Introduction Solar neutrinos and oscillation theory The SNO experiment SNO physics results Summary + Outlook Neutrino Oscillations - Solar Neutrinos Nobel Prizes in Particle Physics Philipp Kühnl 12.02.2016 Introduction Solar neutrinos and oscillation theory The SNO experiment SNO physics results Summary + Outlook The solar neutrino problem Homestake experiment (1970-’94) Goal: Measure solar neutrino flux. Figure: Construction in Figure: Raymond Davis Jr, 1966.[5] 1978.[5] Results: flux roughly 1/3 of theory prediction. )Either solar model way different, or ν must have oscillated/decayed. Remark: after SNO results, Nobel prize for Davis in 2002. Introduction Solar neutrinos and oscillation theory The SNO experiment SNO physics results Summary + Outlook The solar neutrino problem Homestake experiment Detecting neutrinos via the reaction 37 37 − νe + Cl ! Ar + e (−0:814 MeV). Extraction of Argon, radioactive isotope !number of ν )Either solar model way different, or ν must have oscillated/decayed. Remark: after SNO results, Nobel prize for Davis in 2002. Introduction Solar neutrinos and oscillation theory The SNO experiment SNO physics results Summary + Outlook The solar neutrino problem Homestake experiment Detecting neutrinos via the reaction 37 37 − νe + Cl ! Ar + e (−0:814 MeV). Extraction of Argon, radioactive isotope !number of ν Results: flux roughly 1/3 of theory prediction. Remark: after SNO results, Nobel prize for Davis in 2002. Introduction Solar neutrinos and oscillation theory The SNO experiment SNO physics results Summary + Outlook The solar neutrino problem Homestake experiment Detecting neutrinos via the reaction 37 37 − νe + Cl ! Ar + e (−0:814 MeV). Extraction of Argon, radioactive isotope !number of ν Results: flux roughly 1/3 of theory prediction. )Either solar model way different, or ν must have oscillated/decayed. Introduction Solar neutrinos and oscillation theory The SNO experiment SNO physics results Summary + Outlook The solar neutrino problem Homestake experiment Detecting neutrinos via the reaction 37 37 − νe + Cl ! Ar + e (−0:814 MeV). Extraction of Argon, radioactive isotope !number of ν Results: flux roughly 1/3 of theory prediction. )Either solar model way different, or ν must have oscillated/decayed. Remark: after SNO results, Nobel prize for Davis in 2002. Introduction Solar neutrinos and oscillation theory The SNO experiment SNO physics results Summary + Outlook Outline 1 Solar neutrinos and oscillation theory 2 The SNO experiment 3 SNO physics results 4 Summary + Outlook Introduction Solar neutrinos and oscillation theory The SNO experiment SNO physics results Summary + Outlook Outline 1 Solar neutrinos and oscillation theory 2 The SNO experiment 3 SNO physics results 4 Summary + Outlook Introduction Solar neutrinos and oscillation theory The SNO experiment SNO physics results Summary + Outlook Outline 1 Solar neutrinos and oscillation theory 2 The SNO experiment 3 SNO physics results 4 Summary + Outlook Introduction Solar neutrinos and oscillation theory The SNO experiment SNO physics results Summary + Outlook Outline 1 Solar neutrinos and oscillation theory 2 The SNO experiment 3 SNO physics results 4 Summary + Outlook Introduction Solar neutrinos and oscillation theory The SNO experiment SNO physics results Summary + Outlook Standard Solar Model (SSM) Neutrino production via pp-chain and CNO cycle. + p + p ! d + e + νe d + p ! 3He + γ 3He +4He ! 7Be + γ 7Be + p ! 8B + γ 8 8 ∗ + B ! Be + e + νe Summary: 4p + 2e− ! 4 He + 2νe(+26:731 MeV) Figure: Solar neutrino spectrum.[2] νe = Ue1ν1 + Ue2ν2 + Ue3ν3 only if non-zero masses: −iE1t −iE2t −iE3t νe = Ue1ν1e + Ue2ν2e + Ue3ν3e Introduction Solar neutrinos and oscillation theory The SNO experiment SNO physics results Summary + Outlook Mixing of neutrinos UPMNS: Pontecorvo-Maki-Nakagawa-Sakata matrix UPMNS can be parametrized by 3 mixing angles and 1 CP-violating phase. only if non-zero masses: −iE1t −iE2t −iE3t νe = Ue1ν1e + Ue2ν2e + Ue3ν3e Introduction Solar neutrinos and oscillation theory The SNO experiment SNO physics results Summary + Outlook Mixing of neutrinos UPMNS: Pontecorvo-Maki-Nakagawa-Sakata matrix UPMNS can be parametrized by 3 mixing angles and 1 CP-violating phase. νe = Ue1ν1 + Ue2ν2 + Ue3ν3 Introduction Solar neutrinos and oscillation theory The SNO experiment SNO physics results Summary + Outlook Mixing of neutrinos UPMNS: Pontecorvo-Maki-Nakagawa-Sakata matrix UPMNS can be parametrized by 3 mixing angles and 1 CP-violating phase. νe = Ue1ν1 + Ue2ν2 + Ue3ν3 only if non-zero masses: −iE1t −iE2t −iE3t νe = Ue1ν1e + Ue2ν2e + Ue3ν3e In matter, modified by Mikheev-Smirnov-Wolfenstein (MSW) effect: ∆m2 x (ν ! ν ) = 2(2θ ) · 2( M ) P i j sin M sin 4E with 2 2(2θ ) = sin (2θ) sin M sin2(2θ)+(cos(2θ)−x)2 , ∆ 2 = ∆ 2p 2(2θ) + ( (2θ) − )2 mMp m sin cos x , = 2 2GF Ne E x ∆m2 . For x = cos 2θ amplitude of 1, resonant behaviour. Introduction Solar neutrinos and oscillation theory The SNO experiment SNO physics results Summary + Outlook Oscillations in matter In vacuum (simplified for 2 flavors): 2 (ν ! ν ) = 2(2θ) · 2( ∆m L ) P i j sin sin 4E (∆m in eV 2, L in km, E in GeV) For x = cos 2θ amplitude of 1, resonant behaviour. Introduction Solar neutrinos and oscillation theory The SNO experiment SNO physics results Summary + Outlook Oscillations in matter In vacuum (simplified for 2 flavors): 2 (ν ! ν ) = 2(2θ) · 2( ∆m L ) P i j sin sin 4E (∆m in eV 2, L in km, E in GeV) In matter, modified by Mikheev-Smirnov-Wolfenstein (MSW) effect: ∆m2 x (ν ! ν ) = 2(2θ ) · 2( M ) P i j sin M sin 4E with 2 2(2θ ) = sin (2θ) sin M sin2(2θ)+(cos(2θ)−x)2 , ∆ 2 = ∆ 2p 2(2θ) + ( (2θ) − )2 mMp m sin cos x , = 2 2GF Ne E x ∆m2 . Introduction Solar neutrinos and oscillation theory The SNO experiment SNO physics results Summary + Outlook Oscillations in matter In vacuum (simplified for 2 flavors): 2 (ν ! ν ) = 2(2θ) · 2( ∆m L ) P i j sin sin 4E (∆m in eV 2, L in km, E in GeV) In matter, modified by Mikheev-Smirnov-Wolfenstein (MSW) effect: ∆m2 x (ν ! ν ) = 2(2θ ) · 2( M ) P i j sin M sin 4E with 2 2(2θ ) = sin (2θ) sin M sin2(2θ)+(cos(2θ)−x)2 , ∆ 2 = ∆ 2p 2(2θ) + ( (2θ) − )2 mMp m sin cos x , = 2 2GF Ne E x ∆m2 . For x = cos 2θ amplitude of 1, resonant behaviour. Introduction Solar neutrinos and oscillation theory The SNO experiment SNO physics results Summary + Outlook Arthur B. McDonald born 1943 in Sydney, Canada, BSc and MSc at Dalhousie University, Halifax (1964/65), PhD at CALTECH (1969) Professor at Princeton, later Queen’s University Director of SNO Collaboration (since 1989) Director of SNO Institute Figure: A.B. McDonald, (1991-2003, 2006-2009) Stockholm, Dec 2015 Nobel Prize in 2015. Neutral current (NC): νi + d ! p + n + νi (−2:22MeV) S: to all νi . D: produces free neutron, capture by deuterium emits γ Introduction Solar neutrinos and oscillation theory The SNO experiment SNO physics results Summary + Outlook Detection of solar neutrinos Charged current (CC) reaction: − νe + d ! p + p + e (−1:44 MeV) Sensitivity: only to νe. Detection: e− produces Cherenkov radiation. Introduction Solar neutrinos and oscillation theory The SNO experiment SNO physics results Summary + Outlook Detection of solar neutrinos Charged current (CC) reaction: − νe + d ! p + p + e (−1:44 MeV) Sensitivity: only to νe. Detection: e− produces Cherenkov radiation. Neutral current (NC): νi + d ! p + n + νi (−2:22MeV) S: to all νi . D: produces free neutron, capture by deuterium emits γ Introduction Solar neutrinos and oscillation theory The SNO experiment SNO physics results Summary + Outlook Detection of solar neutrinos Elastic scattering (ES): − − νi + e ! νi + e S: in general to all νi , but larger cross section for νe. D: direction of e− close to incoming ν, use as check for sun as source. Introduction Solar neutrinos and oscillation theory The SNO experiment SNO physics results Summary + Outlook The Sudbury Neutrino Observatory Detector design acrylic sphere (r = 6m) filled with 1000t of heavy water, rest of cavity filled with ultrapure light water, support structure holding the PMTs Figure: Schematic view of the detector. [3] Introduction Solar neutrinos and oscillation theory The SNO experiment SNO physics results Summary + Outlook The Sudbury Neutrino Observatory Signal detection Cherenkov light collected with 9400 Photomultiplier tubes, covering an effective area of 54%. Figure: Left: Look at PMT’s from inside the sphere, right: outside support structure [6]. Introduction Solar neutrinos and oscillation theory The SNO experiment SNO physics results Summary + Outlook The Sudbury Neutrino Observatory Experimental challenges Main challenge: exclusion of radioactive background. ! Need for ultra pure water, careful material choices. Shielding from environmental radioactivity tested by deploying source near to active volume. )total radioactivity contribution < 0:2% (low energy bgr), < 0:8% (high energy bgr) Figure: Radiation backgrounds from U and Th.[2] fiducial volume cut: Threshold Teff ≥ 6:75 MeV. Figure: Radial event rate [2]. Introduction Solar neutrinos and oscillation theory The SNO experiment SNO physics results Summary + Outlook Data reduction Phase 1, first analysis published 13.08.2001 [1], data corresponding to live time of 241 days, initially 355 Mio. total event triggers, application of several cuts and triggers to reduce instrumental noise, require Nhit ≥ 30 (PMT), Threshold Teff ≥ 6:75 MeV. Introduction Solar neutrinos and oscillation theory The SNO experiment SNO physics results Summary + Outlook Data reduction Phase 1, first analysis fiducial volume cut: published 13.08.2001 [1], data corresponding to live time of 241 days, initially 355 Mio. total event triggers, application of several cuts and triggers to reduce instrumental noise, require Nhit ≥ 30 (PMT), Figure: Radial event rate [2]. Introduction Solar neutrinos and oscillation theory The SNO experiment SNO physics results Summary + Outlook Data reduction Phase 1, first analysis fiducial volume cut: published 13.08.2001 [1], data corresponding to live time of 241 days, initially 355 Mio.