Many-body soliton dynamics: Modification of nucleon properties in nuclei

Abstract

We propose a model of nuclear structure in which the degrees of freedom are quarks and mesonic fields. The quarks are organized into nucleons which interact via the exchange of mesons (o. ,m, p,~) .The model is so structured as to reproduce the results of recently developed relativistic models of nuclear structure in which the degrees of freedom are nucleons and mesons. The model used to describe nucleon structure is taken from a previous work in which a fully covariant (soliton) model of the nucleon was developed. The model also allows one to consider the dynamics of solitons in the presence of the fields generated by other solitons. This feature enables us to investigate the modification of nucleon properties when the nucleon is inside a nucleus. Our central result is the prediction that nucleons will be bigger in the nucleus than in free space. Evidence for this modification of nucleon properties is discussed. We consider deep ine1astic electron scattering from nuclei: We discuss the European-Muon-Collaboration effect and some recent (e, e') experiments and relate the experimental results to our prediction of modified nucleon radii and form factors.

Modified quark-meson coupling model for nuclear matter

“…The quark RMS radius also increases with density, with essentially the same rate as for the bag radius. This implies a "swollen" nucleon in nuclear medium, which has many attendant consequences [17][18][19][20][21][22][23]. It is also interesting to note that the result of 25 − 30% increase in the nucleon size is comparable to those suggested in Refs.…”

“…It is also interesting to note that the result of 25 − 30% increase in the nucleon size is comparable to those suggested in Refs. [17][18][19] (see, however, Ref. [20]).…”

“…We see that when the bag constant drops the quark wave functions are pushed outward. This depicts a "swollen" nucleon picture, which has important implications in many nuclear physics issues [17][18][19][20][21][22][23].…”

Medium modifications of baryon properties in nuclear matter and hypernuclei

“…In past decades, the FL model has been extensively used to study the properties of hadrons in free space [26][27][28][29][30][31][32][33][34]. It has also been applied to study the medium modifications of the nucleon [4,35] and dense-matter properties [6,36]. In our previous work [37], we studied the properties of nuclear matter and finite nuclei by describing the nuclear many-body system as a collection of nontopological solitons within the FL model.…”

“…Recent experiments at Jefferson Laboratory have provided precise measurements of the EMC effect in light nuclei [2,3]. On the other hand, there are many theoretical works on the study of in-medium hadron properties based on various models [4][5][6][7]. The quark-meson coupling (QMC) model proposed by Guichon [8] opens the possibility of understanding the change of the nucleon internal structure in nuclei based on quark degrees of freedom.…”