1,565 research outputs found
Development of an electron density probe Final report, 22 Jun. 1964 - 22 Mar. 1965
Electron density probes to perform measurements in flow fields at high altitude
A solenoidal electron spectrometer for a precision measurement of the neutron -asymmetry with ultracold neutrons
We describe an electron spectrometer designed for a precision measurement of
the neutron -asymmetry with spin-polarized ultracold neutrons. The
spectrometer consists of a 1.0-Tesla solenoidal field with two identical
multiwire proportional chamber and plastic scintillator electron detector
packages situated within 0.6-Tesla field-expansion regions. Select results from
performance studies of the spectrometer with calibration sources are reported.Comment: 30 pages, 19 figures, 1 table, submitted to NIM
Measurement of the neutron lifetime using a gravitational trap and a low-temperature Fomblin coating
We present a new value for the neutron lifetime of 878.5 +- 0.7 stat. +- 0.3
syst. This result differs from the world average value (885.7 +- 0.8 s) by 6.5
standard deviations and by 5.6 standard deviations from the previous most
precise result. However, this new value for the neutron lifetime together with
a beta-asymmetry in neutron decay, Ao, of -0.1189(7) is in a good agreement
with the Standard Model.Comment: 11 pages, 9 figures; extended content with some correction
The influence of the chameleon field potential on transition frequencies of gravitationally bound quantum states of ultra-cold neutrons
We calculate the chameleon field potential for ultracold neutrons, bouncing
on top of one or between two neutron mirrors in the gravitational field of the
Earth. For the resulting non--linear equations of motion we give approximate
analytical solutions and compare them with exact numerical ones for which we
propose the analytical fit. The obtained solutions may be used for the
quantitative analysis of contributions of a chameleon field to the transition
frequencies of quantum states of ultra-cold neutrons bound in the gravitational
field of the Earth.Comment: 11 pages, 4 figure
Three channel model of meson-meson scattering and scalar meson spectroscopy
New solutions on the scalar -- isoscalar phase shifts are analysed
together with previous results using a separable potential model of
three coupled channels (, and an effective
system). Model parameters are fitted to two sets of solutions obtained in a
recent analysis of the CERN-Cracow-Munich measurements of the reaction on a polarized target. A relatively
narrow (90 -- 180 MeV) scalar resonance is found, in contrast
to a much broader ( MeV) state emerging from the analysis
of previous unpolarized target data.Comment: 10 Latex pages + 6 postscript figure
Properties of scalar--isoscalar mesons from multichannel interaction analysis below 1800 MeV
Scalar-isoscalar mesons are studied using an unitary model in three channels:
pi-pi, K-anti K and an effective 2pi-2pi.
All the solutions, fitted to the pi-pi and K-anti K data, exhibit a wide
f0(500), a narrow f0(980) and two relatively narrow resonances, lying on
different sheets between 1300 MeV and 1500 MeV.
These latter states are similar to the f0(1370) and f0(1500) seen in
experiments at CERN. Branching ratios are compared with available data. We have
started investigations of some crossing symmetry and chiral constraints imposed
near the pi-pi threshold on the scalar-isoscalar, scalar-isotensor and P-wave
pi-pi amplitudes.Comment: Talk given at XVth Particles and Nuclei Int. Conf. (PANIC99),
Uppsala, Sweden, June 10-16, 1999; 4 pages, 3 figures, file espcrc1.sty
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