Nuclear Theory·nucl-th

Wednesday·May 6, 2020

7 papers—1 primary·6 cross-listed

02
[Submitted on 4 May 2020] (cross-list from cond-mat.mes-hall)
Nonadiabatic Nonlinear Optics and Quantum Geometry -- Application to the Twisted Schwinger Effect
Shintaro Takayoshi🇩🇪 · Jianda Wu🇨🇳 · Takashi Oka🇩🇪
We study the tunneling mechanism of nonlinear optical processes in solids induced by strong coherent laser fields. The theory is based on an extension of the Landau-Zener model with nonadiabatic geometric effects. In addition to the rectification effect known previously, we find two effects, namely perfect tunneling and counterdiabaticity at fast sweep speed. We apply this theory to the twisted Schwinger effect, i.e., nonadiabatic pair production of particles by rotating electric fields, and find a nonperturbative generation mechanism of the opto-valley polarization and photo-current in Dirac and Weyl fermions.
Comments:
24 pages, Accepted by SciPost
Subjects:
Mesoscale and Nanoscale Physics (cond-mat.mes-hall); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2005.01755 [pdf]
SciPost Phys.(2021)·20 citations
03
[Submitted on 4 May 2020] (cross-list from hep-ph)
Sterile Neutrinos and the Global Reactor Antineutrino Dataset
Jeffrey M. Berryman🇺🇸 · Patrick Huber🇺🇸
We present results from global fits to the available reactor antineutrino dataset, as of Fall 2019, to determine the global preference for a fourth, sterile neutrino. We have separately considered experiments that measure the integrated inverse-beta decay (IBD) rate from those that measure the energy spectrum of IBD events at one or more locations. The software used is the newly developed GLoBESfit tool set which is based on the publicly available GLoBES framework and will be released as open-source software.
Comments:
49 pages, 41 figures; code available at www.globesfit.org; manuscript has been updated to reflect bug fixes
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2005.01756 [pdf]
JHEP(2021)·63 citations
04
[Submitted on 5 May 2020] (cross-list from hep-ph)
Graphic Method for Arbitrary $n$ -body Phase Space
Hao-Jie Jing🇨🇳 · Chao-Wei Shen🇨🇳 · Feng-Kun Guo🇨🇳
In quantum field theory, the phase space integration is an essential part in all theoretical calculations of cross sections and decay widths. It is also needed for computing the imaginary part of a physical amplitude. A key problem is to get the phase space formula expressed in terms of any chosen invariant masses in an $n$ -body system. We propose a graphic method to quickly get the phase space formula of any given invariant masses intuitively for an arbitrary $n$ -body system in general $D$ -dimensional spacetime, with the involved momenta in any reference frame. The method also greatly simplifies the phase space calculation just as what Feynman diagrams do in calculating scattering amplitudes.
Comments:
More explanations, generalization to the general spacetime dimensions included
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Theory (hep-th); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2005.01942 [pdf]
Sci.Bull.(2021)·11 citations
05
[Submitted on 5 May 2020] (cross-list from hep-lat)
Finite-volume formalism in the $2 H_{I} + H_{I} 2$ transition: an application to the lattice QCD calculation of double beta decays
Xu Feng🇨🇳 · Lu-Chang Jin🇺🇸 · Zi-Yu Wang🇨🇳 · Zheng Zhang🇨🇳
We present the formalism for connecting a second-order electroweak $2 H_{I} + H_{I} 2$ transition amplitudes in the finite volume (with two hadrons in the initial and final states) to the physical amplitudes in the infinite volume. Our study mainly focus on the case where the low-lying intermediate state consists of two scattering hadrons. As a side product we also reproduce the finite-volume formula for $2 H_{I} 2$ transition, originally obtained by Briceño and Hansen. With the available finite-volume formalism, we further discuss how to treat with the finite-volume problem in the double beta decays $nn \to pp ee ν ˉ ν ˉ$ and $nn \to pp ee$ .
Comments:
18 pages
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2005.01956 [pdf]
PRD(2021)·29 citations
06
[Submitted on 5 May 2020] (cross-list from astro-ph.HE)
Inner crust of a neutron star at crystallization in a multi-component approach
T. Carreau🇫🇷 · A. F. Fantina🇫🇷 · F. Gulminelli🇫🇷
The possible presence of amorphous and heterogeneous phases in the inner crust of a neutron star is expected to reduce the electrical conductivity of the crust, with potentially important consequences on the magneto-thermal evolution of the star. In cooling simulations, the disorder is quantified by an impurity parameter which is often taken as a free parameter. We aim to give a quantitative prediction of the impurity parameter as a function of the density in the crust,performing microscopic calculations including up-to-date microphysics of the crust. A multi-component approach is developed at finite temperature using a compressible liquid drop description of the ions with an improved energy functional based on recent microscopic nuclear models and optimized on extended Thomas-Fermi calculations. Thermodynamic consistency is ensured by adding a rearrangement term and deviations from the linear mixing rule are included in the liquid phase. The impurity parameter is consistently calculated at the crystallization temperature as determined in the one-component plasma approximation for the different functionals. Our calculations show that at the crystallization temperature the composition of the inner crust is dominated by nuclei with charge number around $Z \approx 40$ , while the range of the $Z$ distribution varies from about 20 near the neutron drip to about 40 closer to the crust-core transition. This reflects on the behavior of the impurity parameter that monotonically increases with density up to around 40 in the deeper regions of the inner crust. Our study shows that the contribution of impurities is non-negligible, thus potentially having an impact on the transport properties in the neutron-star crust. The obtained values of the impurity parameter represent a lower limit; larger values are expected in the presence of non-spherical geometries and/or fast cooling dynamics.
Comments:
10 pages, 6 figures
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2005.02089 [pdf]
Astron.Astrophys.(2020)·33 citations
07
[Submitted on 5 May 2020] (cross-list from hep-lat)
Flavor non-singlet parton distribution functions from lattice QCD at physical quark masses via the pseudo-distribution approach
Manjunath Bhat🇵🇱 · Krzysztof Cichy🇵🇱 · Martha Constantinou🇺🇸 · Aurora Scapellato🇵🇱
One of the great challenges of QCD is to determine the partonic structure of the nucleon from first principles. In this work, we provide such a determination of the flavor non-singlet ( $u - d$ ) unpolarized parton distribution function (PDF), utilizing the non-perturbative formulation of QCD on the lattice. We apply Radyushkin's pseudo-distribution approach to lattice results obtained using simulations with the light quark mass fixed to its physical value; this is the first ever attempt for this approach directly at the physical point. The extracted coordinate-space matrix elements are used to find the relevant physical Ioffe time distributions from a matching procedure. The full Bjorken- $x$ dependence of PDFs is resolved using several reconstruction methods to tackle the ill-conditioned inverse problem encountered when using discrete lattice data. We consider both the valence distribution $q_{v}$ and the combination with antiquarks $q_{v} + 2 q ˉ$ , related to, respectively, the real and imaginary part of extracted matrix elements. Good agreement is found with PDFs from global fits already within statistical uncertainties and it is further improved by quantifying several systematic effects. The results presented here are the first ever \emph{ab initio} determinations of PDFs fully consistent with global fits in the whole $x$ -range. Thus, they pave the way to investigating a wider class of partonic distributions, such as e.g.\ singlet PDFs and generalized parton distributions. Therefore, essential and yet missing first-principle insights can be achieved, complementing the rich experimental programs dedicated to the structure of the nucleon.
Comments:
Matches journal version. Added an alternative interpolation procedure + analysis of PDF moments + comparison with NNPDF ITDs. Main results and conclusions unchanged. 24 pages, 17 figures
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2005.02102 [pdf]
PRD(2021)·88 citations

Affiliations

first authorsco-authorsvia INSPIRE

Nonadiabatic Nonlinear Optics and Quantum Geometry -- Application to the Twisted Schwinger Effect

Sterile Neutrinos and the Global Reactor Antineutrino Dataset

Graphic Method for Arbitrary n-body Phase Space

Finite-volume formalism in the 2HI​+HI​​2 transition: an application to the lattice QCD calculation of double beta decays

Inner crust of a neutron star at crystallization in a multi-component approach

Flavor non-singlet parton distribution functions from lattice QCD at physical quark masses via the pseudo-distribution approach

Affiliations

Graphic Method for Arbitrary $n$ -body Phase Space

Finite-volume formalism in the $2 H_{I} + H_{I} 2$ transition: an application to the lattice QCD calculation of double beta decays