A brief overview of neutrino oscillaon results and future prospects Trevor Stewart On behalf of the T2K collaboraon Rutherford Appleton Laboratory ICNFP 2016 01/01/2015 Trevor Stewart, RAL 1 The Nobel Prize in Physics 2015 Takaaki Kajita, Arthur B. McDonald “for the discovery of neutrino oscillaons, which shows that neutrinos have mass" 06/07/2016 Trevor Stewart, RAL 2 Intoduc2on • This talk will discuss recent neutrino oscillaon results and how they contribute to our overall understanding of the physics of neutrinos • Will present results from current experiments such as T2K, NOνA, Daya Bay, RENO, and Double Chooz • Discuss future experiments such as Hyper- Kamiokande, DUNE, and JUNO • If I do not men2on your favourite experiment then please forgive me, it is for the sake of brevity 01/01/2015 Trevor Stewart, RAL 3 Two-flavour neutrino oscillaons ⌫ cos✓ sin✓ ⌫ • e = 1 Two sets of eigenstates for ⌫µ sin✓ cos✓ ⌫2 neutrinos ✓ ◆ ✓− ◆✓ 2 ◆ - Flavour states which 2 2 ⎛ Δm L ⎞ P(ν →ν ) = sin (2θ )sin ⎜ ⎟ interact µ e ⎜ 4E ⎟ ∆m2 = m2 m2 ⎝ ⎠ - Mass states which 2 − 1 propagate ⌫µ ⌫1, ⌫2 ⌫µ or ⌫e • Measure • Result probabili2es – Mixing angle(s) – Disappearance – Mass differences – Appearance 01/01/2015 Trevor Stewart, RAL 4 The Pontecorvo-Maki-Nakagawa-Sakata (PMNS) mixing matrix ⌫e ⌫1 • Unfortunately things are not as ⌫ = U ⌫ 0 µ1 0 21 simple as the 2-flavour mixing ⌫⌧ ⌫3 shown on the previous slide @ A @ A • 3-flavour mixing Flavour eigenstates Mass eigenstates - Three independent mixing (coupling to the W, Z) (definite masses) angles and CP violang phase iδ 10 0 cos✓13 0 sin✓13e− cos✓12 sin✓12 0 10 0 U = 0 cos✓ sin✓ 010 sin✓ cos✓ 0 0 eiδ2 0 0 23 23 1 0 1 0− 12 12 1 0 1 0 sin✓ cos✓ sin✓ eiδ 0 cos✓ 00100eiδ3 − 23 23 − 13 13 @ A @ A @ A @ A Appearance Solar neutrino Neutrino-less Reactor measurements Atmospheric and long- measurements double beta baseline disappearance disappearance decay measurements measurements 01/01/2015 Trevor Stewart, RAL 5 Open quesons o • Is θ23 = 45 ? Which octant? • The large value of θ13 allows for large CP-violaon effects - what is δCP? • Oscillaon experiments can only probe the squared differences between the neutrino masses: - m2 > m1 - Sll unknown if m3 > m2 m3 > m2: normal hierarchy m2 > m3: inverted hierarchy • Precision tests of the PMNS framework are s2ll needed 06/07/2016 Trevor Stewart, RAL 6 Accelerator measurements 06/07/2016 Trevor Stewart, RAL 7 Oscillaon probabili2es νμ disappearance ∆m2 L P (⌫ ⌫ ) 1 (cos4✓ sin22✓ +sin2✓ sin22✓ )sin2 31 µ ! µ ⇡ − 13 23 23 13 4E νe appearance 2 2 2 2 2 2 ∆m31L sin2✓12sin2✓23 2 ∆m21L 2 2 ∆m31L P (⌫µ ⌫e) sin 2✓13sin ✓23sin sin sin 2✓13sin sinδCP ! ⇡ 4E − 2sin✓13 4E 4E • νμ disappearance: Sensi2ve to θ23 and o o its octant (θ23 > 45 ? or θ23 < 45 ) PDG 2014 • ν appearance: Sensi2ve to θ and δ e 13 CP o θ23 = 45.8 ± 3.2 • Dependence on L/E (distance o θ12 = 33.4 ± 0.85 travelled/Energy of neutrino) o θ13 = 8.88 ± 0.39 2 -5 2 Δm 21 = (7.53 ± 0.18) x 10 eV 2 -3 2 |Δm 32| = (2.44 ± 0.06) x 10 eV 06/07/2016 Trevor Stewart, RAL 8 The T2K experiment Started collec2ng data in 2010 Increasing beam power: currently stable running achieved at 420 kW νe, νμ νμ, Long-baseline neutrino ντ oscillaon experiment Primarily studies νμ ND280 +INGRID disappearance and νμèνe appearance to measure 2 θ13, θ23 (and its octant), Δm 32 and δcp 06/07/2016 Trevor Stewart, RAL 9 NOνA experiment • Like T2K, a long- baseline neutrino oscillaon experiment – Similari2es and differences described on next slide • Star2ng taking physics data in 2014 • Func2onally iden2cal near and far detectors 01/01/2015 Trevor Stewart, RAL 10 T2K and NOνA Off-axis beam allows one to have a larger flux at the energy where oscillaons to electron neutrinos are expected to be at maximum Narrowness of the beam aids in rejec2ng π0 background and νe contaminaon of the νμ beam T2K NOνA 01/01/2015 Trevor Stewart, RAL 11 T2K beam 2011 2012 2013 2014 2015 2016 27 May 2016 !-mode POT: 7.57×1020 (50.14%) POT total: 1.510×1021 !-mode POT: 7.53×1020 (49.86%) • First data useable for physics analysis in 2010 • Steady rise in beam power from • Run 1 ≈ 50 kW • Run 7 420 kW • Total of 15.1 x 1020 POT (protons on target) accumulated by 27 May 2016 06/07/2016 Trevor Stewart, RAL 12 T2K beam See Andrea Longhin2011 2012 talk 2013Recent results 2014 2015 2016 from the T2K experiment 27 May 2016 !-mode POT: 7.57×1020 (50.14%) th POT total: 1.510×1021 !-mode POT: 7.53×1020 (49.86%) • First data useable for physics analysis in 2010 July 13 @ 09:00 for more details • Steady rise in beam power from • Run 1 ≈ 50 kW • Run 7 420 kW • Total of 15.1 x 1020 POT (protons on target) accumulated by 27 May 2016 06/07/2016 Trevor Stewart, RAL 13 Where are we?: T2K 80 T2K Run17b preliminary Unoscillated 14 T2K Run17b preliminary Unoscillated Prediction Prediction 70 Events Best-Fit Events 12 Best-Fit 60 10 Data ⌫ Data 50 e New results, presented 8 40 ⌫ 6 30 µ 2 days ago at Neutrino 20 4 10 2 2016 0 0 o 4 -1 o 150 200 400 600 800 1000 1200 1400 103 1 Rati Rati 10 2 1 5 0 0 10-1 2×10-1 1 2 3 4 5 6 7 8 0 200 400 600 800 1000 1200 1400 Reconstructed Energy [GeV] Reconstructed Momentum [MeV/c] Muon neutrino disappearance 3.5 T2K Run17b preliminary Unoscillated T2K Run17b preliminary Unoscillated 25 Prediction 3 Prediction Events Best-Fit Events Best-Fit observed in both 20 2.5 Data Data 2 ⌫¯ 15 e neutrino and an2- ⌫¯ 1.5 10 µ 1 neutrino beams 5 0.5 0 0 o 4 o -1 80 200 400 600 800 1000 1200 1400 103 1 Rati Rati 6 2 4 1 2 An2-electron neutrino 0 0 10-1 2×10-1 1 2 3 4 5 6 7 8 0 200 400 600 800 1000 1200 1400 Reconstructed Energy [MeV] Reconstructed Momentum [MeV/c] appearance (4 events) How about measurements of the oscillaon parameters? 06/07/2016 Trevor Stewart, RAL 14 Oscillaon measurements: T2K 3 25 T2K Run1-7b preliminary T2K Run1-7b preliminary -2lnL 2 68%CL (-2ln L = 2.3) 20 (radians) Normal Hierarchy 90%CL (-2ln Lcrit = 4.61) CP T2K only crit δ 1 Best-fit Inverted Hierarchy PDG 2015 15 0 Normal Hierarchy 10 -1 Inverted Hierarchy -2 5 Fixed Mass Hierarchy -3 0 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.1 -3 -2 -1 0 1 2 3 2 (radians) sin θ13 δCP 3 T2K Run1-7b preliminary • δCP vs. θ13 (le) 2 T2K + reactor (radians) 68%CL (-2ln L = 2.3) • Data @ 90% CL CP θ13 crit δ 1 90%CL (-2ln L = 4.61) crit - δ = [-3.02, -0.49] for NH Best-fit CP 0 - δCP = [-1.87, -0.98] for IH Normal Hierarchy -1 Inverted Hierarchy -2 Fixed Mass Hierarchy -3 0.0160.018 0.02 0.0220.0240.0260.028 0.03 0.0320.0340.036 sin2 θ 06/07/2016 13 Trevor Stewart, RAL 15 Oscillaon measurements: T2K ) 3.6 4 /c 68%CL 2 3.4 90%CL Normal Hierarchy eV 3.2 T2K best-fit • Results consistent with -3 3 maximal mixing | (10 2 32 2.8 • 2016: m Δ | 2.6 - A new joint analysis using 2.4 neutrino and an2- 2.2 2 IceCube Super-K neutrino disappearance 1.8 T2K Run1-7b preliminary NOvA (2015) MINOS+ and appearance 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 0.7 measurements (lez) sin2 θ 23 01/01/2015 Trevor Stewart, RAL 16 NuMI beam • Data taken 6th Feb. 2014 to 2 May 2016 - 6.05 x 1020 POT • NuMI beamline provides neutrino beams to a number of different experiments • MINOS, MicroBooNE, ICARUS, SBND, MINERvA • Con2nuously increasing beam power - Currently operang at design power of 700 kW 01/01/2015 Trevor Stewart, RAL 17 Oscillaon measurements: NOνA νμ disappearance ν appearance • New results, presented 2 days ago at Neutrino e 2016 • νμ disappearance - Results already in good agreement with other oscillaon experiments - Maximal mixing excluded at 2.5σ • νe appearance - 33 events observed - >8σ significance 01/01/2015 Trevor Stewart, RAL 18 Reactor measurements 01/01/2015 Trevor Stewart, RAL 19 Reactor experiments • Nuclear reactors provide very intense sources of with a well understood spectrum ⌫¯e - @ 3 GW – 6 x 1020 ⌫¯e /s - Spectrum peaks at 3.7 MeV (low energy compared to accelerator experiments) - Energy not sufficient to create νμ or ντ • No appearance measurements, only νe disappearance - Not sensi2ve to δCP • Both reactor and accelerator measurements needed Look for small rate deviaon from 1/r2 measured at near and far detectors Will discuss results from 3 reactor neutrino experiments: Double Chooz RENO DAYA Bay 01/01/2015 Trevor Stewart, RAL 20 Measuring θ13 ∆m2 L ∆m2 L P (¯⌫ ⌫¯ ) 1 sin22✓ sin2 ee cos4✓ sin22✓ sin2 21 e ! e ⇡ − 13 4E − 13 12 4E ∆m2 = cos2✓ ∆m2 +sin2✓ ∆m2 | ee| 12| 31| 12| 32| Reactor oscillaMon experiments provide a straighOorward way to measure θ13 with no dependence on δCP or maer effects • θ13 measurements affect θ12, θ23, and δCP measurements at long-baseline accelerator experiments - Thus, the need to measure it as precisely as possible at reactor experiments 01/01/2015 Trevor Stewart, RAL 21 Current experiments Daya Bay @ Daya Bay, China Double Chooz @ Chooz, France RENO @ Yonggwang, Korea 01/01/2015 Trevor Stewart, RAL 22 θ13 Double Chooz Moriond 2016 2 2 Best-fit value for sin 2θ13 = 0.111 ± 0.018 (stat.