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Nuclear Theory·nucl-th

Tuesday·November 8, 2022

14 papers—7 primary·7 cross-listed

All14Primary7Cross-lists7
  1. 08

    The Electron-Ion Collider -- A U.S. facility for the European community to explore the mysteries of the building blocks of matter

    Marco Radici🇮🇹 · Silvia Dalla Torre🇮🇹 · Daria Sokhan🇫🇷

    This document is submitted as input to the NuPECC Long Range Plan 2024 by three European members of the EIC Users Group Steering Committee (Vice Chair, one at-large member, and the EU Representative). We submit the document on behalf of the international EIC Users Group (EICUG) community, but we specifically represent 335 European members of the EICUG (25%) based in 80 institutions (30% of the total) located in Armenia, Czech Republic, Finland, France, Germany, Hungary, Ireland, Israel, Italy, Netherlands, Norway, Poland, Slovenia, Spain, Sweden, Switzerland, Ukraine, and the United Kingdom. This European involvement is an important driver of the EIC, but can also be beneficial for a number of related ongoing and planned nuclear physics experiments in Europe. In this document, the shared interest regarding scientific questions and detector R&D between the EIC and European nuclear physics communities is outlined. The aim is to highlight how these synergies offer ample opportunities to foster progress at the forefront of nuclear physics.

    ↳ hep-phhep-exnucl-exnucl-th1 citation
  2. 09

    Isoscaling in central Sn+Sn collisions at 270 MeV/u

    J.W. Lee (1)🇰🇷 · M.B. Tsang (2 and 3)🇺🇸 · C.Y. Tsang (2 and 3)🇺🇸 · R. Wang (2)🇺🇸 · J. Barney (2 and 3)🇺🇸 · J. Estee (2 and 3)🇺🇸 · T. Isobe (4)🇯🇵 · M. Kaneko (4 and 5)🇯🇵 · M. Kurata-Nishimura (4)🇯🇵 · W.G. Lynch (2 and 3)🇺🇸 · T. Murakami (e6 and 4 and 5)🇯🇵 · A. Ono (6)🇯🇵 and 52 other authors

    Experimental information on fragment emissions is important in understanding the dynamics of nuclear collisions and in the development of transport model simulating heavy-ion collisions. The composition of complex fragments emitted in the heavy-ion collisions can be explained by statistical models, which assume that thermal equilibrium is achieved at collision energies below 100 MeV/u. Our new experimental data together with theoretical analyses for light particles from Sn+Sn collisions at 270 MeV/u, suggest that the hypothesis of thermal equilibrium breaks down for particles emitted with high transfer momentum. To inspect the system's properties in such limit, the scaling features of the yield ratios of particles from two systems, a neutron-rich system of and a nearly symmetric system of , are examined in the framework of the statistical multifragmentation model and the antisymmetrized molecular dynamics model. The isoscaling from low energy particles agree with both models. However the observed breakdown of isoscaling for particles with high transverse momentum cannot be explained by the antisymmetrized molecular dynamics model.

    ↳ nucl-exnucl-thEPJA(2022)·15 citations
  3. 10

    State-Specific Configuration Interaction for Excited States

    Fábris Kossoski · Pierre-François Loos

    We introduce and benchmark a systematically improvable route for excited-state calculations, state-specific configuration interaction (CI), \alert{which is a particular realization of multiconfigurational self-consistent field and multireference configuration interaction.} Starting with a reference built from optimized configuration state functions, separate CI calculations are performed for each targeted state (hence state-specific orbitals and determinants). Accounting for single and double excitations produces the CISD model, which can be improved with second-order Epstein-Nesbet perturbation theory (CISD+EN2) or a posteriori Davidson corrections (CISD+Q). These models were gauged against a vast and diverse set of 294 reference excitation energies. We have found that CI is significantly more accurate than standard ground-state-based CI, whereas close performances were found between CISD and EOM-CC2, and between CISD+EN2 and EOM-CCSD. For larger systems, CISD+Q delivers more accurate results than EOM-CC2 and EOM-CCSD. The CI route can handle challenging multireference problems, singly- and doubly-excited states, from closed- and open-shell species, with overall comparable accuracy, and thus represents a promising alternative to more established methodologies. In its current form, however, it is only reliable for relatively low-lying excited states.

    ↳ physics.chem-phcond-mat.mtrl-scicond-mat.str-elnucl-thJ.Chem.Theor.Comput.(2023)·7 citations
  4. 11

    Space-time variation of the s and c quark masses

    V.V. Flambaum🇦🇺 · P. Munro-Laylim🇦🇺

    Space-time variation of fundamental physical constants in expanding Universe is predicted by a number of popular models. The masses of second generation quarks are larger than first generation quark masses by several orders of magnitude, therefore space-time variation in quark masses may significantly vary between each generation. We evaluate limits on variation in the s and c quark masses from Big Bang nucleosynthesis, Oklo natural nuclear reactor, Yb+, Cs and Rb clock data. The construction of 229Th nuclear clock is expected to enhance these limits by several orders of magnitude. Furthermore, constraints are obtained on an oscillating scalar or pseudoscalar cold dark matter field, as interactions of the field with quarks produce variations in quark masses.

    ↳ hep-phastro-ph.COnucl-thphysics.atom-phPRD(2023)·6 citations
  5. 12

    Proton structure functions at NLO in the dipole picture with massive quarks

    Henri Hänninen🇫🇮 · Heikki Mäntysaari🇫🇮 · Risto Paatelainen🇫🇮 · Jani Penttala🇫🇮

    We predict heavy quark production cross sections in Deep Inelastic Scattering at high energy by applying the Color Glass Condensate effective theory. We demonstrate that when the calculation is performed consistently at next-to-leading order accuracy with massive quarks it becomes possible, for the first time in the dipole picture with perturbatively calculated center-of-mass energy evolution, to simultaneously describe both light and heavy quark production data at small . We furthermore show how the heavy quark cross section data provides additional strong constraints on the extracted non-perturbative initial condition for the small- evolution equations.

    ↳ hep-phnucl-thPRL(2023)·41 citations
  6. 13

    A coupled-channel system with anomalous thresholds and unitarity

    Csaba L. Korpa🇭🇺 · Matthias F.M. Lutz🇩🇪 · Xiao-Yu Guo🇨🇳 · Yonggoo Heo🇩🇪

    We consider the isospin one-half example system, with coupled channels in the partial wave, chosen such that various phenomena that come with the opening of an anomalous threshold can be illustrated in a step-wise procedure by a suitable variation of up, down and strange quark masses. We use a set of LEC in the chiral Lagrangian that were adjusted to a large set of Lattice QCD results. The six phase shifts and inelasticity parameters are presented for various choices of the pion mass. For a pion mass of 150 MeV there are no anomalous thresholds encountered. The small change from 150 MeV to 145 MeV pion mass causes a dramatic impact of the anomalous threshold on the phase shifts.

    ↳ hep-phhep-latnucl-thPRD(2023)·10 citations
  7. 14

    Counting States: A Combinatorial Analysis of SQM Fragmentation

    A. Bernardo · L. Paulucci · L. M. de Sá · J. E. Horvath

    The Strange Quark matter (SQM) hypothesis states that at extreme pressure and density conditions a new ground state of matter would arise, in which half of the \textit{down} quarks become strange quarks. If true, it would mean that at least the core of neutron stars is made of SQM. In this hypothesis, SQM would be released in the inter-stellar medium when two of these objects merge. It is estimated that of SQM would be released this way. This matter will undergo a sequence of processes that should result in a fraction of the released SQM becoming heavy nuclei through \textit{r-process}. In this work we are interested in characterizing the fragmentation of SQM, with the novelty of keeping track of the \textit{quark configuration} of the fragmented matter. This is accomplished by developing a methodology to estimate the energy of each fragment as the sum of its \textit{constituent quarks}, the Coulomb interaction among the quarks and fragments' momenta. The determination of the fragmentation output is crucial to fully characterize the subsequent nucleosynthesis.

    ↳ astro-ph.HEnucl-thAstron.Nachr.(2023)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE