Riunione Settembre 2007 Gruppo 2 Inizio presa dati 2007: Auger, Borexino, Agile, Pamela Rivelatore on 2008: Gerda, Icarus, Opera,Warp, Glast, Antares, Nemo Running: Magic, Antenne, Virgo …….. Gran Sasso: fase emergenziale terminata

AUGER Settembre 2007 Surface Detector (1600 tanks) ~ 1400 tanks installate Problema proprietari quasi risolto. Completamento Osservatorio nel 2007 Fluorescence Detector (24 telescopi in 4 edifici) Completamente installato e operativo Los Leones: Aprile 2004 Coihueco: Settembre 2004 Los Morados: Aprile 2005 Loma Amarilla: Marzo 2007 G.Matthiae ~ 85% SD

50 km Malargue

AUGER - Settembre 2007

X max Depth of the maximum Study of composition – mass of the primaries

Xmax as a function of the energy Photons: LPM + low initial multiplicity

Elongation Rate measured over two decades of energy ( ~ 5) Energia minima: 0.5 x eV Syst error on Xmax < 15 g /cm 2

Exposure 5165 km 2 sr yr ~ 0.8 full Auger year Exp Obs > / > / Spectrum from Auger Surface Detectors Fit

Borexino is located under the Gran Sasso mountain which provides a shield against cosmic rays (4000 m water equivalent); Core of the detector: 278 tons of liquid scintillator contained in a nylon vessel of 4.25 m radius (PC+PPO); 1 st shield: 890 tons of ultra-pure buffer liquid (PC+quencher) contained in a stainless steel sphere of 6.75 m radius; 2 nd shield: 2100 tons of ultra-pure water contained in a cylindrical dome; 2214 photomultipliers pointing towards the center to view the light emitted by the scintillator (1843 with opt. concentr.) 200 PMTs mounted on the SSS pointing outwards to detect light emitted in the water by muons crossing the detector; External nylon vessel; it is a barrier against Rn emitted by PMT and s.steel

Commissione II : 24 settembre 2007 Emanuela Meroni Final spectrum after all cuts  Kr+  Be 14 C 210 Po (only, not in eq. with 210 Pb!) 11 C Understanding the final spectrum: main components

Commissione II : 24 settembre 2007 Emanuela Meroni 7 Be signal: fit without  subtraction Strategy: –Fit the shoulder region only –Use between 14 C end point and 210 Po peak to limit 85 Kr content –pep neutrinos fixed at SSM- LMA value Fit components – 7 Be – 85 Kr –CNO+ 210 Bi combined very similar in this limited energy region –Light yield left free These bins used to limit 85 Kr content in fit 210 Po peak not included in this fit

Commissione II : 24 settembre 2007 Emanuela Meroni 7 Be signal: fit  subtraction of 210 Po peak The large 210 Po background is subtracted in the following way: –For each energy bin, a fit to the  Gatti variable is done with two gaussians –From the fit result, the number of  particles in that bin is determined –This number is subtracted –The resulting spectrum is fitted in the energy range between 270 and 800 KeV A small 210 Po residual background is allowed in the fit 7 Be Rate: 47 ± 7 STAT ± 12 SYS c/d/100 t   The two analysis yield fully compatible results No oscillation expectation: 75 ± 4 c/d Theoretical prediction with oscillations: 49 ± 4 c/d

Commissione II : 24 settembre 2007 Emanuela Meroni 47 ± 7 stat cpd/100tons for 862 keV 7 Be solar Using LMA with:  m 12 2 =7.92·10 -5 eV 2 sin 2  12 =0.314 and BPS07(GS98) Syst. Error: 25%

Commissione II : 24 settembre 2007 Emanuela Meroni Comments on errors Statistical: –Right now, it includes combined the effect of statistics itself, the lack of knowledge of 85Kr content, and the lack of a precise energy calibration –These components are left free in the final fit, and contribute to the statistical error Systematic: –Mostly due to fiducial volume determination –With 45 days of data taking, and without an internal source calibration, we estimate an upper limit of 25% for this error Can be much improved even without internal calibration with more statistics and better understanding of the detector response