Tue·Jan 22, 2019Tuesday·January 22, 2019

1. 01*

   Higher order Symmetric Cumulants

   Cindy Mordasini🇩🇪 · Ante Bilandzic🇩🇪 · Deniz Karakoç🇩🇪 · Seyed Farid Taghavi🇩🇪

   We present the generalization of recently introduced observables for the studies of correlated fluctuations of different anisotropic flow amplitudes, dubbed Symmetric Cumulants. We introduce a new set of higher order observables and outline a unique way how the genuine multi-harmonic correlations can be extracted from multi-particle azimuthal correlators. We argue that correlations among flow amplitudes can be studied reliably with the general mathematical formalism of cumulants only if that formalism is applied directly on the flow amplitudes. We have tested all the desired properties of new observables with the carefully designed Toy Monte Carlo studies. By using the realistic iEBE-VISHNU model, we have demonstrated that their measurements are feasible and we have provided the predictions for the centrality dependence in Pb--Pb collisions at LHC energies. A separate study was performed for their values in the coordinate space. The new observables contain information which is inaccessible to individual flow amplitudes and correlated fluctuations of only two flow amplitudes, and therefore they provide further and independent constraints for the initial conditions and the properties of Quark-Gluon Plasma in high-energy nuclear collisions.

   nucl-exhep-exnucl-thPRC(2020)·42 citations
2. 02*

   Towards a better understanding of the symmetry energy within neutron stars

   C.Y. Tsang🇺🇸 · M.B. Tsang🇺🇸 · P. Danielewicz🇺🇸 · W.G. Lynch🇺🇸 · F.J. Fattoyev🇺🇸

   The LIGO-Virgo collaboration ground-breaking detection of the binary neutron-star merger event, GW170817, has expanded efforts to understand the Equation of State (EoS) of nuclear matter. These measurements provide new constraints on the overall pressure, but do not, by itself, elucidate its microscopic origins, including the pressure arising from the symmetry energy, that governs much of the internal structure of a neutron star. To correlate microscopic constraints from nuclear measurements to the GW170817 constraints, we calculate neutron star properties with more than 200 Skyrme energy density functionals that describe properties of nuclei. Calculated neutron-star radii (R) and the tidal deformabilities which show a strong correlation with pressure at twice saturation density. By combining the neutron star EoS extracted from the GW170817 event and the EoS of symmetric matter from nucleus-nucleus collision experiments, we extract the density dependence of the symmetry pressure from 1.2 to 4.5 times saturation density. While the uncertainties in the symmetry pressure are large, they can be reduced with new experimental and astrophysical results.

   nucl-exnucl-th8 citations
3. 03*

   Heavy-Flavor Theory at "Hard and Electromagnetic Probes 2018"

   Ralf Rapp🇺🇸

   An overview is given of the theoretical developments on heavy quarks and quarkonia in heavy-ion collisions as reported at the "Hard and EM Probes 2018" conference. Specifically, we address progress in the understanding of heavy-flavor diffusion and its hadronization, quarkonium transport and the extraction of quarkonium melting temperatures, energy loss of heavy quarks at high momentum, and their rescattering in small colliding systems.

   ↳ nucl-thhep-phnucl-exPoS(2019)·3 citations
4. 04*

   Developing a silica aerogel radiator for the HELIX ring-imaging Cherenkov system

   Makoto Tabata🇯🇵 · Patrick Allison🇺🇸 · James J. Beatty🇺🇸 · Stephane Coutu🇺🇸 · Mark Gebhard🇺🇸 · Noah Green🇺🇸 · David Hanna🇨🇦 · Brandon Kunkler🇺🇸 · Mike Lang🇺🇸 · Keith McBride🇺🇸 · Isaac Mognet🇺🇸 · Dietrich Müller🇺🇸 and 9 other authors

   This paper reports the successful fabrication of silica aerogel Cherenkov radiators produced in the first batches from a 96-tile mass production performed using pin-drying technique in our laboratory. The aerogels are to be used in a ring-imaging Cherenkov detector in the spectrometer of a planned balloon-borne cosmic-ray observation program, HELIX (High Energy Light Isotope eXperiment). A total of 36 transparent, hydrophobic aerogel tiles with a high refractive index of 1.16 and dimensions of 10 cm $\times$ 10 cm $\times$ 1 cm will be chosen as the flight radiators. Thus far, 40 out of the 48 tiles fabricated were confirmed as having no tile cracking. In the first screening, 8 out of the first 16 tiles were accepted as flight-qualified candidates, based on basic optical measurement results. To fit the aerogel tiles into a radiator support structure, the trimming of previously manufactured prototype tiles using a water-jet cutting device was successful.

   ↳ physics.ins-detastro-ph.IMcond-mat.mtrl-scihep-ex+1Nucl.Instrum.Meth.A(2020)·14 citations
5. 05*

   Consistency Examinations of Calculations of Nuclear Matrix Elements of Double-$\beta$ Decay by QRPA

   J. Terasaki🇨🇿

   The neutrinoless double-$\beta$ decay is a hypothetical rare nuclear decay, which can be used for determining the neutrino-mass scale. The scheme to use this decay for determining the neutrino-mass scale is one of few limited methods possible to determine that. Nuclear matrix element of this decay is an important input to this method, and this matrix element cannot be determined by experiment. I examine the validity of the transition density used for calculating the nuclear matrix element by comparing the experimental data and my calculated result of the charge-change strength functions of ${}^{48}$Ca and ${}^{48}$Ti. The nuclear wave functions are obtained by the quasiparticle random-phase approximation. A new idea is proposed on the transition operator for this strength function, and the data of those nuclei are reproduced well consistently. Reduced half-life of a few nuclei to the neutrinoless double-$\beta$ decay are shown.

   ↳ nucl-thhep-exnucl-exNucl.Theor.(2018)·0 citations
6. 06*

   Determination of Strength of Isoscalar Pairing Interaction by a Mathematical Identity in QRPA

   J. Terasaki🇨🇿

   I propose a new method to determine the strength of the isoscalar proton-neutron pairing interaction by a mathematical identity derived in the quasiparticle random-phase approximation. This method is applied for a few nuclei possibly having the neutrinoless double-$\beta$ decay. Reduced half-life, the theoretical quantity necessary for determining the effective neutrino mass, is calculated for ${}^{48}$Ca.

   ↳ nucl-thnucl-ex0 citations
7. 07*

   Symmetry restoration in mean-field approaches

   J.A. Sheikh🇮🇳 · J. Dobaczewski🇬🇧 · P. Ring🇩🇪 · L. M. Robledo🇪🇸 · C. Yannouleas🇺🇸

   The mean-field approximation based on effective interactions or density functionals plays a pivotal role in the description of finite quantum many-body systems that are too large to be treated by ab initio methods. Some examples are strongly interacting medium and heavy mass atomic nuclei and mesoscopic condensed matter systems. In this approach, the linear Schrodinger equation for the exact many-body wave function is mapped onto a non-linear density-dependent one-body potential problem. This approximation, not only provides computationally very simple solutions even for systems with many particles, but due to the non-linearity, it also allows for obtaining solutions that break essential symmetries of the system, often connected with phase transitions. In this way, additional correlations are subsumed in the system. However, the mean-field approach suffers from the drawback that the corresponding wave functions do not have sharp quantum numbers and, therefore, many results cannot be compared directly with experimental data. In this article, we discuss general group-theory techniques to restore the broken symmetries, and provide detailed expressions on the restoration of translational, rotational, spin, isospin, parity and gauge symmetries, where the latter corresponds to the restoration of the particle number. In order to avoid the numerical complexity of exact projection techniques, various approximation methods available in the literature are examined. Applications of the projection methods are presented for simple nuclear models, realistic calculations in relatively small configuration spaces, nuclear energy density functional theory, as well as in other mesoscopic systems. Further, unresolved problems in the application of the symmetry restoration methods to the energy density functional theories are highlighted in the present work.

   ↳ nucl-thcond-mat.othernucl-exJ.Phys.G(2021)·144 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.