Astrophysical neutrinos at Hyper-Kamiokande Topics in Astroparticle - PowerPoint PPT Presentation

Astrophysical neutrinos at Hyper-Kamiokande Topics in Astroparticle and Underground Physics 2019 Toyama, Japan 10 Sept. 2019 Takatomi Yano ICRR, University of Tokyo For Hyper-Kamiokande Proto Collaboration 1

50 kt / 22.5 kt Improved 0.26 Mt / 0.19Mt (Design Report) Total / Fiducial V. 40% detection) 40% (×2 efficient p.e. coverage Photocathode 11,129 / 1,885 40,000 / 6,700 (Design Report) No. of PMTs (ID/OD) Super-Kamiokande Hyper-Kamiokande Design photo-sensors Hyper-Kamiokande Project D:68m 42m Water Depth: 71 m Tot. Vol. 0.26Mt H: D:39m at 2027 . Tot.Vol. 0.05Mt Super-K Our observation will be started 2

Hyper-Kamiokande Project The property of neutrinos could be measured with the charged Improved “Real Time” and “Event by Event” measurement is possible. identified at each event, with charge and time of PMT hits. lepton generated by reactions in ultra pure water. photo-sensors Neutrino Charged particle Cherenkov light • e.g. : ν + e - → ν + e - . • The energy, position, direction and type of the particle can be • 3

Astrophysical Neutrino at HK Star formation history sis Nucleosynthe Extraordinary SN monitor SNe mechanism SN explosion modeling of the Sun SN relic ν Supernova ν Solar neutrino and DM annihilation, GRB ν (~GeV)… Target energy: ~O(10) MeV. kpc ~ Mpc Mpc ~ ~5μpc HK SN mechanism • Burning processes, • • Property of neutrino • • NASA, Chandra & Hubble 2007 • • wikimedia • NASA, Hubble 2009 4

Solar neutrino 14% bring out the solar center. emitting neutrinos. and CNO-cycle, reactions, i.e. pp-chain with nuclear fusion statistics is expected : pp-chain & ν Energy specturm 0.15% 99.85% -5 % “today’s” status of 2×10 85% 7 Li + p → 2 4 He 130 νev./day/tank , 7 Be + p → 8 B + γ E vis >4.5MeV (15 ν ev./day in SK-I ~ IV) 3 He + 4 He → 7 Be + γ Visible with 2 H + p → 3 He + γ Hyper-K information of • The Sun is burning p + p → 2 H + e + + ν e (99.75%) 7 Be + e - → 7 Li + ν e p + e - + p → 2 H + ν e (0.25%) 3 He + p → 4 He + e + + ν e 8 B → 8 Be * + e + + ν e 3 He + 3 He → 4 He + 2p 8 Be * → 2 4 He • Only neutrinos can • With Hyper-K , a large 5

Solar neutrino observation Day-Night asymmetry in SK neutrino analysis, comparing to [PRL 1212, 091805(2014)] matter effect is indicated by SK. solar ν caused by terrestrial Yearly ν variation & Sun spots (SK) reactor neutrino analysis (~2σ). particle physics and astrophysics • Importance of solar nu meas. in • Precision measurement, Δm 221 • Day/Night asymmetry • Solar nu spectrum up-turn • Discovery of Hep neutrino • Variation of solar ν flux Y. Nakano ICRC2015 6 • Nonzero D/N asymmetry of sin 2 θ 12 =0.314, sin 2 θ 13 =0.025 1 σ Solar 1 σ KamLAND expected SK-I,II,III,IV combined 1 σ range • The D/N asymmetry leads smaller Δm 221 value in solar PRL 112, 091805 (2014)

Precision oscillation measurement 10 years with 1 tank, 0.3% sys. Err. KamLAND best above 4σ. analysis, comparing to reactor neutrino analysis. (~2σ tension) • The D/N asymmetry leads smaller Δm 221 value in solar neutrino • With Hyper-K statistics, we can separate solar best Δm 221 and • → CPT violation test, difference between P νe -> νx and P νe -> νe . ∆χ 2 28 26 24 5 σ 22 20 18 ∆χ 2 8 → Precise Δm 221 also contributes to CPV test in HK long-baseline. 3 σ 16 4 σ 14 6 12 April 2018 (SK) 10 + HK 20years 4 8 2 σ 3 σ 6 2 4 2 σ 2 1 σ 1 σ 21 in 10 -5 eV 2 -5 ∆ m 2 in eV 2 2 ( Θ 12 )=0.316 +0.034 2 -5 eV 2 2 ( Θ 13 )=0.0219 ± 0.0014 x10 sin ∆ m 21 =(7.54 +0.19 -0.18 ) 10 sin sin 2 ( Θ 12 )=0.308 ± 0.013 ∆ m 2 -0.36 ) 10 -5 eV 2 sin 2 ( Θ 13 )=0.0219 ± 0.0014 21 =(4.85 +0.45 -0.026 2 ( Θ 12 )=0.310 ± 0.014 2 -5 eV 2 sin ∆ m 21 =(4.82 +1.20 -0.60 ) 10 18 2 ( Θ 12 )=0.310 ± 0.012 2 21 =(7.49 +0.19 -5 eV 2 sin ∆ m -0.17 ) 10 17 16 15 15 14 13 ∆ m 2 KamLAND 3σ 12 11 Combined 3σ 10 10 Reactor best Δm 2 9 8 7 6 5 5 4 3 2 Solar global 3 s Solar global + HK 20y 3σ Very Preliminary 1 1 σ 2 σ 3 σ 1 σ 2 σ 3 σ 4 σ 5 σ 0.1 0.2 0.3 0.4 0.5 2 4 6 8 0.1 0.2 0.3 0.4 0.5 2 4 6 810121416182022242628 7 sin 2 ( θ ) ∆χ 2 sin 2 ( θ 12 ) ∆χ 2

: 0.3% sys.err. - - - : 0.1% sys.err. KamLAND best Separation with Separation with non-D/N Precision oscillation measurement 10 years with 1 tank, 0.3% sys. Err. KamLAND best above 4σ. analysis, comparing to reactor neutrino analysis. (~2σ tension) • The D/N asymmetry leads smaller Δm 221 value in solar neutrino • With Hyper-K statistics, we can separate solar best Δm 221 and • → CPT violation test, difference between P νe -> νx and P νe -> νe . ∆χ 2 8 → Precise Δm 221 also contributes to CPV test in HK long-baseline. 3 σ 6 April 2018 (SK) Δm 2 separation w/ HK 4 2 σ 2 1 σ 21 in 10 -5 eV 2 2 ( Θ 12 )=0.316 +0.034 2 -5 eV 2 2 ( Θ 13 )=0.0219 ± 0.0014 sin ∆ m 21 =(7.54 +0.19 -0.18 ) 10 sin -0.026 Sensitivity (sigma) 2 ( Θ 12 )=0.310 ± 0.014 2 -5 eV 2 sin ∆ m 21 =(4.82 +1.20 -0.60 ) 10 2 ( Θ 12 )=0.310 ± 0.012 21 =(7.49 +0.19 2 -5 eV 2 sin ∆ m -0.17 ) 10 10 15 8 ∆ m 2 KamLAND 3σ Combined 3σ 10 6 4 5 2 Solar global 3 s Very Preliminary 1 σ 2 σ 3 σ 0.1 0.2 0.3 0.4 0.5 2 4 6 8 0 8 0 2 4 6 8 10 12 14 16 18 20 sin 2 ( θ 12 ) ∆χ 2 Year

8 B and Hep nu spectrum, HK 10 years Other solar ν topics & software Optimization of Detector Hyper-K 4.5 (3.5) MeV threshold, 10y up-trun with ~3(4)σ . sterile neutrinos … → Non-standard interaction, oscillation, or to search new Energy spectrum up-turn → To test the solar models. chance to discover. with small branching ratio. Hep process neutrino physics beyond the SM. Solar 8B + hep spectrum, HK 10 years, 73% signal eff. Solar 8B + hep spectrum, HK 10 years, 73% signal eff. 5 10 Number of events / 0.5 MeV 8B+hep (BP2004 SSM) • Undiscovered solar neutrino, only 8B 4 10 Data points w/ stat. err. (sqrt(N)) 3 10 • With Hyper-K 10 years, there is 2 10 10 • 1 • 1.8 ~ 3 σ , 10y - 1 10 - 2 10 10 12 14 16 18 20 22 24 E [MeV] visible Maltoni et al. Arxiv:1507.05287 • Verification of neutrino 0.8 8 B) Brx (pp) 7 Be) Brx (pep) Borexino ( Super-K 0.7 KL ( SNO 0.6 ee 〉 = Φ CC / Φ NC pp 0.5 7 Be) Brx ( 0.4 • Separable w/ up-turn from w/o 〈 P 0.3 Standard NSI-up 0.2 • Sterile NSI-dw 9 0.1 0.1 0.5 1 2 3 5 7 10 14 E ν [MeV]

10kpc Neutrino Physics Core collapse supernova emits all kinds of neutrinos. Supernova Neutrino 11 neutrino events by Kamiokande from SN1987A at 50kpc (LMC). gamma-ray, X-ray, telescope… 50 ~ 80k events/tank are expected in HK from SN at 10kpc (galactic center). Physics Motivation Multi-messenger analysis Core collapse SN physics Betelgeuse Galactic Antares center LMC M31 10 9 events/0.22Mega-ton 10 8 10 7 10 6 • – ν 10 5 e +p ν +e - 10 4 – 10 3 ν e + 16 O ν e + 16 O 10 2 • 10 1 -1 2 3 10 1 10 10 10 distance(kpc) events/0.22Mt/20msec Nakazato et al. (2015),1D,30M,BH • Nakazato et al. (2015),1D,20M 3000 Takiwaki et al. (2014),3D,11.2M Bruenn et al. (2016),2D,20M Dolence et al. (2015),2D,20M – Explosion mechanism 2500 Pan et al. (2016),2D,21M Tamborra et al. (2014),3D,27M Totani et al. (1998),1D,20M – Proto-neutron star formation 2000 – Black hole formation 1500 • 1000 • 500 – With gravitational wave, 0 10 0 0.05 0.1 0.15 0.2 0.25 0.3 Time (sec)

SASI model, 10kpc (SASI/Rotation/Convection) BH formation Dim SN Features Proving dim supernova/BH formation Investigation of the SN mechanism Energy spectrum measurement Precise SN neutrino time profile nu Flux from I. Tamborra PRL 111, 121104 (2013) 150 Counts / 0.22 Mt / 2 ms • 100 • – 50 • 0 0 100 200 300 400 500 Time [ ms ] Horiuchi et al. AstroP.J769,113 (2013) Sekiguchi ApJ, 737.6.2 (2011) 11

Supernova Relic Neutrino 1 Billion years from Bigbang 14 Billion years from Bigbang is diffused neutrinos coming from all past supernovae. source of extra-galactic neutrino. • Supernova Relic Neutrino (SRN) • Not discovered but promising 12

measurement of SRN. Physics of SRN discovery and aim to We will go beyond the Factor ~2 discrepancy between rates of formations and SNe. It is > 4σ for SRN signal. burst neutrinos 10y with ~70±17 events. Temperature inside the SN SRN can be observed by HK in SRN with Hyper-K BH formation, dim supernova SRN with HK 25 Events/MeV/0.187Mt/10y SRN 4MeV 100% SRN 4MeV 70% + BH 30% SRN 6MeV 100% 20 SRN 6MeV 70% + BH 30% Horiuchi (2009, 2017) • Test of star formation rate 15 Energy spectrums – with BH formation 10 • Energy spectrum of supernova 5 – • Extraordinary SN 0 0 5 10 15 20 25 30 35 40 45 50 E [MeV] vis – Events/2MeV/0.187Mton/10years 60 SRN+B.G.(inv.mu 1/5) 50 • 40 spallation B.G. • 30 total B.G. • ) 5 20 / 1 ( u m . v n i – 10 atmsph. ν e 0 10 15 20 25 30 35 40 45 50 Energy (MeV)