New limits on the ultrahigh energy cosmic neutrino flux from the ANITA experiment.
We report initial results of the first flight of the Antarctic Impulsive Transient Antenna (ANITA-1) 2006-2007 Long Duration Balloon flight, which searched for evidence of a diffuse flux of cosmic neutrinos above energies of E(nu) approximately 3 x 10(18) eV. ANITA-1 flew for 35 days looking for radio impulses due to the Askaryan effect in neutrino-induced electromagnetic showers within the Antarctic ice sheets. We report here on our initial analysis, which was performed as a blind search of the data. No neutrino candidates are seen, with no detected physics background. We set model-independent limits based on this result. Upper limits derived from our analysis rule out the highest cosmogenic neutrino models. In a background horizontal-polarization channel, we also detect six events consistent with radio impulses from ultrahigh energy extensive air showers.
Department of Physics and Astronomy, University of Hawaii, Manoa, Hawaii 96822, USA.
P W
PW
Gorham
P
P
Allison
S W
SW
Barwick
J J
JJ
Beatty
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DZ
Besson
W R
WR
Binns
C
C
Chen
P
P
Chen
J M
JM
Clem
A
A
Connolly
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Dowkontt
M A
MA
Duvernois
R C
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Field
D
D
Goldstein
A
A
Goodhue
C
C
Hast
C L
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Hebert
S
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Hoover
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Israel
J
J
Kowalski
J G
JG
Learned
K M
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Liewer
J T
JT
Link
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E
Lusczek
S
S
Matsuno
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BC
Mercurio
C
C
Miki
P
P
Miocinović
J
J
Nam
C J
CJ
Naudet
J
J
Ng
R J
RJ
Nichol
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K
Palladino
K
K
Reil
A
A
Romero-Wolf
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M
Rosen
L
L
Ruckman
D
D
Saltzberg
D
D
Seckel
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Varner
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Walz
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Wang
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Wu