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12-6-02
A new result confirming electron neutrino oscillations was just made
public on Friday (12-6-02). The KamLAND experiment detects electron
anti-neutrinos using a liquid scintillator detector (old Kamiokande).
The neutrino source is a number of nuclear power plants at an average
distance of 180km.
Over a 145 day period in 2002 they expect a flux of 86.5 +- 5.6 events from the reactors and a background of 1+-1, while they observe only 54 events.
N_Detected - N_Background
------------------------- = .611 +- .085 +- .041
N_Expected
The result is consistent with the Large Mixing Angle (LMA) solutuion
for solar neutrino oscillations observed by SuperKamiokande and SNO.
Curiously only the US collaborators are announcing the result (see the
LBL web page and press release below). The official (Japanese) web
page does not mention it. Also note that the preprint, mentioned in
the e-mail given below, has disappeared from the LBL web site. I
already downloaded it before it went away. If you are desparate to see
it, please let me know (I did not find any preprint from them on the
LANL server).
LBL KamLAND home page with link to LBL press release (12-6-02)
http://kamland.lbl.gov/
Official KamLAND home page http://www.awa.tohoku.ac.jp/html/KamLAND/ |