228,076 research outputs found
N K Pi molecular state with I=1 and J(Pi)=3/2-
The structure of the molecule-like state of with spin-parity
and isospin I=1 is studied within the chiral SU(3) quark
model. First we calculate the , , and phase shifts in the
framework of the resonating group method (RGM), and a qualitative agreement
with the experimental data is obtained. Then we perform a rough estimation for
the energy of , and the effect of the mixing to
the configuration is also considered. The
calculated energy is very close to the threshold of the system. A
detailed investigation is worth doing in the further study.Comment: 11 pages, 3 figures; accepted for publication in Phys. Rev.
Resonating group method study of kaon-nucleon elastic scattering in the chiral SU(3) quark model
The chiral SU(3) quark model is extended to include an antiquark in order to
study the kaon-nucleon system. The model input parameters , ,
are taken to be the same as in our previous work which focused on the
nucleon-nucleon and nucleon-hyperon interactions. The mass of the scalar meson
is chosen to be 675 MeV and the mixing of and is
considered. Using this model the kaon-nucleon and partial waves phase
shifts of isospin I=0 and I=1 have been studied by solving a resonating group
method (RGM) equation. The numerical results of , , ,
, and partial waves are in good agreement with the
experimental data while the phase shifts of partial wave are a little
bit too repulsive when the laboratory momentum of the kaon meson is greater
than 500 MeV in this present calculation.Comment: 17 pages, 6 figures. Final version for publicatio
Baryon-meson interactions in chiral quark model
Using the resonating group method (RGM), we dynamically study the
baryon-meson interactions in chiral quark model. Some interesting results are
obtained: (1) The Sigma K state has an attractive interaction, which
consequently results in a Sigma K quasibound state. When the channel coupling
of Sigma K and Lambda K is considered, a sharp resonance appears between the
thresholds of these two channels. (2) The interaction of Delta K state with
isospin I=1 is attractive, which can make for a Delta K quasibound state. (3)
When the coupling to the Lambda K* channel is considered, the N phi is found to
be a quasibound state in the extended chiral SU(3) quark model with several MeV
binding energy. (4) The calculated S-, P-, D-, and F-wave KN phase shifts
achieve a considerable improvement in not only the signs but also the
magnitudes in comparison with other's previous quark model study.Comment: 5 pages, 2 figures. Talk given at 3rd Asia Pacific Conference on
Few-Body Problems in Physics (APFB05), Korat, Nakhon Ratchasima, Thailand,
26-30 Jul 200
S, P, D, F wave KN phase shifts in the chiral SU(3) quark model
The , , , wave phase shifts have been studied in the chiral
SU(3) quark model by solving a resonating group method equation. The numerical
results of different partial waves are in agreement with the experimental data
except for the cases of and , which are less well described
when the laboratory momentum of the kaon meson is greater than 400 MeV.Comment: Prepared for 10th International Symposium on Meson-Nucleon Physics
and the Structure of the Nucleon (MENU 2004), Beijing, China, 29 Aug - 4 Sep
200
Possible Weyl fermions in the magnetic Kondo system CeSb
Materials where the electronic bands have unusual topologies allow for the
realization of novel physics and have a wide range of potential applications.
When two electronic bands with linear dispersions intersect at a point, the
excitations could be described as Weyl fermions which are massless particles
with a particular chirality. Here we report evidence for the presence of Weyl
fermions in the ferromagnetic state of the low-carrier density, strongly
correlated Kondo lattice system CeSb, from electronic structure calculations
and angle-dependent magnetoresistance measurements. When the applied magnetic
field is parallel to the electric current, a pronounced negative
magnetoresistance is observed within the ferromagnetic state, which is
destroyed upon slightly rotating the field away. These results give evidence
for CeSb belonging to a new class of Kondo lattice materials with Weyl fermions
in the ferromagnetic state.Comment: 18 pages, 4 figures, Supplementary Information available from journal
link (open access
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