1,004 research outputs found
Spectral function of the meson in nuclear medium based on phenomenological models
The in-medium modification of the spectral function of the meson with
and without the spatial momentum is studied with the approximation by
employing two phenomenological models for the scattering; one is
called \com{coupled channels model} and the other the -dominance
model. In the former model, the scattering amplitude is calculated in
the unitarized coupled-channel approach involving the channel, while
in the latter model the scattering process is dominated by the
resonance with the spin and parity . In the \com{coupled
channels model}, one single peak of the in-medium mode appears in the
spectral function and the peak position shifts to higher energies along with
the increase of the nuclear density reflecting the repulsive
scattering length of the unitarized coupled-channel amplitude. On the other
hand, two branches related to the and -hole modes appear in
the -dominance model. In both models, the shift of the peak position
and the width in the spectral function are a few tens of MeV at the normal
nuclear density for the meson at rest in the nuclear medium. Once the
spatial momentum is turned on, the peak positions in the spectral function
approach the energies without the nuclear medium effect. Particularly, in the
-dominance model, the peak strength of the -hole mode gets
smaller with the finite momentum and the spectral function comes to have one
single peak.Comment: 16 pages, 14 figure
meson under partial restoration of chiral symmetry in nuclear medium
In-medium modification of the eta' mass is discussed in the context of
partial restoration of chiral symmetry in nuclear medium. We emphasize that the
U_A(1) anomaly effects causes the eta'-eta mass difference necessarily through
the chiral symmetry breaking. As a consequence, the eta' mass is expected to be
reduced by order of 100 MeV in nuclear matter where about 30% reduction of
chiral symmetry takes place. The strong attraction relating to the eta' mass
generation eventually implies that there should be also a strong attractive
interaction in the scalar channel of the eta'-N two-body system. We find that
the attraction can be strong enough to form a bound state.Comment: 4 pages, 3 figures. Talk given at the XI International Conference on
Hypernuclear and Strange Particle Physics (HYP2012), Oct. 1-5, 2012,
Barcelona, Spain. Accepted version. Some typos were correcte
Application of tensor network method to two dimensional lattice Wess-Zumino model
We study a tensor network formulation of the two dimensional lattice
Wess-Zumino model with Wilson derivatives for both fermions and
bosons. The tensor renormalization group allows us to compute the partition
function without the sign problem, and basic ideas to obtain a tensor network
for both fermion and scalar boson systems were already given in previous works.
In addition to improving the methods, we have constructed a tensor network
representation of the model including the Yukawa-type interaction of Majorana
fermions and real scalar bosons. We present some numerical results.Comment: 8 pages, 4 figures, talk presented at the 35th International
Symposium on Lattice Field Theory (Lattice 2017), 18-24 June 2017, Granada,
Spai
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