Tue·Dec 13, 2022Tuesday·December 13, 2022

1. 01*

   Study of Proton and Deuteron Pickup Reactions 2H(10Be,3He)9Li an 2H(10Be,4He)8Li with 44 A MeV 10Be Radioactive Beam at ACCULINNA-2 Fragment Separator

   E. Yu. Nikolskii · S. A. Krupko · I. A. Muzalevskii · A. A. Bezbakh · R. Wolski · C. Yuan · S. G. Belogurov · D. Biare · V. Chudoba · A. S. Fomichev · E. M. Gazeeva · M. S. Golovkov and 16 other authors

   The proton and deuteron pickup reactions 2H(10Be,3He)9Li and 2H(10Be,4He)8Li radioactive beam produced by the new fragment separator ACCULINNA-2 at FLNR, JINR\@. These measurements were initially motivated as test reactions intended for the elucidation of results obtained in the study of the extremely neutron-rich 7H and 6H systems created in the 2H(10Be,3He)9Li and 2H(10Be,4He)8Li reactions using the same setup. In the 2H(10Be,3He)9Li reaction the 9Li ground-state ($3/2^{-}$) and its first excited state (2.69MeV, $1/2^{-}$) were identified in the low-energy region of its excitation spectrum. The differential cross sections for the 9Li g.~s.) population were extracted at forward center-of-mass angles ($3^{\circ }-13^{\circ }$) and compared with the FRESCO calculations. Spectroscopic factor of $\sim 1.7$, derived by a model for the 10Be$=p+$9Li(g.s.) clustering was found in accord with the experimental data. The energy spectrum of 8Li populated in the 2H(10Be,4He)8Li reaction shows the strong peak which corresponds to excitation of the second excited state of 8Li (2.25 MeV, $3^{+}$). The fact that the ground and the first excited states of 8Li were not observed is fully consistent with Shell-Model calculations carried out for the 10Be g.\,s. and 8Li level structure applying momentum selection rules.

   nucl-exNucl.Instrum.Meth.B(2023)·2 citations
2. 02*

   Measurement of the ${}^{14}$N(n,p)${}^{14}$C cross section at the CERN n_TOF facility from sub-thermal energy to 800 keV

   P. Torres-Sánchez (1) · J. Praena (1) · I. Porras (1) · M. Sabaté-Gilarte (2 and 3) · C. Lederer-Woods (4) · O. Aberle (2) · V. Alcayne (5) · S. Amaducci (6 and 7) · J. Andrzejewski (8) · L. Audouin (9) · V. Bécares (5) · V. Babiano-Suarez (10) and 120 other authors

   Background: The ${}^{14}$N(n,p)${}^{14}$C reaction is of interest in neutron capture therapy, where nitrogen-related dose is the main component due to low-energy neutrons, and in astrophysics, where 14N acts as a neutron poison in the s-process. Several discrepancies remain between the existing data obtained in partial energy ranges: thermal energy, keV region and resonance region. Purpose: Measuring the 14N(n,p)14C cross section from thermal to the resonance region in a single measurement for the first time, including characterization of the first resonances, and providing calculations of Maxwellian averaged cross sections (MACS). Method: Time-of-flight technique. Experimental Area 2 (EAR-2) of the neutron time-of-flight (n_TOF) facility at CERN. ${}^{10}$B(n,$\alpha$)${}^7$Li and ${}^{235}$U(n,f) reactions as references. Two detection systems running simultaneously, one on-beam and another off-beam. Description of the resonances with the R-matrix code sammy. Results: The cross section has been measured from sub-thermal energy to 800 keV resolving the two first resonances (at 492.7 and 644 keV). A thermal cross-section (1.809$\pm$0.045 b) lower than the two most recent measurements by slightly more than one standard deviation, but in line with the ENDF/B-VIII.0 and JEFF-3.3 evaluations has been obtained. A 1/v energy dependence of the cross section has been confirmed up to tens of keV neutron energy. The low energy tail of the first resonance at 492.7 keV is lower than suggested by evaluated values, while the overall resonance strength agrees with evaluations. Conclusions: Our measurement has allowed to determine the ${}^{14}$N(n,p) cross-section over a wide energy range for the first time. We have obtained cross-sections with high accuracy (2.5 %) from sub-thermal energy to 800 keV and used these data to calculate the MACS for kT = 5 to kT = 100 keV.

   nucl-exPRC(2023)·3 citations
3. 03*

   Measurement of the total neutron cross section on argon in the 20 to 70 keV energy range

   S. Andringa🇵🇹 · Y. Bezawada · T. Erjavec🇺🇸 · J. He🇨🇳 · J. Huang🇨🇭 · P. Koehler · M. Mocko · M. Mulhearn · L. Pagani🇺🇸 · E. Pantic🇺🇸 · L. Pickard🇺🇸 · R. Svoboda🇺🇸 · J. Ullmann · J. Wang🇨🇳

   The cross section for neutron interactions on argon is an important design and operational parameter for a number of neutrino, dark matter, and neutrinoless double beta decay experiments which use liquid argon as a detection or shielding medium. There is a discrepancy between the evaluated total cross section in the $20$ to $70$\,keV neutron kinetic energy region given in the ENDF database and a single measurement conducted by an experiment with a thin target (0.2 atoms/barn) optimized for higher cross sections. This gives rise to significant uncertainty in the interaction length of neutrons in liquid argon. This discrepancy is now resolved by new results presented here from the Argon Resonance Transport Interaction Experiment (ARTIE), a thick target experiment (3.3 atoms/barn) optimized for the small cross sections in this energy region.

   nucl-exhep-exPRC(2023)·5 citations
4. 04*

   Weak decay of halo nuclei

   Wael Elkamhawy🇩🇪 · Hans-Werner Hammer🇩🇪 · Lucas Platter🇺🇸

   We investigate the weak decay of one-neutron halo nuclei into the proton-core continuum, i.e., beta-delayed proton emission from the halo nucleus using a cluster effective field theory for halo nuclei. On the one hand, we calculate the direct decay into the continuum. On the other hand, we consider the case of resonant final state interactions between the proton and the core. We present our formalism and discuss the application to the decay of ${}^{11}$Be in detail. Moreover, we compare to recent experimental results for the branching ratio and resonance parameters. As another example, we consider the case of ${}^{19}$C and predict the branching ratio for beta-delayed proton emission.

   ↳ nucl-thnucl-exPRC(2023)·2 citations
5. 05*

   Detector array for the ${}^7$H nucleus multi-neutron decay study

   A. A. Bezbakh🇷🇺 · S. G. Belogurov🇷🇺 · V. Chudoba · A. S. Fomichev🇷🇺 · A. V. Gorshkov🇺🇸 · L. V. Grigorenko🇷🇺 · G. Kaminski · M. S. Khirk🇷🇺 · A. G. Knyazev · S. A. Krupko🇷🇺 · B. Mauyey🇷🇺 · I A. Muzalevskii🇷🇺 and 7 other authors

   Setup fitting the requirements for the detailed study of the five-body decay of the 7H nucleus obtained as a result of the proton transfer from the 8He projectiles to the deuterium target nuclei is being built at the radioactive beam line of ACCULINNA-2 separator in the G.N. Flerov Laboratory of Nuclear Reactions. Described here is the assembly of 100 BC-404 plastic scintillators, intended for neutron detection, the annular Si detector telescope for the 3He recoils, and the detector array providing the $\Delta E$-$E$-TOF registration of 3H nuclei emitted at the 7H decay. Results obtained by the Monte Carlo simulations made for the energy values and flight passes of all these particles are given together with the luminosity expected for the discussed experiments.

   ↳ physics.ins-detnucl-exPhys.Part.Nucl.Lett.(2023)·1 citation
6. 06*

   Resistive Plate Chambers for Precise Measurement of High-Momentum Protons in Short Range Correlations at R${}^3$B

   M. Xarepe🇵🇹 · T. Aumann🇩🇪 · A. Blanco🇵🇹 · A. Corsi🇫🇷 · D. Galaviz🇵🇹 · H. Johansson🇸🇪 · S. Linev🇩🇪 · B. Löher🇩🇪 · L. Lopes🇧🇷 · J. Michel🇩🇪 · V. Panin🇩🇪 · D. Rossi🇩🇪 and 3 other authors

   The Reactions with Relativistic Radioactive Beams (R${}^3$B) collaboration of the Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany, has constructed an experimental setup to perform fundamental studies of nuclear matter, using as a probe reactions with exotic nuclei at relativistic energies. Among the various detection systems, one of the most recent upgrades consisted on the installation of a large area, around 2 m${}^2$, multi-gap Resistive Plate Chamber (RPC), equipped with twelve 0.3 mm gaps and readout by 30 mm pitch strips, exhibiting a timing precision down to 50 ps and efficiencies above 98% for MIPs in a previous characterization of the detector. The RPC was part of the setup of the FAIR Phase 0 experiment that focused on measuring, for the first time, nucleon-nucleon short-range correlations (SRC) inside an exotic nucleus (${}^{16}$C) that occurred in Spring 2022. The excellent timing precision of this detector will allow the measurement of the forward emitted proton momentum with a resolution of around 1%. In beam measurements show an RPC efficiency above 95% and a time precision better than 100 ps (including the contribution of a reference scintillator and the momentum spread of the particles) for forward emitted particles.

   ↳ physics.ins-detnucl-exNucl.Instrum.Meth.A(2023)·5 citations
7. 07*

   A Compact TPC for the sPHENIX Experiment

   Henry T. Klest (for the sPHENIX Collaboration)🇺🇸

   The sPHENIX detector to be installed at RHIC in 2022 is designed to precisely measure jets, jet correlations, and dilepton pairs in heavy-ion collisions. With these measurements in mind, sPHENIX will employ a compact TPC covering 20cm < r < 78 cm and |{\eta}| < 1.1 as the central tracker. Utilizing an optimized Ar-CF4 gas mixture, zigzag readout pads, a 1.4 T solenoid, and a modified SAMPA chip for streaming readout, the TPC will provide a position resolution sufficient for measuring target observables in a high event rate environment. The design of the TPC will be discussed, as well as test beam data and potential applicability to the EIC

   ↳ physics.ins-detnucl-exJ.Phys.Conf.Ser.(2022)·4 citations
8. 08*

   Deep Inelastic Scattering with Application to Nuclear Targets: Lectures at the 1985 Los Alamos School on Relativistic Dynamics and Quark Nuclear Physics

   Robert L. Jaffe🇺🇸

   This paper is essentially a verbatim reconstruction of lectures that I gave at the Los Alamos School on Relativistic Dynamics and Quark Nuclear Physics in 1985. They were published in the school proceedings, but the book is not widely available. The Los Alamos School took place at the height of the first wave of interest in the quark substructure of nuclei, stimulated by the 1983 discovery of the EMC Effect. Interest in this subject has been increasing for years and the prospect of a dedicated Electron Ion Collider within the decade guarantees even greater attention to quarks and gluons in nuclei among both theorists and experimentalists. Recently, to my surprise, I learned that copies of my old lectures have been circulating and been found useful by the relatively few people who know about them. The are, of course, dated: experiments have far outstripped what was available 37 years ago and theory has progressed too. However, the rest frame derivation of the parton model, the derivation and discussion of the convolution formalism for nucleons, nucleon correlations, and other, virtual, constituents of nuclei, and sections on scaling violation and the operator product expansion have aged pretty well and seem to still be useful. With the help and encouragement of Richard Milner, I have recreated the LaTeX files necessary to post the 1985 Lectures on the arXiv, making them available to the nuclear and particle physics community. Apart from correcting some typographical errors, I have made no attempt to edit, improve, or update these lectures. I hope readers will nevertheless find them useful.

   ↳ hep-phhep-thnucl-exnucl-thPublished in M. B. Johnson and A. Pickles…·9 citations
9. 09*

   Possible neutron halo in triaxial nucleus 42Al

   K. Y. Zhang🇨🇳 · S. Q. Zhang🇨🇳 · J. Meng🇨🇳

   A microscopic self-consistent triaxial relativistic Hartree-Bogoliubov theory in continuum (TRHBc), which simultaneously takes into account the triaxiality and pairing correlations as well as continuum effects, is established and applied to explore the novel halo phenomenon in aluminum isotopes. The experimental proton drip line and the available data of neutron separation energies and charge radii are reproduced well without any free parameters. The neutron-richest odd-odd aluminum isotope observed so far, 42Al, is predicted to be triaxially deformed with beta=0.35 and gamma=42. Its one-neutron separation energy is predicted to be 0.68 MeV, in agreement with the AME2020, and the neutron rms radius is 3.94 fm, remarkably larger than the empirical value. The density distribution of the valance neutron, which extends much farther in space than the core, suggests a possible neutron halo in 42Al. The dominant components responsible for the spatial extension of the halo are revealed by the single-neutron orbitals around the Fermi energy. A novel phenomenon, the exchange of the intermediate and short axes between the triaxial core with beta=0.38 and gamma=50, and the triaxial halo with beta=0.79 and gamma=-23, is found. Future experiments to explore the halo phenomenon and the novel shape decoupling in 42Al are highly demanded.

   ↳ nucl-thnucl-exPRC(2023)·41 citations
10. 10*

    Quantifying uncertainties due to optical potentials in one-neutron knockout reactions

    Chloë Hebborn🇺🇸 · T. R. Whitehead🇺🇸 · Amy E. Lovell🇺🇸 · Filomena M. Nunes🇺🇸

    One-neutron knockout reactions have been widely used to extract information about the single-particle structure of nuclei from the valley of stability to the driplines. The interpretation of knockout data relies on reaction models, where the uncertainties are typically not accounted for. In this work we quantify uncertainties of optical potentials used in these reaction models and propagate them, for the first time, to knockout observables using a Bayesian analysis. We study two reactions in the present paper, the first of which involves a loosely-bound halo projectile, ${}^{11}$Be, and the second a tightly-bound projectile, ${}^{12}$C. We first quantify the parametric uncertainties associated with phenomenological optical potentials. Complementing to this approach, we also quantify the model uncertainties associated with the chiral forces that can be used to construct microscopic optical potentials. For the phenomenological study, we investigate the impact of the imaginary terms of the optical potential on the breakup and stripping components of the knockout cross sections as well as the impact of the angular range. For the ${}^{11}$Be case, the theoretical uncertainty from the phenomenological method is on the order of the experiment uncertainty on the knockout observables; however, for the ${}^{12}$C case, the theoretical uncertainty is significantly larger. The widths of the confidence intervals for the knockout observables obtained for the microscopic study and the phenomenological approach are of similar order of magnitude. Based on this work we conclude that structure information inferred from the ratio of the knockout cross sections, will carry a theoretical uncertainty of at least $20\%$ for halo nuclei and at least $40\%$ for tightly-bound nuclei.

    ↳ nucl-thnucl-exPRC(2023)·14 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.