Tue·Feb 23, 2021Tuesday·February 23, 2021

1. 01*

   Accurate Determination of the Neutron Skin Thickness of ${}^{208}$Pb through Parity-Violation in Electron Scattering

   D. Adhikari (1) · H. Albataineh (2) · D. Androic (3) · K. Aniol (4) · D.S. Armstrong (5) · T. Averett (5) · S. Barcus (6) · V. Bellini (7) · R.S. Beminiwattha (8) · J.F. Benesch (6) · H. Bhatt (9) · D. Bhatta Pathak (8) and 87 other authors

   We report a precision measurement of the parity-violating asymmetry $A_{PV}$ in the elastic scattering of longitudinally polarized electrons from ${}^{208}$Pb. We measure $A_{PV}=550\pm 16(\mathrm{stat})\pm 8(\mathrm{syst})$ parts per billion, leading to an extraction of the neutral weak form factor $F_W(Q^2=0.00616{\mathrm{GeV}}^2)=0.368\pm 0.013$. Combined with our previous measurement, the extracted neutron skin thickness is $R_n-R_p=0.283\pm 0.071$~fm. The result also yields the first significant direct measurement of the interior weak density of ${}^{208}$Pb: ${\rho }_W^0=-0.0796\pm 0.0036(exp.)\pm 0.0013(theo.){\mathrm{fm}}^{-3}$ leading to the interior baryon density ${\rho }_b^0=0.1480\pm 0.0036(exp.)\pm 0.0013(theo.){\mathrm{fm}}^{-3}$. The measurement accurately constrains the density dependence of the symmetry energy of nuclear matter near saturation density, with implications for the size and composition of neutron stars.

   nucl-exPRL(2021)·749 citations
2. 02*

   The quest for light multineutron systems

   F. Miguel Marques🇫🇷 · Jaume Carbonell🇫🇷

   The long history of the research concerning the possible existence of bound or resonant states in light multineutron systems, essentially ${}^3$n and ${}^4$n, is reviewed. Both the experimental and the theoretical points of view have been considered, with the aim of showing a clear picture of all the different detection and calculation techniques that have been used, with particular emphasis in the issues that have been found. Finally, some aspects of the present and future research in this field are discussed.

   nucl-exnucl-thEPJA(2021)·47 citations
3. 03*

   A Review of Basic Energy Reconstruction Techniques in Liquid Xenon and Argon Detectors for Dark Matter and Neutrino Physics Using NEST

   M. Szydagis🇺🇸 · G.A. Block🇺🇸 · C. Farquhar🇺🇸 · A.J. Flesher🇺🇸 · E.S. Kozlova🇷🇺 · C. Levy🇺🇸 · E.A. Mangus🇺🇸 · M. Mooney🇺🇸 · J. Mueller🇺🇸 · G.R.C. Rischbieter🇺🇸 · A.K. Schwartz🇺🇸

   Detectors based upon the noble elements, especially liquid xenon as well as liquid argon, as both single- and dual-phase types, require reconstruction of the energies of interacting particles, both in the field of direct detection of dark matter (Weakly Interacting Massive Particles or WIMPs, axions, etc.) and in neutrino physics. Experimentalists, as well as theorists who reanalyze/reinterpret experimental data, have used a few different techniques over the past few decades. In this paper, we review techniques based on solely the primary scintillation channel, the ionization or secondary channel available at non-zero drift electric fields, and combined techniques that include a simple linear combination and weighted averages, with a brief discussion of the applications of profile likelihood, maximum likelihood, and machine learning. Comparing results for electron recoils (beta and gamma interactions) and nuclear recoils (primarily from neutrons) from the Noble Element Simulation Technique (NEST) simulation to available data, we confirm that combining all available information generates higher-precision means, lower widths (energy resolution), and more symmetric shapes (approximately Gaussian) especially at keV-scale energies, with the symmetry even greater when thresholding is addressed. Near thresholds, bias from upward fluctuations matters. For MeV-GeV scales, if only one channel is utilized, an ionization-only-based energy scale outperforms scintillation; channel combination remains beneficial. We discuss here what major collaborations use.

   ↳ hep-exastro-ph.IMnucl-exInstruments(2021)·61 citations
4. 04*

   Analysis methods and code for very high-precision mass measurements of unstable isotopes

   Jonas Karthein🇨🇭 · Dinko Atanasov🇨🇭 · Klaus Blaum🇩🇪 · David Lunney🇫🇷 · Vladimir Manea🇫🇷 · Maxime Mougeot🇨🇭

   We present a robust analysis code developed in the Python language and incorporating libraries of the ROOT data analysis framework for the state-of-the-art mass spectrometry method called phase-imaging ion-cyclotron-resonance (PI-ICR). A step-by-step description of the dataset construction and analysis algorithm is given. The code features a new phase-determination approach that offers up to 10 times smaller statistical uncertainties. This improvement in statistical uncertainty is confirmed using extensive Monte-Carlo simulations and allows for very high-precision studies of exotic nuclear masses to test, among others, the standard model of particle physics.

   ↳ physics.comp-phnucl-exComput.Phys.Commun.(2021)·4 citations
5. 05*

   Self-consistent calculations of electron-capture decays in Z=118, 119, and 120 superheavy isotopes

   Pedro Sarriguren🇪🇸

   Weak decays in superheavy nuclei with proton numbers Z = 118 - 120 and neutron numbers N = 175 - 184 are studied within a microscopic formalism based on deformed self-consistent Skyrme Hartree-Fock mean-field calculations with pairing correlations. The half-lives of beta+ decay and electron capture are compared with alpha-decay half-lives obtained from phenomenological formulas. The sensitivity of the half-lives to the unknown Q-energies is studied by comparing the results obtained from different approaches for the masses. It is shown that alpha-decay is always dominant in this mass region. The competition between alpha and beta+/EC decay modes is studied in seven alpha-decay chains starting at different isotopes of Z=118, 119, and 120.

   ↳ nucl-thnucl-exPLB(2021)·10 citations
6. 06*

   Differential analysis of incompressibility in neutron-rich nuclei

   Bao-An Li🇺🇸 · Wen-Jie Xie🇨🇳

   Both the incompressibility \Ka of a finite nucleus of mass A and that ($K_{\infty }$) of infinite nuclear matter are fundamentally important for many critical issues in nuclear physics and astrophysics. While some consensus has been reached about the $K_{\infty }$, accurate theoretical predictions and experimental extractions of $K_{\tau }$ characterizing the isospin dependence of \Ka have been very difficult. We propose a differential approach to extract the \Kt and \Ki independently from the \Ka data of any two nuclei in a given isotope chain. Applying this new method to the \Ka data from isoscalar giant monopole resonances (ISGMR) in even-even Pb, Sn, Cd and Ca isotopes taken by U. Garg {\it et al.} at the Research Center for Nuclear Physics (RCNP), Osaka University, Japan, we find that the ${}^{106}$Cd-${}^{116}$Cd and ${}^{112}$Sn-${}^{124}$Sn pairs having the largest differences in isospin asymmetries in their respective isotope chains measured so far provide consistently the most accurate up-to-date \Kt value of $K_{\tau }=-616\pm 59$ MeV and $K_{\tau }=-623\pm 86$ MeV, respectively, largely independent of the remaining uncertainties of the surface and Coulomb terms in expanding the $K_{\mathrm{A}}$, while the $K_{\infty }$ values extracted from different isotopes chains are all well within the current uncertainty range of the community consensus for $K_{\infty }$. Moreover, the size and origin of the "Soft Sn Puzzle" is studied with respect to the "Stiff Pb Phenomenon". It is found that the latter is favored due to a much larger (by $\sim 380$ MeV) \Kt for Pb isotopes than for Sn isotopes, while the \Ki from analyzing the \Ka data of Sn isotopes is only about 5 MeV less than that from analyzing the Pb data.

   ↳ nucl-thastro-ph.HEnucl-exPRC(2021)·11 citations
7. 07*

   RF pulse amplifier for CVD-diamond particle detectors

   C. Hoarau🇫🇷 · G. Bosson🇫🇷 · J.-L. Bouly🇫🇷 · S. Curtoni🇫🇷 · D. Dauvergne🇫🇷 · P. Everaere🇫🇷 · M.-L. Gallin-Martel🇫🇷 · S. Marcatili🇫🇷 · J.-F. Muraz🇫🇷 · A. Portier🇫🇷 · N. Rosuel🇫🇷

   This article introduces a design of a Low Noise Amplifier (LNA), for the field of diamond particle detectors. This amplifier is described from simulation to measurements, which include pulses from {\alpha} particles detection. In hadron therapy, with high-frequency pulsed particle beams, the diamond detector is a promising candidate for beam monitoring and time-stamping, with prerequisite of fast electronics. The LNA is designed with surface mounted components and RF layout techniques to control costs and to allow timing performance suitable for sub-nanosecond edges of pulses. Also this amplifier offers the possibility of high voltage biasing, a characteristic essential for driving diamond detectors. Finally the greatest asset of this study is certainly the minimization of the power consumption, which allows us to consider designs with multiple amplifiers, in limited space, for striped diamond detectors.

   ↳ physics.ins-detnucl-exJINST(2021)·15 citations
8. 08*

   Forces inside the nucleon on the light front from 3D Breit frame force distributions: Abel tomography case

   Julia Yu. Panteleeva🇩🇪 · Maxim V. Polyakov🇩🇪

   We derive simple relations which express 2D light front force distributions in terms of 3D Breit frame pressure and shear force distributions. Mathematically the relations correspond to invertible Abel transformation and they establish one-to-one mathematical equivalence of 3D Breit frame force distributions and 2D light front ones. Any knowledge (model calculation, experimental measurement, etc.) about pressure and shear force distributions in Breit frame can be unambiguously transformed into light front force distributions with the help of Abel transformation. It is important that the transformation ensures 2D stability conditions if the 3D stability conditions are satisfied. As an illustration of how the relations work, we calculated the light front force distributions for a large nucleus as a liquid drop, and for large $N_c$ nucleon as a chiral soliton.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2021)·63 citations
9. 09*

   $\gamma \gamma$ decay as a probe of neutrinoless $\beta \beta$ decay nuclear matrix elements

   B. Romeo🇪🇸 · J. Menéndez🇪🇸 · C. Peña🇪🇸

   We study double gamma ($\gamma \gamma$) decay nuclear matrix elements (NMEs) for a wide range of nuclei from titanium to xenon, and explore their relation to neutrinoless double-beta ($0\nu \beta \beta$) NMEs. To favor the comparison, we focus on double-magnetic dipole transitions in the final $\beta \beta$ nuclei, in particular the $\gamma \gamma$ decay of the double isobaric analog of the initial $\beta \beta$ state into the ground state. For the decay with equal-energy photons, our large-scale nuclear shell model results show a good linear correlation between the $\gamma \gamma$ and $0\nu \beta \beta$ NMEs. Our analysis reveals that the correlation holds for $\gamma \gamma$ transitions driven by the spin or orbital angular momentum due to the dominance of zero-coupled nucleon pairs, a feature common to $0\nu \beta \beta$ decay. Our shell-model findings point out the potential of future $\gamma \gamma$ decay measurements to constrain $0\nu \beta \beta$ NMEs, which are key to answer fundamental physics questions based on $0\nu \beta \beta$ experiments.

   ↳ nucl-thhep-exhep-phnucl-exPLB(2022)·29 citations
10. 10*

    Eliminating $volume$ fluctuations in fixed-target heavy-ion experiments

    M. Mackowiak-Pawlowska🇵🇱 · M. Naskręt🇵🇱 · M. Gazdzicki🇩🇪

    Experimental and theoretical studies of fluctuations in nucleus-nucleus interactions at high energies have started to play a major role in understanding of the concept of strong interactions. The elaborated procedures have been developed to disentangle different processes happening during nucleus-nucleus collisions. The fluctuations caused by a variation of the number of nucleons which participated in a collision are frequently considered the unwanted one. The methods to eliminate these fluctuations in fixed-target experiments are reviewed and tested. They can be of key importance in the following ongoing fixed-target heavy-ion experiments: NA61/SHINE at the CERN SPS, STAR-FT at the BNL RHIC, BM\@N at JINR Nuclotron, HADES at the GSI SIS18 and in future experiments such as NA60+ at the CERN SPS, CBM at the FAIR SIS100, JHITS at J-PARC-HI MR.

    ↳ hep-exnucl-exNPA(2021)·5 citations
11. 11*

    The smallest fluid on earth

    Björn Schenke🇺🇸

    High energy heavy ion collisions create quark gluon plasmas that behave like almost perfect fluids. Very similar features to those that led to this insight have also been observed in experimental data from collisions of small systems, involving protons or other light nuclei. We describe recent developments aimed at understanding whether, and if so how, systems that produce relatively few particles (orders of magnitude less than in typical heavy ion collisions) and are only one to a few times the size of a proton, can behave like fluids. This involves a deeper understanding of fluid dynamics and its applicability, improvements of our understanding of the initial geometry of the collisions by considering fluctuations of the proton shape, as well as advancements in the calculation of initial state effects within an effective theory of quantum chromodynamics, which can affect the observables that are used to study fluid behavior. We further address open questions and discuss future directions.

    ↳ nucl-thhep-phnucl-exRept.Prog.Phys.(2021)·108 citations
12. 12*

    Supernova neutrino signals based on long-term axisymmetric simulations

    Hiroki Nagakura🇺🇸 · Adam Burrows🇺🇸 · David Vartanyan🇺🇸

    We study theoretical neutrino signals from core-collapse supernova (CCSN) computed using axisymmetric CCSN simulations that cover the post-bounce phase up to $\sim 4$~s. We provide basic quantities of the neutrino signals such as event rates, energy spectra, and cumulative number of events at some terrestrial neutrino detectors, and then discuss some new features in the late phase that emerge in our models. Contrary to popular belief, neutrino emissions in the late phase are not always steady, but rather have temporal fluctuations, the vigor of which hinges on the CCSN model and neutrino flavor. We find that such temporal variations are not primarily driven by proto-neutron star (PNS) convection, but by fallback accretion in exploding models. We assess the detectability of these temporal variations, and find that IceCube is the most promising detector with which to resolve them. We also update fitting formulae first proposed in our previous paper for which the total neutrino energy (TONE) emitted at the CCSN source is estimated from the cumulative number of events in each detector. This will be a powerful technique with which to analyze real observations, particularly for low-statistics data.

    ↳ astro-ph.HEhep-exhep-thnucl-ex+1MNRAS(2021)·53 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.