1 EUS O Extreme Universe Space Observatory Sergio Bottai INFN Firenze on behalf of the EUSO Collaboration DETECTING NEUTRINOS WITH EUSO Paris neutrino2004

2 #2 EUSO Consortium - Institutes Participant Nations and Institutions BrazilGermanySpainUSAJapanSwitzerlandPortugalItalyFrance –APC, Paris –CdF, Paris –IAP, Paris –LPSC, Grenoble –LPTHE, Paris –OdP, Paris –IASF, Palermo –ISAC-CNR, Bologna –INFN & Univ. Genova –INFN & Univ. Firenze –INFN & Univ. Torino –INFN & Univ. Trieste –INFN Catania & Univ. Palermo –Univ. Roma “La Sapienza” –Scuola Normale Sup. Pisa –Oss. Astrofisico Arcetri –Oss. Astrofisico Catania –CARSO –INOA –LIP, Lisbon –MSFC & NSSTC, Huntsville –UAH, Huntsville –UCB, Berkeley –UCLA, Los Angeles –Vanderbilt Univ. –Obs. Neuchatel –RIKEN –ICRR –Konan Univ. –ISAS –Rikkyo –KEK –NAO –Tokyo Univ. –Saytama –Aoyama –Kinki –Seikei –Kanazawa –MPIfP, Munich –MPIHLL, Munich –MPIfRA, Bonn –Univ. Wuerzburg –IAG, Univ Sao Paulo –IAA-CSIC, Granada –Dpt.FTC & CAFPE, Univ. Granada The EUSO instrument consortium is truly global in nature with >150 researchers in 50 institutions in 6 countries in Europe, the USA, Japan and Brazil.

3 BASIC GUIDELINE  EUSO is an experiment devoted to measure the cosmic ray spectrum above eV with high statistic  EUSO is at present in a phase of ‘feasibility study’  EUSO has also some potentiality to detect extraterrestrial neutrinos of energy close to eV. The sensitivity for such neutrino discover will be discussed in the presentation

4 #4 UHECR Observational Situation as today E>10 20 eV particles hit the atmosphere at a rate of <1/(100km 2 year). A great experimental challenge. P γ3K Δ Ｎ π GZK mechanism WE NEED NEW EXPERIMENTS : CONTROLL SYSTEMATICS -> AUGER INCREASE STATISTICS -> AUGER-EUSO AGASA - HIRES

5 Exposure (AGASA unit) EUSO

6 EHECR FROM SPACE Photons per m isotropic 330 – 400 nm Euso Area vs Auger EUSO Pierre- Auger

7 #7 Geometrical Factor (A ·  )  6 · 10 5 km 2 sr (FoV=±30° at ISS mean distance h ISS  430km) rather constant signal attenuation ~0.5 Negligible Proximity Effect (  D ist. /D ist. < 1%) (acceptance not depending on energy) Full Sky Coverage Cerenkov “footprint” of shower Advantage of a space-based fluorescence detector for EECR ATMOSPHERE

8 #8 ELECTRONICS : PHOTON COUNTING TIME INFORMATION FOCAL SURFACE LIGHT SENSORS LENSES The instrument

9 #9 Optics Requirements –FoV  30° –Pupil entrance pupil  2 m –F/#  1.15 –Spot dimension ~ 0.1° –Spectral range nm – Limited mass !! EUSO -The Optical System VERY challenging 2 Double sided Fresnel lens ! Pupil diameter 2.3m

10 #10 Support Structure Focal Surface assembly Microcell Macrocell EUSO – The Focal Surface pixels at single PE R8900 – M36 Filters MAPMT R8900 – M36 FILLING>0.9

11 G. D’Alì Staiti, Bologna, May 24, 2004 #11 The Atmosphering sounding Cloud topology survey Atmospheric transmission calibration LIDAR + IR camera LIDAR

12 #12 The detected signal FOR eV SIMULATION : The Detector Light Sensitivity The trigger efficiency Random Noise Signal ~10 The trigger efficiency for a subsample 20% Threshold reach ~5*10 19 eV

13 #13 The Real Atmosphere no trigger clear MCM’02

14 #14 The EUSO Acceptance In clear sky… …and in real atmosphere Golden Cerenkov only F max only The EUSO statistics E>10 20 eV ~1000 events/year in SuperGZK mode >70 events/year in GZK-suppressed mode REALISTIC CLOUDS SCENARIO KILL ~40% OF SHOWERS

15 #15 EUSO resolution Angular res = 1 o – 4 o Energy res = 20% (RMS)+.. (with Lidar info) Xmax res = 50 g/cm 2 (with Lidar info)

16 SHOWERS NEUTRINO EVENTS IN ATMOSPHERE ( e     ) 2000 km 3 we of target for EUSO But : duty cycle, efficiency, very high energy threshold

17 Proton – neutrino discrimination The probability of neutrino interaction in atmosphere is proportional to the atmospheric density. NEUTRINOS CC INTERACTIONS (LPM effect included) P+

18 DOWNWARD NEUTRINO ACCEPTANCE FOR EUSO Rejection > Golden events Fluorescence only events Xmax Select. Shape Select. P+P+ P+ 1600g/cm 2 Neutrino domain

19 TOP ATMOSPHERE P+ NEUTRINO Ground level Showers The probability of a neutrino interaction in a volume element dV is proportional to density NEUTRINO

20 EFFECTIVE ACCEPTANCE (g*sr) FOR NEUTRINOS Clear sky With clouds (duty cycle not contained) CC NC ~300 km 3 we + Shower max visible Trigger + Selection ~50 km 3 we duty cycle

21 log(E 2  Flux) log(E/GeV) TeV PeV EeV pp core AGN p  blazar jet Top-Down models GRB (W&B) Classes of UHE Models GZK neutrinos EUSO

22 Neutrino sensitivity Auger EUSO Sensitivity 1 events/decade/year EUSO has 10 times larger Aperture than Auger above GZK energy EUSO is sensitive Z-Burst, Top Down Models and High (MAXIMUM) GZK flux. ~ 10 events/year detected WB

23 EUSO threshold UPWARD TAU SHOWERS EUSO X 20 S. Bottai, S. Giurgola ICRC 2001 S. Bottai,S.Giurgola Astr. Phys

24 #24 EUSO AC/DB Just wishful thinking? on June 2004 ESA ‘SCIENCE DIRECTORATE’ DID NOT INCLUDED EUSO IN THE PRIORITY LIST OF CANDIDATE EXPERIMENT UP (“wait AUGER results”) The possibility to mantain the time schedule is under investigation ESA-EUSO STARTED A PHASE A STUDY FOR ISS PHASE A UFFICIALLY CLOSE IN JULY 2004 LAUNCH 2010

25 #25 Conclusion  EUSO is a pioneering experiment for studying EAS from space: An instantaneous aperture of 6×10 5 km 2 sr with a duty cycle ~20% is a technically achievable goal with up-to-date technology; The acceptance reduction due to cloud effect has been evaluated to be ~ km 2 sr effective acceptance ~10 3 events/year can be expected according to AGASA findings; ~10 2 events/year can be expected according to GZK-suppressed spectrum due to uniform source distribution.  for with E>5*10 19 eV EUSO will have a competitive sensitivity (50 km 3 we effective) TOP DOWN MODELS CAN BE SEEN IF THEY EXISTS  TIME SCHEDULE 2010 ???????

26 Design of a mirror optics, based on the Schmidt camera principle, with FOV up to 25° A proposed large mirror system correcting plate and/or filter mirror light shield focal plane FEATURES 3 identical DETECTORS ASSEMBLED INSIDE THE ISS ? Solid state detectors ? 5-7 m

27 GZK(A)~0.3 events/year in EUSO EUSO AUGER q.e=50% Eth=3EeV D=7.5m FOV= EUSO X 3 GZK(A)~ 40 events/year S. Bottai, P. Spillantini, “ FROM THE EXTREME UNIVERSE SPACE OBSERVATORY (EUSO) TO THE EXTREME ENERGY NEUTRINO OBSERVATORY “ prooceedings of the XIth Lomonosov Conferenceq WB