Nuclear Theory·nucl-th

Tuesday·January 31, 2023

13 papers—4 primary·9 cross-listed

05
[Submitted on 27 Jan 2023] (cross-list from astro-ph.HE)
Fast Neutrino Flavor Conversion in Core-Collapse Supernovae: A Parametric Study in 1D Models
Jakob Ehring (1,2,3)🇩🇪 · Sajad Abbar (1)🇩🇪 · Hans-Thomas Janka (2)🇩🇪 · Georg Raffelt (1)🇩🇪 · Irene Tamborra (4) ((1) MPI Physik, (2) MPI Astrophysik, (3) TUM Garching, (4) Niels Bohr Institute)🇩🇰
We explore the impact of small-scale flavor conversions of neutrinos, the so-called fast flavor conversions (FFCs), on the dynamical evolution and neutrino emission of core-collapse supernovae (CCSNe). In order to do that, we implement FFCs in the spherically symmetric (1D) CCSN simulations of a 20 solar-mass progenitor model parametrically, assuming that FFCs happen at densities lower than a systematically varied threshold value and lead to an immediate flavor equilibrium consistent with lepton number conservation. We find that besides hardening the electron neutrino and antineutrino spectra, which helps the expansion of the shock by enhanced postshock heating, FFCs can cause significant, nontrivial modifications of the energy transport in the SN environment via increasing the heavy-lepton neutrino luminosities. In our non-exploding models this results in extra cooling of the layers around the neutrinospheres, which triggers a faster contraction of the proto-neutron star and hence, in our 1D models, hampers the CCSN explosion. Although our study is limited by the 1D nature of our simulations, it provides valuable insights into how neutrino flavor conversions in the deepest CCSN regions can impact the neutrino release and the corresponding response of the stellar medium.
Comments:
20 pages, 10 figures, slightly extended version, accepted by PRD
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2301.11938 [pdf]
PRD(2023)·107 citations
06
[Submitted on 27 Jan 2023] (cross-list from hep-ph)
Understanding parton evolution in matter from renormalization group analysis
Weiyao Ke🇺🇸 · Ivan Vitev🇺🇸
We perform a renormalization group (RG) analysis of collinear hadron production in deep inelastic scattering on nuclei. We consider the limit where the parent parton energy $E$ is large, while the medium opacity $L / λ_{g}$ remains small. We identify the fixed order and leading $ln (E / ξ^{2} L)$ enhanced medium contributions to the semi-inclusive cross sections and derive RG equations that resum multiple emissions near the endpoints of the splitting functions at first order in opacity. These evolution equations treat the same type of radiation enhancement in matter as the modified Dokshitzer-Gribov-Lipatov-Altarelli-Parisi approach, but differ in the way one regulates the collinear divergences. They provide a unique analytic insight into the problem of resummation and a faster and more efficient path to phenomenology. The new RG evolution framework is applied to study fragmentation in $e$ A reactions.
Comments:
Accepted by Phys. Lett. B., 7 pages, 2 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2301.11940 [pdf]
PLB(2024)·17 citations
07
[Submitted on 27 Jan 2023] (cross-list from hep-ph)
Real-time non-perturbative dynamics of jet production: quantum entanglement and vacuum modification
Adrien Florio🇺🇸 · David Frenklakh🇺🇸 · Kazuki Ikeda🇺🇸 · Dmitri Kharzeev🇺🇸 · Vladimir Korepin🇺🇸 · Shuzhe Shi🇺🇸 · Kwangmin Yu🇺🇸
The production of jets should allow testing the real-time response of the QCD vacuum disturbed by the propagation of high-momentum color charges. Addressing this problem theoretically requires a real-time, non-perturbative method. It is well known that the Schwinger model [QED in $(1 + 1)$ dimensions] shares many common properties with QCD, including confinement, chiral symmetry breaking, and the existence of vacuum fermion condensate. As a step in developing such an approach, we report here on fully quantum simulations of a massive Schwinger model coupled to external sources representing quark and antiquark jets as produced in $e^{+} e^{-}$ annihilation. We study, for the first time, the modification of the vacuum chiral condensate by the propagating jets and the quantum entanglement between the fragmenting jets. Our results indicate strong entanglement between the fragmentation products of the two jets at rapidity separations $Δ η \leq 2$ , which can potentially exist also in QCD and can be studied in experiments.
Comments:
5 pages + supplementary materials, 10 figures; final version
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2301.11991 [pdf]
PRL(2023)·86 citations
08
[Submitted on 27 Jan 2023] (cross-list from nucl-ex)
New isomeric transition in $^{36}$ Mg: Bridging the N=20 and N=28 islands of inversion
M. Madurga · J.M. Christie · Z. Xu · R. Grzywacz · A. Poves · T. King · J.M. Allmond · A. Chester · I. Cox · J. Farr · I. Fletcher · J. Heideman and 11 other authors
We observed a new isomeric gamma transition at 168 keV in $^{36}$ Mg, with a half-life of T $_{1/2}$ =[130-500] $(\pm 40) (_{- 20}^{+ 800})_{sy s}$ ns. We propose that the observed transition de-excites a new 0 $^{+}$ isomeric state and populates the previously known first 2 $^{+}$ state. The existence of this isomer is consistent with the predictions of the large-scale shell model calculations of $^{36}$ Mg using the sdpf-u-mix interaction. The observed excitation energy of the second 0 $^{+}$ state is caused by the small energy separation between two prolate-deformed configurations where the intruder configuration corresponds to two neutron excitations from the {\it sd} to the {\it pf} shell. Within this interpretation, $^{36}$ Mg becomes the crossing point between nuclei in which ground state deformed/superdeformed configurations are caused by the dominance of N=20 intruders ( $^{32, 34}$ Mg) and nuclei where deformed configurations are associated with N=28 intruders ( $^{38}$ Mg and beyond). We found the lack of three-body monopole corrections in other effective interactions results in a predominance of N=20 intruder configurations past $^{38}$ Mg incompatible with our observation. We conclude that $^{36}$ Mg bridges the N=20 and N=28 islands of inversion, forming the so-called Big Island of Deformation.
Comments:
7 pages, 4 figures
Subjects:
Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2301.12002 [pdf]
PRC(2024)·3 citations
09
[Submitted on 29 Jan 2023] (cross-list from hep-ph)
Revealing a deep connection between factorization and saturation: New insight into modeling high-energy proton-proton and nucleus-nucleus scattering in the EPOS4 framework
Klaus Werner🇫🇷
It is known that multiple partonic scatterings in high-energy proton-proton ( $pp$ ) collisions must happen in parallel. However, a rigorous parallel scattering formalism, taking energy sharing properly into account, fails to reproduce factorization, which on the other hand is the basis of almost all $pp$ event generators. In addition, binary scaling in nuclear scatterings is badly violated. These problems are usually ``solved'' by simply not considering strictly parallel scatterings, which is not a solution. I will report on new ideas (leading to EPOS4), which allow recovering perfectly factorization, and also binary scaling in $AA$ collisions, in a rigorous unbiased parallel scattering formalism. In this new approach, dynamical saturation scales play a crucial role, and this seems to be the missing piece needed to reconcile parallel scattering with factorization. From a practical point of view, one can compute within the EPOS4 framework parton distribution functions (EPOS PDFs) and use them to compute inclusive $pp$ cross sections. So, for the first time, one may compute inclusive jet production (for heavy or light flavors) at very high transverse momentum ( $p_{t}$ ) and at the same time in the same formalism study flow effects at low $p_{t}$ in high-multiplicity $pp$ events, making EPOS4 a full-scale ``general purpose event generator''. I discuss applications, essentially multiplicity dependencies (of particle ratios, mean $p_{t}$ , charm production) which are very strongly affected by the saturation issues discussed in this paper.
Comments:
24 pages, 37 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2301.12517 [pdf]
PRC(2023)·106 citations
10
[Submitted on 30 Jan 2023] (cross-list from astro-ph.HE)
Constraining the Surface Curvature of an Anisotropic Neutron Star
H. C. Das · Jeet Amrit Pattnaik · S. K. Patra
The anisotropy of pressure arises due to the various complex phenomena that happen inside the neutron star (NS). In this study, we calculate the degree of anisotropy inside the NS using the scalar pressure anisotropy model. Macroscopic properties such as mass, radius, compactness, redshift, tidal deformability, the moment of inertia, and surface curvature (SC) are computed for the anisotropic NS with the equation of states spanning from relativistic to nonrelativistic cases. The variation of SC as the functions of the above-mentioned quantities are computed by changing the degree of anisotropy. Pressure anisotropy has significant effects on the magnitude of SC. The universal relations between the canonical SC $- Λ$ and SC $- I ˉ$ are studied. From the GW170817 tidal deformability data constraints on SC are found to be SC $_{1.4} (1 0^{14}) = 3.4 4_{- 1.0}^{+ 0.4}, 2.8 5_{- 1.20}^{+ 0.62}, and 2.5 2_{- 1.02}^{+ 0.61}$ for $λ_{BL} = 0.0, 1.0$ , and $2.0$ respectively.
Comments:
8 pages, 6 figures, 1 table, Published in Phys. Rev. D
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2301.12673 [pdf]
PRD(2023)·11 citations
11
[Submitted on 30 Jan 2023] (cross-list from astro-ph.HE)
Insights into the physics of neutron star interiors from pulsar glitches
Marco Antonelli🇫🇷 · Alessandro Montoli🇮🇹 · Pierre Pizzochero🇮🇹
The presence of superfluid phases in the interior of a neutron star affects its dynamics, as neutrons can flow relative to the non-superfluid (normal) components of the star with little or no viscosity. A probe of superfluidity comes from pulsar glitches, sudden jumps in the observed rotational period of radio pulsars. Most models of glitches build on the idea that a superfluid component of the star is decoupled from the spin-down of the normal component, and its sudden recoupling leads to a glitch. This transition in the strength of the hydrodynamic coupling is explained in terms of quantum vortices (long-lived vortices that are naturally present in the neutron superfluid at the microscopic scale). After introducing some basic ideas, we derive (as a pedagogical exercise) the formal scheme shared by many glitch studies. Then, we apply these notions to present some recent advances and discuss how observations can help us to indirectly probe the internal physics of neutron stars.
Comments:
30 pages, 7 figures. Chapter 7 of the volume "Astrophysics in the XXI Century with Compact Stars", Eds. C.A.Z. Vasconcellos and F. Weber, World Scientific (2022), submitted in August 2021. Minor corrections implemented
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2301.12769 [pdf]
Astrophysics in the XXI Century with Comp…·25 citations
12
[Submitted on 30 Jan 2023] (cross-list from hep-ph)
Transverse structure of the pion beyond leading twist with basis light-front quantization
Zhimin Zhu · Zhi Hu · Jiangshan Lan · Chandan Mondal · Xingbo Zhao · James P. Vary · BLFQ Collaboration
We investigate the twist- $3$ transverse-momentum-dependent parton distribution functions (TMDs) of the pion with basis light-front quantization. The twist-3 TMDs are not independent and can be decomposed into twist- $2$ and genuine twist- $3$ terms from the equations of motion (EOM). We compute the TMDs from the resulting light-front wave functions obtained by diagonalizing the light-front QCD Hamiltonian, determined for pion's constituent quark-antiquark and quark-antiquark-gluon Fock sectors, with three-dimensional confinement. We also obtain the twist-3 parton distribution functions (PDFs) and show that they preserve the sum rule, which affirms the robustness of our approach. This is the first time that theoretical predictions are made for subleading twist structures of the pion containing interference terms between two light-front Fock sectors.
Comments:
12 pages, 7 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2301.12994 [pdf]
PLB(2023)·36 citations
13
[Submitted on 30 Jan 2023] (cross-list from hep-ph)
Exploring Current Constraints on Antineutrino Production by $^{241}$ Pu and Paths Towards the Precision Reactor Flux Era
Yoshi Fujikake🇺🇸 · Bryce Littlejohn🇺🇸 · Ohana B. Rodrigues🇺🇸 · Pranava Teja Surukuchi🇺🇸
By performing global fits to inverse beta decay (IBD) yield measurements from existing neutrino experiments based at highly $^{235}$ U enriched reactor cores and conventional low-enriched cores, we explore current direct bounds on neutrino production by the sub-dominant fission isotope $^{241}$ Pu. For this nuclide, we determine an IBD yield of $σ_{241}$ = 8.16 $\pm$ 3.47 cm $^{2}$ /fission, a value (135 $\pm$ 58)% that of current beta conversion models. This constraint is shown to derive from the non-linear relationship between burn-in of $^{241}$ Pu and $^{239}$ Pu in conventional reactor fuel. By considering new hypothetical neutrino measurements at high-enriched, low-enriched, mixed-oxide, and fast reactor facilities, we investigate the feasible limits of future knowledge of IBD yields for $^{235}$ U, $^{238}$ U, $^{239}$ Pu, $^{241}$ Pu, and $^{240}$ Pu. We find that the first direct measurement of the $^{240}$ Pu IBD yield can be performed at plutonium-burning fast reactors, while a suite of correlated measurements at multiple reactor types can achieve precision in direct $^{238}$ U, $^{239}$ Pu, and $^{241}$ Pu yield knowledge that meets or exceeds that of current theoretical predictions.
Comments:
13 page, 6 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2301.13123 [pdf]
PRD(2023)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE