Fri·Mar 11, 2016Friday·March 11, 2016

1. 01*

   ALICE overview

   Sami S. Räsänen (for the ALICE Collaboration)🇫🇮

   Recent results from the ALICE experiment are presented with a particular emphasis on particle identification, the nuclear modification factor ($R_{AA}$) and azimuthal anisotropy ($v_2$). Comparison of lead-lead and proton-lead results reveals evidence of collectivity in small systems.

   nucl-exEPJ Web Conf.(2016)·6 citations
2. 02*

   Deuterium target data for precision neutrino-nucleus cross sections

   Aaron S. Meyer🇺🇸 · Minerba Betancourt🇺🇸 · Richard Gran🇺🇸 · Richard J. Hill🇺🇸

   Amplitudes derived from scattering data on elementary targets are basic inputs to neutrino-nucleus cross section predictions. A prominent example is the isovector axial nucleon form factor, $F_A(q^2)$, which controls charged current signal processes at accelerator-based neutrino oscillation experiments. Previous extractions of $F_A$ from neutrino-deuteron scattering data rely on a dipole shape assumption that introduces an unquantified error. A new analysis of world data for neutrino-deuteron scattering is performed using a model-independent, and systematically improvable, representation of $F_A$. A complete error budget for the nucleon isovector axial radius leads to $r_A^2=0.46(22){\mathrm{fm}}^2$, with a much larger uncertainty than determined in the original analyses. The quasielastic neutrino-neutron cross section is determined as $\sigma ({\nu }_{\mu }n\to {\mu }^{-}p){|}_{E_{\nu }=1\mathrm{GeV}}=10.1(0.9)\times 10^{-39}{\mathrm{cm}}^2$. The propagation of nucleon-level constraints and uncertainties to nuclear cross sections is illustrated using MINERvA data and the GENIE event generator. These techniques can be readily extended to other amplitudes and processes.

   ↳ hep-phhep-exnucl-exnucl-thPRD(2016)·242 citations
3. 03*

   Decay dynamics of the unbound ${}^{25}$O and ${}^{26}$O nuclei

   K. Hagino🇯🇵 · H. Sagawa🇯🇵

   We study the ground and excited resonance states of ${}^{26}$O with a three-body model of ${}^{24}$O+n+n taking into account the coupling to the continuum. To this end, we use the new experimental data for the invariant mass spectroscopy of the unbound ${}^{25}$O and ${}^{26}$O nuclei, and present an update of three-body model calculations for the two-neutron decay of the ${}^{26}$O nucleus. With the new model inputs determined with the ground state decay of ${}^{26}$O, we discuss the di-neurtron correlations and a halo nature of this nucleus, as well as the structure of the excited states. For the energy of the 2${}^{+}$ state, we achieve an excellent agreement with the experimental data with this calculation. We show that the 2${}^{+}$ state consists predominantly of the $(d_{3/2}{)}^2$ configuration, for which the pairing interaction between the valence neutrons slightly decreases its energy from the unperturbed one. We also discuss the structure of excited 0${}^{+}$ states of the ${}^{26}$O nucleus. In particular, we show the existence of an excited 0${}^{+}$ state at 3.38 MeV, which is mainly composed of the $(f_{7/2}{)}^2$ configuration.

   ↳ nucl-thnucl-exPRC(2016)·34 citations
4. 04*

   Electric dipole moment of ${}^{13}$C

   Nodoka Yamanaka🇫🇷 · Taiichi Yamada🇯🇵 · Emiko Hiyama🇯🇵 · Yasuro Funaki🇨🇳

   We calculate for the first time the electric dipole moment (EDM) of ${}^{13}$C generated by the isovector CP-odd pion exchange nuclear force in the $\alpha$-cluster model, which describes well the structures of low lying states of the ${}^{13}$C nucleus. The linear dependence of the EDM of ${}^{13}$C on the neutron EDM and the isovector CP-odd nuclear coupling is found to be $d_{{}^{13}\mathrm{C}}=-0.33d_n-0.0020{\bar{G}}_{\pi }^{(1)}$. The linear enhancement factor of the CP-odd nuclear coupling is smaller than that of the deuteron, due to the difference of the structure between the $1/2_1^{-}$ state and the opposite parity ($1/2^{+}$) states. We clarify the role of the structure played in the enhancement of the EDM. This result provides good guiding principles to search for other nuclei with large enhancement factor. We also mention the role of the EDM of ${}^{13}$C in determining the new physics beyond the standard model.

   ↳ nucl-thhep-exhep-phnucl-exPRC(2017)·29 citations
5. 05*

   Study of the process $e^{+}{e}^{-}\to K\bar{K}$ in the center-of-mass energy range 1004--1060 MeV with the CMD-3 detector at $e^{+}{e}^{-}$ VEPP-2000 collider

   E.A. Kozyrev (CMD-3 collaboration)🇷🇺

   The $e^{+}{e}^{-}\to K_S^0{K}_L^0$ and $e^{+}{e}^{-}\to K^{-}{K}^{+}$ cross sections have been measured in the center-of-mass energy range 1004--1060 MeV for 25 energy points with about 2$÷$3\% systematic uncertainties. The analysis is based on 5.5 pb${}^{-1}$ of integrated luminosity collected with the CMD-3 detector at the VEPP-2000 $e^{+}{e}^{-}$ collider. The measured cross section is approximated according to Vector Meson Dominance model as a sum of $\varphi ,\omega ,\rho$-like amplitudes and their excitations, and $\varphi (1020)$ meson parameters have been obtained.

   ↳ hep-exnucl-exJ.Univ.Sci.Tech.China(2016)·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.