Guido Pizzella Universita’ di Roma Tor Vergata INFN- Frascati
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Guido Pizzella Universita’ di Roma Tor Vergata INFN- Frascati Coincidences between the g.w. detectors EXPLORER and NAUTILUS
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Guido Pizzella Universita’ di Roma Tor Vergata INFN- Frascati. Coincidences between the g.w. detectors EXPLORER and NAUTILUS. LISA. ROG Collaboration LNF, Roma1, Roma2. CERN RE 5. LNF INFN. LNGS. Calibration: a) gravity induced by a rotor b) cosmic ray showers. - PowerPoint PPT Presentation
Transcript of Guido Pizzella Universita’ di Roma Tor Vergata INFN- Frascati
Guido PizzellaUniversita’ di Roma Tor VergataINFN- Frascati
Coincidences between the g.w. detectors EXPLORER and NAUTILUS
LISA
CERN RE 5
LNF INFN
LNGS
ROG CollaborationLNF, Roma1, Roma2
Calibration:a) gravity induced by
a rotorb) cosmic ray showers
(in addition to small applied forces)
Vmeasured=19.1±0.7mV
Vexpected=21.1±0.6mV
Astone et al., Z.Phys.C50:21-29,1991Eur. Phys. J. C 5, 651-664 (1998)
Cosmic Rays
a) Large signalsb) Small signals
threshold
time
energy
ExplorerLarge signalsExplorer 2003
Large signalsNautilus 2004
Small signals
Measurements with an electron beam at DANE
Buonomo et al., Astropart.Phys.24:65-74,2005
aluminum
niobium
Search for coincidences
Cross-section depending on orientation
= osin4()
Sidereal hour 3.5
Sidereal hour 12.2
Sidereal hour
Efficiency of detection
3.5 hour
Polarized sources in the Galactic CentreAstron.Astrophys.421:811-813,2004
3.5±1.5
Sidereal hour
Sources uniform over the galactic disk
Measurements during the years1998, 2001,
2003, 2004
threshold
time
energy
1998
...we find an excess of coincidences
at zero time delay in the direction of the galactic
centre.
Class.Quant.Grav.18:243-252,2001
In the conclusions of the 1998 paper presented to the IGEC collaboration
in 1999 and 2000 and written together with the LSU group:
2001Class.Quant.Grav.19:5449-5463,2002
2003Class.Quant.Grav.23:S169-S178,2006
2004
all sidereal hours3.5±1.5
sidereal hours
Combining the probabilities
The coincidences excesses are
concentrated at certain times
1998
2001
2003
2004
Day of year
Searching if any special astrophysical phenomena occurred in
the period 7-17 September 1998
Last figure
1.1 10-4
7-17 September 1998
ConclusionWe have shown a
coincidence excess with very small
probability to be accidental (1% in total, 0.02% at
selected sidereal hours).Gravitational waves ?
end
6432 ore 2004nc=27<n>=1.8Offset=6.7 ms=5.9 ms
