Fri·Feb 1, 2019Friday·February 1, 2019

1. 01*

   High-resolution, accurate MR-TOF-MS for short-lived, exotic nuclei of few events in their ground and low-lying isomeric states

   S. Ayet · C. Hornung · J. Ebert · W. R. Plaß · T. Dickel · H. Geissel · C. Scheidenberger · J. Bergmann · F. Greiner · E. Haettner · C. Jesch · W. Lippert and 28 other authors

   Mass measurements of fission and projectile fragments, produced via ${}^{238}$U and ${}^{124}$Xe primary beams, have been performed with the multiple-reflection time-of-flight mass spectrometer (MR-TOF-MS) of the FRS Ion Catcher with a mass resolving powers (FWHM) up to 410,000 and an uncertainty of $6\cdot 10^{-8}$. The nuclides were produced and separated in-flight with the fragment separator FRS at 300 to 1000 MeV/u and thermalized in a cryogenic stopping cell. The data-analysis procedure was developed to determine with highest accuracy the mass values and the corresponding uncertainties for the most challenging conditions: down to a few events in a spectrum and overlapping distributions, characterized only by a broader common peak shape. With this procedure, the resolution of low-lying isomers is increased by a factor of up to three compared to standard data analysis. The ground-state masses of 31 short-lived nuclides of 15 different elements with half-lives down to 17.9~ms and count rates as low as 11 events per nuclide were determined. This is the first direct mass measurement for seven nuclides. The excitation energies and the isomer-to-ground state ratios of six isomeric states with excitation energies down to about 280~keV were measured. For nuclides with known mass values, the average relative deviation from the literature values is $(2.9\pm 6.2)\cdot 10^{-8}$. The measured two-neutron separation energies and their slopes near and at the N=126 and Z=82 shell closures indicate a strong element-dependent binding energy of the first neutron above the closed proton shell Z=82. The experimental results deviate strongly from the theoretical predictions, especially for N=126 and N=127.

   nucl-exphysics.ins-detPRC(2019)·61 citations
2. 02*

   Possibilities of future double beta decay experiments to investigate inverted and normal ordering region of neutrino mass

   A.S. Barabash🇷🇺

   An overview of modern experiments on the search for neutrinoless double decay is presented. The obtained limits on the effective mass of the Majorana neutrino $⟨m_{\nu }⟩$ are discussed taking into account the uncertainties in the value of the nuclear matrix elements (NMEs) and the value of the axial-vector constant $g_A$. Predictions for the values of $⟨m_{\nu }⟩$ from the results of oscillation experiments and modern cosmological data are presented. The possibilities of the next generation experiments with sensitivity to $⟨m_{\nu }⟩$ at the level of $\sim$ 10-50 meV (studying mainly the inverted ordering (IO) region) are discussed. %Description of the most developed and promising projects is presented. The prospects for studying the normal ordering (NO) region are discussed too. It is shown that the possibilities of studying the NO depend on the mass of the lightest neutrino m${}_0$. In the limiting case of small mass (m${}_0$ $\le$ 0.1 meV), the values of $⟨m_{\nu }⟩$ $\approx$ 1-4 meV are predicted, which makes the study of this region inaccessible by the next generation experiments. But there is an allowed region of m${}_0$ (7-30 meV) in the framework of NO, where the predicted values for $⟨m_{\nu }⟩$ could be $\sim$ 10-30 meV and that is quite achievable for the next generation experiments. The possibility to rich in the future sensitivity to $⟨m_{\nu }⟩$ at the level of $\sim$ 1-10 meV is also discussed.

   nucl-exnucl-thFront.in Phys.(2019)·26 citations
3. 03*

   Symmetries and order in cluster nuclei

   Roelof Bijker🇲🇽

   It is shown that the rotational band structure of the cluster states in 12C and 16O can be understood in terms of the underlying discrete symmetry that characterizes the geometrical configuration of the alpha-particles, i.e. an equilateral triangle for 12C, and a regular tetrahedron for 16O. The structure of rotational bands provides a fingerprint of the underlying geometrical configuration of alpha-particles. Finally, some first results are presented for odd-cluster nuclei.

   ↳ nucl-thnucl-exAIP Conf.Proc.(2019)·4 citations
4. 04*

   Dynamically Integrated Transport Approach for High-Energy Nuclear Collisions at High Baryon Density

   Koichi Murase🇯🇵 · Yukinao Akamatsu🇯🇵 · Masayuki Asakawa🇯🇵 · Tetsufumi Hirano🇯🇵 · Masakiyo Kitazawa🇯🇵 · Kenji Morita🇵🇱 · Yasushi Nara🇯🇵 · Chiho Nonaka🇯🇵 · Akira Ohnishi🇯🇵

   To explore the structure of the QCD phase diagram in high baryon density domain, several high-energy nuclear collision experiments in a wide range of beam energies are currently performed or planned using many accelerator facilities. In these experiments search for a first-order phase transition and the QCD critical point is one of the most important topics. To find the signature of the phase transition, experimental data should be compared to appropriate dynamical models which quantitatively describe the process of the collisions. In this study we develop a new dynamical model on the basis of the non-equilibrium hadronic transport model JAM and 3+1D hydrodynamics. We show that the new model reproduce well the experimental beam-energy dependence of hadron yields and particle ratio by the partial thermalization of the system in our core-corona approach.

   ↳ nucl-thhep-phnucl-exJPS Conf.Proc.(2019)·2 citations
5. 05*

   Probing QCD critical fluctuations from intermittency analysis in relativistic heavy-ion collisions

   Jin Wu🇨🇳 · Yufu Lin🇨🇳 · Yuanfang Wu🇨🇳 · Zhiming Li🇨🇳

   It is shown that intermittency, a self-similar correlation with respect to the size of the phase space volume, is sensitive to critical density fluctuations of baryon numbers in a system belonging to the three-dimensional (3D) Ising universality class. The relation between intermittency index and relative baryon density fluctuation is obtained. We thus suggest that measuring the intermittency in relativistic heavy-ion collisions could be used as a good probe of density fluctuations associated with the QCD critical phenomena. From recent preliminary results on neutron density fluctuations in central Au + Au collisions at $\sqrt{s_{NN}}$ = 7.7, 11.5, 19.6, 27, 39, 62.4 and 200 GeV at RHIC/STAR, the collision energy dependence of intermittency index is extracted and shows a non-monotonic behavior with a peak at around 20 - 27 GeV, indicating that the strength of intermittency becomes the largest in this energy region. The transport UrQMD model without implementing critical physics cannot describe the observed behavior.

   ↳ nucl-thhep-exhep-phnucl-exPLB(2020)·31 citations
6. 06*

   Equation of state of dense matter in the multimessenger era

   Ying Zhou🇨🇳 · Lie-Wen Chen🇨🇳 · Zhen Zhang🇨🇳

   While the equation of state (EOS) of symmetric nuclear matter (SNM) at suprasaturation densities has been relatively well constrained from heavy-ion collisions, the EOS of high-density neutron-rich matter is still largely uncertain due to the poorly known high-density behavior of the symmetry energy. Using the constraints on the EOS of SNM at suprasaturation densities from heavy-ion collisions together with the data of finite nuclei and the existence of $2M_{\odot }$ neutron stars from electromagnetic (EM) observations, we show that the high-density symmetry energy cannot be too soft, which leads to lower bounds on dimensionless tidal deformability of ${\Lambda }_{1.4}\ge 193$ and radius of $R_{1.4}\ge 11.1$ km for $1.4M_{\odot }$ neutron star. Furthermore, we find that the recent constraint of ${\Lambda }_{1.4}\le 580$ from the gravitational wave signal GW170817 detected from the binary neutron star merger by the LIGO and Virgo Collaborations rules out too stiff high-density symmetry energy, leading to an upper limit of $R_{1.4}\le 13.3$ km. All these terrestrial nuclear experiments and astrophysical observations based on strong, EM and gravitational measurements together put stringent constraints on the high-density symmetry energy and the EOS of SNM, pure neutron matter and neutron star matter.

   ↳ nucl-thastro-ph.HEastro-ph.SRhep-ph+1PRD(2019)·64 citations
7. 07*

   Spectrum of light- and heavy-baryons

   Si-Xue Qin🇨🇳 · Craig D. Roberts🇺🇸 · Sebastian M. Schmidt🇩🇪

   A symmetry-preserving truncation of the strong-interaction bound-state equations is used to calculate the spectrum of ground-state $J=1/2^{+}$, $3/2^{+}$ $(q{q}^{\prime }{q}^{\prime \prime })$-baryons, where $q,q^{\prime },q^{\prime \prime }\in \{u,d,s,c,b\}$, their first positive-parity excitations and parity partners. Using two parameters, a description of the known spectrum of 39 such states is obtained, with a mean-absolute-relative-difference between calculation and experiment of 3.6(2.7)%. From this foundation, the framework is subsequently used to predict the masses of 90 states not yet seen empirically.

   ↳ nucl-thhep-exhep-lathep-ph+1Few Body Syst.(2019)·123 citations
8. 08*

   A next-generation LHC heavy-ion experiment

   D. Adamová🇨🇿 · G. Aglieri Rinella🇨🇭 · M. Agnello🇮🇹 · Z. Ahammed🇮🇳 · D. Aleksandrov🇷🇺 · A. Alici🇮🇹 · A. Alkin🇺🇦 · T. Alt🇩🇪 · I. Altsybeev🇷🇺 · D. Andreou🇨🇭 · A. Andronic🇩🇪 · F. Antinori🇮🇹 and 387 other authors

   The present document discusses plans for a compact, next-generation multi-purpose detector at the LHC as a follow-up to the present ALICE experiment. The aim is to build a nearly massless barrel detector consisting of truly cylindrical layers based on curved wafer-scale ultra-thin silicon sensors with MAPS technology, featuring an unprecedented low material budget of 0.05% X${}_0$ per layer, with the innermost layers possibly positioned inside the beam pipe. In addition to superior tracking and vertexing capabilities over a wide momentum range down to a few tens of MeV/$c$, the detector will provide particle identification via time-of-flight determination with about 20~ps resolution. In addition, electron and photon identification will be performed in a separate shower detector. The proposed detector is conceived for studies of pp, pA and AA collisions at luminosities a factor of 20 to 50 times higher than possible with the upgraded ALICE detector, enabling a rich physics program ranging from measurements with electromagnetic probes at ultra-low transverse momenta to precision physics in the charm and beauty sector.

   ↳ physics.ins-dethep-exnucl-exnucl-th62 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.