the observed u, d, s and c quark mesons, a large-scale variational treatment predicts that the lightest hybrid has J(PC) = 0(++) and mass 2.1 GeV. The lightest exotic 1(-+) state is just above 2.2 GeV, near the upper limit of lattice and flux tube predictions. These theoretical formulations all indicate that the observed 1(-+) pi(1)(1600) and, more clearly, pi(1)(1400) are not hybrid states. The Coulomb gauge approach further predicts that in the strange and charmed sectors, respectively, the ground state hybrids have 1(+-) with masses 2.1 and 3.8 GeV, while the. rst exotic 1( +) states are at 2.4 and 4.0 GeV. Finally, using our hybrid wavefunctions and the Franck-Condon principle, a novel experimental signature is presented to assist heavy hybrid meson searches