Fri·Mar 6, 2020Friday·March 6, 2020

1. 01*

   Testing Parameterizations of the Deuteron Quasi-Elastic Peak

   Iu. A. Skorodumina🇺🇸 · G. V. Fedotov🇷🇺 · R. W. Gothe🇺🇸

   This study introduces common parameterizations of the quasi-elastic peak in the electron scattering spectrum off deuterium and provides the comparison of the parameterized cross sections with published experimental data. The comparison is performed in the wide $Q^2$ range from $\sim$0.3 GeV${}^2$ to $\sim$4 GeV${}^2$. In this way the performance of the parameterizations and their ability to describe experimental measurements are impartially tested and the conclusion on the description reliability is made.

   nucl-exnucl-th1 citation
2. 02*

   Multiplicity dependence of $\pi$, K, and p production in pp collisions at $\sqrt{s}=13$ TeV

   ALICE Collaboration

   This paper presents the measurements of ${\pi }^{\pm }$, ${\mathrm{K}}^{\pm }$, $\mathrm{p}$ and $\bar{\mathrm{p}}$ transverse momentum ($p_{\mathrm{T}}$) spectra as a function of charged-particle multiplicity density in proton-proton (pp) collisions at $\sqrt{s}$ = 13 TeV with the ALICE detector at the LHC. Such study allows us to isolate the center-of-mass energy dependence of light-flavour particle production. The measurements reported here cover a $p_{\mathrm{T}}$ range from 0.1 GeV/$c$ to 20 GeV/$c$ and are done in the rapidity interval $|y|<0.5$. The $p_{\mathrm{T}}$-differential particle ratios exhibit an evolution with multiplicity, similar to that observed in pp collisions at $\sqrt{s}$ = 7 TeV, which is qualitatively described by some of the hydrodynamical and pQCD-inspired models discussed in this paper. Furthermore, the $p_{\mathrm{T}}$-integrated hadron-to-pion yield ratios measured in pp collisions at two different center-of-mass energies are consistent when compared at similar multiplicities. This also extends to strange and multistrange hadrons, suggesting that, at LHC energies, particle hadrochemistry scales with particle multiplicity the same way under different collision energies and colliding systems.

   nucl-exhep-exEPJC(2020)·195 citations
3. 03*

   An extended $R_{{\Psi }_m}^{(2)}(\Delta S_2)$ correlator for detecting and characterizing the Chiral Magnetic Wave

   Niseem Magdy (1)🇺🇸 · Mao-Wu Nie (2,3)🇨🇳 · Ling Huang (4,5,6)🇨🇳 · Guo-Liang Ma (4,6)🇨🇳 · Roy. A. Lacey (7) ((1) Department of Physics, University of Illinois at Chicago, IL, USA, (2) Institute of Frontier and Interdisciplinary Science, Shandong University, China, (3) Key Laboratory of Particle Physics and Particle Irradiation, Ministry of Education, Shandong University, China, (4) Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, China, (5) University of Chinese Academy of Sciences, Beijing, China, (6) Key Laboratory of Nuclear Physics and Ion-beam Application (MOE), Institute of Modern Physics, Fudan University, Shanghai, China, (7) Depts. of Chemistry & Physics, Stony Brook University, Stony Brook, NY)🇺🇸

   The extended $R_{{\Psi }_m}^{(2)}(\Delta S_2)$ correlator is presented and examined for its efficacy to detect and characterize the quadrupole charge separation ($\Delta S_2$) associated with the purported Chiral Magnetic Wave (CMW) produced in heavy-ion collisions. Sensitivity tests involving varying degrees of proxy CMW signals injected into events simulated with the Multi-Phase Transport Model (AMPT), show that the $R_{{\Psi }_m}^{(2)}(\Delta S_2)$ correlator provides discernible responses for the background- and CMW-driven charge separation. This distinction could aid identification of the CMW via measurements of the $R_{{\Psi }_2}^{(2)}(\Delta S_2)$ and $R_{{\Psi }_3}^{(2)}(\Delta S_2)$ correlators, relative to the second- (${\Psi }_2$) and third-order (${\Psi }_3$) event planes. The tests also indicate a level of sensitivity that would allow for robust experimental characterization of the CMW signal.

   nucl-exhep-exhep-phnucl-thPLB(2020)·6 citations
4. 04*

   Determination of the cluster-decay branching ratio from a near-threshold molecular state in ${}^{10}$Be

   W. Jiang · Y. L. Ye🇨🇳 · C. J. Lin🇨🇳 · Z. H. Li🇨🇳 · J. L. Lou🇨🇳 · X. F. Yang🇨🇳 · Q. T. Li🇨🇳 · Y. C. Ge🇨🇳 · H. Hua🇨🇳 · D. X. Jiang🇨🇳 · D. Y. Pang🇨🇳 · J. Li🇨🇳 and 18 other authors

   A puzzle has long existed for the $\alpha$-cluster content in the near-threshold 7.54 MeV state of ${}^{10}$Be. A new measurement was conducted to measure the cluster-decay partial width of this state, using the reaction ${}^9\mathrm{Be}({}^9\mathrm{Be},{{}^{10}\mathrm{Be}}^{\ast }\to \alpha +{}^6\mathrm{He}){}^8\mathrm{Be}$ at 45 MeV beam energy. Special measures were taken to reduce the strong near-threshold background. The neutron-decay strength was also obtained based on the three-fold coincident measurement. A cluster-decay branching ratio of $(4.04\pm 1.26)\times 10^{-4}$ is obtained, resulting in a reasonably large $\alpha$-cluster spectroscopic factor. The present work confirms the formation of the $\sigma$-bond molecular rotational band headed by the 6.18 MeV state in ${}^{10}$Be.

   nucl-exPRC(2020)·17 citations
5. 05*

   The measurement of the quadrupole moment of 185-Re and 187-Re from the hyperfine structure of muonic X rays

   A. Antognini🇨🇭 · N. Berger🇩🇪 · T. E. Cocolios🇧🇪 · R. Dressler🇨🇭 · R. Eichler🇨🇭 · A. Eggenberger🇨🇭 · P. Indelicato🇫🇷 · K.-P. Jungmann🇳🇱 · C. H. Keitel🇩🇪 · K. Kirch🇨🇭 · A. Knecht🇨🇭 · N. Michel🇩🇪 and 14 other authors

   The hyperfine splitting of the 5g -> 4f transitions in muonic 185,187-Re has been measured using high resolution HPGe detectors and compared to state-of-the-art atomic theoretical predictions. The spectroscopic quadrupole moment has been extracted using modern fitting procedures and compared to the values available in literature obtained from muonic X rays of natural rhenium. The extracted values of the nuclear spectroscopic quadrupole moment are 2.07(5) barn and 1.94(5) barn, respectively for 185-Re and 187-Re. This work is part of a larger effort at the Paul Scherrer Institut towards the measurement of the nuclear charge radii of radioactive elements.

   nucl-exPRC(2020)·27 citations
6. 06*

   Generalized Contact Formalism Analysis of the ${}^4$He$(e,e^{\prime }pN)$ Reaction

   J.R. Pybus🇺🇸 · I. Korover🇮🇱 · R. Weiss🇮🇱 · A. Schmidt🇺🇸 · N. Barnea🇮🇱 · D.W. Higinbotham🇺🇸 · E. Piasetzky🇮🇱 · M. Strikman🇺🇸 · L.B. Weinstein🇺🇸 · O. Hen🇺🇸

   Measurements of short-range correlations in exclusive ${}^4$He$(e,e^{\prime }pN)$ reactions are analyzed using the Generalized Contact Formalism (GCF). We consider both instant-form and light-cone formulations with both the AV18 and local N2LO(1.0) nucleon-nucleon ($NN$) potentials. We find that kinematic distributions, such as the reconstructed pair opening angle, recoil neutron momentum distribution, and pair center of mass motion, as well as the measured missing energy, missing mass distributions, are all well reproduced by GCF calculations. The missing momentum dependence of the measured ${}^4$He$(e,e^{\prime }pN)$ / ${}^4$He$(e,e^{\prime }p)$ cross-section ratios, sensitive to nature of the $NN$ interaction at short-distacnes, are also well reproduced by GCF calculations using either interaction and formulation. This gives credence to the GCF scale-separated factorized description of the short-distance many-body nuclear wave-function.

   ↳ nucl-thnucl-exPLB(2020)·35 citations
7. 07*

   Neutron-neutron scattering length from ${\pi }^{+}$ photoproduction on the deuteron

   Satoshi X. Nakamura (Univ. Science and Technology of China)🇨🇳 · Takatsugu Ishikawa (ELPH, Tohoku Univ.)🇯🇵 · Toru Sato (RCNP, Osaka Univ.)🇯🇵

   We discuss the possibility of extracting the neutron-neutron scattering length $a_{nn}$ and effective range $r_{nn}$ from cross section data ($d^2\sigma /d{M}_{nn}/d{\Omega }_{\pi }$), as a function of the $nn$ invariant mass $M_{nn}$, for ${\pi }^{+}$ photoproduction on the deuteron ($\gamma d\to {\pi }^{+}nn$). The analysis is based on a $\gamma d\to {\pi }^{+}nn$ reaction model in which realistic elementary amplitudes for $\gamma p\to {\pi }^{+}n$, $NN\to NN$, and $\pi N\to \pi N$ are built in. We show that $M_{nn}$ dependence (lineshape) of a ratio $R_{\mathrm{th}}$, $d^2\sigma /d{M}_{nn}/d{\Omega }_{\pi }$ normalized by $d\sigma /d{\Omega }_{\pi }$ for $\gamma p\to {\pi }^{+}n$ and the nucleon momentum distribution inside the deuteron, at the kinematics with ${\theta }_{\pi }=0^{\circ }$ and $E_{\gamma }\sim 250$ MeV is particularly useful for extracting $a_{nn}$ and $r_{nn}$ from the corresponding data $R_{\exp }$. It is found that $R_{\exp }$ with 2% error, resolved into the $M_{nn}$ bin width of 0.04 MeV (corresponding to the $p_{\pi }$ bin width of 0.05 MeV$/c$), can determine $a_{nn}$ and $r_{nn}$ with uncertainties of $\pm 0.21$ fm and $\pm 0.06$ fm, respectively, for the case of $a_{nn}=-18.9$ fm and $r_{nn}=2.75$ fm. The requirement of such narrow bin widths indicates that the momenta of the incident photon and the emitted ${\pi }^{+}$ have to be measured with high resolutions. This can be achieved by utilizing virtual photons of very small $Q^2$ from electron scattering at Mainz MAMI facility. The proposed method for determining $a_{nn}$ and $r_{nn}$ from $\gamma d\to {\pi }^{+}nn$ has a great experimental advantage over the previous one utilizing ${\pi }^{-}d\to \gamma nn$ for being free from the formidable task of controlling the neutron detection efficiency and its uncertainty.

   ↳ nucl-thhep-phnucl-ex5 citations
8. 08*

   Collision dynamics at medium and relativistic energies

   Maria Colonna🇮🇹

   Recent results connected to nuclear collision dynamics, from low up to relativistic energies, are reviewed. Heavy ion reactions offer the unique opportunity to probe the complex nuclear many-body dynamics and to explore, in laboratory experiments, transient states of nuclear matter under several conditions of density, temperature and charge asymmetry. From the theoretical point of view, transport models are an essential tool to undertake these investigations and make a connection between the nuclear effective interaction and sensitive observables of experimental interest. In this article, we mainly focus on the description of results of transport models for a selection of reaction mechanisms, also considering comparisons of predictions of different approaches. This analysis can help understanding the impact of the interplay between mean-field and correlation effects, as well as of in-medium effects, on reaction observables, which is an essential point also for extracting information on the nuclear Equation of State. A special emphasis will be given to the review of recent studies aimed at constraining the density behavior of the nuclear symmetry energy. For reactions at medium (Fermi) energies, we will describe light particle and fragment emission mechanisms, together with isospin transport effects. Collective effects characterizing nuclear collision dynamics, such as transverse and elliptic flows, will be discussed for relativistic heavy ion reactions, together with meson production and isotopic ratios.

   ↳ nucl-thnucl-exPPNP·54 citations
9. 09*

   On microscopic theory of pygmy- and giant resonances

   S. Kamerdzhiev · M. Shitov🇷🇺

   The Green function formalism with a consistent account for phonon coupling (PC), based on the self-consistent theory of finite Fermi-systems, is applied for pygmy- and giant multipole resonances in magic nuclei with the aim to consider particle-hole (ph) and complex 1p1h phonon configurations. A new equation for the effective field, which describes nuclear polarizability, is obtained. It contains new PC contributions which are of interest in the energy region under consideration. They are due to: i)the tadpole effect in the standard ph-propagator, ii)two new induced interactions (caused by the exchange of ph-phonon) in the second ph-channel and in the particle-particle channels, and iii) the first and second variations of the effective interaction in the phonon field. The general expressions for energies and probabilities of transitions between the ground and excited states are obtained. The qualitative analysis and discussion of the new terms are performed.

   ↳ nucl-thnucl-exEPJA(2020)·5 citations
10. 10*

    Understanding fission fragment mass distributions in a modified shape of random neck rupture model

    Yogesh Sawant · S. V. Suryanarayana · B. K. Nayak🇮🇳 · A. Saxena🇮🇳 · R. K. Choudhury🇮🇳

    The variances of the fission fragment mass distributions for symmetric fission over a wide range of the fissility of the compound nucleus have been investigated within the frame work of Random Neck Rupture Model (RNRM) proposed by Brosa et. al.,. The shape of the fissioning nucleus is generated using crel=1 in the RNRM model, which results in a smooth and continuous shape of fissioning nucleus. This modified shape of RNRM model has been used to analyse experimental data of mass variances for symmetric mass distributions of 27 systems leading to understanding of scission shape dynamics in a wide region of fissility 0.7-0.95. The neck radius is an important parameter of the RNRM model and this has been varied to fit the experimental mass variances data. The systematics of resulting neck radii are studied of as a function fissility and nuclear potential through {\gamma}o, the surface energy coefficient. Further average total kinetic energies of fission fragments <TKE> are studied of as a function of fissility and {\gamma}o parameter. It is observed that the neck radii that fit the experimentally observed variances of the mass distributions fall into two groups and these groups are related to two groups of experimentally observed <TKE>s. Empirical formulae have been obtained for the neck radii for these two groups of fissioning systems. Use of the empirical formulae for neck radii predict the mass variances reasonably well for these systems and it is shown that these empirical neck radii are better estimates than starting with the Rayleigh criterion.16pages,7 figures

    ↳ nucl-thnucl-exPramana(2022)·0 citations
11. 11*

    ADC Nonlinearity Correction for the MAJORANA DEMONSTRATOR

    N. Abgrall🇺🇸 · J.M. Allmond🇺🇸 · I.J. Arnquist🇺🇸 · F.T. Avignone III🇺🇸 · A.S. Barabash🇷🇺 · C.J. Barton🇺🇸 · F.E. Bertrand🇺🇸 · B. Bos🇺🇸 · M. Busch🇺🇸 · M. Buuck🇺🇸 · T.S. Caldwell🇺🇸 · C.M. Campbell🇺🇸 and 55 other authors

    Imperfections in analog-to-digital conversion (ADC) cannot be ignored when signal digitization requirements demand both wide dynamic range and high resolution, as is the case for the Majorana Demonstrator 76Ge neutrinoless double beta decay search. Enabling the experiment's high-resolution spectral analysis and efficient pulse shape discrimination required careful measurement and correction of ADC nonlinearites. A simple measurement protocol was developed that did not require sophisticated equipment or lengthy data taking campaigns. A slope-dependent hysteresis was observed and characterized. A correction applied to digitized waveforms prior to signal processing reduced the differential and integral nonlinearites by an order of magnitude, eliminating these as dominant contributions to the systematic energy uncertainty at the double-beta decay Q value.

    ↳ physics.ins-detnucl-exIEEE Trans.Nucl.Sci.(2021)·21 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.