Neutrinos @ HiRes

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Neutrinos _at_ HiRes
HR2
HR1

• Kai Martens
• High Energy Astrophysics Institute
• Department of Physics, University of Utah

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The Experiment
HiRes on DPG
HR2 12/1999 42 mirrors 3?-31? elevation
Dugway Proving Grounds
HR1 6/1997 19 mirrors 3?-17?elevation
12.6 km apart
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HiRes Optics
low resolution high speed
Camera 16 x 16 PMT each sees 1o x 1o in sky
Mirror surface 5.1 m2 Field of view 16? x 14?
UV filter !!! (protecting PMTs)
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HiRes Stereo!!!
July 11, 1999 Energy 19 EeV
Light Propagation Atmosphere
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The Collaboration
S. BenZvi, J. Boyer, B. Connolly, C.B. Finley,
B. Knapp, E.J. Mannel, A. ONeill, M. Seman, S.
Westerhoff Columbia University J.F. Amman, M.D.
Cooper, C.M. Hoffman, M.H. Holzscheiter, C.A.
Painter, J.S. Sarracino, G. Sinnis, T.N.
Thompson, D. Tupa Los Alamos National
Laboratory J. Belz, M. Kirn University of
Montana J.A.J. Matthews, M. Roberts University
of New Mexico D.R. Bergman, G. Hughes, D.
Ivanov, L. Perera, S.R. Schnetzer, L. Scott, S.
Stratton, G.B. Thomson, A. Zech Rutgers
University N. Manago, M. Sasaki University of
Tokyo R.U. Abbasi, T. Abu-Zayyad, G. Archbold,
K. Belov, Z. Cao, W. Deng, W. Hanlon, P.
Huentemeyer, C.C.H. Jui, E.C. Loh, K. Martens,
J.N. Matthews, K. Reil, J. Smith, P. Sokolsky,
R.W. Springer, B.T. Stokes, J.R. Thomas, S.B.
Thomas, L. Wiencke University of Utah Z. Cao, B.
Zhang, Y. Zhang, Y. Yang IHEP Bejing
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Highest Energy ? Cosmogenic
Graph by Semikoz Sigl
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( Imagine ) a Mountain
Daniele Fargion - or whos idea was it?
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Tau Neutrinos ?

• ? m nm nt 17
• ? track
• ? e ne nt 18
• ? shower
• ? hh nt 65
• ? shower

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ANIS (by Gazizov Kowalski, AMANDA)
All Neutrino Interaction Simulation
we use

• Incorporates
• cross sections
• CC, NC, ne-e- (resonant)
• - t(m) energy loss (parameterization)
• decay tables
• - TAUOLA for t-decay

But made for detectors inside a spherical
earth (i.e. underground)
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GTOPO 30 ANIS
GTOPO30 30 arcsec ? 1km 33 tiles one boundary
22km south of our detectors
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MC Topology at Work
Neutrino interaction points (tau decay above
ground)
Cedar Mtns
Stansbury Mtns
Oquirrh Mtns
Deep Creek Rng
Sheeprock Mtns
Fish Springs Rng
Thomas Rng
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Neutrino Injection
HiRes Impact Parameter lt 75km
Earth
Zenith 90?10 deg
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Neutrinos Zenith Angle q gt 90
up
shower axis
q
nt

• MC input
• triggered events
• both detectors
• MC generated geometries

Cosmic Ray MC distorted too many high E
Cosmic Rays
Zenith is the discriminator! ? Get geometry
right !!!
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Finding the good guys
and keeping as many as possible!!! ? efficiency
? sensitivity
Review reconstruction First step SDP
SDP normal uncertainty
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Event Geometry II 2-dim ? 1-dim
in the SDP
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Curvature in the Timing Fit
longitude in plane angle
use ratio of tan(q/2) and linear fit in longitude
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Well Reconstructed Events
ratio tan(q/2) fit to linear fit gt 100 ?
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Another Difference that Matters
horizontal CR events top of atmosphere ? large
Rp horizontal nt out of mountain low in
atmosphere ? small Rp
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Mapping out the lasers
y-component
SDP normal vector
x-component
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MC Reduction
ANIS total of 494,440,080 nt towards HiRes
? 4297 trigger HR1, 2496 trigger HR2
MC survivors Energy ANIS
input HR1 HR2 stereo 1018 1019 445,425,435 26
5 169 10 1019 1020 44,558,618 97
38 11 1020 1021 4,456,027 4 2 0
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Data Reduction 152 neutrinos ???
conclusion all lasers!
some examples
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Flux Limit for Cosmogenic Neutrinos

• Efficiency of HiRes to neutrino events from MC.
• Zero events found.
• Estimate upper limit with Poisson Statistics.
• Cosmogenic Neutrino Flux j(E) fE-2
• F ? eV s-1 sr-1 cm-2

HiRes-1
HiRes-2
Stereo
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The HiRes Tau Neutrino Limits
Injection E-2 spectrum
90 CL, units eVcm-2 s-1 sr-1 (uncertainty MC
statistics only) 1018 1019 420 -20
25 1019 1020 1340 -110 140 1020
1021 29400 -8900 22100
SemikozSigl ni,max
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Interaction Length in Standard Rock
(Rock??? ? r2.65 g/cm3)
lInt,t
Conclusion NO upward going neutrinos _at_ 1018eV
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Interpretation of HiRes monocular CR
changed interpretation of ankle
Doug Bergman, Rutgers
Fits interpret spectrum in terms of extragalactic
protons that traveled from cosmological sources
pg ? D(1232) ? pN
p? ? m? nm m? ? e? ne nm
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Some Input
garbage in, garbage out (this is MC!)