Fri·Jun 28, 2019Friday·June 28, 2019

1. 01*

   Particle decays of levels in ${}^{11,12}$N and ${}^{12}$O investigated with the invariant-mass method

   T.B. Webb🇺🇸 · R.J. Charity🇺🇸 · J.M. Elson🇺🇸 · D.E.M Hoff🇺🇸 · C.D. Pruitt🇺🇸 · L.G. Sobotka🇺🇸 · K.W. Brown🇺🇸 · J. Barney🇺🇸 · G. Cerizza🇺🇸 · J. Estee🇺🇸 · G. Jhang🇺🇸 · W.G. Lynch🇺🇸 and 14 other authors

   Particle-decaying states of the light nuclei ${}^{11,12}$N and ${}^{12}$O were studied using the invariant-mass method. The decay energies and intrinsic widths of a number of states were measured, and the momentum correlations of three-body decaying states were considered. A second 2$p$-decaying 2${}^{+}$ state of ${}^{12}$O was observed for the first time, and a higher energy ${}^{12}$O state was observed in the 4$p$+2$\alpha$ decay channel. This 4$p$+2$\alpha$ channel also contains contributions from fission-like decay paths, including ${}^6$Be${}_{g.s.}$+${}^6$Be${}_{g.s.}$. Analogs to these states in ${}^{12}$O were found in ${}^{12}$N in the 2$p$+${}^{10}$B and 2$p$+$\alpha$+${}^6$Li channels. The momentum correlations for the prompt 2$p$ decay of ${}^{12}$O${}_{g.s.}$ were found to be nearly identical to those of ${}^{16}$Ne${}_{g.s.}$, and the correlations for the new 2${}^{+}$ state were found to be consistent with sequential decay through excited states in ${}^{11}$N. The momentum correlations for the 2${}_1^{+}$ state in ${}^{12}$O provide a new value for the ${}^{11}$N ground-state energy. The states in ${}^{12}$N/${}^{12}$O that belong to the $A$=12 isobaric sextet do not deviate from the quadratic isobaric multiplet mass equation (IMME) form.

   nucl-exPRC(2019)·28 citations
2. 02*

   Experimental searches for the chiral magnetic effect in heavy-ion collisions

   Jie Zhao🇺🇸 · Fuqiang Wang🇺🇸

   The chiral magnetic effect (CME) in quantum chromodynamics (QCD) refers to a charge separation (an electric current) of chirality imbalanced quarks generated along an external strong magnetic field. The chirality imbalance results from interactions of quarks, under the approximate chiral symmetry restoration, with metastable local domains of gluon fields of non-zero topological charges out of QCD vacuum fluctuations. Those local domains violate the $\mathcal{P}$ and $\mathcal{C}\mathcal{P}$ invariance, potentially offering a solution to the strong $\mathcal{C}\mathcal{P}$ problem in explaining the magnitude of the matter-antimatter asymmetry in today's universe. Relativistic heavy-ion collisions, with the likely creation of the high energy density quark-gluon plasma and restoration of the approximate chiral symmetry, and the possibly long-lived strong magnetic field, provide a unique opportunity to detect the CME. Early measurements of the CME-induced charge separation in heavy-ion collisions are dominated by physics backgrounds. Major efforts have been devoted to eliminate or reduce those backgrounds. We review those efforts, with a somewhat historical perspective, and focus on the recent innovative experimental undertakings in the search for the CME in heavy-ion collisions.

   nucl-exhep-exhep-phnucl-thPPNP(2019)·123 citations
3. 03*

   Studies on small charge packet transport in high-resistivity fully-depleted CCDs

   Miguel Sofo Haro🇺🇸 · Guillermo Fernandez Moroni🇺🇸 · Javier Tiffenberg🇺🇸

   In this work, we will present a physical model and measurements of the transport of small charge packets in the bulk of thick high resistivity CCD before being collected by the pixel potential wells. A new technique to measure the lateral spread of the charge as a function of the ionization depth in the bulk is presented. Results from measurements on CCD currently in use for several scientific instruments are shown and validated with a new mathematical algorithm to extend the current modeling based only on the diffusion of the charge in silicon.

   ↳ physics.ins-dethep-exnucl-exIEEE Trans.Electron.Dev.(2020)·14 citations
4. 04*

   Searching for Neutrino-less Double Beta Decay of ${}^{136}$Xe with PandaX-II Liquid Xenon Detector

   Kaixiang Ni🇨🇳 · Yihui Lai🇨🇳 · Abdusalam Abdukerim🇨🇳 · Wei Chen🇨🇳 · Xun Chen🇨🇳 · Yunhua Chen🇨🇳 · Xiangyi Cui🇨🇳 · Yingjie Fan🇨🇳 · Deqing Fang🇨🇳 · Changbo Fu🇨🇳 · Lisheng Geng🇨🇳 · Karl Giboni🇨🇳 and 51 other authors

   We report the Neutrino-less Double Beta Decay (NLDBD) search results from PandaX-II dual-phase liquid xenon time projection chamber. The total live time used in this analysis is 403.1 days from June 2016 to August 2018. With NLDBD-optimized event selection criteria, we obtain a fiducial mass of 219 kg of natural xenon. The accumulated xenon exposure is 242 kg$\cdot$yr, or equivalently 22.2 kg$\cdot$yr of ${}^{136}$Xe exposure. At the region around ${}^{136}$Xe decay Q-value of 2458 keV, the energy resolution of PandaX-II is 4.2%. We find no evidence of NLDBD in PandaX-II and establish a lower limit for decay half-life of 2.4 $\times 10^{23}$ yr at the 90% confidence level, which corresponds to an effective Majorana neutrino mass $m_{\beta \beta }<(1.3-3.5)$ eV. This is the first NLDBD result reported from a dual-phase xenon experiment.

   ↳ hep-exnucl-exphysics.ins-detCPC(2019)·43 citations
5. 05*

   Role of radon as a precursor to earthquakes:An appraisal

   R. Biswas🇮🇳

   Radon monitoring has recently gained extensive attention among seismologists. It is now widely reported as a precursssory signal prior to occurrence of a seismic event. The enhanced estimation of radon in soil gas is basically attributed to the strain changes which arise within the earth surface. In this chapter, the role of radon as a precurssor is eleborated, acompanied by the anomalies which come across during observation. Additionally, the recent studies done in Himalayan Belt is also reviewd along with future perspectives in radon estimation.

   ↳ physics.geo-phnucl-ex0 citations
6. 06*

   Statistical Methods Applied to the Search of Sterile Neutrinos

   Matteo Agostini🇩🇪 · Birgit Neumair🇩🇪

   The frequentist statistical methods applied to search for short-baseline neutrino oscillations induced by a sterile neutrino with mass at the eV scale are reviewed and compared. The comparison is performed under limit setting and signal discovery scenarios, considering both when an oscillation would enhance the neutrino interaction rate in the detector and when it would reduce it. The sensitivity of the experiments and the confidence regions extracted for specific data sets change considerably according to which test statistic is used and the assumptions on its probability distribution. A standardized analysis approach based on the most general kind of hypothesis test is proposed.

   ↳ hep-exhep-phnucl-exphysics.data-anEPJC(2020)·30 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.