Tue·Jun 2, 2020Tuesday·June 2, 2020

1. 01*

   Isotopically resolved neutron total cross sections at intermediate energies

   C. D. Pruitt🇺🇸 · R. J. Charity🇺🇸 · L. G. Sobotka🇺🇸 · J. M. Elson🇺🇸 · D. E. M. Hoff🇺🇸 · K. W. Brown🇺🇸 · M. C. Atkinson🇨🇦 · W. H. Dickhoff🇺🇸 · H. Y. Lee · M. Devlin🇺🇸 · N. Fotiades🇺🇸 · S. Mosby🇺🇸

   The neutron total cross sections ${\sigma }_{tot}$ of ${}^{16,18}$O, ${}^{58,64}$Ni, ${}^{103}$Rh, and ${}^{112,124}$Sn have been measured at the Los Alamos Neutron Science Center (LANSCE) from low to intermediate energies (3 $\le E_{lab}\le$ 450 MeV) by leveraging waveform-digitizer technology. The ${\sigma }_{tot}$ relative differences between isotopes are presented, revealing additional information about the isovector components needed for an accurate optical-model description away from stability. Digitizer-enabled ${\sigma }_{tot}$-measurement techniques are discussed and a series of uncertainty-quantified dispersive optical model (DOM) analyses using these new data is presented, validating the use of the DOM for modeling light systems (${}^{16,18}$O) and systems with open neutron shells (${}^{58,64}$Ni and ${}^{112,124}$Sn). The valence-nucleon spectroscopic factors extracted for each isotope reaffirm the usefulness of high-energy proton reaction cross sections for characterizing depletion from the mean-field expectation.

   nucl-exnucl-thPRC(2020)·28 citations
2. 02*

   ${}^{23}$Ne Production at SARAF-I

   Yonatan Mishnayot🇮🇱 · Hitesh Rahangdale🇮🇱 · Ben Ohayon🇨🇭 · Sergey Vaintraub🇮🇱 · Tsviki Hirsh🇮🇱 · Leo Weismann · Amichay Perry🇮🇱 · Asher Shor🇮🇱 · Arik Kreisel🇮🇱 · Shadi Ya'akobi · Einat Buznach · Guy Ron🇮🇱

   In this article, we present a measurement of flow rate, yield and effusion time of a ${}^{23}$Ne production and transport system. We used an accelerator-driven Li(d,n) neutron source to produce neutrons up to 20 MeV. The radioactive atoms were produced by a ${}^{23}$Na(n,p) reaction at a NaCl target. Later, the atoms were diffused out from the NaCl crystals and effused from the production chamber via a 10 m hose to a measurement cell and their decay products were detected using high purity germanium (HPGe) and plastic scintillator detectors. The resulting flow rate was $6.9\pm 0.5\cdot 10^4\text{sfrac}atomssec$ and the total yield was $3.2\pm 0.4\cdot 10^{-9}\text{sfrac}atomsdeuteron$. We summarize our methods and estimates of efficiencies, rates of production and effusion.

   nucl-exphysics.acc-phNucl.Instrum.Meth.A(2020)·1 citation
3. 03*

   Measurement of inclusive charged-particle jet production in Au+Au collisions at $\sqrt{s_{NN}}$=200 GeV

   STAR Collaboration: J. Adam · L. Adamczyk · J. R. Adams · J. K. Adkins · G. Agakishiev · M. M. Aggarwal · Z. Ahammed · I. Alekseev · D. M. Anderson · A. Aparin · E. C. Aschenauer · M. U. Ashraf and 352 other authors

   The STAR Collaboration at the Relativistic Heavy Ion Collider reports the first measurement of inclusive jet production in peripheral and central Au+Au collisions at $\sqrt{s_{NN}}$=200 GeV. Jets are reconstructed with the anti-k${}_T$ algorithm using charged tracks with pseudorapidity $|\eta |<1.0$ and transverse momentum $0.2<p_{T,jet}^{ch}<30$ GeV/$c$, with jet resolution parameter $R$=0.2, 0.3, and 0.4. The large background yield uncorrelated with the jet signal is observed to be dominated by statistical phase space, consistent with a previous coincidence measurement. This background is suppressed by requiring a high-transverse-momentum (high-$p_T$) leading hadron in accepted jet candidates. The bias imposed by this requirement is assessed, and the $p_T$ region in which the bias is small is identified. Inclusive charged-particle jet distributions are reported in peripheral and central Au+Au collisions for $5<p_{T,jet}^{ch}<25$ GeV/$c$ and $5<p_{T,jet}^{ch}<30$ GeV/$c$, respectively. The charged-particle jet inclusive yield is suppressed for central Au+Au collisions, compared to both the peripheral Au+Au yield from this measurement and to the $pp$ yield calculated using the PYTHIA event generator. The magnitude of the suppression is consistent with that of inclusive hadron production at high $p_T$, and that of semi-inclusive recoil jet yield when expressed in terms of energy loss due to medium-induced energy transport. Comparison of inclusive charged-particle jet yields for different values of $R$ exhibits no significant evidence for medium-induced broadening of the transverse jet profile for $R<0.4$ in central Au+Au collisions. The measured distributions are consistent with theoretical model calculations that incorporate jet quenching.

   nucl-exhep-exPRC(2020)·85 citations
4. 04*

   Employing $p{+}^{58}$Ni elastic scattering for determination of $K$-shell ionization cross section of ${}^{58}$Ni${}^{19+}$ in collisions with hydrogen gas target at 95 MeV/u

   J. T. Zhang🇺🇸 · K. Yue · C. J. Shao · X. L. Tu🇨🇳 · Y. Y. Wang🇨🇳 · P. Ma🇨🇳 · B. Mei🇩🇪 · X. C. Chen🇨🇳 · Y. Y. Yang🇨🇳 · Z. Y. Sun🇨🇳 · M. Wang🇨🇳 · V. P. Shevelko🇷🇺 and 4 other authors

   We present a new experimental method for measuring inner-shell ionization cross sections of low-charged ions colliding with hydrogen gas target in a storage ring. The method is based on a calibration by the well-known differential cross sections of proton elastic scattering on nuclei. $K$-shell ionization cross section of 1047(100) barn for the 95 MeV/u ${}^{58}$Ni${}^{19+}$ ions colliding with hydrogen atoms was obtained in this work. Compared to the measured ionization cross section, a good agreement is achieved with the prediction by the Relativistic Ionization CODE Modified program (RICODE-M).

   nucl-exNucl.Instrum.Meth.B(2020)·2 citations
5. 05*

   First Measurement of Differential Charged Current Quasielastic-like ${\nu }_{\mu }$-Argon Scattering Cross Sections with the MicroBooNE Detector

   P. Abratenko · M. Alrashed · R. An · J. Anthony · J. Asaadi · A. Ashkenazi · S. Balasubramanian · B. Baller · C. Barnes · G. Barr · V. Basque · L. Bathe-Peters and 172 other authors

   We report on the first measurement of flux-integrated single differential cross sections for charged-current (CC) muon neutrino (${\nu }_{\mu }$) scattering on argon with a muon and a proton in the final state, ${}^{40}$Ar(${\nu }_{\mu }$,$\mu$p)X. The measurement was carried out using the Booster Neutrino Beam at Fermi National Accelerator Laboratory and the MicroBooNE liquid argon time projection chamber detector with an exposure of 4.59 $\times$ 10${}^{19}$ protons on target. Events are selected to enhance the contribution of CC quasielastic (CCQE) interactions. The data are reported in terms of a total cross section as well as single differential cross sections in final state muon and proton kinematics. We measure the integrated per-nucleus CCQE-like cross section (i.e. for interactions leading to a muon, one proton and no pions above detection threshold) of (4.93 $\pm$ 0.76stat $\pm$ 1.29sys) $\times$ 10${}^{-38}$cm${}^2$, in good agreement with theoretical calculations. The single differential cross sections are also in overall good agreement with theoretical predictions, except at very forward muon scattering angles that correspond to low momentum-transfer events.

   ↳ hep-exhep-phnucl-exnucl-thPRL(2020)·87 citations
6. 06*

   $g$-factor and static quadrupole moment for the wobbling mode in ${}^{133}$La

   Q. B. Chen🇩🇪 · S. Frauendorf🇺🇸 · N. Kaiser🇩🇪 · Ulf-G. Meißner🇩🇪 · J. Meng🇨🇳

   The $g$-factor and static quadrupole moment for the wobbling mode in the nuclide ${}^{133}$La are investigated as functions of the spin $I$by employing the particle rotor model. The model can reproduce the available experimental data of $g$-factor and static quadrupole moment. The properties of the $g$-factor and static quadrupole moment as functions of $I$ are interpreted by analyzing the angular momentum geometry of the collective rotor, proton-particle, and total nuclear system. It is demonstrated that the experimental value of the $g$-factor at the bandhead of the yrast band leads to the conclusion that the rotor angular momentum is $R\simeq 2$. Furthermore, the variation of the $g$-factor with the spin $I$ yields the information that the angular momenta of the proton-particle and total nuclear system are oriented parallel to each other. The negative values of the static quadrupole moment over the entire spin region are caused by an alignment of the total angular momentum mainly along the short axis. Static quadrupole moment differences between the wobbling and yrast band originate from a wobbling excitation with respect to the short axis.

   ↳ nucl-thnucl-exPLB(2020)·26 citations
7. 07*

   The isoscalar features of Pygmy Dipole Resonance: a subtle game of symmetry energy

   V. Baran🇷🇴 · T. Isdraila · M. Colonna🇮🇹 · D. I. Palade · A. I. Nicolin

   The vibrational structure of the Pygmy Dipole Resonance (PDR) is investigated within a quantum many-body treatment with extended separable interactions able to encode the dependence of nuclear symmetry energy on density. A new picture of PDR is unveiled in terms of a combined dynamics of the neutron skin and of the core isovector polarization, which determines the isoscalar features of PDR while reproducing the isovector properties of Giant Dipole Resonance. The key role played by the variation with density of the symmetry energy on shaping the low-lying dipole response and its isoscalar-isovector structure is underlined. Our results provide insights for the challenge of clarifying the transition from skin oscillation to a highly bulk collective dynamics.

   ↳ nucl-thnucl-ex0 citations
8. 08*

   Muon capture rates: Evaluation within the Quasiparticle Random Phase Approximation

   Fedor Simkovic🇸🇰 · Rastislav Dvornicky🇷🇺 · Petr Vogel🇺🇸

   The Quasiparticle Random Phase Approximation (QRPA) is used in evaluation of the total muon capture ratesfor the final nuclei participating in double-beta decay. Several variants of the method are used, depending on the size of the single particle model space used, or treatment of the initial bound muon wave function. The resulting capture rates are all reasonably close to each other. In particular, the variant that appears to be most realistic, results in rates in good agreement with the experimental values. There is no necessity for an empirical quenching of the axial current coupling constant $g_A$. Its standard value $g_A$ = 1.27 seems to be adequate.

   ↳ nucl-thhep-phnucl-exPRC(2020)·20 citations
9. 09*

   Magnetic field effects in peripheral heavy-ion collisions around 1 GeV/nucleon

   X. G. Deng🇨🇳 · Y. G. Ma🇨🇳

   Magnetic field effects on free nucleons are studied in peripheral collisions of ${}^{197}$Au + ${}^{197}$Au at energies ranging from 600 to 1500 MeV/nucleon by utilizing an isospin-dependent quantum molecular dynamics (IQMD) model. With the help of angular distributions and two-particle angular correlators, the magnetic field effect at an impact parameter of 11 fm is found to be more obvious than at an impact parameter of 8 fm. Moreover, the results suggest that with an increase in the number of peripheral collisions, protons are more easily condensed with the magnetic field. Magnetic field effects are further investigated by the ratio of free neutrons to free protons as functions of a two-particle correlator $C_2$, four-particle correlator $C_4$ and six-particle correlator $C_6$ of angle $\varphi$, rapidity $Y$ and transverse momentum $p_T$. The results show that weak magnetic field effects could be revealed more clearly by these multiple-particle correlators, with the larger number of particle correlators demonstrating a clear signal. The results highlight a new method to search for weak signals using multi-particle correlators.

   ↳ nucl-thnucl-exPRC(2020)·7 citations
10. 10*

    Two-proton momentum correlation from photondisintegration of $\alpha$-clustering light nuclei in the quasi-deuteron region

    B. S. Huang🇨🇳 · Y. G. Ma🇨🇳

    The proton-proton momentum correlation function is constructed in three-body photo-disintegration channels from ${}^{12}$C and ${}^{16}$O targets in the quasi-deuteron regime within the framework of an extended quantum molecular dynamics model. Using the formula of Lednicky and Lyuboshitz (LL) for the momentum correlation function, we obtain a proton-proton momentum correlation function for the specific three-body photon-disintegration channels of ${}^{12}$C and ${}^{16}$O targets, which are assumed to have different initial geometric structures, and extract their respective emission source sizes for the proton-proton pair. The results demonstrate that constructing a proton-proton momentum correlation is feasible in photo-nuclear reactions, and it is sensitive to the initial nuclear structure. For future experimental studies investigating the $\alpha$-clustering structures of light nuclei, the present work can be used to shed light on the performance and correlation function analysis of ($\gamma$,pp) or (e,$e^{\prime }$pp) reactions.

    ↳ nucl-thnucl-exPRC(2020)·23 citations
11. 11*

    Strength of pairing interaction for hyperons in multistrangeness hypernuclei

    Yu-Ting Rong🇨🇳 · Pengwei Zhao🇨🇳 · Shan-Gui Zhou🇨🇳

    Pairing correlations play a very important role in atomic nuclei. Although several effective pairing interactions have been used in mean field calculations for nucleons, little is known about effective pairing interactions for hyperons. Based on the quark model, we propose a relationship between effective pairing interactions for hyperons and for nucleons; e.g., for $\Lambda$s, the strength of the pairing interaction is 4/9 of that for nucleons. A separable pairing force of finite range which has been widely applied to describing pairing correlations in normal nuclei is used to investigate pairing effects in multi-$\Lambda$ Ca, Sn and Pb hypernuclei.

    ↳ nucl-thnucl-exPLB(2020)·32 citations
12. 12*

    $d^{\ast }(2380)$ dibaryon from lattice QCD

    Shinya Gongyo🇯🇵 · Kenji Sasaki🇯🇵 · Takaya Miyamoto🇯🇵 · Sinya Aoki🇯🇵 · Takumi Doi🇯🇵 · Tetsuo Hatsuda🇯🇵 · Yoichi Ikeda🇯🇵 · Takashi Inoue🇯🇵 · Noriyoshi Ishii🇯🇵

    The $\Delta \Delta$ dibaryon resonance $d^{\ast }(2380)$ with $(J^P,I)=(3^{+},0)$ is studied theoretically on the basis of the 3-flavor lattice QCD simulation with heavy pion masses ($m_{\pi }=679,841$ and $1018$ MeV). By using the HAL QCD method, the central $\Delta$-$\Delta$ potential in the ${}^7{S}_3$ channel is obtained from the lattice data with the lattice spacing $a\simeq 0.121$ fm and the lattice size $L\simeq 3.87$ fm. The resultant potential shows a strong short-range attraction, so that a quasi-bound state corresponding to $d^{\ast }(2380)$ is formed with the binding energy $25$-$40$ MeV below the $\Delta \Delta$ threshold for the heavy pion masses. The tensor part of the transition potential from $\Delta \Delta$ to $NN$ is also extracted to investigate the coupling strength between the $S$-wave $\Delta \Delta$ system with $J^P=3^{+}$ and the $D$-wave $NN$ system. Although the transition potential is strong at short distances, the decay width of $d^{\ast }(2380)$ to $NN$ in the $D$-wave is kinematically suppressed, which justifies our single-channel analysis at the range of the pion mass explored in this study.

    ↳ hep-lathep-exhep-phnucl-ex+1PLB(2020)·25 citations
13. 13*

    Dynamical Evidence For a Fifth Force Explanation of the ATOMKI Nuclear Anomalies

    Jonathan L. Feng🇺🇸 · Tim M. P. Tait🇺🇸 · Christopher B. Verhaaren🇺🇸

    Recent anomalies in ${}^8$Be and ${}^4$He nuclear decays can be explained by postulating a fifth force mediated by a new boson $X$. The distributions of both transitions are consistent with the same $X$ mass, 17 MeV, providing kinematic evidence for a single new particle explanation. In this work, we examine whether the new results also provide dynamical evidence for a new particle explanation, that is, whether the observed decay rates of both anomalies can be described by a single hypothesis for the $X$ boson's interactions. We consider the observed ${}^8$Be and ${}^4$He excited nuclei, as well as a ${}^{12}$C excited nucleus; together these span the possible $J^P$ quantum numbers up to spin 1. For each transition, we determine whether scalar, pseudoscalar, vector, or axial vector $X$ particles can mediate the decay, and we construct the leading operators in a nuclear physics effective field theory that describes them. Assuming parity conservation, the scalar case is excluded and the pseudoscalar case is highly disfavored. Remarkably, however, the protophobic vector gauge boson, first proposed to explain only the ${}^8$Be anomaly, also explains the ${}^4$He anomaly within experimental uncertainties. We predict signal rates for other closely related nuclear measurements, which, if confirmed, will provide overwhelming evidence that a fifth force has been discovered.

    ↳ hep-phhep-exnucl-exnucl-thPRD(2020)·71 citations
14. 14*

    Minimal Theory of Isomerism -Q.Q and Other Interactions

    Praveen Srivastava🇮🇳 · Larry Zamick🇺🇸

    We perform shell model calculations using a quadrupole-quadrupole interaction (Q.Q) in single a j shell space. We show that this one-parameter interaction is a good predictor of where nuclear isomerism occurs and where it does not occur. The limitations of this interaction are also discussed. We then include other interactions e.g. in the f_{7/2} shell those obtained from the (local) spectrum of a 2 particle system and then from a 2 hole system. In the g_{9/2}where there is insufficient empirical data from the 2 hole system and so various empirical interactions are used.

    ↳ nucl-thnucl-exPhys.Scripta(2021)·5 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.