Searcharxiv⌕ Search
Home/Archive/arXiv

arXiv · nucl-th/0608044

Cold, dense nuclear matter in a SU(2) parity doublet model

D. Zschiesche·L. Tolos·Jürgen Schaffner-Bielich·Robert D. Pisarski
View original source ↗Read source document ↗Export metadata ↓

Abstract

We study dense nuclear matter and the chiral phase transition in a SU(2) parity doublet model at zero temperature. The model is defined by adding the chiral partner of the nucleon, the N', to the linear sigma model, treating the mass of the N' as an unknown free parameter. The parity doublet model gives a reasonable description of the properties of cold nuclear matter, and avoids unphysical behaviour present in the standard SU(2) linear sigma model. If the N' is identified as the N'(1535), the parity doublet model shows a first order phase transition to a chirally restored phase at large densities, $ρ\approx 10 ρ_0$, defining the transition by the degeneracy of the masses of the nucleon and the N'. If the mass of the N' is chosen to be 1.2 GeV, then the critical density of the chiral phase transition is lowered to three times normal nuclear matter density, and for physical values of the pion mass, the first order transition turns into a smooth crossover.

Explore related subjects

nucl-th

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

D. Zschiesche, L. Tolos, Jürgen Schaffner-Bielich, Robert D. Pisarski. 2006-09-07. Cold, dense nuclear matter in a SU(2) parity doublet model. https://doi.org/10.1103/physrevc.75.055202

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

A short-range effective theory for single-neutron halo nuclei with a deformed core

We establish a short-range effective theory for deformed s-wave halos. The theory applies to a system in which neutrons are weakly bound to a core nucleus, and that core nucleus also exhibits a low-lying rotational band with a $0^+$ ground state and a first $2_1^+$ excited state. The effective theory then must have both halo degrees of freedom and degrees of freedom associated with rotation of the core. This leads to the particle plus rotor model of Bohr and Mottelson at leading order. We identify the relevant leading-order operators in the Hamiltonian that respect the symmetries of the system and the small parameters which define the effective theory's power counting. We carry out calculations for the $^{11}$Be and $^{17}$C systems in which we compute the low-lying positive-parity states of the core $+$ neutron systems up to the core$(2_1^+)$-neutron threshold. We do this for several different regulator parameters and establish that these energies can be renormalized using the leading-order set of operators. The spectrum is accurately described at leading order in both cases. Decay widths to d-wave core-neutron states have sizable cutoff dependence, but the Asymptotic Normalization Coefficients (ANCs) in $s$-wave channels exhibit regulator dependence of a size consistent with next-to-leading-order effects. We also compute Coulomb breakup observables and compare with experimental data, finding leading-order results in reasonable agreement with data for both ${}^{11}$Be and ${}^{17}$C. The addition of one next-to-leading-order operator renders the ANCs of all s-wave states stable with respect to the regulator. It consequently also removes most of the 30\% variation of the leading-order Coulomb dissociation cross section with the regulator.

nucl-th↗
arXiv2026

Systematic Study of Proton, Two-Proton, Alpha, and Cluster Radioactivity Half-Lives based on the Deformed Gamow-like Model and Tabular Prior-data Fitted Network ($\mathrm{TabPFN}$)

A hybrid framework combining the deformed Gamow-like model ($\mathrm{DGLM}$) with the Tabular Prior-data Fitted Network ($\mathrm{TabPFN}$) is developed to improve half-life predictions for two-proton emission, proton emission, $α$ decay, and cluster radioactivity. A total of 583 radioactive nuclei are investigated, including 17 two-proton emitters, 42 proton emitters, 498 $α$ emitters, and 26 cluster emitters. Among the four considered models, $\mathrm{DGLM}^{b}+\mathrm{TabPFN}$ achieves the best overall performance, with $σ_{\mathrm{RMS}}=0.423$, corresponding to an improvement of approximately $82.2\%$ over $\mathrm{DGLM}^{b}$. The model parameters are optimized for each decay mode using the least-squares method. After introducing $\mathrm{TabPFN}$, the prediction errors for proton emission and $α$ decay are reduced by approximately $80.6\%$ and $87.6\%$, respectively. For $α$ decay, the training, test, and overall RMSEs are 0.208, 0.305, and 0.240, indicating good generalization capability without evident overfitting. The model also reproduces the systematic evolution of $α$-decay half-lives and the shell-closure effect around $N=126$. These results demonstrate that combining $\mathrm{DGLM}$ with $\mathrm{TabPFN}$ significantly improves the accuracy and robustness of radioactive-decay half-life predictions while retaining the physical interpretability of the original model.

nucl-th↗
arXiv2026

Enhanced structure-dependent alpha decay tunneling in deformed odd-odd nuclei via intense two-color laser pulses

In the present work, we investigate the effect of ultra-intense laser fields on the $α$ decay tunneling of deformed odd-odd nuclei. Calculations performed within the deformed density-dependent cluster model show that, for deformed odd-odd $α$ emitters, the laser-induced variation in the penetration probability separates into distinct branches associated with different valence particle-hole configurations relative to the $Z=82$ and $N=126$ shell closures. In contrast to the even-even and odd-$A$ cases, the odd-odd parent nucleus most sensitive to the laser field is not the one with the lowest $α$ decay energy. This indicates that the laser response is governed not only by $Q_α$ but also by structural correlations associated with the simultaneously unpaired proton and neutron. We further examine the pulse-averaged response under a two-color laser field. The results show that an optimized two-color field enhances the pulse-averaged laser response for most of the studied nuclei, while highly sensitive nuclei exhibit an effective gain equivalent to increasing the laser intensity by more than one order of magnitude. These findings identify structural determinants of laser-assisted $α$ decay in odd-odd nuclei and provide guidance for selecting candidate nuclei and optimizing laser parameters in future experiments.

nucl-th↗