626 research outputs found
Upper Limits in the Case That Zero Events are Observed: An Intuitive Solution to the Background Dependence Puzzle
We compare the ``unified approach'' for the estimation of upper limits with
an approach based on the Bayes theory, in the special case that no events are
observed. The ``unified approach'' predicts, in this case, an upper limit that
decreases with the increase in the expected level of background. This seems
absurd. On the other hand, the Bayesian approach leads to a result which is
background independent. An explanation of the Bayesian result is presented,
together with suggested reasons for the paradoxical result of the ``unified
approach''.Comment: Latex file (compiled with cernrep.cls included) 5 pages, no figures.
To appear in the Proceed. of the workshop on ''Confidence limits'' (CERN, Jan
2000). This paper and related papers also available at
http://grwav3.roma1.infn.it
Energy spectrums for proton /200 eV + or = E + or = 1 MeV/ intensities in the outer radiation zone
Energy spectrums for proton intensities in outer radiation zon
Note on the Electron Energy Spectrum in the Inner Van Allen Belt
Electron energy spectrum in the inner van allen bel
Measuring Propagation Speed of Coulomb Fields
The problem of gravity propagation has been subject of discussion for quite a
long time: Newton, Laplace and, in relatively more modern times, Eddington
pointed out that, if gravity propagated with finite velocity, planets motion
around the sun would become unstable due to a torque originating from time lag
of the gravitational interactions.
Such an odd behavior can be found also in electromagnetism, when one computes
the propagation of the electric fields generated by a set of uniformly moving
charges. As a matter of fact the Li\'enard-Weichert retarded potential leads to
a formula indistinguishable from the one obtained assuming that the electric
field propagates with infinite velocity. Feyman explanation for this apparent
paradox was based on the fact that uniform motions last indefinitely.
To verify such an explanation, we performed an experiment to measure the
time/space evolution of the electric field generated by an uniformely moving
electron beam. The results we obtain on such a finite lifetime kinematical
state seem compatible with an electric field rigidly carried by the beam
itself.Comment: 23 pages, 15 figure
New analysis for the correlation between gravitational waves and neutrino detectors during SN1987A
Two major problems, still associated with the SN1987A, are: a) the signals observed with the gravitational waves detectors, b) the duration of the collapse. Indeed, a) the sensitivity of the gravitational wave detectors seems to be small for detecting gravitational waves and, b) while some experimental data indicate a duration of order of hours, most theories assume that the collapse develops in a few seconds. Since recent data of the X-ray NuSTAR satellite show a clear evidence of an asymmetric collapse, we have revisited the experimental data recorded by the underground and gravitational wave detectors running during the SN1987A. New evidence is shown that con rms previous results, namely that the data recorded by the gravitational wave detectors running in Rome and in Maryland are strongly correlated with the data of both the Mont Blanc and the Kamiokande detectors, and that the correlation extends over a long period of time (one or two hours) centered at the Mont Blanc time. This result indicates that also Kamiokande detected neutrinos at the Mont Blanc time, and these interactions were not identi ed because not grouped in a burst
Studying the coincidence excess between EXPLORER and NAUTILUS during 1998
The coincidences between EXPLORER and NAUTILUS during 1998 (Astone et al.
2001) are more deeply studied. It is found that the coincidence excess is
greater in the ten-day period 7-17 September 1998 and it occurs at the sidereal
hour 4, when the detectors axes are perpendicular to the Galactic Disk. The
purpose of this paper is to bring our results with the GW detectors to the
attention of scientists working in the astrophysical field, and ask them
whether are they aware of any special phenomenon occurring when EXPLORER and
NAUTILUS showed a coincidence excess.Comment: 5 pages, 7 figures, submitted to A &
SN1987A: Revisiting the Data and the Correlation between Neutrino and Gravitational Detectors
We re-examine the data taken by the neutrino detectors during the supernova
SN1987A. It is found that the Kamiokande data, in addition to the well known
burst at 7:35 hours UT, show another one at 7:54 hours, with seven pulses in
6.2 seconds. This second burst supports the idea that the duration of the
collapse was much longer than a few seconds, as already suggested by the LSD
detection at 2:56 hours the same day, i.e. four and a half hours earlier. The
correlations between the gravitational wave detectors (Rome and Maryland) and
the neutrino detectors are also revisited. It is shown that the g.w. detectors
exhibit significant correlations with both the LSD and the Kamiokande detectors
over periods of one-two hours that are centered, in both cases, at the LSD
time.Comment: Presented at the VULCANO WOKSHOP 2008, Frontier Objects in
Astrophysics and Particle Physics, May 26-3
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