Measurement of single pi0 production in neutral current neutrino interactions with water by a 1.3 GeV wide band muon neutrino beam

Neutral current single pi0 production induced by neutrinos with a mean energy of 1.3 GeV is measured at a 1000 ton water Cherenkov detector as a near detector of the K2K long baseline neutrino experiment. The cross section for this process relative to the total charged current cross section is measured to be 0.064 +- 0.001 (stat.) +- 0.007 (sys.). The momentum distribution of produced pi0s is measured and is found to be in good agreement with an expectation from the present knowledge of the neutrino cross sections.Comment: 6 pages, 4 figures, Submitted to Phys. Lett.

Evidence for muon neutrino oscillation in an accelerator-based experiment

We present results for muon neutrino oscillation in the KEK to Kamioka (K2K) long-baseline neutrino oscillation experiment. K2K uses an accelerator-produced muon neutrino beam with a mean energy of 1.3 GeV directed at the Super-Kamiokande detector. We observed the energy dependent disappearance of muon neutrino, which we presume have oscillated to tau neutrino. The probability that we would observe these results if there is no neutrino oscillation is 0.0050% (4.0 sigma).Comment: 5 pages, 4 figure

Selective Formation of Conductive Network by Radical-Induced Oxidation

Cd-based coordination networks having channels were formed selectively by using a redox-active aromatic ligand 2,5,8-tri(4-pyridyl)1,3-diazaphenalene (TPDAP, H+1-). An electron-conductive network having a π-π stacking columnar structure of TPDAP formed in the presence of a trace amount of TPDAP radical (1•). In contrast, a nonconductive network having a dimer unit of H+1- formed in the absence of 1•. These results suggest the presence of a unique oxidation mechanism of TPDAP induced by formation of H+1--1• dimer, which was initiated by a trace amount of 1•. The dimerization increased HOMO level of H+1- moiety within the dimer to generate further radicals that could not form when H+1- was well isolated in CH3OH. © 2016 American Chemical Society1991sciescopu

New mass anchor points for neutron-deficient heavy nuclei from direct mass measurements of radium and actinium isotopes

International audienceThe masses of the exotic isotopes Ac210−214 and Ra210−214 have been measured with a multireflection time-of-flight mass spectrograph. These isotopes were obtained in flight as fusion-evaporation products behind the gas-filled recoil ion separator GARIS-II at RIKEN. The new direct mass measurements serve as an independent and direct benchmark for existing α-γ spectroscopy data in this mass region. Further, new mass anchor points are set for U and Np nuclei close to the N=126 shell closure for a future benchmark of the Z=92 subshell for neutron-deficient heavy isotopes. Our mass results are in general in good agreement with the previously indirectly determined mass values. Together with the measurement data, reasons for possible mass ambiguities from decay-data links between ground states are discussed

First Direct Mass Measurements of Nuclides around Z=100Z=100 with a Multireflection Time-of-Flight Mass Spectrograph

International audienceThe masses of Es246, Fm251, and the transfermium nuclei Md249−252 and No254, produced by hot- and cold-fusion reactions, in the vicinity of the deformed N=152 neutron shell closure, have been directly measured using a multireflection time-of-flight mass spectrograph. The masses of Es246 and Md249,250,252 were measured for the first time. Using the masses of Md249,250 as anchor points for α decay chains, the masses of heavier nuclei, up to Bh261 and Mt266, were determined. These new masses were compared with theoretical global mass models and demonstrated to be in good agreement with macroscopic-microscopic models in this region. The empirical shell gap parameter δ2n derived from three isotopic masses was updated with the new masses and corroborates the existence of the deformed N=152 neutron shell closure for Md and Lr