Mon·Jan 11, 2021Monday·January 11, 2021

1. 01*

   Statistical properties of the well deformed ${}^{153,155}$Sm nuclei and the scissors resonance

   K. L. Malatji🇿🇦 · K. S. Beckmann🇳🇴 · M. Wiedeking🇿🇦 · S. Siem🇳🇴 · S. Goriely🇧🇪 · A. C. Larsen🇳🇴 · K. O. Ay🇹🇷 · F. L. Bello Garrote🇳🇴 · L. Crespo Campo🇳🇴 · A. Görgen🇳🇴 · M. Guttormsen🇳🇴 · V. W. Ingeberg🇳🇴 and 9 other authors

   The Nuclear Level Densities (NLDs) and the $\gamma$-ray Strength Functions ($\gamma$SFs) of ${}^{153,155}$Sm have been extracted from (d,p$\gamma$) coincidences using the Oslo method. The experimental NLD of ${}^{153}$Sm is higher than the NLD of ${}^{155}$Sm, in accordance with microscopic calculations. The $\gamma$SFs of ${}^{153,155}$Sm are in fair agreement with QRPA calculations based on the D1M Gogny interaction. An enhancement is observed in the $\gamma$SF for both ${}^{153,155}$Sm nuclei around 3 MeV in excitation energy and is attributed to the M1 Scissors Resonance (SR). Their integrated strengths were found to be in the range 1.3 - 2.1 and 4.4 - 6.4 ${\mu }_N^2$ for ${}^{153}$Sm and ${}^{155}$Sm, respectively. The strength of the SR for ${}^{155}$Sm is comparable to those for deformed even-even Sm isotopes from nuclear resonance fluorescence measurements, while that of ${}^{153}$Sm is lower than expected.

   nucl-exPRC(2021)·12 citations
2. 02*

   Large back-angle quasielastic scattering for ${}^7$Li+${}^{159}$Tb

   Piyasi Biswas🇮🇳 · A. Mukherjee🇮🇳 · D. Chattopadhyay🇮🇳 · Saikat Bhattacharjee🇮🇳 · M.K. Pradhan🇮🇳 · Md. Moin Shaikh🇮🇳 · Subinit Roy🇮🇳 · A. Goswami🇮🇳 · P. Basu🇮🇳 · S. Santra🇮🇳 · S.K. Pandit🇮🇳 · K. Mahata🇮🇳 · A. Shrivastava🇮🇳

   Quasielastic scattering excitation function at large backward angle has been measured for the weakly bound system, ${}^7$Li+${}^{159}$Tb at energies around the Coulomb barrier. The corresponding quasielastic barrier distribution has been derived from the excitation function, both including and excluding the $\alpha$-particles produced in the reaction. The centroid of the barrier distribution obtained after inclusion of $\alpha$-particles was found to be shifted higher in energy, compared to the distribution excluding the $\alpha$-particles. The quasielastic data, excluding the $\alpha$-particles, have been analyzed in the framework of continuum discretized coupled channel calculations. The quasielastic barrier distribution for ${}^7$Li+${}^{159}$Tb, has also been compared with the fusion barrier distribution for the system.

   nucl-exPRC(2021)·3 citations
3. 03*

   Production of pions, kaons, (anti-)protons and $\varphi$ mesons in Xe-Xe collisions at $\sqrt{s_{\mathrm{NN}}}=5.44$ TeV

   ALICE Collaboration

   The first measurement of the production of pions, kaons, (anti-)protons and $\varphi$ mesons at midrapidity in Xe-Xe collisions at $\sqrt{s_{\mathrm{NN}}}=5.44$ TeV is presented. Transverse momentum ($p_{\mathrm{T}}$) spectra and $p_{\mathrm{T}}$-integrated yields are extracted in several centrality intervals bridging from p-Pb to mid-central Pb-Pb collisions in terms of final-state multiplicity. The study of Xe-Xe and Pb-Pb collisions allows systems at similar charged-particle multiplicities but with different initial geometrical eccentricities to be investigated. A detailed comparison of the spectral shapes in the two systems reveals an opposite behaviour for radial and elliptic flow. In particular, this study shows that the radial flow does not depend on the colliding system when compared at similar charged-particle multiplicity. In terms of hadron chemistry, the previously observed smooth evolution of particle ratios with multiplicity from small to large collision systems is also found to hold in Xe-Xe. In addition, our results confirm that two remarkable features of particle production at LHC energies are also valid in the collision of medium-sized nuclei: the lower proton-to-pion ratio with respect to the thermal model expectations and the increase of the $\varphi$-to-pion ratio with increasing final-state multiplicity.

   nucl-exhep-exEPJC(2021)·53 citations
4. 04*

   Long- and short-range correlations and their event-scale dependence in high-multiplicity pp collisions at $\sqrt{\text{s}}=13$ TeV

   ALICE Collaboration

   Two-particle angular correlations are measured in high-multiplicity proton-proton collisions at $\sqrt{s}=13$ TeV by the ALICE Collaboration. The yields of particle pairs at short-($\Delta \eta$ $\sim$ 0) and long-range ($1.6<|\Delta \eta |<1.8$) in pseudorapidity are extracted on the near-side ($\Delta \phi$ $\sim$ 0). They are reported as a function of transverse momentum ($p_{\mathrm{T}}$) in the range $1<p_{\mathrm{T}}<4$ GeV/$c$. Furthermore, the event-scale dependence is studied for the first time by requiring the presence of high-$p_{\mathrm{T}}$ leading particles and jets for varying $p_{\mathrm{T}}$ thresholds. The results demonstrate that the long-range "ridge" yield, possibly related to the collective behavior of the system, is present in events with high-$p_{\mathrm{T}}$ processes. The magnitudes of the short- and long-range yields are found to grow with the event scale. The results are compared to EPOS LHC and PYTHIA 8 calculations, with and without string-shoving interactions. It is found that while both models describe the qualitative trends in the data, calculations from EPOS LHC show a better quantitative agreement, in particular for the $p_{\mathrm{T}}$ and event-scale dependencies.

   nucl-exhep-exJHEP(2021)·46 citations
5. 05*

   A unified description of the structure and electromagnetic breakup of ${}^{11}$Be

   M. Dan (IITR)🇮🇳 · R. Chatterjee (IITR)🇮🇳 · M. Kimura (Uni Hokkaido)🇯🇵

   We study both the static properties of ${}^{11}$Be and its reaction dynamics during electromagnetic breakup under a unified framework. A many-body approach - the antisymmetrized molecular dynamics (AMD) is used to describe the structure of the neutron-halo nucleus, ${}^{11}$Be. The same AMD wave function is then adapted as an input to the fully quantum theory of Coulomb breakup under the aegis of the finite range distorted wave Born approximation theory. The calculated observables are also compared with those obtained with a phenomenological Woods-Saxon potential model wave function. The experimental core-valence neutron relative energy spectrum and dipole response along with other observables are well described by our calculations.

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

   Microscopic description of octupole collective excitations near $N=56$ and $N=88$

   K. Nomura🇭🇷 · L. Lotina🇭🇷 · T. Nikšić🇭🇷 · D. Vretenar🇭🇷

   Octupole deformations and related collective excitations are analyzed using the framework of nuclear density functional theory. Axially-symmetric quadrupole-octupole constrained self-consistent mean-field (SCMF) calculations with a choice of universal energy density functional and a pairing interaction are performed for Xe, Ba, and Ce isotopes from proton-rich to neutron-rich regions, and neutron-rich Se, Kr, and Sr isotopes, in which enhanced octupole correlations are expected to occur. Low-energy positive- and negative-parity spectra and transition strengths are computed by solving the quadrupole-octupole collective Hamiltonian, with the inertia parameters and collective potential determined by the constrained SCMF calculations. Octupole-deformed equilibrium states are found in the potential energy surfaces of the Ba and Ce isotopes with $N\approx 56$ and 88. The evolution of spectroscopic properties indicates enhanced octupole correlations in the regions corresponding to $N\approx Z\approx 56$, $Z\approx 88$ and $Z\approx 56$, and $N\approx 56$ and $Z\approx 34$. The average ${\beta }_{30}$ deformation parameter and its fluctuation exhibit signatures of octupole shape phase transition around $N=56$ and 88.

   ↳ nucl-thnucl-exPRC(2021)·25 citations
7. 07*

   The relevance of nuclear reactions for Standard Solar Models construction

   Francesco L. Villante🇮🇹 · Aldo Serenelli🇪🇸

   The fundamental processes by which nuclear energy is generated in the Sun have been known for many years. However, continuous progress in areas such as neutrino experiments, stellar spectroscopy and helioseismic data and techniques requires ever more accurate and precise determination of nuclear reaction cross sections, a fundamental physical input for solar models. In this work, we review the current status of (standard) solar models and present a detailed discussion on the relevance of nuclear reactions for detailed predictions of solar properties. In addition, we also provide an analytical model that helps understanding the relation between nuclear cross sections, neutrino fluxes and the possibility they offer for determining physical characteristics of the solar interior. The latter is of particular relevance in the context of the conundrum posed by the solar composition, the solar abundance problem, and in the light of the first ever direct detection of solar CN neutrinos recently obtained by the Borexino collaboration. Finally, we present a short list of wishes about the precision with which nuclear reaction rates should be determined to allow for further progress in our understanding of the Sun.

   ↳ astro-ph.SRnucl-exnucl-thFront.Astron.Space 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.