Nuclear Theory·nucl-th

Monday·November 14, 2016

12 papers—8 primary·4 cross-listed

01
Scale-setting, flavour dependence and chiral symmetry restoration
Daniele Binosi🇮🇹 · Craig D. Roberts🇺🇸 · Jose Rodriguez-Quintero🇪🇸
We determine the flavour dependence of the renormalisation-group-invariant running interaction through judicious use of both unquenched Dyson-Schwinger equation and lattice results for QCD's gauge-sector two-point functions. An important step is the introduction of a physical scale setting procedure that enables a realistic expression of the effect of different numbers of active quark flavours on the interaction. Using this running interaction in concert with a well constrained class of dressed--gluon-quark vertices, we estimate the critical number of active lighter-quarks above which dynamical chiral symmetry breaking becomes impossible: $n_{f}^{cr} \approx 9$ ; and hence in whose neighbourhood QCD is plausibly a conformal theory.
nucl-thhep-lathep-phPRD(2017)·55 citations
02
A Novel Algorithm for Extracting the Parton Distribution Amplitude from the Euclidean Bethe-Salpeter Wave Function
Fei Gao🇨🇳 · Lei Chang🇨🇳 · Yu-xin Liu🇨🇳
We propose a new numerical method to compute parton distribution amplitude(PDA) from the Euclidean Bethe-Salpeter wave function. The essential step is to extract the weight function in the Nakanishi representation of the Bethe-Salpeter wave function in Euclidean space, which is an ill-posed inversion problem, via the maximum entropy method(MEM). The Nakanishi weight function as well as the corresponding light-front PDA can be well determined. We confirm the previous works on PDA computation therein the different method has been performed.
nucl-thhep-phPLB(2017)·26 citations
03
Mean field approaches for $Ξ^{-}$ hypernuclei and current experimental data
T. T. Sun🇯🇵 · E. Hiyama🇯🇵 · H. Sagawa🇯🇵 · H.-J. Schulze🇮🇹 · J. Meng🇨🇳
Motivated by the recently observed hypernucleus (Kiso event) $_{Ξ}^{15}$ C ( $^{14}$ N $+ Ξ^{-}$ ), we identify the state of this system theoretically within the framework of the relativistic-mean-field and Skyrme-Hartree-Fock models. The $Ξ N$ interactions are constructed to reproduce the two possibly observed $Ξ^{-}$ removal energies, $4.38 \pm 0.25$ MeV or $1.11 \pm 0.25$ MeV. The present result is preferable to be $^{14} N (g.s.) + Ξ^{-} (1 p)$ , corresponding to the latter value.
nucl-thPRC(2016)·69 citations
04
Quantifying statistical uncertainties in ab initio nuclear physics using Lagrange multipliers
B. D. Carlsson
Theoretical predictions need quantified uncertainties for a meaningful comparison to experimental results. This is an idea which presently permeates the field of theoretical nuclear physics. In light of the recent progress in estimating theoretical uncertainties in ab initio nuclear physics, we here present and compare methods for evaluating the statistical part of the uncertainties. A special focus is put on the (for the field) novel method of Lagrange multipliers (LM). Uncertainties from the fit of the nuclear interaction to experimental data are propagated to a few observables in light-mass nuclei to highlight any differences between the presented methods. The main conclusion is that the LM method is more robust, while covariance based methods are less demanding in their evaluation.
nucl-thPRC(2017)·9 citations
05
Finite volume corrections and low momentum cuts in the thermodynamics of quantum gases
Krzysztof Redlich (Wroclaw U)🇵🇱 · Kacper Zalewski (Cracow, INP & Jagiellonian U.)🇵🇱
The conjecture, that the finite volume corrections to the thermodynamic functions can be correctly reproduced by using the thermodynamic limit with low particle momenta cutoff is examined in a very transparent example of an ideal boson gas in one dimension. We show that this conjecture is always true in principle, and derive convenient relations for the momentum cutoff dependence on thermal parameters in the asymptotic limits of large and small volume.
nucl-thhep-ph13 citations
06
On the PBF neutrino losses in superfluid cores of neutron stars
Lev B Leinson
Axial anomalous contributions into neutrino PBF losses due to triplet pairing of neutrons are still ignored in modeling the evolution of neutron stars. In this paper, the influence of the anomalous axial contributions onto the rate of neutron stars cooling is estimated.
nucl-thastro-ph.HE7 citations
07
Applying the Density Matrix Expansion with Coordinate-Space Chiral Interactions
A. Dyhdalo · S.K. Bogner · R.J. Furnstahl
We apply the density matrix expansion (DME) at Hartree-Fock level with long-range chiral effective field theory interactions defined in coordinate space up to next-to-next-to-leading order. We consider chiral potentials both with and without explicit Delta isobars. The challenging algebra associated with applying the DME to three-nucleon forces is tamed using a new organization scheme, which will also facilitate generalizations. We include local regulators on the interactions to mitigate the effects of singular potentials on the DME couplings and simplify the optimization of generalized Skyrme-like functionals.
nucl-thPRC(2017)·20 citations
08
Constraining gravity with hadron physics: neutron stars, modified gravity and gravitational waves
Felipe J. Llanes-Estrada (Univ. Complutense de Madrid)🇪🇸
The finding of Gravitational Waves by the aLIGO scientific and VIRGO collaborations opens opportunities to better test and understand strong interactions, both nuclear-hadronic and gravitational. Assuming General Relativity holds, one can constrain hadron physics at a neutron star. But precise knowledge of the Equation of State and transport properties in hadron matter can also be used to constrain the theory of gravity itself. I review a couple of these opportunities in the context of modified f(R) gravity, the maximum mass of neutron stars, and progress in the Equation of State of neutron matter from the chiral effective field theory of QCD.
nucl-thgr-qcEPJ Web Conf.(2017)·4 citations
09
Gluon and Ghost Dynamics from Lattice QCD
O. Oliveira🇵🇹 · A. G. Duarte🇵🇹 · D. Dudal🇧🇪 · P. J. Silva🇵🇹
The two point gluon and ghost correlation functions and the three gluon vertex are investigated, in the Landau gauge, using lattice simulations. For the two point functions, we discuss the approach to the continuum limit looking at the dependence on the lattice spacing and volume. The analytical structure of the propagators is also investigated by computing the corresponding spectral functions using an implementation of the Tikhonov regularisation to solve the integral equation. For the three point function we report results when the momentum of one of the gluon lines is set to zero and discuss its implications.
↳ hep-lathep-phhep-thnucl-thFew Body Syst.(2017)·9 citations
10
Chiral Thermodynamics in a finite box
Ana Juričić🇦🇹 · Bernd-Jochen Schaefer🇩🇪
Finite-volume modifications of the two-flavor chiral phase diagram are investigated within an effective quark-meson model in various mean-field approximations. The role of vacuum fluctuations and boundary conditions, their influence on higher cumulants and signatures of a possible pseudo-critical endpoint are amplified with smaller volumes.
↳ hep-phhep-thnucl-thActa Phys.Polon.Supp.(2017)·9 citations
11
Holographic Heavy-Light Chiral Effective Action
Yizhuang Liu🇺🇸 · Ismail Zahed🇺🇸
We propose a variant of the $D 4$ - $D 8$ construction to describe the low energy effective theory of heavy-light mesons, interacting with the lowest lying pseudoscalar and vector mesons. The heavy degrees of freedom are identified with the $D 8_{L}$ - $D 8_{H}$ string low energy modes, and are approximated near the world volume of $N_{f} - 1$ light $D 8_{L}$ branes, by fundamental vector field valued in $U (N_{f} - 1)$ . The effective action follows from the reduction of the bulk D-brane Born-Infeld (DBI) and Chern-Simons (CS) actions, and is shown to exhibit both chiral and heavy-quark symmetry. The action interpolates continuously between the $U (N_{f})$ case with massless mesons, and the $U (N_{f} - 1)$ case with heavy-light mesons. The heavy-light meson radial spectrum is Regge-like. The one-pion and two-pion couplings to the heavy-light multiplets are evaluated. The partial widths for the charged decays $G \to H + π$ are shown to be comparable to the recently reported full widths for both the charm and bottom mesons.
↳ hep-phhep-thnucl-thPRD(2017)·31 citations
12
Bound state structure and electromagnetic form factor beyond the ladder approximation
V. Gigante🇧🇷 · J. H. Alvarenga Nogueira🇧🇷 · E. Ydrefors🇧🇷 · C. Gutierrez🇧🇷 · V.A. Karmanov🇷🇺 · T. Frederico🇧🇷
We investigate the response of the bound state structure of a two-boson system, within a Yukawa model with a scalar boson exchange, to the inclusion of the cross-ladder contribution to the ladder kernel of the Bethe-Salpeter equation. The equation is solved by means of the Nakanishi integral representation and light-front projection. The valence light-front wave function and the elastic electromagnetic form factor beyond the impulse approximation, with the inclusion of the two-body current, generated by the cross-ladder kernel, are computed. The valence wave function and electromagnetic form factor, considering both ladder and ladder plus cross-ladder kernels, are studied in detail. Their asymptotic forms are found to be quite independent of the inclusion of the cross-ladder kernel, for a given binding energy. The asymptotic decrease of form factor agrees with the counting rules. This analysis can be generalized to fermionic systems, with a wide application in the study of the meson structure.
↳ hep-phnucl-thPRD(2017)·15 citations

Affiliations

first authorsco-authorsvia INSPIRE