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Sensitivity Studies for KM3NeT Rezo Shanidze, Sebastian Kuch University of Erlangen. WP2 (. ) Meeting. CPPM, Marseille, 24-25/10/2006. Introduction/Motivation. What is the minimal flux of high energy cosmic neutrinos which can be detected with KM3NeT detector ?
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Sensitivity Studies for KM3NeTRezo Shanidze, Sebastian Kuch University of Erlangen WP2 ( ) Meeting CPPM, Marseille, 24-25/10/2006
Introduction/Motivation • What is the minimal flux of high energy cosmic neutrinos which can be detected with KM3NeT detector ? • What is the minimal flux which is necessary for 5s discovery of neutrino point sources ? - How KM3NeT sensitivity depends on detector configuration (geometry, OM) and environmental (site) parameters ? - How the sensitivity depends on KM3NeT performance parameters, for example energy and angular resolution ? CPPM, Marseille, 25/10/2006
Current Limit (Diffuse nm Flux ) Current AMANDA limit diffuse kn E-2nm -flux, ( En> 100-300 TeV) , kn ~ 10 -7(GeV-1 cm-2s-1sr-1) with ~30% systematic uncertainty IceCube (1 year): 5s:10-8 E-2 90%c.l. : 4 10-9 E-2 Astropart.Phys. 20(2004), 507 astro-ph/0305196 T.Montaruli, asto-ph/0608140 CPPM, Marseille, 25/10/2006
Current Limit ( Point Sources ) Flux model: F(En)= kn E-2 Current AMANDA limit: kn~ 10 -7 ( GeV-1 cm-2 s-1 ) IceCube (1 year): 5s : 7 10-9 E-2 90% c.l.: 2 10-9 E-2 T.Montaruli, astro-ph/0608140 Astropart.Phys. 20(2004), 507 astro-ph/0305196 CPPM, Marseille, 25/10/2006
Sentivity and Event Rates Events in n-experiment (KM3NET): - Number of detected (observed) events – ND(E) - Number of background (from MC) events – NB(E) Sensitivity: ND(E) ~ NB(E) gmax.(Nmax) of cosmic n (NC): Fn(En) upper limit (90% c.l.) ND(E) > NB(E) g cosmic n events (NC) and significance (>3s): Fn(En) cosmic n-flux Cosmic neutrino flux: F(En) = kn E-G ‘Sensitivity: (kn)depends: • - energy threshold (E) - power index (G) CPPM, Marseille, 25/10/2006
Event Rates and Detector Models Numbers of neutrino events: N(E) = T∫F(En,Wn) A(En,Wn) dEn dWn KM3NeT detector models/effective area: talk by Sebastian Kuch ( asto-ph/0606507) Different configurations: - Homogeneous geometry - Ring geometry -Cluster geometry with multPMT OMs. Detector effects not considered: • Trigger and reconstruction efficiency, • Energy reconstruction and resolution • Direction reconstruction and angular resolution E CPPM, Marseille, 25/10/2006
KM3NeT Detectors For each KM3NeT detector: - Detector geometry (OM grid) - OM type - number of OMs - Effective area Detector performance vs. nm energy: - Diffuse flux sensitivity for knE-G flux, (G=1,5-2.5) - WB events contribution from : B. Hussendörfer Cube geometry CPPM, Marseille, 25/10/2006
KM3NeT Detector Configurations Ring geometry Cluster geometry CPPM, Marseille, 25/10/2006
Upper Limit (Diffuse Flux) Most simple case (Unfortunately most unrealistic !): no background (atm- nm) events: NB(E) =0 Upper limit (Nmax m) from Poisson statistics P(m,n) P(m,0)=1-c.l. (Confidence Level) For 90% c.l. gm=2.3 Feldman and Cousins approach: m=2.44 (Phys. Rev. D57(1998) 3873, physics/9711021) kn(E) = Nmax / (2p T ∫ E-G A(En) dEn) P(2.3,n) Probability Events Observed (n) CPPM, Marseille, 25/10/2006
Upper Limits with Background No cosmic neutrinos observed ND(E)=NB(E) Number of background events NB(E) g calculated from atm-n flux (Volkova) Nmax (90% c.l.) obtained from Feldman-Cousins approach: TFeldmanCousins class in ROOT. Nmax (90% c.l.) Number of events (NB) CPPM, Marseille, 25/10/2006
Upper Limit (vs Emin ) • Upper Limit for the E-2 neutrino diffuse flux • ( no background case): • for different KM3NeT models: • 1. Homogeneous • geometry • (Cuboid grid) • 2. Ring geometry • 3. Cluster geometry Atm-n kn (GeV-1cm-2 s-1sr-1) IceCube E > Emin (GeV) CPPM, Marseille, 25/10/2006
Upper Limit (vs Emin ) • Upper Limit for the E-2 neutrino diffuse flux • ( no background case): • for different KM3NeT models: • 1. Homogeneous • geometry • (Cuboid grid) • for different G= • 1, 1.5, 2, 2.5 kn (GeV-1cm-2 s-1sr-1) E-2.5 E-2.0 E-1.5 E-1.0 E > Emin (GeV) CPPM, Marseille, 25/10/2006
Upper Limit (vs G) Upper limit (sensitivity) of KM3NeT detector to the diffuse knE-2 flux of cosmic neutrinos vs. G The sensitivity calculated with different Emin = 100 TeV. KM3NeT model used in Calculations: Homogeneous cube E> 100 TeV kn ( GeV-1 cm-2 s-1sr-1) ANTARES KM3NeT power index (G) CPPM, Marseille, 25/10/2006
Diffuse Flux Sensitivity • Upper Limit for the E-2 • neutrino diffuse flux • above Emin > 100 TeV • Nmax obtained for • Feldman-Cousins • approach • Calculations for • homogeneous cube kn (GeV-1 cm-2 s-1sr-1) E > Emin (GeV) CPPM, Marseille, 25/10/2006
Sensitivity to Point Sources • Sensitivity for • kn E-G • point sources: • DW(En) g • Emin > 1 TeV • KM3NeT sensitivity • (90% c.l.) for point • sources vs. G , • in the absence • of atm-n background E> 1 TeV kn (GeV -1 cm-2 s-1) ANTARES KM3NeT power Index (G) CPPM, Marseille, 25/10/2006
Sensitivity to H.E.S.S. Sources • KM3NeT sensitivity (90% c.l.) for point sources in the absence of atm-n background. and spectral parameters of 26 H.E.S.S. sources from A.Kappes et al., astro-ph/0607286 • - visibility factor for the source is included. E> 1 TeV ANTARES knx 10 -12 ( TeV -1 cm-2 s-1) KM3NeT (•) H.E.S.S. sources power Index (G) CPPM, Marseille, 25/10/2006
Summary and Outlook • Simple model for KM3NeT sensitivity considered Very preliminary ! • 90% c.l. upper limits for diffuse neutrino flux estimated for for different KM3NeT detectors in the simple cases. - upper limit for point like sources compared to potential neutrino fluxes from Galactic H.E.S.S. sources • Next steps: - Sensitivity study for selected KM3NeT detectors, with selected (benchmark) atm-n background flux. - Comparison with other MC studies. CPPM, Marseille, 25/10/2006