1. Neutrino Physics with IceCube
IceCube Design, Status and Recent Results
IceCube Potential*
Astrophysics
Particle Physics
Neutrino properties
Atmospheric neutrinos
VEP, VLI
WIMPs
Monopoles, Exotica
Beyond IceCube
Low energy core
Ultrahigh energy radio/acoustic extensions
*See AMANDA talk by B. Baret for more
concrete evidence of IceCube’s potential
D. Cowen/Penn State

2. The IceCube Collaboration
University of Alaska, Anchorage
University of California, Berkeley
University of California, Irvine
Clark-Atlanta University
University of Delaware / Bartol
Research Institute
University of Kansas
Lawrence Berkeley Natl. Laboratory
University of Maryland
Pennsylvania State University
Southern University and A&M College
University of Wisconsin, Madison
University of Wisconsin, River Falls
RWTH Aachen
DESY, Zeuthen
Universität Dortmund
MPIfK Heidelberg
Humboldt Universität, Berlin
Universität Mainz
BUGH Wuppertal
Stockholms Universitet
Uppsala Universitet
Vrije Universiteit Brussel
Université Libre de Bruxelles
Universiteit Gent
Université de Mons-Hainaut
Chiba University
University of Canterbury, Christchurch
Universiteit Utrecht
Oxford University
South Pole University
D. Cowen/Penn State

3. IceCube & AMANDA Site and Design
2 DOMs in each of 160 IceTop tanks
two tanks deployed atop each string
station
runway
60 Digital Optical Modules (DOMs) on each of 70+ strings
strings 125 m apart
DOMs 17 m apart in z on string
1450m-2450m below surface
~1km3 physical volume, ~1 GTon
D. Cowen/Penn State

4. IceCube Construction Status
1320 DOMs on 22 strings
~0.25km3 physical volume
surround AMANDA
677 OMs deployed
104 DOMs in 52 IceTop tanks
AMANDA
IceCube currently
instrumented
IceTop
Digital Optical Module (DOM)
cartoon
photo
D. Cowen/Penn State

5. IceCube Construction Status
Year: Strings
2005: 1
2006: 8
2007: 13 (12 planned)
2008: 14
2009: 14
2010: 14
2011: 11+
AMANDA 01/ 2000 78 74 73 72 67 66 65
IceCube string and IceTop station 01/05 58 59 57 56 50 49 48 47 46
IceCube string and IceTop station 01/06 39 40 38 30 29
IceTop station only 2006 21
IceCube string and IceTop station 02/07
D. Cowen/Penn State

6. How IceCube and AMANDA Work
Neutrino interacts in or near the detector
Imparts energy to charged particle(s)
Charged particle(s) emit Cherenkov light
directly, and
by imparting energy to other charged particles
Cherenkov light detected by PMTs in modules in the detection medium
AMANDA OMs: analog signals, digitized on surface
IceCube DOMs: digitization in situ, bits to surface
Trigger: >Nmodules hit in Dt
AMANDA: tighter spacing
IceCube: quieter modules, local coincidence—more flexible trigger
Joint event triggering/building implemented this year
Filter: select events for satellite transfer north
D. Cowen/Penn State

7. IceCube Data Taking Status
Physics data taking since May 23, 2007
We are running shifts (remotely)
Approaching 96% live time
Should get above 99% very soon
Event rate is ~600Hz, acquiring 180 GB/day, over one billion events recorded so far
Detector performance is excellent
98.5% of deployed DOMs are commissioned and delivering physics data
1000 DOM-years of live time accumulated thus far
2 sensors failed after commissioning
estimated survival rate after 15 years: 97% +1.5/-3.5%
Fundamental parameters meet or exceed design specifications. Examples:
individual DOM timing
multi-string timing
in situ LED flashers
etc.
D. Cowen/Penn State

8. IceCube Data Quality Assurance
Example: Use in situ remotely-controllable LEDs and downward-going muons to check relative DOM timing
DOMs have individual free-running clocks
clocks must be calibrated to within several ns to allow us to reconstruct events
figure shows example of how this works with LEDs
Timing excellent
on all new DOMs Dt
Timing stable over
>1 year period
D. Cowen/Penn State

9. IceCube Results Atmospheric neutrino “test beam”
Upward going atmospheric nm-induced muon sample extracted from 2006 data
Note: only had 9 strings in 2006
Zenith
Azimuth
(upgoing)
(horiz.)
Residual 10%
bkgd. near horizon
Saw 234 events on expectation of 25580
Reference: arXiv: v1 (accepted by PRD)
D. Cowen/Penn State

10. IceCube Results Other analyses nearing fruition:
Search for Extremely High Energy Neutrinos
One Year IceCube Point Source Analysis
Please see B. Baret’s talk on AMANDA (this conference) and IceCube’s contributions to ICRC 2007 for these and many other IceCube/IceTop/AMANDA results
D. Cowen/Penn State

11. IceCube Astrophysics Potential
Neutrinos from cosmic accelerators
Strong circumstantial evidence that sources of high energy photons are hadronic accelerators*
Detecting neutrinos from cosmological source(s) would be ironclad evidence
p + p(g)  p’s  g’s and n’s
May point way to understanding origin of, and acceleration mechanism for, detected ultrahigh energy (E>~1020eV) cosmic rays
Possible “bottom up” astrophysical accelerator sources of UHE neutrinos (En>~TeV):
GRBs, SNe, AGN
“Point source” analyses
Can enhance potential to discover neutrinos from transient sources with “target of opportunity” and “optical follow-up” techniques
See plenary session talk by E. Bernardini
Look also for UHE neutrino signals from diffuse sources
*E.g., HESS observation of SN remnant RX J ; arXiv:astro-ph/
D. Cowen/Penn State

12. IceCube Particle Physics Potential
soft decay spectrum
hard decay spectrum
hard
soft
AMANDA limit
IC22+A limit
(anticipated)
WIMPs (a “top down” source of UHE neutrinos)
can be trapped in gravitational potential wells, annihilate, create neutrinos
earth core, solar core, galactic center
complementary to direct detection technique
Violation of Equivalence Principle (VEP), Violation of Lorentz Invariance (VLI)
Results in measurable departures from standard neutrino oscillation expectations
linear energy dependence of oscillation frequency
IceCube will do >10x better than AMANDA-II result*
Monopoles
Slow-moving, bright
Exotica
Closely spaced upgoing track pairs (SUSY staus)
*presented at ICRC 2007
D. Cowen/Penn State

13. IceCube & Atmospheric n Oscillations
En (GeV)
nm survival probability
Dm2 = 2.4e-3 eV2
vertically upward nm
Atmospheric neutrino oscillations
Difficult: need “low” threshold E<50 GeV
may be able to reach E<30 GeV with vertical muons
denser 17m spacing in z-dimension
muon travels ~5 m/GeV
need at least 5 DOMs: 68 m
Em,min = 68/4 = 17 GeV (En,min = ~25 GeV)
IceCube is implementing specialized low-energy trigger
Look at mup/mdown as a function of m track length
and maybe use initial creation shower to further refine measurement of E
Related idea discussed in Albuquerque and Smoot, PRD
issues:
kinematic n-m angle
~flat inelasticity (y) distribution
cosmic ray muon background
if successful, this would be highest energy measurement of neutrino oscillations
a low energy sub-array within IceCube would do a better job at this
Initial IceCube study to be presented at TeV Astro Conference in August (Venice, Italy)
4x17m m nm
D. Cowen/Penn State

14. Tau Neutrinos
At E > ~100 TeV, nt background-free source of cosmological neutrinos
no nt from atmospheric neutrinos
oscillation effect negligible at these energies
“prompt” nt from charm decay small
only cosmological sources can give nt
Starting with ne:nm:nt::1:2:0 at source, end up with 1:1:1 at earth due to oscillations
Also:
pointing resolution of nm
energy resolution of ne
large acceptance
rich set of signatures allows systematic crosschecks
tau travels long distances (50m per PeV)
tau has many decay channels
Finally…
…the total sample of nt is…4*
*DONUT Collaboration, arXiv:hep-ex/
D. Cowen/Penn State

15. Tau Neutrino Signatures
D. Cowen/Penn State

16. IceCube n Flavor Separation
550 GeV ne
14 TeV ne
100 PeV ne
downgoing m (data)
9.5 PeV nt double bang
77 PeV nt lollipop

17. IceCube n Flavor Separationnt
full flavor ID ne
Neutrino flavor ne
(supernovæ)
showers vs. tracks nm 6 9 12 15 18 21
Log(E/eV)
D. Cowen/Penn State

18. IceCube & Fundamental Neutrino Properties
New n or source properties distort expected 1:1:1 neutrino flavor ratio
Source Flavor Ratio
Neutrino Physics
Detected Flavor Ratio
Assumptions/Comments
References
1:2:0
Standard vacuum oscillations
1:1:1
0:1:0
4:7:7
Muon damped sources
Rachen & Meszaros astro-ph/ ; Kashti & Waxman arXiv:astro-ph/ v4
n decay (normal hierarchy)
6:1:1
Ue3=0; Complete decay.
Current limits on n decay are weak. No initial flavor ratio can give either 6:1:1 or 0:1:1.
Beacom et al. arXiv:hep-ph/
n decay (inverted hierarchy)
0:1:1
pure anti-ne
5:2:2
Neutron accelerator
Anchordoqui et al., arXiv:astro-ph/ v3
1:2:0 and 0:1:0
CP violation
Complicated, but flavor ID critical
Q13 not too small; DQ12 and DQ23 reduced; 10% error on flux.
Optimistic…
Blum, Nir and Waxman arXiv: v1
Incomplete list!
Incomplete list!
D. Cowen/Penn State

19. IceCube Extensions Low Energy (En > ~10 GeV) AMANDA
closely coupled operation with IceCube
coincident triggering
joint event building
combined event filtering and reconstruction
New core (just playing around with the idea…)
deploy additional strings of DOMs in close-pack array deep in center of IceCube
lower energy threshold, lower background
deeper, veto, specialized trigger
D. Cowen/Penn State

20. IceCube Extensions High energy (E > ~10 PeV) Acoustic Radio
SPATS 06/07
deployed 3 strings stages)
Radio
AURA 06/07
deployed 3 clusters dipoles)
Acoustic string stage
being deployed
(No children were
co-deployed with
dipoles this season)
Radio cluster
being deployed
A possible future hybrid array
D. Cowen/Penn State

21. Conclusions
IceCube is functioning well with ~¼km3 fiducial volume deployed
Began physics data taking ~1 month ago
Mother Nature willing, IceCube will study fundamental neutrino properties
tau neutrinos, n oscillations, n decay, Q13,..
…And it can do other interesting particle physics and astrophysics
WIMPs, monopoles, other exotica
neutrinos from GRBs, AGN, SNe,…
Planning and R&D for low and high energy extensions are underway
D. Cowen/Penn State

22. What Happens to Neutrinos Afterwards
McMurdo Station,
Antarctica
D. Cowen/Penn State