Nuclear Theory·nucl-th

Wednesday·May 15, 2019

8 papers—3 primary·5 cross-listed

01
[Submitted on 13 May 2019]
Symmetry, symmetry breaking, and pion parton distributions
Minghui Ding🇨🇳 · Khepani Raya🇲🇽 · Daniele Binosi🇮🇹 · Lei Chang🇨🇳 · C. D. Roberts🇺🇸 · S. M. Schmidt🇩🇪
Pion valence, glue and sea distributions are calculated using a continuum approach to the two valence-body bound-state problem. Since the framework is symmetry preserving, physical features of the distributions are properly expressed. The analysis reveals that the emergent phenomenon of dynamical chiral symmetry breaking causes a hardening of the valence-quark distribution function, $q^{π} (x)$ . Nevertheless, this distribution exhibits the $x ≃ 1$ behaviour predicted by quantum chromodynamics (QCD). At the scale $ζ_{2} := 2$ GeV, the following momentum fractions are predicted: $⟨ x_{valence} ⟩ = 0.48 (3)$ , $⟨ x_{glue} ⟩ = 0.41 (2)$ , $⟨ x_{sea} ⟩ = 0.11 (2)$ . Evolving to $ζ = 5.2$ GeV, the result for $q^{π} (x)$ agrees with that computed using lattice QCD. These outcomes should both spur improved analyses of existing experiments and stimulate efforts to obtain new data on the pion distribution functions using available and envisioned facilities.
Comments:
13 pages, 7 figures, 2 tables
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
1905.05208 [pdf]
PRD(2020)·129 citations
02
[Submitted on 13 May 2019]
Extracting free-space observables from trapped interacting clusters
Xilin Zhang
The energy spectrum of two short-range interacting particles in a harmonic potential trap has previously been related to free-space scattering phase shifts. But the existing formula for this purpose is exact only in the limit of an infinitely shallow trap. Here we provide a systematically improved formula---describing the low-energy dynamics---that enables the use of finite traps. This paves the way for extracting nuclear scattering phase shifts from {\it ab initio} nuclear many-body structure calculations, a long-sought goal in nuclear physics. The derivation establishes effective field theory as a powerful framework for studying the connection between structure information of a trapped system (with two or more sub-clusters) and continuum physics in the fields of both nuclear and condensed-matter physics.
Comments:
12 Pages, 5 figures. Version 3---close to publication version---has more figures included
Subjects:
Nuclear Theory (nucl-th); Quantum Gases (cond-mat.quant-gas); Nuclear Experiment (nucl-ex)
arXiv:
1905.05275 [pdf]
PRC(2020)·31 citations
03
[Submitted on 13 May 2019]
Thermodynamic Geometry of Nambu -- Jona Lasinio model
P. Castorina🇮🇹 · D. Lanteri🇮🇹 · S. Mancani🇮🇹
The formalism of Riemannian geometry is applied to study the phase transitions in Nambu -Jona Lasinio (NJL) model. Thermodynamic geometry reliably describes the phase diagram, both in the chiral limit and for finite quark masses. The comparison between the geometrical study of NJL model and of (2+1) Quantum Chromodynamics at high temperature and small baryon density shows a clear connection between chiral symmetry restoration/breaking and deconfinement/confinement regimes.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
1905.05296 [pdf]
Eur.Phys.J.Plus(2020)·9 citations

Affiliations

first authorsco-authorsvia INSPIRE

Symmetry, symmetry breaking, and pion parton distributions

Extracting free-space observables from trapped interacting clusters

Thermodynamic Geometry of Nambu -- Jona Lasinio model

Affiliations