Nuclear Theory·nucl-th

Monday·May 23, 2022

10 papers—5 primary·5 cross-listed

01
[Submitted on 20 May 2022]
The proton structure in and out of muonic hydrogen
Aldo Antognini (PSI, ETH Zürich)🇨🇭 · Franziska Hagelstein (JGU Mainz, PSI)🇨🇭 · Vladimir Pascalutsa (JGU Mainz)🇩🇪
Laser spectroscopy of muonic atoms has been recently used to probe properties of light nuclei with unprecedented precision. We introduce nuclear effects in hydrogen-like atoms, nucleon structure quantities (form factors, structure functions, polarizabilities) and their effects in the Lamb shift and hyperfine splitting (HFS) of muonic hydrogen ( $μ$ H). Updated theory predictions for the Lamb shift and HFS in $μ$ H are presented. We review the challenges of the ongoing effort to measure the ground-state HFS in $μ$ H and its impact on our understanding of the nucleon spin structure. To narrow down this search, we present a novel theory prediction obtained by scaling the measured HFS in hydrogen leveraging radiative corrections. We also summarize recent developments in the spectroscopy of simple atomic and molecular systems and emphasize how they allow for precise determinations of fundamental constants, bound-state QED tests and New Physics searches.
Comments:
48 pages; 11 figures; 4 tables; final version with extended Supplement; posted with permission from the Annual Review of Nuclear and Particle Science, Volume 72 by Annual Reviews, http://www.annualreviews.org
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Atomic Physics (physics.atom-ph)
arXiv:
2205.10076 [pdf]
Ann.Rev.Nucl.Part.Sci.(2022)·70 citations
02
[Submitted on 20 May 2022]
Least-square approach for singular value decompositions of scattering problems
A. Tichai🇩🇪 · P. Arthuis🇩🇪 · K. Hebeler🇩🇪 · M. Heinz🇩🇪 · J. Hoppe🇩🇪 · A. Schwenk🇩🇪 · L. Zurek🇩🇪
It was recently observed that chiral two-body interactions can be efficiently represented using matrix factorization techniques such as the singular value decomposition. However, the exploitation of these low-rank structures in a few- or many-body framework is nontrivial and requires reformulations that explicitly utilize the decomposition format. In this work, we present a general least-square approach that is applicable to different few- and many-body frameworks and allows for an efficient reduction to a low number of singular values in the least-square iteration. We verify the feasibility of the least-square approach by solving the Lippmann-Schwinger equation in factorized form. The resulting low-rank approximations of the $T$ matrix are found to fully capture scattering observables. Potential applications of the least-square approach to other frameworks with the goal of employing tensor factorization techniques are discussed.
Comments:
8 pages, 4 figures, 1 table, version accepted at Phys. Rev. C
Subjects:
Nuclear Theory (nucl-th); Strongly Correlated Electrons (cond-mat.str-el)
arXiv:
2205.10087 [pdf]
PRC(2022)·9 citations
03
[Submitted on 20 May 2022]
In-medium effects in $ϕ$ meson production in heavy-ion collisions from subthreshold to relativistic energies
Taesoo Song🇩🇪 · Joerg Aichelin🇫🇷 · Elena Bratkovskaya🇩🇪
We investigate the hidden strange $ϕ$ meson production in heavy-ion collisions from subthreshold ( $E_{k in} \approx 1$ A GeV) to relativistic ( $E_{k in} \approx 21$ A TeV) energies as well as its coupling to the open strange mesons (kaons, antikaons) and their productions. Our study is based on the off-shell microscopic Parton-Hadron-String Dynamics (PHSD) transport approach which is applicable for the dynamical description of strongly interacting hadronic and partonic degrees-of-freedom created in heavy-ion collisions. Implementing novel meson-baryon and meson-hyperon production channels for $ϕ$ mesons, calculated within a T-matrix coupled channel approach based on the extended SU(6) chiral effective Lagrangian model, along with the collisional broadening of the $ϕ$ -meson in-medium spectral function, we find a substantial enhancement of $ϕ$ meson production in heavy-ion collisions, especially at sub- and near-thresholds. This allows to describe the experimentally observed strong enhancement of the $ϕ / K^{-}$ ratio at low energies without including hypothetical decays of heavy baryonic resonances to $ϕ$ as in alternative approaches. Moreover, we show that in spite of a stronger contribution from enhanced $ϕ$ to $K^{-}$ production, the majority of the experimental data for different A+A systems at low energies favor the scenario with in-medium modifications of the kaon and antikaon properties in the hot and dense environment. Moreover, we study the influence of the final state interactions of $K, K ˉ$ mesons on the reconstruction of $ϕ$ 's by the by invariant mass method.
Comments:
24 pages, 22 figures
Subjects:
Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
arXiv:
2205.10251 [pdf]
PRC(2022)·22 citations
04
[Submitted on 20 May 2022]
Relativistic mean-field theories for neutron-star physics based on chiral effective field theory
Mark G. Alford🇺🇸 · Liam Brodie🇺🇸 · Alexander Haber🇺🇸 · Ingo Tews🇺🇸
We describe and implement a procedure for determining the couplings of a Relativistic Mean-Field Theory (RMFT) that is optimized for application to neutron star phenomenology. In the standard RMFT approach, the couplings are constrained by comparing the theory's predictions for symmetric matter at saturation density with measured nuclear properties. The theory is then applied to neutron stars which consist of neutron-rich matter at densities ranging up to several times saturation density, which allows for additional astrophysical constraints. In our approach, rather than using the RMFT to extrapolate from symmetric to neutron-rich matter and from finite-sized nuclei to uniform matter, we fit the RMFT to properties of uniform pure neutron matter obtained from chiral effective field theory. Chiral effective field theory incorporates the experimental data for nuclei in the framework of a controlled expansion for nuclear forces valid at nuclear densities and enables us to account for theoretical uncertainties when fitting the RMFT. We construct four simple RMFTs that span the uncertainties provided by chiral effective field theory for neutron matter, and are consistent with current astrophysical constraints on the equation of state. Our RMFTs can be used to model the properties of neutron-rich matter across the vast range of densities and temperatures encountered in neutron stars and their mergers.
Comments:
V2: Minor corrections, version published in PRC. 12 pages and 5 figures
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph)
arXiv:
2205.10283 [pdf]
PRC(2022)·73 citations
05
[Submitted on 20 May 2022]
Numerical Simulation of Shell Model Single Particle Energy States using Matrix Numerov Method in Gnumeric Worksheet
Shikha Awasthi · Aditi Sharma · Swapna Gora · O.S.K.S. Sastri
Single particle energy states as described by nuclear shell model are obtained for doubly magic nuclei using Gnumeric worksheet environment. Numerov method rephrased in matrix form is utilised to solve time-independent Schrodinger equation (TISE) within mean-field approximation, described by Woods-Saxon (WS) potential along with spin-orbit term, to obtain the single particle energies for both neutron and proton states. The WS model parameters are chosen from previous simulation results performed using matrix methods technique involving sine basis, where optimization was done w.r.t available experimental single particle energies for 208Pb and 48Ca. In this paper, only the algorithm parameters, step size h and matrix size N are optimized to obtain the expected energy level sequence obtained using matrix methods. An attempt is made, by incorporating this tool within the framework of guided inquiry strategy (a constructivist approach to learning), to actively engage the students in assigning appropriate spin-parity configurations for ground states of nuclei neighbouring the doubly magic ones. It has been observed that the ground state configurations could be better predicted when energy level sequences are known for all nuclei as compared to what is usually obtained from that of 208Pb alone.
Comments:
17 pages, 2 Figures, 4 Tables
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2205.10335 [pdf]
0 citations
06
[Submitted on 19 May 2022] (cross-list from astro-ph.HE)
Exploring the effects of Delta Baryons in magnetars
K. D. Marquez🇧🇷 · M. R. Pelicer🇧🇷 · S. Ghosh🇮🇳 · J. Peterson🇺🇸 · D. Chatterjee🇮🇳 · V. Dexheimer🇺🇸 · D. P. Menezes🇧🇷
Strong magnetic fields can modify the microscopic composition of matter with consequences on stellar macroscopic properties. Within this context, we study, for the first time, the possibility of the appearance of spin-3/2 $Δ$ baryons in magnetars. We make use of two different relativistic models for the equation of state of dense matter under the influence of strong magnetic fields considering the effects of Landau levels and the anomalous magnetic moment (AMM) proportional to the spin of all baryons and leptons. In particular, we analyze the effects of the AMM of $Δ$ baryons in dense matter for the first time. {We also obtain global properties corresponding to the EoS models numerically and study the corresponding role of the $Δ$ baryons.} We find that they are favored over hyperons, which causes an increase in isopin asymmetry and a decrease in spin polarization. We also find that, contrary to what generally occurs when new degrees of freedom are introduced, the $Δ$ s do not make the EoS significantly softer and magnetars less massive. Finally, the magnetic field distribution inside a given star is not affected by the presence of $Δ$ s.
Comments:
14 pages, 9 figures, 2 tables
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2205.09827 [pdf]
PRC(2022)·20 citations
07
[Submitted on 20 May 2022] (cross-list from hep-ph)
Ratio of baryon and electric-charge cumulants at second order with acceptance corrections
Masakiyo Kitazawa🇯🇵 · ShinIchi Esumi🇯🇵 · Toshihiro Nonaka🇯🇵
We evaluate the ratio of baryon and electric-charge cumulants at second order from the recent experimental results at $s_{_{N N}} = 200$ GeV by the STAR Collaboration. The baryon number cumulant is reconstructed from the proton number distribution, and effects of the finite acceptance on the transverse momentum are corrected assuming the independent particle emission. We show that the obtained ratio has a dependence on the rapidity window. Comparison of the result with the hadron resonance gas model and lattice QCD numerical simulations suggests that if the fluctuations are generated from a thermal medium its temperature is significantly lower than the chemical freezeout temperature.
Comments:
6 pages, 3 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2205.10030 [pdf]
NPA(2023)·4 citations
08
[Submitted on 20 May 2022] (cross-list from nucl-ex)
First results from the INDRA-FAZIA apparatus on isospin diffusion in $^{58, 64}$ Ni+ $^{58, 64}$ Ni systems at Fermi energies
C. Ciampi · S. Piantelli · G. Casini · G. Pasquali · J. Quicray · L. Baldesi · S. Barlini · B. Borderie · R. Bougault · A. Camaiani · A. Chbihi · D. Dell'Aquila and 34 other authors
An investigation of the isospin equilibration process in the reactions $^{58, 64}$ Ni+ $^{58, 64}$ Ni at two bombarding energies in the Fermi regime ( $32$ MeV/nucleon and $52$ MeV/nucleon) is presented. Data have been acquired during the first experimental campaign of the coupled INDRA-FAZIA apparatus in GANIL. Selecting from peripheral to semi-central collisions, both the neutron content of the quasiprojectile residue and that of the light ejectiles coming from the quasiprojectile evaporation have been used as probes of the dynamical process of isospin diffusion between projectile and target for the asymmetric systems. The isospin transport ratio technique has been employed. The relaxation of the initial isospin imbalance with increasing centrality has been clearly evidenced. The isospin equilibration appears stronger for the reactions at $32$ MeV/nucleon, as expected due to the longer projectile-target interaction time than at $52$ MeV/nucleon. Coherent indications of isospin equilibration come from the quasiprojectile residue characteristics and from particles ascribed to the quasiprojectile decay.
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2205.10171 [pdf]
PRC(2022)·28 citations
09
[Submitted on 20 May 2022] (cross-list from hep-ph)
Response of a baryon-charged medium to energetic partons
Lipei Du (McGill U., Ohio State U.)🇨🇦 · Ulrich Heinz (Ohio State U.)🇺🇸
We explore the response to energetic partons of a baryon-charged medium produced in low energy heavy-ion collisions in which the partonic energy loss rate is expected to depend on both temperature and baryon chemical potential. The energy and momentum deposited by the partons are described by dynamical sources added to hydrodynamic equations of motion. We study the distortions of various hydrodynamic quantities, especially the energy and baryon densities, induced by energetic partons plowing through the medium. By studying the contribution from this medium response to the emission spectra of several identified hadron species we identify qualitative differences between the jet-induced modifications for mesons and net protons.
Comments:
v3: title changed, published on PRC
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2205.10262 [pdf]
PRC(2022)·7 citations
10
[Submitted on 20 May 2022] (cross-list from hep-ph)
Heavy quarkonium dynamics at next-to-leading order in the binding energy over temperature
Nora Brambilla🇩🇪 · Miguel Ángel Escobedo🇪🇸 · Ajaharul Islam🇺🇸 · Michael Strickland🇺🇸 · Anurag Tiwari🇺🇸 · Antonio Vairo🇩🇪 · Peter Vander Griend🇩🇪
Using the potential non-relativistic quantum chromodynamics (pNRQCD) effective field theory, we derive a Lindblad equation for the evolution of the heavy-quarkonium reduced density matrix that is accurate to next-to-leading order (NLO) in the ratio of the binding energy of the state to the temperature of the medium. The resulting NLO Lindblad equation can be used to more reliably describe heavy-quarkonium evolution in the quark-gluon plasma at low temperatures compared to the leading-order truncation. For phenomenological application, we numerically solve the resulting NLO Lindblad equation using the quantum trajectories algorithm. To achieve this, we map the solution of the three-dimensional Lindblad equation to the solution of an ensemble of one-dimensional Schrödinger evolutions with Monte-Carlo sampled quantum jumps. Averaging over the Monte-Carlo sampled quantum jumps, we obtain the solution to the NLO Lindblad equation without truncation in the angular momentum quantum number of the states considered. We also consider the evolution of the system using only the complex effective Hamiltonian without stochastic jumps and find that this provides a reliable approximation for the ground state survival probability at LO and NLO. Finally, we make comparisons with our prior leading-order pNRQCD results and experimental data available from the ATLAS, ALICE, and CMS collaborations.
Comments:
40 pages, 8 figures; corrections to secs. 2.4, 3.2 and 3.4 as detailed in erratum
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th); Computational Physics (physics.comp-ph)
arXiv:
2205.10289 [pdf]
JHEP(2022)·59 citations

Affiliations

first authorsco-authorsvia INSPIRE