A chiral lagrangian with Broken Scale: testing the restoration of symmetries in astrophysics and in the laboratory

Abstract

We study matter at high density and temperature using a chiral lagrangian in which the breaking of scale invariance is regulated by the value of a scalar field, called dilaton \cite{Heide:1993yz,Carter:1995zi,Carter:1996rf,Carter:1997fn}. We provide a phase diagram describing the restoration of chiral and scale symmetries. We show that chiral symmetry is restored at large temperatures, but at low temperatures it remains broken at all densities. We also show that scale invariance is more easily restored at low rather than large baryon densities. The masses of vector mesons scale with the value of the dilaton and their values initially slightly decrease with the density but then they increase again for densities larger than $\sim 3{\rho }_0$. The pion mass increases continuously with the density and at ${\rho }_0$ and T=0 its value is $\sim$ 30 MeV larger than in the vacuum. We show that the model is compatible with the bounds stemming from astrophysics, as e.g. the one associated with the maximum mass of a neutron star. The most striking feature of the model is a very significant softening at large densities, which manifests also as a strong reduction of the adiabatic index. While the softening has probably no consequence for Supernova explosion via the direct mechanism, it could modify the signal in gravitational waves associated with the merging of two neutron stars.

arXiv comment16 pages, 18 figures, published version

References in corpus (41)

• The equation of state for nucleon matter and neutron star structure
• Phases of Dense Quarks at Large N_c
• Constraints on the high-density nuclear equation of state from the phenomenology of compact stars and heavy-ion collisions
• The transition temperature in QCD
• First Measurement of the rho Spectral Function in High-Energy Nuclear Collisions
• The Physics of Core-Collapse Supernovae
• Nuclei in a chiral SU(3) model
• Asymmetric nuclear matter:the role of the isovector scalar channel
• A 2.1 Solar Mass Pulsar Measured by Relativistic Orbital Decay
• Proto-Neutron and Neutron Stars in a Chiral SU(3) Model
• Effective Nucleon Masses in Symmetric and Asymmetric Nuclear Matter
• On the Lorentz structure of the symmetry energy
• Analysis of Chiral Mean-Field Models for Nuclei
• First observation of in-medium modifications of the omega meson
• Relativistic model for nuclear matter and atomic nuclei with momentum-dependent self-energies
• Evidence for in-medium modification of the $\varphi$ meson at normal nuclear density
• Chiral Lagrangian for strange hadronic matter
• The Relativistic Dirac-Brueckner Approach to Asymmetric Nuclear Matter
• Enhanced Production of Low-Mass Electron Pairs in 40 AGeV Pb-Au Collisions at the CERN SPS
• Covariant representations of the relativistic Brueckner T-matrix and the nuclear matter problem
• Vacuum Contributions in a Chiral Effective Lagrangian for Nuclei
• Dynamical phase trajectories for relativistic nuclear collisions
• An Effective Lagrangian with Broken Scale and Chiral Symmetry Applied to Nuclear Matter and Finite Nuclei
• Search for medium modification of the $\rho$ meson
• Nuclear Matter and Neutron stars in a Parity Doublet Model
• High density QCD with static quarks
• Relativistic Mean-Field Models with Effective Hadron Masses and Coupling Constants, and rho^- Condensation
• An Effective Lagrangian with Broken Scale and Chiral Symmetry II: Pion Phenomenology
• Role of Fluctuations in the Linear Sigma Model with Quarks
• Relativistic Brueckner-Hartree-Fock calculations with explicit intermediate negative energy states
• The Deconfinement Phase Transition in Asymmetric Matter
• Softening of the equation of state of matter at large densities and temperatures: chiral symmetry restoration vs. quark deconfinement
• Study of the finite temperature transition in 3-flavor QCD using the R and RHMC algorithms
• Collective Flow in Heavy-Ion Collisions from AGS to SPS
• Neutron stars within the SU(2) parity doublet model
• An Effective Lagrangian with Broken Scale and Chiral Symmetry III: Mesons at Finite Temperature
• An Effective Lagrangian with Broken Scale and Chiral Symmetry IV: Nucleons and Mesons at Finite Temperature
• On the determination of the pion effective mass in nuclei from pionic atoms
• Evaporation of the gluon condensate: a model for pure gauge SU(3)_c phase transition
• Chiral symmetry restoration in strange hadronic matter
• Neutron Stars in a Chiral Model with Finite Temperature

Cited by in corpus (23)

• Meson vacuum phenomenology in a three-flavor linear sigma model with (axial-)vector mesons
• A Novel Approach to Model Hybrid Stars
• Hybrid Stars in a Strong Magnetic Field
• Non-congruence of the nuclear liquid-gas and deconfinement phase transitions
• Nuclear matter within a dilatation-invariant parity doublet model: the role of the tetraquark at nonzero density
• Bayesian Inference of Dense Matter Equation of State within Relativistic Mean Field Models using Astrophysical Measurements
• A little inflation at the cosmological QCD phase transition
• The role of strangeness in hybrid stars and possible observables
• Reconciling Nuclear and Astrophysical Constraints
• Phase transition from nuclear matter to color superconducting quark matter: the effect of the isospin
• Neutron star collapse and gravitational waves with a non-convex equation of state
• The internal composition of proto-neutron stars under strong magnetic fields
• Charged $\rho$-meson condensation in neutron stars
• Astrophysics and Nuclear Physics Informed Interactions in Dense Matter: Inclusion of PSR J0437-4715
• Does nuclear matter bind at large $N_c$?
• Chiral Symmetry Restoration and Deconfinement to Quark Matter in Neutron Stars
• Modern nuclear and astrophysical constraints of dense matter in a renormalized chiral approach
• The half-skyrmion phase in a chiral-quark model
• Properties of hadrons in a chiral model with (axial-)vector mesons
• A chiral quark-soliton model with broken scale invariance for nuclear matter
• Neutron stars in the large-$N_c$ limit
• The soliton-soliton interaction in the Chiral Dilaton Model
• A hybrid-chiral soliton model with broken scale invariance for nuclear matter