Nuclear Theory·nucl-th

Tuesday·February 23, 2021

22 papers—12 primary·10 cross-listed

01
[Submitted on 19 Feb 2021]
In-medium $k$ -body reduction of $n$ -body operators
Mikael Frosini🇫🇷 · Thomas Duguet🇫🇷 · Benjamin Bally🇪🇸 · Yann Beaujeault-Taudière🇫🇷 · Jean-Paul Ebran🇫🇷 · Vittorio Somà🇫🇷
The computational cost of ab initio nuclear structure calculations is rendered particularly acute by the presence of (at least) three-nucleon interactions. This feature becomes especially critical now that many-body methods aim at extending their reach beyond mid-mass nuclei. Consequently, state-of-the-art ab initio calculations are typically performed while approximating three-nucleon interactions in terms of effective, i.e. system-dependent, zero-, one- and two-nucleon operators. While straightforward in doubly closed-shell nuclei, existing approximation methods based on normal-ordering techniques involve either two- and three-body density matrices or a symmetry-breaking one-body density matrix in open-shell systems. In order to avoid such complications, a simple, flexible, universal and accurate approximation technique involving the convolution of the initial operator with a sole symmetry-invariant one-body matrix is presently formulated and tested numerically. Employed with a low-resolution Hamiltonian, the novel approximation method is shown to induce errors below $2 - 3%$ across a large range of nuclei, observables and many-body methods.
Comments:
31 pages, 14 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2102.10120 [pdf]
EPJA(2021)·57 citations
02
[Submitted on 20 Feb 2021]
Elastic scattering of twisted neutrons by nuclei
A.V. Afanasev · D.V. Karlovets · V.G. Serbo
We present a theoretical formalism for scattering of the twisted neutrons by nuclei in a kinematic regime where interference between Coulomb interaction and the strong interaction is essential. Twisted neutrons have definite quantized values of an angular momentum projection along the direction of propagation, and we show that it results in novel observable effects for the scattering cross section, spin asymmetries and polarization of the scattered neutrons. We demonstrate that additional capabilities provided by beam's orbital angular momentum enable new techniques for measuring both real and imaginary parts of the scattering amplitude. Several possible observables are considered, for which the targets may be either well-localized with respect to the spatial beam profile, or the scattering occurs incoherently on nuclei in a bulk target. The developed approach can be applied to other nuclear reactions with strongly interacting twisted particles.
Comments:
15 pages, 10 figures; typos and references fixed
Subjects:
Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2102.10380 [pdf]
PRC(2021)·23 citations
03
[Submitted on 21 Feb 2021]
Self-consistent calculations of electron-capture decays in Z=118, 119, and 120 superheavy isotopes
Pedro Sarriguren🇪🇸
Weak decays in superheavy nuclei with proton numbers Z = 118 - 120 and neutron numbers N = 175 - 184 are studied within a microscopic formalism based on deformed self-consistent Skyrme Hartree-Fock mean-field calculations with pairing correlations. The half-lives of beta+ decay and electron capture are compared with alpha-decay half-lives obtained from phenomenological formulas. The sensitivity of the half-lives to the unknown Q-energies is studied by comparing the results obtained from different approaches for the masses. It is shown that alpha-decay is always dominant in this mass region. The competition between alpha and beta+/EC decay modes is studied in seven alpha-decay chains starting at different isotopes of Z=118, 119, and 120.
Comments:
8 pages, 5 figures. arXiv admin note: text overlap with arXiv:2009.02103
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2102.10577 [pdf]
PLB(2021)·10 citations
04
[Submitted on 21 Feb 2021]
Differential analysis of incompressibility in neutron-rich nuclei
Bao-An Li · Wen-Jie Xie
Both the incompressibility \Ka of a finite nucleus of mass A and that ( $K_{\infty}$ ) of infinite nuclear matter are fundamentally important for many critical issues in nuclear physics and astrophysics. While some consensus has been reached about the $K_{\infty}$ , accurate theoretical predictions and experimental extractions of $K_{τ}$ characterizing the isospin dependence of \Ka have been very difficult. We propose a differential approach to extract the \Kt and \Ki independently from the \Ka data of any two nuclei in a given isotope chain. Applying this new method to the \Ka data from isoscalar giant monopole resonances (ISGMR) in even-even Pb, Sn, Cd and Ca isotopes taken by U. Garg {\it et al.} at the Research Center for Nuclear Physics (RCNP), Osaka University, Japan, we find that the $^{106}$ Cd- $^{116}$ Cd and $^{112}$ Sn- $^{124}$ Sn pairs having the largest differences in isospin asymmetries in their respective isotope chains measured so far provide consistently the most accurate up-to-date \Kt value of $K_{τ} = - 616 \pm 59$ MeV and $K_{τ} = - 623 \pm 86$ MeV, respectively, largely independent of the remaining uncertainties of the surface and Coulomb terms in expanding the $K_{A}$ , while the $K_{\infty}$ values extracted from different isotopes chains are all well within the current uncertainty range of the community consensus for $K_{\infty}$ . Moreover, the size and origin of the "Soft Sn Puzzle" is studied with respect to the "Stiff Pb Phenomenon". It is found that the latter is favored due to a much larger (by $\sim 380$ MeV) \Kt for Pb isotopes than for Sn isotopes, while the \Ki from analyzing the \Ka data of Sn isotopes is only about 5 MeV less than that from analyzing the Pb data.
Comments:
More discussions added. Phys. Rev. C in press
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Experiment (nucl-ex)
arXiv:
2102.10683 [pdf]
PRC(2021)·11 citations
05
[Submitted on 22 Feb 2021]
On nonadditive anisotropic relativistic hydrodynamics
A.V. Leonidov🇷🇺
Non-additive generalisation of relativistic anisotropic anisotropic hydrodynamics is described. In the particular case of 0+1 boost-invariant hydrodynamics additional entropy production due to non-additivity is calculated.
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2102.10819 [pdf]
JETP Lett.(2021)·2 citations
06
[Submitted on 22 Feb 2021]
ADG: Automated generation and evaluation of many-body diagrams III. Bogoliubov in-medium similarity renormalization group formalism
A. Tichai🇩🇪 · P. Arthuis🇩🇪 · H. Hergert🇺🇸 · T. Duguet🇫🇷
The goal of the present paper is twofold. First, a novel expansion many-body method applicable to superfluid open-shell nuclei, the so-called Bogoliubov in-medium similarity renormalization group (BIMSRG) theory, is formulated. This generalization of standard single-reference IMSRG theory for closed-shell systems parallels the recent extensions of coupled cluster, self-consistent Green's function or many-body perturbation theory. Within the realm of IMSRG theories, BIMSRG provides an interesting alternative to the already existing multi-reference IMSRG (MR-IMSRG) method applicable to open-shell nuclei. The algebraic equations for low-order approximations, i.e., BIMSRG(1) and BIMSRG(2), can be derived manually without much difficulty. However, such a methodology becomes already impractical and error prone for the derivation of the BIMSRG(3) equations, which are eventually needed to reach high accuracy. Based on a diagrammatic formulation of BIMSRG theory, the second objective of the present paper is thus to describe the third version (v3.0.0) of the ADG code that automatically (1) generates all valid BIMSRG(n) diagrams and (2) evaluates their algebraic expressions in a matter of seconds. This is achieved in such a way that equations can easily be retrieved for both the flow equation and the Magnus expansion formulations of BIMSRG. Expanding on this work, the first future objective is to numerically implement BIMSRG(2) (eventually BIMSRG(3)) equations and perform ab initio calculations of mid-mass open-shell nuclei.
Comments:
17 pages, 6 figures, 1 table, source code available at https://github.com/adgproject/adg
Subjects:
Nuclear Theory (nucl-th); Strongly Correlated Electrons (cond-mat.str-el); Superconductivity (cond-mat.supr-con); physics.chem-ph (physics.chem-ph)
arXiv:
2102.10889 [pdf]
EPJA(2022)·20 citations
07
[Submitted on 22 Feb 2021]
Crust-core interface and bulk neutron star properties
Ch. Margaritis · P.S. Koliogiannis · A. Kanakis-Pegios · Ch.C. Moustakidis
The nuclear symmetry energy plays an important role in the description of the properties of finite nuclei as well as neutron stars. Especially, for low values of baryon density, the accurate description of the crust-core interface strongly depends on the symmetry energy. Usually, the well known parabolic approximation is employed for the definition of the symmetry energy without avoiding some drawbacks. In the present paper, a class of nuclear models, suitable for the description of the inner and outer core of neutron stars, is applied in studying the effect of higher orders of the expansion of the energy on the location of the crust-core transition. The thermodynamical and dynamical methods are used for the determination of the transition density $n_{t}$ and pressure $P_{t}$ . The corresponding energy density functional is applied for the study of some relevant properties of both nonrotating and slowly rotating neutron stars. We found that the larger the value of the slope parameter $L$ , the slower the convergence of the expansion. In addition, a universal relation is presented between $n_{t}$ and $L$ , by employing the full expression and dynamical approach. The crustal moment of inertia is very sensitive to the location of the transition while the effects are moderated concerning the critical angular velocity of the $r$ -mode instability and minimum mass configuration. The effect on the tidal deformability is less but not negligible. In any case, the use of the parabolic approximation leads to the overestimation of $n_{t}$ and $P_{t}$ and consequently, on inaccurate predictions. Moreover, in some cases, even the matching process at the interface may affect considerably the predictions, introducing errors of the same order with the one due to the employed method.
Comments:
v1: 10 pages, 5 figures, 3 tables; v2: 15 pages, 7 figures, 6 tables, appendix and updated references; accepted for publication in Physical Review C; v3: matched the published version
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2102.10948 [pdf]
PRC(2021)·13 citations
08
[Submitted on 22 Feb 2021]
$γ γ$ decay as a probe of neutrinoless $β β$ decay nuclear matrix elements
B. Romeo🇪🇸 · J. Menéndez🇪🇸 · C. Peña🇪🇸
We study double gamma ( $γ γ$ ) decay nuclear matrix elements (NMEs) for a wide range of nuclei from titanium to xenon, and explore their relation to neutrinoless double-beta ( $0 ν β β$ ) NMEs. To favor the comparison, we focus on double-magnetic dipole transitions in the final $β β$ nuclei, in particular the $γ γ$ decay of the double isobaric analog of the initial $β β$ state into the ground state. For the decay with equal-energy photons, our large-scale nuclear shell model results show a good linear correlation between the $γ γ$ and $0 ν β β$ NMEs. Our analysis reveals that the correlation holds for $γ γ$ transitions driven by the spin or orbital angular momentum due to the dominance of zero-coupled nucleon pairs, a feature common to $0 ν β β$ decay. Our shell-model findings point out the potential of future $γ γ$ decay measurements to constrain $0 ν β β$ NMEs, which are key to answer fundamental physics questions based on $0 ν β β$ experiments.
Comments:
6 pages, 4 figures, matches published version
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2102.11101 [pdf]
PLB(2022)·29 citations
09
[Submitted on 22 Feb 2021]
Implementation of local chiral interactions in the hyperspherical harmonics formalism
Simone Salvatore Li Muli · Sonia Bacca · Nir Barnea
With the goal of using chiral interactions at various orders to explore properties of the few-body nuclear systems, we write the recently developed local chiral interactions as spherical irreducible tensors and implement them in the hyperspherical harmonics expansion method. We devote particular attention to three-body forces at next-to-next-to leading order, which play an important role in reproducing experimental data. We check our implementation by benchmarking the ground-state properties of $^{3}$ H, $^{3}$ He and $^{4}$ He against the available Monte Carlo calculations. We then confirm their order-by-order truncation error estimates and further investigate uncertainties in the charge radii obtained by using the precise muonic atom data for single-nucleon radii. Having local chiral Hamiltonians at various orders implemented in our hyperspherical harmonics suites of codes opens up the possibility to test such interactions on other light-nuclei properties, such as electromagnetic reactions.
Comments:
21 pages, 5 figures, 4 tables
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2102.11113 [pdf]
Front.in Phys.(2021)·4 citations
10
[Submitted on 22 Feb 2021]
Nonuniform-temperature effects on the phase transition in an Ising-like model
Jun-Hui Zheng🇳🇴 · Lijia Jiang🇨🇳
In this study, we investigate the spatially nonuniform-temperature effects on the QCD chiral phase transition in the heavy-ion collisions. Since the QCD effective theory and the Ising model belong to the same universality class, we start our discussion by mimicking the QCD effective potential with an Ising-like effective potential. In contrast to the dynamical slowing down effects which delays the phase transition from quark-gluon-plasma to hadron gas, the spatially nonuniform-temperature effects show a possibility to lift the phase transition temperature. Besides, both the fluctuations and the correlation length are enhanced in the phase transition region. Furthermore, the critical phenomena is strongly suppressed like as the critical slowing down effects. The underlying mechanism is the nonzero-momentum mode fluctuations of the order parameter induced by the nonuniform temperature. Our study provides a method to evaluate the nonuniform-temperature effects, and illustrate its potential influence on analyzing the QCD phase transition signals at RHIC.
Comments:
8 pages, 9 figures (Published version)
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2102.11154 [pdf]
PRD(2021)·4 citations
11
[Submitted on 22 Feb 2021]
In-medium similarity renormalization group with three-body operators
M. Heinz🇩🇪 · A. Tichai🇩🇪 · J. Hoppe🇩🇪 · K. Hebeler🇩🇪 · A. Schwenk🇩🇪
Over the past decade the in-medium similarity renormalization group (IMSRG) approach has proven to be a powerful and versatile ab initio many-body method for studying medium-mass nuclei. So far, the IMSRG was limited to the approximation in which only up to two-body operators are incorporated in the renormalization group flow, referred to as the IMSRG(2). In this work, we extend the IMSRG(2) approach to fully include three-body operators yielding the IMSRG(3) approximation. We use a perturbative scaling analysis to estimate the importance of individual terms in this approximation and introduce truncations that aim to approximate the IMSRG(3) at a lower computational cost. The IMSRG(3) is systematically benchmarked for different nuclear Hamiltonians for $^{4} He$ and $^{16} O$ in small model spaces. The IMSRG(3) systematically improves over the IMSRG(2) relative to exact results. Approximate IMSRG(3) truncations constructed based on computational cost are able to reproduce much of the systematic improvement offered by the full IMSRG(3). We also find that the approximate IMSRG(3) truncations behave consistently with expectations from our perturbative analysis, indicating that this strategy may also be used to systematically approximate the IMSRG(3).
Comments:
23 pages, 10 figures, published version
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2102.11172 [pdf]
PRC(2021)·94 citations
12
[Submitted on 22 Feb 2021]
The smallest fluid on earth
Björn Schenke🇺🇸
High energy heavy ion collisions create quark gluon plasmas that behave like almost perfect fluids. Very similar features to those that led to this insight have also been observed in experimental data from collisions of small systems, involving protons or other light nuclei. We describe recent developments aimed at understanding whether, and if so how, systems that produce relatively few particles (orders of magnitude less than in typical heavy ion collisions) and are only one to a few times the size of a proton, can behave like fluids. This involves a deeper understanding of fluid dynamics and its applicability, improvements of our understanding of the initial geometry of the collisions by considering fluctuations of the proton shape, as well as advancements in the calculation of initial state effects within an effective theory of quantum chromodynamics, which can affect the observables that are used to study fluid behavior. We further address open questions and discuss future directions.
Comments:
28 pages, 6 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2102.11189 [pdf]
Rept.Prog.Phys.(2021)·108 citations
13
[Submitted on 19 Feb 2021] (cross-list from physics.chem-ph)
Is Externally Corrected Coupled Cluster Always Better than the Underlying Truncated Configuration Interaction?
Ilias Magoulas · Karthik Gururangan · Piotr Piecuch · J. Emiliano Deustua · Jun Shen
The short answer to the question in the title is 'no'. We identify classes of truncated configuration interaction (CI) wave functions for which the externally corrected coupled-cluster (ec-CC) approach using the three-body ( $T_{3}$ ) and four-body ( $T_{4}$ ) components of the cluster operator extracted from CI does not improve the results of the underlying CI calculations. Implications of our analysis, illustrated by numerical examples, for the ec-CC computations using truncated and selected CI methods are discussed. We also introduce a novel ec-CC approach using the $T_{3}$ and $T_{4}$ amplitudes obtained with the selected CI scheme abbreviated as CIPSI, correcting the resulting energies for the missing $T_{3}$ correlations not captured by CIPSI with the help of moment expansions similar to those employed in the completely renormalized CC methods.
Comments:
70 pages, 4 tables, 2 charts, and 1 figure. Supporting Information as an ancillary file. This article has been accepted for publication in the Journal of Chemical Theory and Computation
Subjects:
physics.chem-ph (physics.chem-ph); Nuclear Theory (nucl-th); Computational Physics (physics.comp-ph)
arXiv:
2102.10143 [pdf]
J.Chem.Theor.Comput.(2021)·6 citations
14
[Submitted on 19 Feb 2021] (cross-list from hep-ph)
Entanglement and Many-Body effects in Collective Neutrino Oscillations
Alessandro Roggero🇺🇸
Collective neutrino oscillations play a crucial role in transporting lepton flavor in astrophysical settings, such as supernovae, where the neutrino density is large. In this regime, neutrino-neutrino interactions are important and simulations in the mean-field approximation show evidence for collective oscillations occurring at time scales much larger than those associated with vacuum oscillations. In this work, we study the out-of-equilibrium dynamics of a corresponding spin model using Matrix Product States and show how collective bipolar oscillations can be triggered by many-body correlations if appropriate initial conditions are present. We find entanglement entropies scaling at most logarithmically in the system size suggesting that classical tensor network methods could be efficient in describing collective neutrino dynamics more generally. These observation provide a clear path forward, not only to increase the accuracy of current simulations, but also to elucidate the mechanism behind collective flavor oscillations without resorting to the mean field approximation.
Comments:
13 pages, 7 figures, added discussion on numerical errors and a direct comparison with mean field, published version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2102.10188 [pdf]
PRD(2021)·71 citations
15
[Submitted on 20 Feb 2021] (cross-list from cond-mat.quant-gas)
Cold atoms beyond atomic physics
Lucas Madeira🇧🇷 · Vanderlei S. Bagnato🇧🇷
In the last 25 years, much progress has been made producing and controlling Bose-Einstein condensates (BECs) and degenerate Fermi gases. The advances in trapping, cooling and tuning the interparticle interactions in these cold atom systems lead to an unprecedented amount of control that one can exert over them. This work aims to show that knowledge acquired studying cold atom systems can be applied to other fields that share similarities and analogies with them, provided that the differences are also known and taken into account. We focus on two specific fields, nuclear physics and statistical optics. The nuclear physics discussion occurs with the BCS-BEC crossover in mind, in which we compare cold Fermi gases with nuclear and neutron matter and nuclei. We connect BECs and atom lasers through both systems' matter-wave character for the analogy with statistical optics. Finally, we present some challenges that, if solved, would increase our understanding of cold atom systems and, thus, the related areas.
Comments:
11 pages, 3 figures
Subjects:
Quantum Gases (cond-mat.quant-gas); Nuclear Theory (nucl-th)
arXiv:
2102.10385 [pdf]
Braz.J.Phys.(2021)·3 citations
16
[Submitted on 20 Feb 2021] (cross-list from hep-ph)
Effects of $N (2000) 5/2^{+}$ on $γ p \to K^{+} Λ (1405)$
Yu Zhang🇨🇳 · Fei Huang🇨🇳
The photoproduction reaction of $γ p \to K^{+} Λ (1405)$ is investigated based on an effective Lagrangian approach at the tree-level approximation with the purpose of understanding the reaction mechanism and extracting the resonance contents and the associated resonance parameters in this reaction. Apart from the $t$ -channel $K$ and $K^{*}$ exchanges, $s$ -channel nucleon ( $N$ ) exchange, $u$ -channel $Σ$ , $Λ$ , and $Λ (1405)$ exchanges, and generalized contact term, the exchanges of a minimum number of $N$ resonances in the $s$ channel are taken into account in constructing the reaction amplitudes to describe the experimental data. It is found that by introducing the $N (2000) 5/2^{+}$ resonance exchange in the $s$ channel, one can reproduce the most recent differential cross-section data from the CLAS Collaboration quite well. Further analysis shows that the cross sections of $γ p \to K^{+} Λ (1405)$ at high energies are dominated by the $t$ -channel $K$ exchange, while the contributions from the $s$ -channel $N$ and $N (2000) 5/2^{+}$ exchanges are rather significant to the cross sections in the near-threshold energy region. Predictions for the beam and target asymmetries for $γ p \to K^{+} Λ (1405)$ are given.
Comments:
8 pages, 6 figures; typos corrected; version published in Phys. Rev. C. arXiv admin note: text overlap with arXiv:2002.04213
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2102.10404 [pdf]
PRC(2021)·10 citations
17
[Submitted on 21 Feb 2021] (cross-list from hep-ph)
Magneto-rotational dissociation of heavy hadrons in Relativistic Heavy-Ion Collisions
Kirill Tuchin🇺🇸
A heavy hadron traversing Quark-Gluon Plasma and dragged along in rotational motion is subject to the Lorentz and centrifugal forces. The Lorentz force, sourced by the valence quarks of heavy-ions, possesses the electric and magnetic components in the hadron comoving frame. The electric component renders the hadron unstable by empowering one of its quarks to tunnel through the potential barrier. Assuming that the magnetic field is parallel to the plasma vorticity, the hadron dissociation probability is computed using the Imaginary Time Method and is found to strongly depend on the sign of the quark electric charge. The dissociation probability monotonically increases as a function of vorticity for negative electric charges, whereas for positive charges it exhibits a minimum at a finite value of vorticity. The dissociation probability for the negative charges is larger than for the positive ones at the same magnetic field and vorticity. In relativistic heavy-ion collisions this implies lower abundance of the negatively charged hadrons as compared to the positively charges ones. This effect is significant at moderate collision energies where the plasma vorticity is comparable or larger than the synchrotron frequency.
Comments:
13 pages, 4 figures; v2: expanded and corrected
Subjects:
High Energy Physics — Phenomenology (hep-ph); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
arXiv:
2102.10659 [pdf]
PLB(2021)·7 citations
18
[Submitted on 22 Feb 2021] (cross-list from nucl-ex)
The quest for light multineutron systems
F. Miguel Marques🇫🇷 · Jaume Carbonell🇫🇷
The long history of the research concerning the possible existence of bound or resonant states in light multineutron systems, essentially $^{3}$ n and $^{4}$ n, is reviewed. Both the experimental and the theoretical points of view have been considered, with the aim of showing a clear picture of all the different detection and calculation techniques that have been used, with particular emphasis in the issues that have been found. Finally, some aspects of the present and future research in this field are discussed.
Comments:
Accepted for publication in European Physical Journal A
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2102.10879 [pdf]
EPJA(2021)·47 citations
19
[Submitted on 22 Feb 2021] (cross-list from hep-ph)
Forces inside the nucleon on the light front from 3D Breit frame force distributions: Abel tomography case
Julia Yu. Panteleeva🇩🇪 · Maxim V. Polyakov🇩🇪
We derive simple relations which express 2D light front force distributions in terms of 3D Breit frame pressure and shear force distributions. Mathematically the relations correspond to invertible Abel transformation and they establish one-to-one mathematical equivalence of 3D Breit frame force distributions and 2D light front ones. Any knowledge (model calculation, experimental measurement, etc.) about pressure and shear force distributions in Breit frame can be unambiguously transformed into light front force distributions with the help of Abel transformation. It is important that the transformation ensures 2D stability conditions if the 3D stability conditions are satisfied. As an illustration of how the relations work, we calculated the light front force distributions for a large nucleus as a liquid drop, and for large $N_{c}$ nucleon as a chiral soliton.
Comments:
8 pages, minor typos are corrected
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2102.10902 [pdf]
PRD(2021)·63 citations
20
[Submitted on 22 Feb 2021] (cross-list from hep-ph)
On long-range pionic Bose-Einstein correlations -- Including analyses of OPAL, L3 and CMS BECs
Takuya Mizoguchi🇯🇵 · Minoru Biyajima🇯🇵
Long-range correlation plays an important role in analyses of pionic Bose-Einstein correlations (BECs). In many cases, such correlations are phenomenologically introduced. In this investigation, we propose an analytic form. By making use of the form, we analyze the OPAL BEC and the L3 BEC at $Z^{0}$ -pole and the CMS BEC at 0.9 and 7 TeV using our formulas and the $τ$ -model. The parameters estimated by both approaches are found to be consistent. Utilizing the Fourier transform in four-dimensional Euclidean space, a number of pion-pair density distributions are also studied.
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2102.11083 [pdf]
1 citation
21
[Submitted on 22 Feb 2021] (cross-list from hep-lat)
Confinement-Deconfinement transition and $Z_{2}$ symmetry in $Z_{2} +$ Higgs theory
Minati Biswal🇮🇳 · Sanatan Digal🇮🇳 · Vinod Mamale🇮🇳 · Sabiar Shaikh🇮🇳
We study the Polyakov loop and the $Z_{2}$ symmetry in the lattice $Z_{2} +$ Higgs theory in 4D Euclidean space using Monte Carlo simulations. The results show that this symmetry is realised in the Higgs symmetric phase for large number of temporal lattice sites. To understand the dependence on the number of temporal sites, we consider a one dimensional model by keeping terms of the original action corresponding to a single spatial site. In this approximation the partition function can be calculated exactly as a function of the Polyakov loop. The resulting free energy is found to have the $Z_{2}$ symmetry in the limit of large temporal sites. We argue that this is due to $Z_{2}$ invariance as well as dominance of the distribution or density of states corresponding to the action.
Comments:
17 pages, 23 figures
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2102.11091 [pdf]
Mod.Phys.Lett.A(2021)·3 citations
22
[Submitted on 22 Feb 2021] (cross-list from hep-th)
Conserved and non-conserved Noether currents from the quantum effective action
Stefan Floerchinger🇩🇪 · Eduardo Grossi🇺🇸
The quantum effective action yields equations of motion and correlation functions including all quantum corrections. We discuss here how it encodes also Noether currents at the full quantum level. Interestingly, the construction can be generalized beyond the standard symmetry transformations that leave the action invariant. We also discuss an extended set of transformations, which change the action by a term that is locally known on the level of the quantum effective action. Associated to such extended gauge transformations are currents for which we obtain a divergence-type equation of motion, but they are not conserved. We call them non-conserved Noether currents. We discuss in particular symmetries and extended transformations associated to space-time geometry for relativistic quantum field theories. These encompass local dilatations or Weyl gauge transformation, local Lorentz transformations and local shear transformations. Together they constitute the symmetry group of the frame bundle GL $(d)$ . The corresponding non-conserved Noether currents are the dilatation or Weyl current, the spin current and the shear current. In particular for the latter we obtain a new divergence-type equations of motion.
Comments:
25 pages
Subjects:
High Energy Physics — Theory (hep-th); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2102.11098 [pdf]
PRD(2022)·15 citations

Affiliations

first authorsco-authorsvia INSPIRE