Proposal for an electron antineutrino disappearance search using high-rate 8Li production and decay.

This paper introduces an experimental probe of the sterile neutrino with a novel, high-intensity source of electron antineutrinos from the production and subsequent decay of 8Li. When paired with an existing ∼1 kton scintillator-based detector, this = 6.4 MeV source opens a wide range of possible searches for beyond standard model physics via studies of the inverse beta decay interaction ν(e) + p → e+ + n. In particular, the experimental design described here has unprecedented sensitivity to ν(e) disappearance at Δm2 ∼ 1 eV2 and features the ability to distinguish between the existence of zero, one, and two sterile neutrinos.

Observation of two-neutrino double-beta decay in 136Xe with the EXO-200 detector.

We report the observation of two-neutrino double-beta decay in (136)Xe with T(1/2) = 2.11 ± 0.04(stat) ± 0.21(syst) × 10(21) yr. This second-order process, predicted by the standard model, has been observed for several nuclei but not for (136)Xe. The observed decay rate provides new input to matrix element calculations and to the search for the more interesting neutrinoless double-beta decay, the most sensitive probe for the existence of Majorana particles and the measurement of the neutrino mass scale.

[Effect of resuming work after myocardial infarction on its recurrence and mortality in long-term observations]. / Podjecie pracy po przebytym zawale serca a nawroty choroby i zgony w obserwacji wieloletniej.

60 to 95% pts in the age group below 60 return to work after having* suffered the first M.I. Up to the present moment, it has not been proved whether such return influences in any (positive or negative) way the recurrence of M.I. or the mortality rate. Two groups of pts who underwent M.I. in the years 1976-84 were included in the long term questionnaire observation: 1. 222 men (mean age 49.3 +/- 3.8 yrs) who resumed work and; 2. 153 men (mean age 50.7 +/- 8.4 yrs) who did not return to work after the first M.I. All pts were sent the questionnaires by post annually. The aim of the questionnaire was to establish whether the patient is alive, if he underwent reinfarction and, in case of death--what was its cause. Until 1985 reinfarction occurred in 25%, and until 1989--in 33% of the pts who resumed work, and 42% of pts who did not. The mean value of reinfarction was about 1.4 in the first group and 1.5 in the latter. Until 1985 the death rate was respectively 15% and 12%. Until 1989--the death rate was 28% and 30%. Thus, the differences between those two groups were statistically insignificant. In conclusion, it may--indirectly--speak in favour of resuming work after the first M.I., showing that, although it does not decrease the reinfarction and mortality rates, it also does not increase the risk.

A magnetically driven piston pump for ultra-clean applications.

A magnetically driven piston pump for xenon gas recirculation is presented. The pump is designed to satisfy extreme purity and containment requirements, as is appropriate for the recirculation of isotopically enriched xenon through the purification system and large liquid xenon time projection chamber of EXO-200. The pump, using sprung polymer gaskets, is capable of pumping more than 16 standard liters per minute of xenon gas with 750 Torr differential pressure.