High Energy Neutrino Astrophysics with IceCube

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1 High Energy Neutrino Astrophysics with IceCube Konstancja Satalecka, DESY Zeuthen UCM, 25th February 2011

2 OUTLINE Neutrino properties Cosmic Neutrinos Neutrino detection Ice/Water Cerenkov Detectors Neutrino Astrophysics Recent results from IceCube Summary & Outlook

3 Neutrinos they are very small. They have no charge and have no mass And do not interact at all. The earth is just a silly ball To them, through which they simply pass... John Updike, Cosmic Gall

4 NEUTRINO PROPERTIES Neutrinos they are very small. They have no charge and have no mass + helicity: we observe only left handed neutrinos (or right handed anti-neutrinos) νlh νrh

5 NEUTRINO PROPERTIES Neutrinos they are very small. They have no charge and have no mass Neutrinos oscillate! Two flavors case: P(να νβ) = sin 2 (2θ)sin 2 (L Δm 2 /4E) ( [ νe ( ) ν1 νμ = ν2 ντ ν3 ) ] Δm 2 21 = ev 2 Δm 2 32 = ev 2 flavor eigenstates mixing matrix mass eigenstates At least two neutrinos have to be massive!

6 NEUTRINO PROPERTIES Neutrinos they are very small. They have no charge and have no mass And do not interact at all. only weakly ν µ ν µ ν µ µ Z 0 W + P u d u u u P u d u u u Neutral Current (NC) Interaction d Charged Current (CC) Interaction u very small cross sections = very big volumes needed for detection

7 NEUTRINO PROPERTIES Neutrinos they are very small. They have no charge and have no mass And do not interact at all. only weakly The earth is just a silly ball To them, through which they simply pass......or not, depending on the energy! For E > 50 TeV the mean free path of neutrino becomes comparable with Earth s diameter.

8 NEUTRINO PROPERTIES Neutrinos they are very small. They have no charge and have no mass And do not interact at all. only weakly The earth is just a silly ball To them, through which they simply pass... or not, depending on the energy.

9 COSMIC NEUTRINOS CνB 300 ν/cm3 1s after BB dn! /de!!gev -1 sr -1 s -1 cm -2 " log(e! /GeV)

10 COSMIC NEUTRINOS missing solar neutrinos first evidence for oscillations Sun CνB dn! /de!!gev -1 sr -1 s -1 cm -2 " log(e! /GeV)

11 COSMIC NEUTRINOS Super Novae Sun CνB dn! /de!!gev -1 sr -1 s -1 cm -2 " % of the explosion s energy goes into neutrinos log(e! /GeV)

12 COSMIC NEUTRINOS Super Novae Sun CνB dn! /de!!gev -1 sr -1 s -1 cm -2 " hadronic accelerators? log(e! /GeV) Active Galactic Nuclei

13 COSMIC NEUTRINOS Super Novae Sun Cosmic CνB dn! /de!!gev -1 sr -1 s -1 cm -2 " Rays Active Galactic log(e! /GeV) Nuclei

14 COSMIC NEUTRINOS Super Novae Sun Cosmic CνB dn! /de!!gev -1 sr -1 s -1 cm -2 " Rays Active Galactic log(e! /GeV) Nuclei

15 COSMIC NEUTRINOS Super Novae Sun Cosmic CνB dn! /de!!gev -1 sr -1 s -1 cm -2 " Rays sources??? Active Galactic log(e! /GeV) Nuclei

16 COSMIC NEUTRINOS Super Novae Sun Cosmic CνB Gamma dn! /de!!gev -1 sr -1 s -1 cm -2 " Rays Ray Bursts????????? Active Galactic log(e! /GeV) Nuclei

17 COSMIC NEUTRINOS Super Novae Sun Cosmic CνB Gamma dn! /de!!gev -1 sr -1 s -1 cm -2 " Rays Ray Bursts Active Galactic log(e! /GeV) Nuclei

18 COSMIC RAYS protons, nuclei from He up to Fe power-law spectrum transition form galactic to extragalactic sources ~10 15 ev (knee) CR interact with atmosphere and produce hadronic cascades atmospheric neutrinos GZK cutoff at ~10 20 ev p+γcmb Δ + p+π 0 or n+π + ±. π ± μ ± νμ e ± νμ νe guaranteed source of UHE neutrinos! LHC GZK = Greisen (1966), Zatsepin & Kuzmin (1966)

19 pictur COSMIC RAYS sources? acceleration of hadrons to Ultra High Energies: p+p or p+γ π 0 π ±... π ± μ ± νμ e ± νμ νe π 0 γ γ ( Mpc distance (GZK cutoff: ~ few10 charged particles are deflected in magnetic fields γ-rays are absorbed on the Extragalactic Background Light (EBL) ν are perfect messengers: point straight to their origin don t get absorbed ν e - γ ray e + γ EBL p

20 EXPERIMENTAL TECHNIQUES 10 9 ev to ev Cherenkov photons in water/ice (IceCube, ANTARES, NESTOR, NEMO) v-induced cascade! µ acoustic pancake coherent radio signal ev to ev Coherent radio pulses in ice, salt and Moon regolith (ANITA, RICE) optical Cherenkov signal > ev Acoustic waves in water/ice and salt (SPATS - feasibility study) µ to ev Extensive air showers (AUGER)

21 CHERENKOV EFFECT IN ICE/WATER detector (PMTs) Cherenkov cone muon interaction ν μ + N μ + N neutrino Infrequently, a cosmic neutrino interacts with an ice/water nucleus A muon (or electron, tau) is produced The arrival time of the Cherenkov photons is measured at a grid of PMTs Goals: detect ν of all flavors at energies ev to ev

22 NEUTRINO TELESCOPES: ICECUBE Digital Optical Module

23 !"#$%&"'()*"+%,)-"./ South Pole!"#$%& IceCube AMANDA (until 2009) '(()*+,(! "#$%&'(!)*%+,#-. /*.-0$.!1%23!4'*5-6*

24 12-)'5+2*"#)- 12-)'3"%,4 <)92:%"'=+>-:2*#-)!"#$?)+"9&'=+>-:2*#-)8 %&'"()"*+, #% - 6#7+8'!13'6#9)%:!"#$%"&'()*+"%,*#-)'./0 ;-:-"8'3#$+ CC for νμ only!"#$%&'()*$+,"-. /*.-0#.(1$23(4&*5-6* 7

25 2$340"+/56+738$7&.,98,7$ :$8/ $7&;+$0*<% 8/+4,"+$7!"#$%&'()&!"*+,-./-/0%&)"1$ ;+$0*<&:$9/-34"/+%!"#$%&$'() #! * NC for all flavors CC for νe and low E νt!"#$%&'()*$+,"-. /*.-0#.(1$23(4&*5-6* 78

26 NEUTRINO DETECTION: BACKGROUND down-going atmospheric muons detector Elevation Number of events data MC atm. µ MC atm. " MC total Muons induced by atmospheric νμ (signal or background) up-going ANTARES Coll. arxiv: Atmospheric muons (background) down-going 10 up-going cosmic neutrino up-going atmospheric neutrino sin! Fig. 4: Distribution of the sine of the elevation angle fo main background: atmospheric μ (99.999% of triggered events) ( background atmospheric ν (residual background rejection: select only events coming from below (up-going)

27 SCIENCE WITH ν TELESCOPES Astrophysics Origin of the cosmic rays (AGN, SNR,...) GRBs Uncovering invisible phenomena Physics beyond the Standard Model Search for Dark Matter Search for Magnetic Monopoles Neutrino-oscillations Quantum gravity, Planck scale Physics, test of Lorentz invariance Standard Model Physics Cross sections at high energies High pt muons from cosmic rays (charm production)

28 COSMIC MUON ANISOTROPY Zhang J.L. et al.: proceedings of the 31st ICRC, Łódź (Poland, 2009) Northern Hemisphere: TIBET 5 o directional resolution 5 TeV median energy Also observed by MILAGRO, ARGO... ) Abbasi R. et al.: Astrophys. J. 718 L194 (2010) Southern Hemisphere: Preliminary IC40 map 12 billion downward going muon events 3 o directional resolution 20 TeV median energy Not compatible with the Compton-Getting effect (relative motion of Solar System) Large scale + Local magnetic fields (e.g. solar magnetotail)? Propagation of cosmic rays from nearby sources (recent SN, pulsars)?

29 ATMOSPHERIC NEUTRINOS 10-5 of triggered events are muons induced by an atmospheric neutrino energy resolution 0.3 in logeν preliminary unfolded energy spectrum of 17,682 atmospheric ν (IC40) highest energy atmospheric ν: ~250 TeV many from decay of charm mesons powerful tool to test HE hadronic interaction models arxiv: v2

30 DIFFUSE NEUTRINO FLUX diffuse flux from unresolved neutrino point sources (νμ + anti-νμ) ANTARES CR dn/de~e -2.7 shock acceleration: dn/de~e -2.0 dominant at HE arxiv: v2 1 yr of IC40 = 5 x sensitivity of 3 yrs AMANDA-II close to discovery!!! in UHE (>10 6 GeV) IC 86 might reach discovery level in 5-8 yrs

31 NEUTRINO POINT SOURCES s -1 ] -2 dn/de [TeV cm Strings Sensitivity d 40 Strings Discovery Potential d 40 Strings Sensitivity d 40 Strings Source List 90% UL 86 Strings Sensitivity 365 d ANTARES Sensitivity 365 d 2 E sin(!) Abbasi R., et al., Astrophys. J. 701, L47 (2009) Abbasi R., et al., Phys. Rev. Lett. 103, (2009) sensitivity (90% C.L.) for a full sky search for steady point sources of E -2.0 spectrum (νμ+anti-νμ) extension to Southern Hemisphere: UHE energy (>100 s TeV) event selection background reduction ~10 5 IC86 point source detection in ~3-5 yrs (depending on the location in the sky)

32 NEUTRINO POINT SOURCES Abbasi R., et al., Astrophys. J. 701, L47 (2009) Abbasi R., et al., Phys. Rev. Lett. 103, (2009) sky map of statistical significance from the full sky search of IC40 no significant localized excess found :( extension to Southern Hemisphere possible by UHE events selection (E>100 s TeV)

33 NEUTRINO POINT SOURCES Search for time-variable sources: flare searches: special algorithms looking for neutrino flux enhancement (on-line and off-line) on-line possibility to send alerts for follow-up observations: to VHE gamma-ray telescopes: Neutrino Target of Opportunity (NToO), main target: AGN to optical telescopes: Optical Follow-Up (OFU), main target: SN and GRBs simultaneous data guaranteed!!! MultiWavelength analysis: use data from other telescopes (optical, X-ray, gamma-ray...) to identify periods of possible neutrino flares (off-line)

34 NToO TEST RUN IN 2006 AMANDA-II + MAGIC-I 5 sources (2 gal. + 3 extragal.) 5 alerts sent (single ν events) 2 follow-up observations no coincidences with gamma-ray flares found Ackermann et al.,icrc 30th, Vol.3, 1257 (2007) AMANDA-II MAGIC-I feasibility of the set-up was proven program will be continued with MAGIC-II and IceCube improvement: algorithm looking for neutrino flares to alert MAGIC Franke et al., ICRC 31 th, (2009)

35 INDIRECT DARK MATTER SEARCH Ackermann M., et al., Astropart. Phys. 24, 459 (2006) Abbasi R., et al., Phys. Rev. Lett. 102, (2009) non baryonic cold Dark Matter: Weakly Interacting Massive Particles (WIMPs) MSSM candidate: neutralino χ interacts only weakly, stable (R-parity conservation) χ can accumulate in the Sun (gravitational attraction) χ anti-χ annihilation produces neutrinos (indirect search) muon flux from Sun measured by IceCube can give us the annihilation rate annihilation rate can be translated in to spin-dependent χ-p cross section σsd (dominates in Sun) requires models for solar DM distribution & annihilation mode, equilibrium between capture and annihilation assumed complementary to the direct DM searches, sensitive to spin-independent σid IC80 + DC6 lower E threshold and sample low neutralino mass region

36 SUMMARY & OUTLOOK Neutrinos they are very small... but powerful tools for discovering the secrets of Nature! After > 20 years first generation neutrino telescopes have set limits to astrophysical neutrinos The hunt for cosmic neutrinos has just begun! IceCube is completed: diffuse searches will cross the W&B bound point source searches will be improved by a factor 2-3 The KM3NeT consortium is ready to construct a cubic-kilometer scale underwater neutrino telescope (expected improvement in angular resolution: factor 2-3 compared to IceCube) Projects are underway to build detectors 100 times larger using techniques (radio, acoustic) that exploit the advantage of much larger attenuation lengths If the predictions from the measured γ-ray fluxes are correct the detection of neutrinos from sources with hard spectra up to O(10 TeV) may become possible with a few years of data

37 BACK-UP

38 NEUTRINO TELESCOPES: ANTARES 12 lines x 25 storeys x 3 PMTs = 885 PMTs Completed 30th May 2008 L12 and IL07 acoustic detection system caveats: high background (bio-luminescence) string move with sea currents

39 Data of (341 days) 750 multi-line neutrino candidates scrambled Latest results: Antares

40 KM3NeT A research facility in the Mediterranean Sea Multi-cubic kilometer size neutrino telescope Cabled observatory for Earth and Marine sciences Conceptual design ready (2008), Technical design ready (2010), Construction phase starts 2013 Prototyping with different alternative designs (layout, optical modules, etc.) Optimization (physics/costs) in progress Standard OM Expected exclusion limits: KM3NeT IceCube OM with many PMTs From U. Katz, Zeuthen 2010 Observed Galactic TeV-! sources (SNR, unidentified, microquasars) F. Aharonian et al. Rep. Prog. Phys. (2008) Abdo et al., MILAGRO, Astrophys. J. 658 L33-L36 (2007)

41 MULTI KM 3 DETECTORS: ACOUSTIC DETECTION Goal: detection of neutrinos with E > ev ~100 km 3 detector needed optical is too expensive Principle: energy deposit in cascade heated volume expands bipolar pressure pulse Feasibility study at South Pole (SPATS): negligible refraction of acoustic waves deeper than 200 m promises: good neutrino direction and energy reconstruction good separation from background events arxiv: Similar effort by ANTARES in water (AMADEUS)

42 MULTI KM 3 DETECTORS: RADIO DETECTION ANITA searches for the radio pulses from electromagnetic cascades induced by UHE neutrinos in the polar icecap Baloon flights around the Antarctic best sensitivity in energy range between ev and ev arxiv: v3 Alternative design: detect radio pulses produced by UHE neutrino interaction in ice with an array of radio receivers (RICE, AURA IceRay) arxiv:

43 Multi-km 3 detectors: Extensive Air Showers Search for young horizontal and Earth skimming air showers ~0.3 GZK events expected per year (large theoretical uncertainty) Assuming a!"(e) = k E!2 " flux Auger obtained a 90% C.L. limit on the diffuse single-flavour neutrino flux of: k < !7 GeV cm!2 s!1 sr!1 (using down-going showers) The limit for Earth-skimming up-going neutrinos is: k < !8 GeV cm!2 s!1 sr! to ev The P. Auger Collaboration, Proc. 31st ICRC, Lodz, Poland (2009).