Hadrons and Few-Body Physics
- PDF / 336,028 Bytes
- 10 Pages / 595.276 x 790.866 pts Page_size
- 19 Downloads / 160 Views
Jean-Marc Richard
Hadrons and Few-Body Physics
Received: 17 September 2020 / Accepted: 16 October 2020 © Springer-Verlag GmbH Austria, part of Springer Nature 2020
Abstract We present a selection of topics with an interplay of hadron and few-body physics. This includes few-nucleon systems, light hypernuclei and quark dynamics for baryons and multiquarks. It is stressed that standard quark models predict very few stable multiquarks. 1 Introduction There are several instances where few-body physics interplays with hadron dynamics. Obviously the properties of light nuclei and the scattering of proton or deuteron on light nuclei constitute the first examples. Its natural extension towards light hypernuclei is also particularly interesting as some systems are at the edge of stability. With the advent of the quark model in the early 60s, few-body techniques have been applied to three-quark and quark-antiquark systems, and more recently to higher configurations, in the search for stable or metastable multiquark systems. 2 Few-Nucleon Systems Various methods have been developed during the years to study the light nuclei with the successive versions of the nucleon-nucleon potential. Among them, one can cite the hyperspherical expansion [1] or the solution of Faddeev-type of equations [2]. The corresponding techniques have proved useful for other systems. Even the famous Efimov effect [3] has been inspired by few-nucleon systems, with the observation that the nucleon-nucleon interaction is at the edge between binding and non-binding, on one side for neutronproton with isospin I = 0 and spin I = 1, and on the other side for proton-proton with isospin I = 1 and spin S = 0.
J.-M. Richard (B) Institut de Physique des 2 Infinis de Lyon, IN2P3-CNRS–UCBL, Université de Lyon, 4 rue Enrico Fermi, 69622 Villeurbanne, France E-mail: [email protected]
0123456789().: V,-vol
44
Page 2 of 10
J.-M. Richard
The ancestor of the Efimov effect,1 the Thomas collapse [5], comes from a comparison of the three-body ground-state energy E 3 and the two-body E 2 . From the data available on E 3 /E 2 , Thomas inferred that the meson predicted by Yukawa but not yet discovered at that time, should be lighter than 200 MeV. More recently, the study of three-body systems 3 H and 3 He and other light nuclei using N N potentials that fit the deuteron energy E 2 and the N N phase-shifts, has revealed the need for three-body forces. This domain is still very active, with, for instance, the speculations about the dineutron and tetraneutron [6].
3 Light Hypernuclei Since the early 50s, there is a continuous activity on hypernuclei with many interesting questions such as the modification of the weak decay for bound hyperons. Most of the identified hypernuclei have strangeness S = −1, but states with S = −2 have also been found. For years, progress on the knowledge of the N and interactions has been purely theoretical, and benefited from our improved approach to the nucleon-nucleon interaction (meson-exchanges, SU(3) constraints, effective
Data Loading...
