116131889
Chiral Model Predictions for Strange Form Factors
15479695
Excited states of heavy baryons in the Skyrme model.
We obtain the spectra of excited heavy baryons containing one heavy quark by quantizing the exactly solved heavy meson bound states to the Skyrme soliton. The results are comparable to the recent experimental observations and quark model predictions, and are consistent with heavy quark spin symmetry. However, the somewhat large dependence of the results on the heavy quark mass strongly calls for the incorporation of the soliton-recoil effects. {copyright} {ital 1996 The American Physical Society.}
119359306
Neutral pion decay in dense Skyrmion matter
We study the density dependence of the decay {pi}{sup 0}{yields}{gamma}{gamma} using the Skyrme Lagrangian to describe simultaneously both the matter background and mesonic fluctuations. The classical ground state configuration has different chiral properties depending on the Skyrmion density, which is reflected in the physical properties of pion fluctuating on top of the classical background. This leads to large suppression at high density of both photo-production from the neutral pion and the reverse process. The effective charges of {pi}{sup {+-}} are also discussed in the same framework.
120803195
Skyrmion and Dense Matter
Skyrme model can provide valuable insights (though qualitative) on high density physics of mesons and baryons in a unified way. First, the dense hadronic matter can be described by the soliton configuration of given meson Lagrangian, which undergoes an interesting chiral phase transition as the baryon density increases. Then, by incorporating the meson fluctuations on top of such ground state we can investigate the in-medium properties of mesons.
119245089
Dense baryonic matter in the hidden local symmetry approach: Half-skyrmions and nucleon mass
Hadron properties in dense medium are treated in a unified way in a skyrmion model constructed with an effective Lagrangian, in which the rho and omega vector mesons are introduced as hidden gauge bosons, valid up to O(p^4) terms in chiral expansion including the homogeneous Wess-Zumino terms. All the low energy constants - apart from f_pi and m_rho - are fixed by the master formula derived from the relation between 5-D hQCD and 4-D HLS. This allows one to pin down the density n_1/2 at which the skyrmions in medium fractionize into half-skyrmions, bringing in a drastic change in the EoS of dense matter. We find that the U(1) field that figures in the CS term in the hQCD action or equivalently the omega field in the hWZ term in the dimensionally reduced HLS action plays a crucial role in the half-skyrmion phase. The importance of the omega degree of freedom may be connected to what happens in the instanton structure of elementary baryon noticed in hQCD. The most striking and intriguing in what is found in the model is that f_pi that smoothly drops with increasing density in the skyrmion phase stops decreasing at n_1/2 and remains nearly constant in the half-skyrmion phase. In accordance with the large N_c consideration, the baryon mass also stays non-scaling in the half-skyrmion phase. This feature which is reminiscent of the parity-doublet baryon model with a chirally invariant mass m_0 is supported by the nuclear EFT with the parameters of the Lagrangian scaling modified at the skyrmion-half-skyrmion phase transition. It also matches with one-loop RG analysis based on HLS. A link between a non-vanishing m_0 and the origin of nucleon mass distinctive from dynamically generated mass is suggested. We briefly discuss the possible consequences of the topology change found in this paper on the forthcoming experiments at the RIB machines under construction.
120786968
Casimir energy of the Skyrmion due to kaon vacuum fluctuations
181523075
Measurements of pion nucleon charge exchange near the Delta resonance using the NMS at LAMPF