Mon·Jun 27, 2016Monday·June 27, 2016

1. 01*

   Enhanced production of multi-strange hadrons in high-multiplicity proton-proton collisions

   ALICE Collaboration

   At sufficiently high temperature and energy density, nuclear matter undergoes a transition to a phase in which quarks and gluons are not confined: the Quark-Gluon Plasma (QGP) [1]. Such an extreme state of strongly-interacting QCD (Quantum Chromo-Dynamics) matter is produced in the laboratory with high-energy collisions of heavy nuclei, where an enhanced production of strange hadrons is observed [2-6]. Strangeness enhancement, originally proposed as a signature of QGP formation in nuclear collisions [7], is more pronounced for multi-strange baryons. Several effects typical of heavy-ion phenomenology have been observed in high-multiplicity proton-proton (pp) collisions [8,9]. Yet, enhanced production of multi-strange particles has not been reported so far. Here we present the first observation of strangeness enhancement in high-multiplicity pp collisions. We find that the integrated yields of strange and multi-strange particles relative to pions increases significantly with the event charged-particle multiplicity. The measurements are in remarkable agreement with p-Pb collision results [10,11] indicating that the phenomenon is related to the final system created in the collision. In high-multiplicity events strangeness production reaches values similar to those observed in Pb-Pb collisions, where a QGP is formed.

   nucl-exhep-exNat.Phys.(2017)·1057 citations
2. 02*

   Atmospheric neutrinos, $n{u}_e-n{u}_s$ oscillations, and a novel neutrino evolution equation

   Evgeny Akhmedov🇩🇪

   If a sterile neutrino nu_s with an eV-scale mass and a sizeable mixing to the electron neutrino exists, as indicated by the reactor and gallium neutrino anomalies, a strong resonance enhancement of nu_e-nu_s oscillations of atmospheric neutrinos should occur in the TeV energy range. At these energies neutrino flavour transitions in the 3+1 scheme depend on just one neutrino mass squared difference and are fully described within a 3-flavour oscillation framework. We demonstrate that the flavour transitions of atmospheric nu_e can actually be very accurately described in a 2-flavour framework, with neutrino flavour evolution governed by an inhomogeneous Schroedinger-like equation. Evolution equations of this type have not been previously considered in the theory of neutrino oscillations.

   ↳ hep-phhep-exnucl-exJHEP(2016)·2 citations
3. 03*

   Simulation of a low-background proton detector for studying low-energy resonances relevant in thermonuclear reactions

   D. Perez-Loureiro (1)🇺🇸 · C. Wrede (1 and 2) ((1) National Superconducting Cyclotron Laboratory, Michigan State University (2) Department of Physics and Astronomy, Michigan State University)🇺🇸

   A new detector is being developed at the National Superconducting Cyclotron Laboratory (NSCL) to measure low energy charged-particles from beta-delayed particle emission. These low energy particles are very important for nuclear astrophysics studies. The use of a gaseous system instead of a solid state detector decreases the sensitivity to betas while keeping high efficiency for higher mass charged particles like protons or alphas. This low sensitivity to betas minimizes their contribution to the background down to 150 keV. A detailed simulation tool based on \textsc{Geant4} has been developed for this future detector.

   ↳ physics.ins-detnucl-exIEEE Nucl.Sci.Symp.Conf.Rec.(2016)·0 citations
4. 04*

   Medium effect in high-density nuclear matter probed by systematic analyses of nucleus-nucleus elastic scattering

   T. Furumoto🇯🇵 · Y. Sakuragi · Y. Yamamoto🇯🇵

   We investigate the property of the high-density nuclear matter probed by the nucleus-nucleus elastic scattering in the framework of the double-folding (DF) model with the complex $G$-matrix interaction. The medium effect including three-body-force (TBF) effect is investigated with present two methods based on the frozen density approximation (FDA). The medium effect is clearly seen on the potential and the elastic cross section for the ${}^{16}$O + ${}^{16}$O system at $E/A=$ 70 MeV. The crucial role of the medium effect is also confirmed with other effective nucleon-nucleon ($NN$) interactions. In addition, the present methods are applied to other heavy-ion elastic scattering systems. Again, the medium effect is clearly seen in the heavy-ion elastic cross section. The medium effect on the elastic cross section becomes invisible with the increase of the target mass and the incident energy (up to $E/A=$ 200 MeV). However, the medium effect is again important to fix the heavy-ion scattering over $E/A=$ 200 MeV. Finally, we make clear the crucial role of the TBF effect up to $k_F=$ 1.6 fm${}^{-1}$ in the nucleus-nucleus elastic scattering.

   ↳ nucl-thnucl-ex13 citations
5. 05*

   First test of an enriched ${}^{116}$CdWO${}_4$ scintillating bolometer for neutrinoless double-beta-decay searches

   A.S. Barabash🇷🇺 · F.A. Danevich🇺🇦 · Y. Gimbal-Zofka🇫🇷 · A. Giuliani🇫🇷 · S.I. Konovalov🇷🇺 · M. Mancuso🇫🇷 · P. de Marcillac🇫🇷 · S. Marnieros🇫🇷 · V. Novati🇫🇷 · G. Pessina · D.V. Poda🇺🇦 · O.G. Polischuk and 4 other authors

   For the first time, a cadmium tungstate crystal scintillator enriched in ${}^{116}$Cd has been succesfully tested as a scintillating bolometer. The measurement was performed above ground at a temperature of 18 mK. The crystal mass was 34.5 g and the enrichment level ~82 %. Despite a substantial pile-up effect due to above-ground operation, the detector demonstrated a high energy resolution (2-7 keV FWHM in 0.2-2.6 MeV $\gamma$ energy range), a powerful particle identification capability and a high level of internal radiopurity. These results prove that cadmium tungstate is an extremely promising detector material for a next-generation neutrinoless double-beta decay bolometric experiment, like that proposed in the CUPID project (CUORE Upgrade with Particle IDentification).

   ↳ physics.ins-detnucl-exEPJC(2016)·18 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.