Origin of Cosmic Rays Part 2: Neutrinos as Cosmic Ray messengers - PowerPoint PPT Presentation

Origin of Cosmic Rays Part 2: Neutrinos as Cosmic Ray messengers Lecture at the J. Stefan Institute Ljubljana within the course: 'Advanced particle detectors and data analysis' Hermann Kolanoski Humboldt-Universität zu Berlin and DESY Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 1

What I want to tell you: want to you – Candidates for cosmic ray accelerators Candidates for cosmic ray accelerators – Neutrinos as messengers for CR sources messengers for CR sources – HE Neutrino telescopes HE Neutrino telescopes – Neutrino detection Neutrino detection – Point source searches – EHE neutrinos and the Muppet Show – Cosmic signals from contained events Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 2

The „non-thermal Universe“ Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 3

Where could particles possibly be accelerated? Hillas diagram Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 4

Active Galactic Nuclei Hubble Heritage Picture of M87 Model of an AGN Origin of the HE cosmic radiation? Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 5

Twisted and Straight Paths Charged Particle Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 6

Neutrino fluxes Cosmic neutrinos should have a hard spectrum F ~ E -2 E -3.7 atmospheric ν F ~ E -3.7 E -2 Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 7

Cosmic Rays, Gammas and Neutrinos CR – ν – γ connection ν π ± accelerator p ν μ ± ν π 0 the γ – ν connection γ target target for hadron accelerators γ CMB 2.7 K → threshold E p ≈ 4 ×10 19 eV Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 8

Three Pillars of HE-Astroparticle Physics Astroparticle • Cosmic Rays CRs • GeV - TeV γ ‘ s • TeV -PeV ν ‘ s TeV γ ‘ s TeV- PeV ν ‘ s 9 Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos

How to detect cosmic high energy neutrinos? quite difficult Absorption small  detection probability small Need something • large • transparent ⇒ water or ice Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 10

Moisej Markov Bruno Pontecorvo M.Ma рков , 1960 : „We propose to install detectors deep in a lake or in the sea and to determine the direction of charged particles with the help of Cherenkov radiation .“ Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 11

Amundsen – Scott Station Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 12

IceCube air shower array IceTop gigaton-scale neutrino telescope • 86 Strings, 2450 m deep • 5160 Optical Modules IceCube • Instrumented: 1 km 3 1000 m • IceTop: 1 km 2 • Installation: 2005-2011 DeepCore Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 13

DOM – Digital Optical Module pressure glas sphere junction cable harness elektronics: high voltage, digitalization, data transfer photomultiplier = light sensor analog transient waveform digitizer (ATWD) 128 Samples in 422 ns Ø 32cm Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 14

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Hot Water Drilling IceCube EHWD operation: entire drill camp setup, including generators, heater plants, fuel systems, and support workshops. 2 drill towers connect to central plants and leapfrog over holes. Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 16

... und dann 2450 m tief versenkt Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 17

Deployment 99% of DOMs survive deployment and freeze-in Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 18

Detection of High Energy Neutrinos atmosph. Muons mean free path 1 lightyear ν µ + N → µ + X 10 12 10 10 µ km 10 8 Radius Erdbahn 10 6 atmosph. 10 4 ν µ Earth diameter Neutrinos 10 2 extraterr. MeV GeV TeV PeV EeV ZeV Neutrinos Energy even for neutrinos the Earth becomes opaque above about 1 PeV Earth as filter ⇒ look upward – atm. background becomes less Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 19

Detection of a Neutrino cos θ c = ( β n) -1 θ c ( β =1) ≈ 40 ° θ c Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 20

Was misst IceCube eigentlich? 21 21 Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos

Was misst IceCube eigentlich? Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 22

Particle Signatures Particle Signatures up-going ν µ → point sources CR shower light collection by DOMs in IceTop µ µ ν µ µ bundle background ν e cascade & → all flavours physics ν e Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 23

Neutrino Signals in IceCube e, μ , τ X W CC ν e , μ , τ N ν e , μ , τ X Z NC ν e , μ , τ N Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 24

Neutrino induced muon tracks. • Only ν μ CC interactions • Angular resolution: < 1˚ • Energy measurement: only dE/dx – μ might have lost significant fraction of energy before entering the detector • Effective volume larger than instrumented volume Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 25

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Muon Energy Loss b(E)E = stochastic losses due to bremsstrahlung critical energy ~E  allows energy reconstruction of muons, not of the neutrinos! Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 27

ν μ Angular and Energy Resolution Moon shadow includes: ν μ energy estimated from dE/dx of muon (bremsstr.) Ljubljana, March 2015 28 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos

Shower-Type Event (Cascade) > ν e + ν μ NC + ν τ interactions > Angular resolution: ≥10˚ > Energy resolution: 15% > Effective volume smaller than instrumented volume Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 29

Cascade Events electron neutrinos produce electrons which deposit there energy locally spherical signal growth Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 30

Angular & energy resolution for shower-type events. > Full likelihood reconstruction of observed waveforms. > ~15% energy resolution. > ≳ 10º angular resolution. > Calibrated by artificial light sources and CR air shower mons. 31 Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos

Search for Diffuse Astrophysical Neutrino Flux Background: Atmospheric Neutrinos ~ 100,000 events per year “prompt” ν’s: from (semi -) leptonic decays of heavy hadrons (mainly charm). Flatter spectrum than “conventional” ν’s ⇒ large uncertainty for astro- ν’s IceCube has now constrained to ~ ERS model (Enberg et al.) E -2 astrophysical? Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 32

Search for Pointsources: The Method 4282 events (small sample) Source ≈ 2 ° - 3 ° background background: atmospheric ν Search for event excess within 2 ° - 3 ° • somewhere in the Northern sky • from list of candidate sources Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 33

The Statistics Problem If you serach long enough we will for sure get an exces at some point Example: “I only believe in statistics Expect 3 events background that I doctored myself” in a search window, but see 7. Winston Churchill How significant is this? <n> = 3 0.25 0.2 w(n>6) = 3,3 % 0.15 0.1 0.05 0 1 2 3 4 5 6 7 8 9 10 Already for about 30 search windows the Significance is determined by ~10000-fold probability to see 7 or more events in any simulation of measurement window is about 60% for background only. Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 34

Point Source Search 2008-2011 IC86+79+59+49 Hottest spot in South: The 4-year skymap: -log10(p) = 5.95 Ra: 296.95 Dec: -75.75 No significant signal Ns: 16.16 Gamma: 2.34 p-value ~9.3% (post trial) Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 35

Improving Statistical Significance • pre-defined source positions • pre-defined time-window • „stacking“ of pre-defined sources „Pre-Definition“ with „multi-messenger“ information of optical, gamma, X-ray, radio telescopes … Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 36

Search for neutrinos which are in time and direction consistent with GRB Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 37

GRB Model Ljubljana, March 2015 H.Kolanoski - 'Origin of Cosmic Rays' - II: Neutrinos 38