Mon·Dec 31, 2018Monday·December 31, 2018

1. 01*

   Measurement of the Antineutrino Spectrum from ${}^{235}$U Fission at HFIR with PROSPECT

   PROSPECT Collaboration · J. Ashenfelter · A. B. Balantekin · H. R. Band · C. D. Bass · D. E. Bergeron · D. Berish · N. S. Bowden · J. P. Brodsky · C. D. Bryan · J. J. Cherwinka · T. Classen and 58 other authors

   This Letter reports the first measurement of the ${}^{235}$U $\overline{{\nu }_e}$ energy spectrum by PROSPECT, the Precision Reactor Oscillation and Spectrum experiment, operating 7.9m from the 85MW${}_{\mathrm{th}}$ highly-enriched uranium (HEU) High Flux Isotope Reactor. With a surface-based, segmented detector, PROSPECT has observed 31678$\pm$304 (stat.) $\overline{{\nu }_e}$-induced inverse beta decays (IBD), the largest sample from HEU fission to date, 99% of which are attributed to ${}^{235}$U. Despite broad agreement, comparison of the Huber ${}^{235}$U model to the measured spectrum produces a ${\chi }^2/ndf=51.4/31$, driven primarily by deviations in two localized energy regions. The measured ${}^{235}$U spectrum shape is consistent with a deviation relative to prediction equal in size to that observed at low-enriched uranium power reactors in the $\overline{{\nu }_e}$ energy region of 5-7MeV.

   nucl-exhep-exphysics.ins-detPRL(2019)·56 citations
2. 02*

   Half-life measurements of ${}^{212}$Po with thorium-loaded liquid scintillator

   P. Belli🇮🇹 · R. Bernabei🇮🇹 · R.S. Boiko🇺🇦 · F.A. Danevich🇺🇦 · A. Di Marco🇮🇹 · A. Incicchitti🇮🇹 · D.V. Kasperovych🇺🇦 · F. Cappella🇮🇹 · V. Caracciolo🇮🇹 · V.V. Kobychev🇺🇦 · O.G. Polischuk🇺🇦 · N.V. Sokur · V.I. Tretyak🇺🇦 · R. Cerulli🇮🇹

   Precise measurement of half-life of ${}^{212}$Po (one of the daughter nuclides in radioactive chain of ${}^{232}$Th) was realized by means of liquid scintillator based on toluene doped by complex of thorium and trioctylphosphine oxide with concentration of Th $\sim 0.1$ mass %. Fast photomultiplier tube and high frequency oscilloscope were used to acquire the scintillation signals waveforms. The algorithms were developed to find pairs of ${}^{212}$Bi beta-decays and subsequent ${}^{212}$Po alpha-decays, to calculate time differences between the events in the pair, and to build ${}^{212}$Bi beta-decay and ${}^{212}$Po alpha-decay energy spectra. Preliminary the ${}^{212}$Po half-life is $T_{1/2}=(294.8\pm 1.9)$ ns. The experiment is in progress aiming at reduction of the statistical and systematic uncertainties.

   nucl-exNucl.Phys.Atom.Energy(2018)·3 citations
3. 03*

   Gluon emission from heavy quarks in dense nuclear matter

   Le Zhang🇨🇳 · De-Fu Hou🇨🇳 · Guang-You Qin🇨🇳

   We study the medium-induced gluon emission process experienced by a hard jet parton propagating through the dense nuclear matter in the framework of deep inelastic scattering off a large nucleus. We work beyond the collinear rescattering expansion and the soft gluon emission limit, and derive a closed formula for the medium-induced single gluon emission spectrum from a heavy or light quark jet interacting with the dense nuclear medium via transverse and longitudinal scatterings. Without performing the collinear rescattering expansion, the medium-induced gluon emission spectrum is controlled by the full distribution of the differential elastic scattering rates between the propagating partons and the medium constituents. We further show that if one utilizes heavy static scattering centers for the traversed nuclear matter and takes the soft gluon emission limit, our result can reduce to the first order in opacity Djordjevic-Gyulassy-Levai-Vitev formula.

   ↳ hep-phnucl-exnucl-thPRC(2019)·18 citations
4. 04*

   On the Neutron Transition Magnetic Moment

   Zurab Berezhiani🇮🇹 · Riccardo Biondi🇮🇹 · Yuri Kamyshkov🇺🇸 · Louis Varriano🇺🇸

   We discuss the possibility of the transition magnetic moments (TMM) between the neutron n and mirror neutron n', its hypothetical sterile twin from parallel particle "mirror" sector. The neutron can be spontaneously converted into mirror neutron via these TMM's (in addition to the more conventional transition channel due to n-n' mass mixing) interacting with the magnetic field B as well as with mirror magnetic field B'. We derive analytic formula for the average probability of n-n' oscillation and consider possible manifestations of the neutron TMM effects. In particular, we discuss potential role of these effects in the neutron lifetime measurement experiments leading us to new, testable predictions.

   ↳ nucl-thnucl-exMDPI Physics(2019)·23 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.