AN EFFECTIVE THEORY FOR NUCLEAR MATTER WITH GENUINE MANY-BODY FORCES

2012 ◽  
Vol 18 ◽  
pp. 182-190 ◽  
Author(s):  
CÉSAR A. Z. VASCONCELLOS ◽  
JORGE HORVATH ◽  
DIMITER HADJIMICHEF ◽  
ROSANA O. GOMES

Nuclear science has developed many excellent descriptions that embody various properties of the nucleus, and nuclear matter at low, medium and high densities. However, a full microscopic understanding of nuclear systems is still lacking. The aim of our theoretical research group is to shed some light on such challenges and particularly on open questions facing the high density nuclear many-body problem. Here we focus our attention on the conceptual issue of naturalness and its role in shaping the baryon-meson phase space dynamics in the description of the equation of state (EoS) of nuclear matter. In particular, in order to stimulate possible new directions of research, we discuss relevant aspects of a recently developed relativistic effective theory for nuclear matter with natural parametric couplings and genuine many-body forces. Among other topics we discuss in this work the connection of this theory with other known effective QHD models of the literature and its potentiality in describing a new physics for dense matter.

1976 ◽  
Vol 268 (3) ◽  
pp. 408-444 ◽  
Author(s):  
Ebbe M. Nyman ◽  
Mannque Rho
Keyword(s):  

2010 ◽  
Vol 19 (11) ◽  
pp. 2077-2122 ◽  
Author(s):  
ERIC VAN DALEN ◽  
HERBERT MÜTHER

The status of relativistic nuclear many-body calculations of nuclear systems to be built up in terms of protons and neutrons is reviewed. In detail, relativistic effects on several aspects of nuclear matter such as the effective mass, saturation mechanism, and the symmetry energy are considered. This review will especially focus on isospin asymmetric issues, since these aspects are of high interest in astrophysical and nuclear structure studies. Furthermore, from the experimental side these aspects are experiencing an additional boost from a new generation of radioactive beam facilities, e.g., the future GSI facility FAIR in Germany or SPIRAL2 at GANIL/France. Finally, the prospects of studying finite nuclei in microscopic calculations which are based on realistic NN interactions by including relativistic effects in calculations of low momentum interactions are discussed.


1974 ◽  
Vol 10 (2) ◽  
pp. 871-887 ◽  
Author(s):  
Bruce H. J. McKellar ◽  
R. Rajaraman

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Martin Bauer ◽  
Matthias Neubert ◽  
Sophie Renner ◽  
Marvin Schnubel ◽  
Andrea Thamm

Abstract Axions and axion-like particles (ALPs) are well-motivated low-energy relics of high-energy extensions of the Standard Model, which interact with the known particles through higher-dimensional operators suppressed by the mass scale Λ of the new-physics sector. Starting from the most general dimension-5 interactions, we discuss in detail the evolution of the ALP couplings from the new-physics scale to energies at and below the scale of electroweak symmetry breaking. We derive the relevant anomalous dimensions at two-loop order in gauge couplings and one-loop order in Yukawa interactions, carefully considering the treatment of a redundant operator involving an ALP coupling to the Higgs current. We account for one-loop (and partially two-loop) matching contributions at the weak scale, including in particular flavor-changing effects. The relations between different equivalent forms of the effective Lagrangian are discussed in detail. We also construct the effective chiral Lagrangian for an ALP interacting with photons and light pseudoscalar mesons, pointing out important differences with the corresponding Lagrangian for the QCD axion.


Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 191
Author(s):  
Alexander Bednyakov ◽  
Alfiia Mukhaeva

Flavour anomalies have attracted a lot of attention over recent years as they provide unique hints for possible New Physics. Here, we consider a supersymmetric (SUSY) extension of the Standard Model (SM) with an additional anomaly-free gauge U(1) group. The key feature of our model is the particular choice of non-universal charges to the gauge boson Z′, which not only allows a relaxation of the flavour discrepancies but, contrary to previous studies, can reproduce the SM mixing matrices both in the quark and lepton sectors. We pay special attention to the latter and explicitly enumerate all parameters relevant for our calculation in the low-energy effective theory. We find regions in the parameter space that satisfy experimental constraints on meson mixing and LHC Z′ searches and can alleviate the flavour anomalies. In addition, we also discuss the predictions for lepton-flavour violating decays B+→K+μτ and B+→K+eτ.


2002 ◽  
Vol 11 (02) ◽  
pp. 83-104 ◽  
Author(s):  
GUILHERME F. MARRANGHELLO ◽  
CESAR A. Z. VASCONCELLOS ◽  
MANFRED DILLIG ◽  
J. A. DE FREITAS PACHECO

Thermodynamical properties of nuclear matter are studied in the framework of an effective many-body field theory at finite temperature, considering the Sommerfeld approximation. We perform the calculations by using the nonlinear Boguta and Bodmer model, extended by the inclusion of the fundamental baryon octet and leptonic degrees of freedom. Trapped neutrinos are also included in order to describe protoneutron star properties through the integration of the Tolman–Oppenheimer–Volkoff equations, from which we obtain, beyond the standard relations for the masses and radii of protoneutron stars as functions of the central density, new results of these quantities as functions of temperature. Our predictions include: the determination of an absolute value for the limiting mass of protoneutron stars; new structural aspects on the nuclear matter phase transition via the behavior of the specific heat and, through the inclusion of quark degrees of freedom, the properties of a hadron-quark phase transition and hybrid protoneutron stars


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