212 research outputs found
Determining Compositeness of Hadronic Resonances: the Radiative Decay and the - Mixing
Recently the concept of compositeness has been developed so as to distinguish
whether interested hadrons are hadronic molecules or not. Here, in terms of
compositeness, we investigate molecular structure of the resonance with the radiative decay and
molecular structure of the and resonances with the
- mixing.Comment: 6 pages, 4 figures, Presentation given at the 2nd International
Symposium on Science at J-PARC (J-PARC 2014), Tsukuba, Japan, July 12-15,
201
Electric Mean Squared Radii of Lambda(1405) in Chiral Dynamics
The electric mean squared radii _E of Lambda(1405) are calculated in the
chiral unitary model. We describe the Lambda(1405) as a dynamically generated
resonance fully in the octet meson and octet baryon scattering. We also
consider ``Lambda(1405)'' as a bound state of KbarN. For the later
``Lambda(1405),'' we obtain negative and larger absolute value of electric mean
squared radius than that of ordinary baryons, which implies that Lambda(1405)
have structure of widely spread K^- around p.Comment: 4 pages, 1 figure, use ws-mpla.cls. Talk given at Workshop on Chiral
Symmetry in Hadron and Nuclear Physics: Chiral07, Osaka, Japan, 13-16 Nov
200
Studies of exotic hadrons by high-energy exclusive reactions
We investigate the possibility of clarifying internal structure of exotic
hadrons by high-energy exclusive reactions. In particular, the
constituent-counting rule could be used for determining the internal
configuration in large-angle exclusive scattering. As an example, we show the
cross section pi^- + p -> K^0 + Lambda(1405) in comparison with the one for the
ground-state Lambda production pi^- + p -> K^0 + Lambda. The counting rule
indicates that the cross section scales as s^8 dsigma /dt=constant if
Lambda(1405) is an ordinary three-quark baryon, whereas it is s^{10} dsigma
/dt=constant if Lambda(1405) is a five-quark baryon. Here, s and t are
Mandelstam variables. Such experiments could be possible at J-PARC, LEP, JLab,
CERN-COMPASS, and other high-energy facilities.Comment: 4 pages, 7 figures, 12th Asia Pacific Physics Conference (APPC12),
JPS Conference Proceedings in pres
Internal structure of exotic hadrons by high-energy exclusive reactions
We propose to use high-energy exclusive reactions for probing internal
structure of exotic hadron candidates. First, the constituent counting rule of
perturbative QCD can be used for finding internal configurations of an exotic
hadron candidate. It is because the number of constituents (), which
participate in the exclusive reaction, is found by the scaling behavior of the
cross section at large momentum transfer, where
is the center-of-mass energy squared. As an example, we show that the
internal structure of should be found, for example, by the
reaction . Second, the internal structure
of exotic hadron candidates should be investigated by hadron tomography with
generalized parton distributions (GPDs) and generalized distribution amplitudes
(GDAs) in exclusive reactions. Exotic nature should be reflected in the GPDs
which contain two factors, longitudinal parton distributions as indicated by
the constituent counting rule and transverse form factors as suggested by the
hadron size. The GDAs should be investigated by the two-photon process
, for example or , in
electron-positron annihilation. Since the GDAs contain information on a
time-like form factor, exotic nature should be found by studying the
invariant mass dependence of the cross section. The internal structure of
exotic hadron candidates should be clarified by the exclusive reactions at
facilities such as J-PARC and KEKB.Comment: 6 pages, LaTeX, 9 eps files, JPS Conference Proceedings of the 2nd
International Symposium on Science at J-PARC (J-PARC 2014), Tsukuba, Japan,
July 12-15, 201
Exotic-Hadron Signature by Constituent-Counting Rule in Perturbative QCD
We explain a method to find internal quark configurations of exotic hadron
candidates by using the constituent counting rule. The counting rule was
theoretically predicted in perturbative QCD for hard exclusive hadron
reactions, and it has been tested in experiments for stable hadrons including
compound systems of hadrons such as the deuteron, H, and He. It
indicates that the cross section scales as , where
is the center-of-mass energy squared and is the total number of
constituents. We apply this method for finding internal configurations of
exotic hadron candidates, especially . There is a possibility
that could be five-quark state or a molecule, and
scaling properties should be different between the ordinary three-quark state
or five-quark one. We predict such a difference in , and it could be experimentally tested, for example, at J-PARC. On the
other hand, there are already measurements for as well as the ground in photoproduction reactions. Analyzing
such data, we found an interesting indication that looks like
a five-quark state at medium energies and a three-quark one at high energies.
However, accurate higher-energy measurements are necessary for drawing a solid
conclusion, and it should be done at JLab by using the updated 12 GeV electron
beam. Furthermore, we discuss studies of exotic hadron candidates, such as and , in electron-positron annihilation by using generalized
distribution amplitudes and the counting rule. These studies should be possible
as a KEKB experiment.Comment: 6 pages, LaTeX, 10 eps files, to be published in JPS Conf. Proc.,
Proceedings of the 14th International Conference on Meson-Nucleon Physics and
the Structure of the Nucleon (MENU2016), July 25-30, 2016, Kyoto, Japa
Lambda(1405) N to Y N transition in nuclear medium for non-mesonic absorption of Kbar in nucleus
Non-mesonic transition of Lambda(1405) N to YN is investigated as one of the
essential processes for the non-mesonic absorption of Kbar in nuclei. Using
one-meson exchange model in the calculation of the transition, we find that the
non-mesonic transition ratio Gamma_{Lambda N} / Gamma_{Sigma N} depends
strongly on the ratio of the Lambda(1405) (Lambda^*) couplings to Kbar N and pi
Sigma. Especially a larger Lambda^*-Kbar N coupling leads to enhancement of the
transition to Lambda N. Using the chiral unitary model for the description of
the Lambda^*, we obtain Gamma_{Lambda N} / Gamma_{Sigma^{0} N} is approximately
1.2 which is almost independent of the nucleon density, and find the total
non-mesonic decay width of the Lambda^* in uniform nuclear matter to be 22 MeV
at the normal density.Comment: Talk given at 10th International Conference on Hypernuclear and
Strange Particle Physics: Hyp-X, Tokai, Japan, 14-18 Sep 200
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