Mon·Apr 16, 2018Monday·April 16, 2018

1. 01*

   Nuclear applications of ANL-Osaka amplitudes: pion photo-productions on deuteron

   S.X. Nakamura (Univ. Cruzeiro do Sul)🇧🇷 · H. Kamano (RCNP)🇯🇵 · T.-S. H. Lee (Argonne Nat'l Lab)🇺🇸 · T. Sato (RCNP, J-PARC)🇯🇵

   The Argonne National Laboratory-Osaka University (ANL-Osaka) amplitudes (http://www.phy.anl.gov/theory/research/anl-osaka-pwa/) are applied to study pion photo-production reactions on the deuteron target. Within the multiple scattering formulation, we predict the cross sections of $d(\gamma ,\pi )NN$ in the nucleon resonance region. The calculations include the impulse term and the final-state interaction (FSI) terms due to pion-exchange and nucleon-exchange. We show that the off-shell effects, calculated from the meson-exchange mechanisms, on the propagations of the exchanged nucleon and pion are significant in determining the reaction amplitudes. The FSI effects on the predicted cross sections are found to be important at energies near the $\Delta$(1232) resonance, and are still significant at higher energies. The results are in good agreement with most of the available data of $d(\gamma ,{\pi }^0)np$ and $d(\gamma ,{\pi }^{-})pp$ reactions.

   ↳ nucl-thhep-phnucl-ex15 citations
2. 02*

   Three-level mixing model for nuclear chiral rotation: Role of planar component

   Q. B. Chen🇩🇪 · K. Starosta🇨🇦 · T. Koike🇯🇵

   Three- and two-level mixing models are proposed to understand the doubling of states at the same spin and parity in triaxially-deformed atomic nuclei with odd numbers of protons and neutrons. The Particle-Rotor Model for such nuclei is solved using the newly proposed basis which couples angular momenta of two valence nucleons and the rotating triaxial mean-field into left-handed $|\mathcal{L}⟩$, right-handed $|\mathcal{R}⟩$, and planar $|\mathcal{P}⟩$ configurations. The presence and the impact of the planar component is investigated as a function of the total spin for mass A$\approx$130 nuclei with the valence h${}_{11/2}$ proton particle, valence h${}_{11/2}$ neutron hole and the maximum difference between principle axes allowed by the quadrupole deformation of the mean field. It is concluded that at each spin value the higher-energy member of a doublet of states is built on the anti-symmetric combination of $|\mathcal{L}⟩$ and $|\mathcal{R}⟩$ and is free of the $|\mathcal{P}⟩$ component, indicating that it is of pure chiral geometry. For the lower-energy member of the doublet, the contribution of the $|\mathcal{P}⟩$ component to the eigenfunction first decreases and then increases as a function of the total spin. This trend as well as the energy splitting between the doublet states are both determined by the Hamiltonian matrix elements between the planar ($|\mathcal{P}⟩$) and non-planar ($|\mathcal{L}⟩$ and $|\mathcal{R}⟩$) subspaces of the full Hilbert space.

   ↳ nucl-thnucl-exPRC(2018)·18 citations
3. 03*

   Interplay of drag by hot matter and electromagnetic force on the directed flow of heavy quarks

   Sandeep Chatterjee🇵🇱 · Piotr Bozek🇵🇱

   Rapidity-odd directed flow in heavy ion collisions can originate from two very distinct sources in the collision dynamics i. an initial tilt of the fireball in the reaction plane that generates directed flow of the constituents independent of their charges, and ii. the Lorentz force due to the strong primordial electromagnetic field that drives the flow in opposite directions for constituents carrying unlike sign charges. We study the directed flow of open charm mesons $D^0$ and $\overline{D^0}$ in the presence of both these sources of directed flow. The drag from the tilted matter dominates over the Lorentz force resulting in same sign flow for both $D^0$ and $\overline{D^0}$, albeit of different magnitudes. Their average directed flow is about ten times larger than their difference. This charge splitting in the directed flow is a sensitive probe of the electrical conductivity of the produced medium. We further study their beam energy dependence; while the average directed flow shows a decreasing trend, the charge splitting remains flat from $\sqrt{s_{NN}}=60$ GeV to $5$ TeV.

   ↳ nucl-thhep-phnucl-exPLB(2019)·76 citations
4. 04*

   Shell-model interactions from chiral effective field theory

   Lukas Huth🇩🇪 · Victoria Durant🇩🇪 · Johannes Simonis🇩🇪 · Achim Schwenk🇩🇪

   We construct valence-space Hamiltonians for use in shell-model calculations, where the residual two-body interaction is based on symmetry principles and the low-momentum expansion from chiral effective field theory. In addition to the usual free-space contact interactions, we also include novel center-of-mass--dependent operators that arise due to the Galilean invariance breaking by in-medium effects. We fitted the low-energy constants to 441 ground- and excited-state energies in the sd shell and obtained a root-mean-square derivation of 1.8 MeV at leading order and of 0.5 MeV at next-to-leading order, with natural low-energy constants in all cases. The developed chiral shell-model interactions enable order-by-order uncertainty estimates and show promising predictions for neutron-rich isotopes beyond the fitted data set.

   ↳ nucl-thnucl-exPRC(2018)·26 citations
5. 05*

   Centrality dependence of freeze-out temperature fluctuations in Pb-Pb collisions at the LHC

   Dariusz Prorok🇵🇱

   Many data in the High Energy Physics are, in fact, sample means. It is shown that when this exact meaning of the data is taken into account and the most weakly bound states are removed from the hadron resonance gas, the whole spectra of pions, kaons and protons measured at midrapidity in Pb-Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV can be fitted simultaneously. The invariant distributions are predicted with the help of the single-freeze-out model in the chemical equilibrium framework. The method is applied to the measurements in centrality bins of Pb-Pb collisions and gives acceptable fits for all but peripheral bins. The comparison with the results obtained in the framework of the original single-freeze-out model is also presented. Some more general, possible implications of this approach are pointed out.

   ↳ hep-phhep-exnucl-exnucl-thEPJA(2019)·6 citations
6. 06*

   Searching Neutrino-Nucleus Coherent Scattering with Mössbauer Spectroscopy

   C. Marques🇧🇷 · G S Dias🇧🇷 · H. S. Chaves · S. B. Duarte🇧🇷

   The Mössbauer technique is proposed as an alternative experimental procedure to be used in the detection of Coherent Elastic $\nu$-Nucleus Scattering (CENNS). The $Z_0$-boson exchange is considered as a perturbation on the nuclear mean-field potential with a change in the valence neutron quantum states in the ${}^{57}Fe$ nucleus of the Mössbauer detector sample. This nuclei is a typical isotope used in Mössbauer spectroscopy. Perturbed level of the valence neutron accommodates the transferred energy, modifying the location of the isometric peak of the Mössbauer electromagnetic resonance. We calculate the isometric shift correction due CENNS and show that this quantity is able to be detected with enough precision. Therefore, the difference between the Mössbauer isometric shift in the presence of a reactor-neutrino beam and without the neutrinos flux is pointed out as a figure of merit to manifest CENNS. In this work, we show that the CENNS correction of the Isomeric Shift is of $\approx 10^{-7}$eV, which is greater than the $10^{-10}$eV resolution of the technique.

   ↳ physics.ins-detnucl-exJ.Phys.Conf.Ser.(2019)·2 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.