Tue·Sep 19, 2023Tuesday·September 19, 2023

1. 01*

   Structure Studies of ${}^{13}\text{Be}$ from the ${}^{12}$Be(d,p) reaction in inverse kinematics on a solid deuteron target

   J. Kovoor · K.L. Jones · J. Hooker🇺🇸 · M. Vostinar · R. Kanungo🇨🇦 · S.D. Pain🇺🇸 · M. Alcorta🇨🇦 · J. Allen · C. Andreoiu🇨🇦 · L. Atar🇩🇪 · D.W. Bardayan🇺🇸 · S.S. Bhattacharjee🇨🇦 and 33 other authors

   The low-lying structure of ${}^{13}$Be has remained an enigma for decades. Despite numerous experimental and theoretical studies, large inconsistencies remain. Being both unbound, and one neutron away from ${}^{14}$Be, the heaviest bound beryllium nucleus, ${}^{13}$Be is difficult to study through simple reactions with weak radioactive ion beams or more complex reactions with stable-ion beams. Here, we present the results of a study using the ${}^{12}$Be(d,p)${}^{13}$Be reaction in inverse kinematics using a 9.5~MeV per nucleon ${}^{12}$Be beam from the ISAC-II facility. The solid deuteron target of IRIS was used to achieve an increased areal thickness compared to conventional deuterated polyethylene targets. The Q-value spectrum below -4.4~MeV was analyzed using a Bayesian method with GEANT4 simulations. A three-point angular distribution with the same Q-value gate was fit with a mixture of $s$- and $p$-wave, $s$- and $d$-wave, or pure $p$-wave transfer. The Q-value spectrum was also compared with GEANT simulations obtained using the energies and widths of states reported in four previous works. It was found that our results are incompatible with works that revealed a wide $5/2^{+}$ resonance but shows better agreement with ones that reported a narrower width.

   nucl-exPRC(2023)·4 citations
2. 02*

   Spin dependence in the $p$-wave resonance of ${}^{139}\overrightarrow{\mathrm{La}}+\vec{n}$

   T. Okudaira · R. Nakabe · S. Endo · H. Fujioka · V. Gudkov · I. Ide · T. Ino · M. Ishikado · W. Kambara · S. Kawamura · R. Kobayashi · M. Kitaguchi and 15 other authors

   We measured the spin dependence in a neutron-induced $p$-wave resonance by using a polarized epithermal neutron beam and a polarized nuclear target. Our study focuses on the 0.75~eV $p$-wave resonance state of ${}^{139}$La+$n$, where largely enhanced parity violation has been observed. We determined the partial neutron width of the $p$-wave resonance by measuring the spin dependence of the neutron absorption cross section between polarized ${}^{139}\mathrm{La}$ and polarized neutrons. Our findings serve as a foundation for the quantitative study of the enhancement effect of the discrete symmetry violations caused by mixing between partial amplitudes in the compound nuclei.

   nucl-exPRC(2024)·4 citations
3. 03*

   Global trends of the electric dipole polarizability from shell-model calculations

   José Nicolás Orce🇿🇦 · Cebo Ngwetsheni🇿🇦 · B. Alex Brown🇺🇸

   Shell-model calculations of the electric dipole (E1) polarizability have been performed for the ground state of selected p- and sd-shell nuclei, substantially advancing previous knowledge. Our results are slightly larger compared with the somewhat more scattered photo-absorption cross-section data, albeit agreeing with ab initio calculations at shell closures and presenting a smooth trend that follows the leptodermus approximation provided by the finite-range droplet model (FRDM). The total E1 strengths also show an increasing trend proportional to the mass number which follows from the classical oscillator strength (TRK) sum rule for the E1 operator. The enhancement of the energy-weighted sum over E1 excitations with respect to the TRK sum rule arises from the use of experimental single-particle energies and the residual particle-hole interaction.

   ↳ nucl-thnucl-exPRC(2023)·13 citations
4. 04*

   Azimuthal distribution of exponential format for particle collective motions in heavy-ion collisions under asynchronous assumption

   Yicheng Feng🇺🇸

   Particle azimuth distributions are widely studied in heavy-ion collisions. They are often expanded in Fourier series to extract anisotropic flow harmonics simultaneously. It was recently proposed that the different orders of flows could happen asynchronously or noninterdependently. This study extends this idea to an exponential format of the azimuth distribution, which makes it straightforward to extract the asynchronous flow coefficients. We compare these new coefficients to the conventional ones, and find consistency in the leading coefficient and discrepancy in higher-order ones.

   ↳ nucl-thnucl-ex0 citations
5. 05*

   Fission Fragment Mass and Kinetic Energy Yields of Fermium Isotopes

   K. Pomorski🇵🇱 · A. Dobrowolski🇵🇱 · B. Nerlo-Pomorska🇵🇱 · M. Warda🇵🇱 · A. Zdeb🇵🇱 · J. Bartel🇫🇷 · H. Molique🇫🇷 · C. Schmitt🇫🇷 · Z. G. Xiao🇨🇳 · Y. J. Chen🇨🇳 · L. L. Liu🇨🇳

   A rapidly converging 4-dimensional Fourier shape parametrization is used to model the fission process of heavy nuclei. Potential energy landscapes are computed within the macroscopic-microscopic approach, on top of which the multi-dimensional Langevin equation is solved to describe the fission dynamics. Charge equilibration at scission and de-excitation by neutron evaporation of the primary fragments after scission is investigated. The model describes various observables, including fission-fragment mass, charge, and kinetic energy yields, as well as post-scission neutron multiplicities and, most importantly, their correlations, which are crucial to unravel the complexity of the fission process. The parameters of the dynamical model were tuned to reproduce experimental data obtained from thermal neutron-induced fission of ${}^{235}$U, which allows us to discuss the transition from asymmetric to symmetric fission along the Fm isotopic chain.

   ↳ nucl-thnucl-exActa Phys.Polon.B(2023)·2 citations
6. 06*

   Generator coordinate method for nuclear octupole excitations: status and perspectives

   E. F. Zhou · J. M. Yao🇨🇳

   Strong octupole correlations have been observed in the low-lying states of atomic nuclei across various mass regions. In this review, we provide an overview of Beyond Mean-Field (BMF) studies of nuclear octupole collective motions with Generator Coordinate Method (GCM) in combination with quantum-number projections that are implemented to restore the broken symmetries in nuclear mean-field states. We highlight recent developments within this framework and their applications to excitation spectra and electromagnetic transition rates in octupole-shaped nuclei and hypernuclei. We discuss the novel phenomena of nucleon clustering in light nuclei. Additionally, we explore the phase transition from octupole vibrations to rotational motions as spin increases in heavy nuclei. Lastly, we examine the status and future prospects of studies on octupole deformation effects in nuclear Schiff moments. These studies, along with the upper limits of atomic Electric Dipole Moment (EDM), impose stringent constraints on beyond-standard-model time-reversal-violating nucleon-nucleon interactions.

   ↳ nucl-thnucl-exIJMPE(2023)·9 citations
7. 07*

   The LHC as a Neutrino-Ion Collider

   Juan M. Cruz-Martinez🇨🇭 · Max Fieg🇺🇸 · Tommaso Giani🇳🇱 · Peter Krack🇳🇱 · Toni Mäkelä🇵🇱 · Tanjona Rabemananjara🇳🇱 · Juan Rojo🇳🇱

   Proton-proton collisions at the LHC generate a high-intensity collimated beam of neutrinos in the forward (beam) direction, characterised by energies of up to several TeV. The recent observation of LHC neutrinos by FASER$\nu$ and SND@LHC signals that this hitherto ignored particle beam is now available for scientific inquiry. Here we quantify the impact that neutrino deep-inelastic scattering (DIS) measurements at the LHC would have on the parton distributions (PDFs) of protons and heavy nuclei. We generate projections for DIS structure functions for FASER$\nu$ and SND@LHC at Run III, as well as for the FASER$\nu$2, AdvSND, and FLArE experiments to be hosted at the proposed Forward Physics Facility (FPF) operating concurrently with the High-Luminosity LHC (HL-LHC). We determine that up to one million electron- and muon-neutrino DIS interactions within detector acceptance can be expected by the end of the HL-LHC, covering a kinematic region in $x$ and $Q^2$ overlapping with that of the Electron-Ion Collider. Including these DIS projections into global (n)PDF analyses, specifically PDF4LHC21, NNPDF4.0, and EPPS21, reveals a significant reduction of PDF uncertainties, in particular for strangeness and the up and down valence PDFs. We show that LHC neutrino data enables improved theoretical predictions for core processes at the HL-LHC, such as Higgs and weak gauge boson production. Our analysis demonstrates that exploiting the LHC neutrino beam effectively provides CERN with a "Neutrino-Ion Collider" without requiring modifications in its accelerator infrastructure.

   ↳ hep-phhep-exnucl-exnucl-thEPJC(2024)·71 citations
8. 08*

   Probe nuclear structure using the anisotropic flow at the Large Hadron Collider

   Zhiyong Lu · Mingrui Zhao · Jiangyong Jia · You Zhou

   Recent studies have shown that the shape and radial profile of the colliding nuclei have strong influences on the initial condition of the heavy ion collisions and the subsequent development of the anisotropic flow. Using A Multi-Phase Transport model (AMPT) model, we investigated the impact of nuclear quadrupole deformation ${\beta }_2$ and nuclear diffuseness $a_0$ of ${}^{129}$Xe on various of flow observables in Xe--Xe collisions at $\text{sqrtnn}=$ 5.44 TeV. We found that ${\beta }_2$ has a strong influence on central collisions while $a_0$ mostly influences the mid-central collisions. The relative change of flow observables induced by a change in ${\beta }_2$ and $a_0$ are also found to be insensitive to the values of parameters controlling the strength of the interaction among final state particles. Our study demonstrates the potential for constraining the initial condition of heavy ion collisions using future system scans at the LHC.

   ↳ nucl-thnucl-exEPJA(2023)·19 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.