Nuclear Theory·nucl-th

Monday·May 27, 2024

15 papers—5 primary·10 cross-listed

06
[Submitted on 16 Apr 2024] (cross-list from physics.soc-ph)
The story around the first 4n signal
F. Miguel Marqués🇫🇷
The GANIL campaign around the first 4n signal was very peculiar. The beginning and end were both dictated by unexpected events that, unfortunately, do not fit within the streamlined format of standard scientific publications. However, they illustrate many aspects of how basic research should work, or at least does work. Therefore, I take this opportunity to share them with those not involved in the campaign, hoping that they will offer a better perspective of that research in particular and of basic research in general. As a disclaimer, this is only a personal recollection of those events.
Comments:
Accepted for publication in "Advances on the Few-Body Problem in Physics - Selected and refereed papers from the 25th European Conference"
Subjects:
physics.soc-ph (physics.soc-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2405.14884 [pdf]
Few Body Syst.(2024)·1 citation
07
[Submitted on 23 May 2024] (cross-list from astro-ph.HE)
First detection of X-ray pulsations and spectrum of the high Galactic latitude pulsar PSR J0837-2454 and direct Urca cooling implications
Wynn C. G. Ho (Haverford) · Nihan Pol (Oregon State) · Adam T. Deller (Swinburne) · Werner Becker (MPE) · Sarah Burke-Spolaor (West Virginia)
PSR J0837-2454 is a young 629 ms radio pulsar whose uncertain distance has important implications. A large distance would place the pulsar far out of the Galactic plane and suggest it is the result of a runaway star, while a short distance would mean the pulsar is extraordinarily cold. Here we present further radio observations and the first deep X-ray observation of PSR J0837-2454. Data from the Parkes Murriyang telescope show flux variations over short and long timescales and also yield an updated timing model, while the position and proper motion (and, less strongly, parallax) of the pulsar are constrained by a number of low-significance detections with the Very Long Baseline Array. XMM-Newton data enable detection of X-ray pulsations for the first time from this pulsar and yield a spectrum that is thermal and blackbody-like, with a cool blackbody temperature ~70 eV or atmosphere temperature ~50 eV, as well as a small hotspot. The spectrum also indicates the pulsar is at a small distance of <~1 kpc, which is compatible with the marginal VLBA parallax constraint that favours a distance of >~330 pc. The low implied luminosity (~7.6x10^31 erg s^-1 at 0.9 kpc) suggests PSR J0837-2454 has a mass high enough that fast neutrino emission from direct Urca reactions operates in this young star and points to a nuclear equation of state that allows for direct Urca reactions at the highest densities present in neutron star cores.
Comments:
11 pages, 9 figures; published in PASA; style change to better match published version
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2405.14952 [pdf]
Publ.Astron.Soc.Austral.(2024)·2 citations
08
[Submitted on 23 May 2024] (cross-list from hep-ph)
Transverse Momentum Dependent PDFs in Chiral Effective Theory
Marston Copeland🇺🇸 · Thomas Mehen🇺🇸
We develop a theoretical framework to match transverse momentum dependent parton distribution functions (TMD PDFs) onto chiral effective theory operators. In this framework the TMD PDF is expressed as a convolution of TMD hadronic distribution functions, which describe fluctuations of initial states into intermediate hadrons in chiral perturbation theory, and short distance matching coefficients, which are the TMD PDFs of intermediate hadrons in the chiral limit. The various limits of the matching condition are explored and an operator product expansion is applied to the high energy TMD matching coefficients, allowing them to be written in terms of the collinear valence PDFs of intermediate hadrons. As an example, we calculate the isovector TMD hadronic distribution functions for the proton at leading order in the chiral expansion.
Comments:
30 pages, 5 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2405.14965 [pdf]
PRD(2024)·6 citations
09
[Submitted on 23 May 2024] (cross-list from hep-ph)
Understanding the puzzle of angular momentum conservation in beta decay and related processes
Gordon Baym🇺🇸 · Jen-Chieh Peng🇺🇸 · C. J. Pethick🇺🇸
We ask the question of how angular momentum is conserved in electroweak interaction processes. To introduce the problem with a minimum of mathematics, we first raise the same issue in elastic scattering of a circularly polarized photon by an atom, where the scattered photon has a different spin direction than the original photon, and note its presence in scattering of a fully relativistic spin-1/2 particle by a central potential. We then consider inverse beta decay in which an electron is emitted following the capture of a neutrino on a nucleus. While both the incident neutrino and final electron spins are antiparallel to their momenta, the final spin is in a different direction than that of the neutrino -- an apparent change of angular momentum. However, prior to measurement of the final particle, in all these cases angular momentum is indeed conserved, The apparent non-conservation of angular momentum arises in the quantum measurement process in which the measuring apparatus does not have an initially well-defined angular momentum, but is localized in the outside world. We generalize the discussion to massive neutrinos and electrons, and examine nuclear beta decay and electron-positron annihilation processes through the same lens, enabling physically transparent derivations of angular and helicity distributions in these reactions.
Comments:
9 pages, 1 figure. Expanded version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2405.15011 [pdf]
Proc.Nat.Acad.Sci.(2024)·1 citation
10
[Submitted on 23 May 2024] (cross-list from nucl-ex)
Modeling of Deuteron Induced Reactions on Molybdenum at Low Energies
M. Avrigeanu · E. Šimečková · J. Mrázek · C. Costache · V. Avrigeanu
The activities of the EUROfusion consortium on the development of high quality nuclear data for fusion applications include evaluations of deuteron induced reactions and related data libraries for needs of the DEMO fusion power plant and IFMIF-DONES neutron--source nuclear analyses. Molybdenum is one of the major constituents of the reference stainless steels used in critical components of these projects. While the TENDL deuteron data library was the current reference used by EUROfusion, need of its further improvement has already been pointed out. The weak binding energy of the deuteron is responsible for the high complexity of its interaction with nuclei, involving also a variety of reactions initiated by the nucleons following the deuteron breakup. Their analysis completed that of the deuteron interactions with Mo and its stable isotopes, from elastic scattering to pre-equilibrium and compound--nucleus reactions, up to 50 MeV. A particular attention has been paid to the breakup, stripping, and pick-up direct interactions which amount to around half of the deuteron total--reaction cross section. The due account of most experimental data has validated the present approach, highlighted some prevalent features, and emphasized weak points and consequently the need for modeling/evaluation upgrade.
Comments:
31 pages, 25 figures
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2405.15014 [pdf]
J.Fusion Energ.(2024)·3 citations
11
[Submitted on 24 May 2024] (cross-list from hep-ph)
Exploring Baryon Resonances with Transition Generalized Parton Distributions: Status and Perspectives
Stefan Diehl🇩🇪 · Kyungseon Joo🇺🇸 · Kirill Semenov-Tian-Shansky🇰🇷 · Christian Weiss🇺🇸 · Vladimir Braun🇩🇪 · Wen-Chen Chang🇹🇼 · Pierre Chatagnon🇺🇸 · Martha Constantinou🇺🇸 · Yuxun Guo🇺🇸 · Parada T. P. Hutauruk🇰🇷 · Hyon-Suk Jo🇰🇷 · Andrey Kim🇺🇸 and 12 other authors
QCD gives rise to a rich spectrum of excited baryon states. Understanding their internal structure is important for many areas of nuclear physics, such as nuclear forces, dense matter, and neutrino-nucleus interactions. Generalized parton distributions (GPDs) are an established tool for characterizing the QCD structure of the ground-state nucleon. They are used to create 3D tomographic images of the quark/gluon structure and quantify the mechanical properties such as the distribution of mass, angular momentum and forces in the system. Transition GPDs extend these concepts to $N \to N^{*}$ transitions and can be used to characterize the 3D structure and mechanical properties of baryon resonances. They can be probed in high-momentum-transfer exclusive electroproduction processes with resonance transitions $e + N \to e^{'} + M + N^{*}$ , such as deeply-virtual Compton scattering ( $M = γ$ ) or meson production ( $M = π, K$ , $e t c .$ ), and in related photon/hadron-induced processes. This White Paper describes a research program aiming to explore baryon resonance structure with transition GPDs. This includes the properties and interpretation of the transition GPDs, theoretical methods for structures and processes, first experimental results from JLab 12 GeV, future measurements with existing and planned facilities (JLab detector and energy upgrades, COMPASS/AMBER, EIC, EicC, J-PARC, LHC ultraperihperal collisions), and the theoretical and experimental developments needed to realize this program.
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2405.15386 [pdf]
EPJA(2025)·32 citations
12
[Submitted on 24 May 2024] (cross-list from nucl-ex)
High-resolution spectroscopy of neutron-rich Br isotopes and signatures for a prolate-to-oblate shape transition at N=56
J. Dudouet🇫🇷 · G. Colombi🇫🇷 · D. Reygadas Tello🇫🇷 · C. Michelagnoli🇫🇷 · D.D. Dao🇫🇷 · F. Nowacki🇫🇷 · M. Abushawish🇫🇷 · E. Clément🇫🇷 · C. Costache🇷🇴 · G. Duchêne🇫🇷 · F. Kandzia🇫🇷 · A. Lemasson🇫🇷 and 30 other authors
The first systematic experimental study of the neutron-rich Br isotopes with two complementary state-of-the-art techniques is presented. These isotopes have been populated in the fission process at two different facilities, GANIL and ILL. New spectroscopic information has been obtained for odd-even $^{87 - 93}$ Br isotopes and the experimental results have been compared with state-of-the-art Large-Scale Shell-Model and DNO Shell-Model calculations. As a result of such theoretical approaches, a transition from prolate ( $^{87, 89}$ Br) to oblate ( $^{91, 93}$ Br) shapes is obtained from the subtle balance between proton and neutron quadrupole deformations, as a clear signature of pseudo-SU3 quadrupole regime.
Comments:
17 pages, 24 figures, 5 tables
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2405.15601 [pdf]
PRC(2024)·5 citations
13
[Submitted on 24 May 2024] (cross-list from astro-ph.HE)
Spin-down of a pulsar with a yielding crust
Denis Nikolaevich Sob'yanin
In light of the discovery of the long-period radio pulsar PSR J0901-4046, it is interesting to revisit a question about how the magnetized neutron star slows down its rotation. In the case of a weak or liquid outer crust, the mechanism of spin-down becomes unclear because the braking stress cannot then be transmitted from the surface to the main bulk of the star. We show that even if the outer crust does not withstand the surface electromagnetic forces creating the braking torque, the stellar spin-down does not stop, and the matter rearranges so that the necessary electromagnetic forces form in more deep and rigid layers capable of withstanding these forces. The spin-down rate remains the same and corresponds to the transformation of the rotational energy of the neutron star into the energy of the generated relativistic electron-positron plasma. The solid iron surface of ultrastrongly magnetized PSR J0901-4046 appears not to be yielding and withstands the braking stress without breaking.
Comments:
5 pages, 1 figure
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th); physics.space-ph (physics.space-ph)
arXiv:
2405.15659 [pdf]
PRD(2024)·0 citations
14
[Submitted on 24 May 2024] (cross-list from hep-ph)
Jet Quenching of the Heavy Quarks in the Quark-Gluon Plasma and the Nonadditive Statistics
Trambak Bhattacharyya🇷🇺 · Eugenio Megias🇪🇸 · Airton Deppman🇧🇷
Using the Plastino-Plastino (PP) equation, we calculate transport coefficients of the heavy-quarks traversing inside the quark-gluon plasma, and generalize their relationship with differential energy loss. The PP equation indicates anomalous diffusion of the probe particles and yields a quasi-exponential stationary distribution obtained also from the nonadditive statistics proposed by C. Tsallis. We estimate energy loss in a nonadditive quark-gluon medium, and calculate the jet-quenching parameter ( $q^$ ) for the PP dynamics. With the help of the estimate of $q^$ , we calculate the nuclear suppression factor ( $R_{AA}$ ) of the heavy-quarks passing through a nonadditive quark-gluon plasma using the model proposed by Dokshitzer and Kharzeev. In many a case, the parameters in the analysis are fixed from the experimental results to minimize arbitrariness. There is a good agreement between the theoretical calculation and experimental $R_{AA}$ data, indicating that fast heavy-quarks may be subjected to anomalous diffusion inside the QGP.
Comments:
12 pages, 4 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2405.15679 [pdf]
PLB(2024)·9 citations
15
[Submitted on 24 May 2024] (cross-list from hep-ph)
Magnetic effects in the Hadron Resonance Gas
Michał Marczenko🇵🇱 · Michał Szymański🇵🇱 · Pok Man Lo🇵🇱 · Bithika Karmakar🇵🇱 · Pasi Huovinen🇵🇱 · Chihiro Sasaki🇵🇱 · Krzysztof Redlich🇵🇱
We discuss the modeling of the hadronic phase of QCD at finite magnetic field in the framework of hadron resonance gas (HRG). We focus on the statistical description of particle yields that include contribution from resonance decays. We demonstrate that the swift increase in the number of protons with magnetic field predicted in the HRG is due to the ill-defined description of higher-spin states. We discuss fluctuations of conserved charges and show that at present the qualitative comparison of the model predictions with the Lattice QCD data should be treated with care. We also discuss the principle of detailed balance which allows to study the magnetic field dependence of neutral resonances.
Comments:
version accepted for publication in PRC
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2405.15745 [pdf]
PRC(2024)·17 citations

Affiliations

first authorsco-authorsvia INSPIRE