The IceCube IceCube The Neutrino Telescope Neutrino Telescope K. Mase , Chiba univ. K. Mase , Chiba univ.
The IceCube Collaboration 34 institutes and >200 physists Bartol Research Inst, Univ. of Delaware, USA Univ. of Alabama, USA Bartol Research Inst, Univ. of Delaware, USA Univ. of Alabama, USA Clark-Atlanta University, USA Pennsylvania State University, USA Clark-Atlanta University, USA Pennsylvania State University, USA Univ. of Wisconsin-Madison, USA Univ. of Maryland, USA Univ. of Wisconsin-Madison, USA Univ. of Maryland, USA Univ. of Wisconsin-River Falls, USA IAS, Princeton, USA Univ. of Wisconsin-River Falls, USA IAS, Princeton, USA LBNL, Berkeley, USA University of Kansas, USA LBNL, Berkeley, USA University of Kansas, USA UC Berkeley, USA Southern Univ. and A&M College, USA UC Berkeley, USA Southern Univ. and A&M College, USA UC Irvine, USA Univ. of Alaska Anchorage, USA UC Irvine, USA Univ. of Alaska Anchorage, USA Chiba Univ., Japan Chiba Univ., Japan Univ. of Canterbury, New Zealand Univ. of Canterbury, New Zealand Univ. Libre de Bruxelles, Belgium Univ. Dortmund, Germany Univ. Libre de Bruxelles, Belgium Univ. Dortmund, Germany Vrije Univ. Brussel, Belgium MPI für Kernphysik, Germany Vrije Univ. Brussel, Belgium MPI für Kernphysik, Germany Univ. de Mons-Hainaut, Belgium Uppsala Universitet, Sweden Univ. de Mons-Hainaut, Belgium Uppsala Universitet, Sweden Univ. of Gent, Belgium Stockholm universitet, Sweden Univ. of Gent, Belgium Stockholm universitet, Sweden Univ., Mainz, Germany Kalmar Universitet, Sweden Univ., Mainz, Germany Kalmar Universitet, Sweden DESY-Zeuthen, Germany Imperial College, London, UK DESY-Zeuthen, Germany Imperial College, London, UK Univ. Wuppertal, Germany University of Oxford, UK Univ. Wuppertal, Germany University of Oxford, UK RWTH Aachen Univ., Germany Utrecht University, Utrecht, NL RWTH Aachen Univ., Germany Utrecht University, Utrecht, NL Humboldt Univ. zu Berlin, Germany Ècole Polytechnique Fèdèrale, Switzerland Humboldt Univ. zu Berlin, Germany Ècole Polytechnique Fèdèrale, Switzerland DBD07 (2007, 12th, June) K. Mase
■ The south pole The south pole ■ South pole IceCube AMANDA AMANDA 1 km DBD07 (2007, 12th, June) K. Mase
■ The IceCube experiment The IceCube experiment ■ � to detect VHE neutrinos from astrophysical sources ~1 km � deployed in the Antarctica glacier IceTop � >70 strings � >4200 photo-multiplier tubes (PMTs) � Detector volume: 〜 1km 3 � ATWD 300MHz, effectively 16 bits � 3 different gains (x16, x2, x0.25) AMANDA-II IceCube � 10 bits FADC for long duration pulse � Neutrino energy of above 100 GeV is detectable. � 22 strings are deployed so far, and taking data as the biggest neutrino detector. ��� 〜 1 km 〜 〜 〜 �������� ������������� ������������� ����������� ���������� 1km 3 ����������� ����������� DBD07 (2007, 12th, June) K. Mase
■ The detection principle The detection principle ■ Cherenkov light muon interaction � A large volume A large volume � neutrino � transparent medium transparent medium � → Antarctica glacier Antarctica glacier → DBD07 (2007, 12th, June) K. Mase
■ Particle identification Particle identification ■ e e τ τ μ μ Particle identification possible from the shape Particle identification possible from the shape DBD07 (2007, 12th, June) K. Mase
■ The deployment The deployment ■ 22 strings deployed! DBD07 (2007, 12th, June) K. Mase
■ The The perfomance perfomance ■ 1 p.e. distribution Gain check Time resolution Multiplicity distribution ~1 ns A. Achterberg et al., Astropart. Phys., 26, 3, 155-173 (2006) The IceCube detectors are working as expected. The IceCube detectors are working as expected. DBD07 (2007, 12th, June) K. Mase
■ The physics of IceCube The physics of IceCube ■ � �#$� �#$� � � Dark Matter Dark Matter � � Cosmic ray origin � �� � �� � � � Extremely high energy (EHE) neutrinos GZK, Z-burst, TDs � !������"� !������"� � DBD07 (2007, 12th, June) K. Mase
■ Point source search by AMANDA II Point source search by AMANDA II ■ Unfortunately, no signal so far… … Unfortunately, no signal so far 2000-2004 (1001 days) Search for clustering in northern hemisphere 4282 ν ν from northern hemisphere ν ν • compare significance of local fluctuation to atmospheric ν ν expectations 4600 ν ν expected from atmosphere ν ν ν ν Random events 2000-2004 Maximum significance 3.7 σ σ σ σ compatible with atmospheric ν ν ν ν A. Achteberg Achteberg et al., Phys. Rev. D, 75, 102001 (2007) et al., Phys. Rev. D, 75, 102001 (2007) A. DBD07 (2007, 12th, June) K. Mase
■ Diffuse neutrinos Diffuse neutrinos ■ Even though we can’ Even though we can ’t t resolve signals from each resolve signals from each source, we can integral source, we can integral signals in all sky and should signals in all sky and should see some excess. see some excess. 2000-2004 AMANDA- -II (2000 II (2000- -3) 3) AMANDA But, no excess so far But, no excess so far W&B limit W&B limit Full IceCube (1yr) Full IceCube (1yr) A. Achteberg Achteberg et al., et al., astro astro- -ph ph 0705.1315 (2007) 0705.1315 (2007) A. DBD07 (2007, 12th, June) K. Mase
� WIMP Search χ 1 0 Neutralino scatters and loses energy Becomes trapped in gravity well Annihilates to pairs of SM particles SM particles decay producing ν τ→µν τ ν µ 0 + χ 1 χ 1 0 → τ + τ - ν χ 1 0 + χ 1 0 → l + l - ,qq,W + W - ,Z 0 Z 0 χ 1 0 + χ 1 0 → H 0 1,2 H 0 3 ,Z 0 H 0 1,2 ,W + H - ,W - H + DBD07 (2007, 12th, June) K. Mase
� WIMP Search Limits AMANDA limit AMANDA limit AMANDA limit AMANDA limit IceCube Best Case DBD07 (2007, 12th, June) K. Mase
■ The extremely high energy The extremely high energy ■ 7 GeV) (EHE) neutrinos (>10 7 GeV) (EHE) neutrinos (>10 GZK neutrinos as GZK neutrinos as a benchmark a benchmark The origin of the EHECRs: The origin of the EHECRs: � Bottom up model Bottom up model (AGNs, GRBs (AGNs, GRBs… …) ) � � Top down model Top down model (super heavy (super heavy � particles, cosmic strings… …) ) particles, cosmic strings � Z Z- -bursts bursts � t e → In either case, neutrinos In either case, neutrinos → → → n → → → → t a t We test We test GZK (p+ GZK (p+ γ→ γ→ N+ N+ π π ): ): i v e conventional conventional a t m µ µ µ µ GZK: S. Yoshida et. al. (1997) GZK: S. Yoshida et. al. (1997) ApJ ApJ 479:547, 479:547, TD: Sigl Sigl et. al.(1999), et. al.(1999), n n UHE n 2K : S.Yoshida et al.(1998), TD: UHE n 2K : S.Yoshida et al.(1998), DBD07 (2007, 12th, June) K. Mase
■ How to detect EHE neutrinos How to detect EHE neutrinos ■ �� �� ���������� µ ��� ν ν ν ν ν ��� ν ν ν Earth is opaque for EHE µ � neutrinos. (The cross section µ,τ µ,τ µ,τ µ,τ increase lineally with the energy.) µ,τ µ,τ µ,τ µ,τ µ µ µ µ Therefore, EHE neutrinos � τ τ τ τ come from above horizontal. τ τ τ τ GZK signal Atmo. . μ GZK signal Atmo μ ν τ ν ν ν τ τ τ θ cos θ θ cos θ cos ν ν τ ν ν ν ν ν ν cos τ τ τ τ τ τ τ ν µ ν ����� ν ν ν ν ν ν µ ����� < 1PeV ν μ μ < 1PeV ν ��� �� ������ ����� µ µ µ µ µ µ µ µ µ µ Total Npe Total Npe Total Npe Total Npe A. Ishihara, astro- A. Ishihara, astro -ph/0611794 ph/0611794 DBD07 (2007, 12th, June) K. Mase
■ The event rate (MC study) The event rate (MC study) ■ IceCube Preliminary GZK µ Atmospheric µ GZK τ µ µ µ µ µ µ τ τ τ Rate [/year] string string string string numbers numbers numbers numbers 9 9 9 9 20 20 20 20 40 40 40 40 60 60 60 60 80 80 80 80 10 7 10 9 10 7 10 9 [GeV] [GeV] event rate (integrated) GZK µ µ µ µ 0.3 event/year 0.3 event/year GZK τ τ τ τ Atmospheric µ µ µ µ The same cut for all string 9 Strings 9 Strings 9 Strings 9 Strings 9 Strings 9 Strings 9 Strings 9 Strings 80 Strings 80 Strings 80 Strings 80 Strings 80 Strings 80 Strings 80 Strings 80 Strings numbers DBD07 (2007, 12th, June) K. Mase
■ EHE analysis 2006 with 9 strings EHE analysis 2006 with 9 strings ■ � Live time ~ 124 days � Npe based study � The signal region (Npe>10 5 ) is blinded � The backgrounds agree well with the MC Data Data � The signal region will be Model 1 Model 1 unblinded soon Model 2 Model 2 The expected rate (/124 days) The expected rate (/124 days) in the signal region in the signal region GZK μ + τ 0.027 GZK ν μ + ν τ 0.024 Atmospheric μ <10 -4 DBD07 (2007, 12th, June) K. Mase
■ The sensitivity with 9 strings The sensitivity with 9 strings ■ If there is no signal If there is no signal The sensitivity becomes better as the string number increases. The sensitivity becomes better as the string number increases. DBD07 (2007, 12th, June) K. Mase
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