Editorial: The Long-Lasting Quest for Nuclear Interactions: The Past, the Present and the Future
- 1Department of Physics “E. Fermi”, University of Pisa, Pisa, Italy
- 2Sezione di Pisa, Istituto Nazionale di Fisica Nucleare, Pisa, Italy
Editorial on the Research Topic
The long-lasting quest for nuclear interactions: the past, the present and the future
As it was stated when this Research Topic was launched, despite many years of intense research, our understanding of the force that holds the atomic nuclei together is still far from complete, and numerous crucial questions are yet to be answered. The theory of nuclear forces has a long and glorious history, as recently summarized in 1. In a nutshell, in the 1990s, meson-theoretic and pure phenomenological approaches were used to describe the nuclear interaction, with models which were able to reproduce the large set of two-nucleon (
At the beginning of the 1990s, we entered in a new still-ongoing phase: nuclear physicists “discovered” QCD and, more importantly, effective field theory (EFT). Following a seminal idea of Weinberg [4, 5], several groups developed nuclear interaction models within the so-called chiral EFT (χEFT), an EFT where the spontaneous breaking of QCD chiral symmetry plays a crucial role. The χEFT approach is reviewed and discussed at length in essentially all contributions to this Research Topic, as we will outline below. Due to lack of space, here we only mention that the accuracy nowadays reached by the chiral models for nuclear interactions is comparable to, if not even better than, the one reached by the “old” phenomenological models.
Let us quickly review the different contributions to this Research Topic. Four of the most active groups working to derive nuclear force within the χEFT approach are among the contributors to this Research Topic. In particular, Epelbaum et al. review the most recent achievements of the so-called Bochum group, focusing on a new generation of nuclear chiral forces derived using the recently proposed semi-local regularization method. The authors also describe the ongoing efforts by the Low-Energy Nuclear Physics International Collaboration (LENPIC) toward developing consistent two- and many-body forces, and discuss selected applications. The contribution of Entem et al. is a clear and thorough review of the latest work of the so-called Idaho group, which has developed χEFT-based potentials, from leading order up to next-to-next-to-next-to-next-to leading order (N4LO). The authors present also a discussion of the most recently developed N5LO contributions, and their effects on
Two essential aspects of χEFT are also reviewed in the Research Topic. The first one is the problem of renormalization of chiral nuclear forces. In his contribution, Van Kolck summarizes the huge body of work done on this subject and describes alternative approaches which can be used to achieve renormalization order by order. The second essential aspect is the proper quantification of uncertainties on
The χEFT approach can be suitably adapted to derive also more general baryon-baryon interactions. For instance, Petschauer et al. review the systematic derivation of hyperon-nuclear forces from the symmetries of QCD within non-relativistic SU(3) χEFT, and also discuss several applications, ranging from hyperon-nucleon scattering up to hyperon-nuclear few- and many-body systems, including hypernuclei and neutron star matter. The contribution of de Vries et al., instead, is about the parity-violating but time-reversal conserving, and the parity-violating and time-reversal-violating forces in nuclei. These forces are a tiny component of the total interaction between nucleons, but their study is extremely interesting, because they allow one to obtain information on fundamental symmetries using nuclear systems. In this contribution, the authors review how the above mentioned interactions are derived in χEFT, and discuss the effects of these forces on several few-nucleon observables.
Two papers are devoted to approaches alternative to χEFT used to derive nuclear interaction models. In the first one, Fernández et al. review the different quark models used to describe
The nuclear interaction models derived in χEFT reproduce with great accuracy
In order to use chiral forces in larger nuclei up to nuclear matter, further work is necessary. Some issues related to the use of nuclear forces in the medium are discussed by Sammarruca et al. and Holt et al. In particular, Sammarruca et al. present a review of their recent studies of the equation of state for symmetric nuclear matter and pure neutron matter, using state-of-the-art chiral interactions. Holt et al. discuss the implementation of
We conclude this overview with the contribution of Richard, which is devoted to the physics of low-energy antiprotons and, most importantly in this context, its link with nuclear forces. In fact, a good understanding of antinucleon-nucleon and antinucleon-nucleus interactions is necessary in order to investigate important phenomena in astrophysics, as high-energy cosmic rays, or the matter-antimatter asymmetry in early Universe.
In conclusion, this Research Topic has collected the contributions of the researchers most active in the development and understanding of the nuclear interaction and some related topics, as those outlined above. At the end, we hope that this article collection will serve as a useful compendium for practitioners, who everyday apply nuclear potentials in their work and wish to learn about the most significant aspects in an efficient way.
The author confirms being the sole contributor of this work and approved it for publication.
Conflict of Interest
The author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
The author would like to warmly thank Prof. Ruprecht Machleidt for his deep insights and great support in proposing, managing, and reviewing large part of the editorial work. Last, but not least, the author would like to thank the many colleagues who have enthusiastically answered to the call of submission, and the many reviewers who, with great professionalism, have worked anonymously together with the authors to improve the submitted articles.
Keywords: Nuclear interactions, two- and three-nucleon interactions, chiral effective field theory, lattice QCD, light nuclei, ab-initio methods
Citation: Marcucci LE (2020) Editorial: The Long-Lasting Quest for Nuclear Interactions: The Past, the Present and the Future. Front. Phys. 8:609907. doi: 10.3389/fphy.2020.609907
Received: 24 September 2020; Accepted: 05 October 2020;
Published: 18 November 2020.
Edited and reviewed by:Alex Hansen, Norwegian University of Science and Technology, Norway
Copyright © 2020 Marcucci. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Laura E. Marcucci, firstname.lastname@example.org