Gaisser

Cosm ic-ray sp ectru m and
com p osition
--Im plications for neu trinos
and vice versa
NuSky 20-June-2011
Tom Gaisser
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Ou tline
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•
•
•
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Cosm ic ray – neu trino connections
Cosm ic rays and neu trinos in IceCu be
Atm ospheric neu trinos
N ew lim its on astrophysical neu trinos
Im plications for m od els of sou rces
Su m m ary
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Cosm ic-ray
connection - I
• Galactic SN R can
accelerate particles into
nearby m olecu lar clou d s
• Extra-galactic jets (in
AGN or GRB) m ay share
pow er betw een c.r. & n
• Expect a few TeV n/ yr in
a gigaton d etector in
had ronic scenarios
• Sets km 3 scale for H E
neu trino astronom y
NuSky 20-June-2011
Galactic
Extra-Galactic
Tom Gaisser
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All-particle spectrum
modeled with 3
populations & 5 groups
of nuclei
Cosm ic-ray
connnection – II:
atm ospheric n from
nu cleon spectru m
Spectrum of
nucleons
Realistic
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N ew inform ation ~TeV
• ATIC, CREAM, PAMELA
– Proton ≠ H eliu m
– Pam ela break 
• N ew popu lation?
– Spectral hard ening
• E > 200 GeV/ A
• Teresa, next talk
PAMELA, Adriani et al., arXiv:1103.4055
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Where is the galactic – extragalactic
transition?
Peters cycle: systematic increase of < A >
approaching Emax
gyro-radius = Pc / ZeB ≡ R (rigidity) / B
 Etotal (knee) ~ Z x R(knee)
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Tom Gaisser
<A> should begin to decrease again
for E > 30 x Eknee
B. Peters, Nuovo Cimento 22 (1961) 800
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HILLAS (Aspen, 2005)
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Galactic com p onent B?
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• Toy m od el fits:
3 p opu lations
5 nu clear grou ps,
Exponential cu toff in rigid ity
All particle spectrum
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Prim ary spectru m
& com position:
All-particle spectrum
modeled with 3
populations & 5 groups
of nuclei
1st knee
Com pon ent B
2nd knee
IceTop
Kascade-Grande
prelimary
(arbitrary
Talk this
normalization)
afternoon
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2004-05
2005-06
2006-07
2007-08
2008-09
2009-10
2010 11
1
8
13
18
19
20
7
IceTop
81 stations, 324 DOMs
1
9
22
40
59
79
86
DeepCore
8 strings
IceCube
86 strings, 5160 DOMS
IceCube construction complete !
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H igh-energy events in IceCu be-40
~ EeV air shower
~100 TeV nm
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induced muon
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More events
A cascade event, candidate for
a high energy ne ~50 TeV
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~100 PeV primary
cosmic ray
IC-79 event:
d ow nw ard
m u on bu nd les
~ 300 muons in
deep IceCube
IceCube Deep Core talk by
Doug Cowen Friday
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Detecting neu trinos
• Rate = N eu trino flu x
x Absorption in Earth
x N eu trino cross section
x Size of d etector
x Range of m u on (for nm)
For threshold
Em > 1 TeV
• Range favors nm
– ~4 to 15 km .w .e. for
En ~ 10 to 1000 TeV
NuSky 20-June-2011
Tom Gaisser
Probability to detect nm-induced m
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Atm ospheric n in IceCu be
S.P.
Zone 1, l: -30 to -90 ; 3.14 sr
Zenith: 90 < q < 120o
(40% of Zone 1 is over the
Antarctic continent)
Zone 2, l: -30 to +30; 2.30 sr
Zenith 120 < q < 150o
Note: 43% of Zone 1 is in
declination -65o < d < -90o -over Antarctica. Contains
~25% of IceCube nm.
Seasonal temperature like
South Pole: dT ~ ± 7.5%,
aT ~ 0.54  dRate ~ ± 4%
NuSky 20-June-2011
Zone 3, l: +30 to +90, 0.84 sr
Zenith: 150 < q < 180o
Cosmic ray produces n in
atmosphere that puts a
muon into the detector
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Cu ts and event reconstru ction
• 40-string IceCu be:
– 375 d ays livetim e in
08/ 09 @ 1 kH z
=3.3x1010 triggers,
99.9999% m u ons
– 8 x 108 filtered & sent
over satellite from S.P.
– Qu ality cu ts applied
to get ~14,000 u pw ard
nm ind u ced m u ons
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Tom Gaisser
Upward
nm  m
Downward
atmos. m
All-sky plot of muons in IceCube-22
from 2007 (P. Berghaus, IceCube,
ISVHECRI-2008
arxiv.org/abs/0902.0021)
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Atm osp heric nm w ith IceCu be-40
Two analyses:
1. Unfolding
2. Forward folding as
a by-product of a
search for diffuse
astrophysical n
Look in detail at 2
Phys. Rev. D 79, 102005 (2009)
arXiv:1104.5187
PHYSICAL REVIEW D 83, 012001 (2011)
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Measu rem ent of nm-ind u ced m
p and K-decay
• Fit 3 com ponents:
– Atm ospheric n from K±
and p± (0.3 – 85 TeV)
• Use H ond a 2007 to 10 TeV
• + pow er-law extrapolation
• ~ cos -1 (q)
Astrophysical
Prompt
• H ard er spectru m to > 107
GeV (~E-2.7), isotropic
– Astrophysical n
• Isotropic, w ith E-2 spectru m
assu m ed (35 – 7000 TeV)
– N ote d ifferent response
for astro. n vs atm os. n
NuSky 20-June-2011
Neutrino energy at production
– Prom pt n ( 10 – 600 TeV )
Tom Gaisser
Measured dE/dX
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Resu lts of likelihood fit
IceCube
preliminary
• Consistent with only K, p atmospheric n to 100 TeV
• Charm component not yet seen; “intrinsic” charm in doubt?
• No astrophysical neutrinos seen yet
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IceCu be nm: m easu rem ents & lim its
Waxman
-Bahcall
Limit
IceCube 40
arXiv:1104.5187
Plot: Sean Grullon, UW
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Com m ents on d iffu se n resu lts
• Inpu t to analysis
– Specific spectru m assu m ed for atm ospheric n from d ecay of p and
K (H ond a et al., PR D75:043006,2007)
• Extrapolate w ith pow er law for E n > 10 TeV up to 10 PeV
– For prom pt n u se Enberg et al.. PR D 78, 043005, 2008
– Overall norm alization fitted for each com ponent w ith a single fitted
slope for both com ponents
• Lim itations of this analysis
– Lim its d epend on sim ple pow er-law extension of conventional
atm ospheric nm to En > PeV
– N eu trino spectru m m u st steepen to som e extent above 100 TeV to
reflect the knee in the primary spectru m
– Bou nd s on prom pt and astrophysical n w ill be relaxed to som e
extent w ith a m ore realistic assu m ption for shape of atm ospheric n
– Recent calcu lation extend s calcu lation of nm to > PeV
• Illana, Lipari, Masip, Meloni, Astropart. Phys. 34 (2011) 663
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Generic m od el I
• CR acceleration occu rs in jets
– AGN or GRB
• Abu nd ant target m aterial
– Most m od els assu m e photo-prod u ction:
• p + g  D+  p + p0  p + g g
• p + g  D+  n + p+  n + m + n
http://www.ucd.ie/math-phy
/rieger/science.gif
• Id eal case ( ~ “Waxm an-Bahcall lim it”)
–
–
–
–
Waxman, Bahcall, PRD 59,
023002 (1998). Also
TKG astro-ph/9707283v1
Strong m agnetic field s retain protons in jets
N eu trons escape, d ecay to protons & becom e UH ECR
Extra-galactic cosm ic rays observed as protons
Energy content in neu trinos ≈ energy in UH ECR
• This pictu re d isfavored as lim its go below W-B
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Generic m od el II
• UH ECR are accelerated in external shocks
analogou s to SN R
– See E.G. Berezhko, 0809.0734 & 0905.4785
– m ixed com position (accelerate w hatever is there)
– Low d ensity of target m aterial
 low er level of TeV-PeV neu trino prod u ction
Diagram from A.Ferrari, Ann Revs A&A 36 (1998) 539
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IceCu be lim its on cosm ogenic n
• GZK search looks for
IceCube-40 arXiv:1103.4250
– Very bright events
– N ear the horizon
– w ith com pact initial
bu rst of light
• Range of sensitivity
– PeV – EeV
– Com plem entary to
d iffu se nm search that
starts by m easu ring
atm ospheric nm
– Mod el 6 (Ferm i m ax):
expect 0.4 events
NuSky 20-June-2011
All-flavor limits assuming nm ~ nt ~ ne
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Su m m ary
• Pu shing below Waxm an -Bahcall “lim it” in
100 TeV – 10 PeV range d isfavors proton
d om inance in 1 – 100 PeV range
• Expect significant im provem ents in
IceCu be sensitivity to astrophysical n:
– IC59 + IC79 in analysis; IC86 ru nning
– Better analysis
• Use m ore realistic atm ospheric neu trino spectru m
• Use angu lar d epend ence
• Better u nd erstand ing of system atics
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