30 years after SN1987A M.Nakahata Kamioka Observatory, ICRR/IPMU, - PowerPoint PPT Presentation

30 years after SN1987A M.Nakahata Kamioka Observatory, ICRR/IPMU, ｔ he Univ. of Tokyo 2017/6/19 The 26th International Workshop on Weak Interactions and Neutrinos (WIN2017) 1 M. Nakahata: 30 years after SN1987A

30 th Anniversary of SN1987A Cake made for an anniversary held on Cake made by Kamioka local people Feb.12, 2017 at the Univ. of Tokyo on Feb.23, 2017 M. Nakahata: 30 years after SN1987A 2017/6/19 2

Contents  Why big underground detectors were made  Observed neutrino data of SN1987A  What we have learned from the observation  Supernova detectors in the world now  Supernova relic neutrinos  Future prospects 3 M. Nakahata: 30 years after SN1987A 2017/6/19

Prediction of GUTs in 1970’s Georgi and Glashow Proton decay was predicted. Expected number of proton decay events was 30 ~ 300 events/1000ton/year for 10 31 ~ 10 30 years of proton lifetime. P. Langacker, Phys. Rep. 72, No.4(1981) 185. 2017/6/19 M. Nakahata: 30 years after SN1987A 4

Large detectors were constructed in early 1980’s IMB (Irvine-Michigan-Brookhaven) KAMIOKANDE 2,140 ton water Cherenkov detector 880 ton fiducial volume • 7,000 ton water Cherenkov detector 1,000 20-inch PMTs • 3,300 ton fiducial volume Kamioka Mine (2700 m.w.e.) • 2,048 5-inch PMTs Started operation in 1983 • Morton-Thiokol salt(1570 m.w.e.) • Started operation in 1982 2017/6/19 M. Nakahata: 30 years after SN1987A 5

Led by F. Reines and M. Koshiba 2017/6/19 M. Nakahata: 30 years after SN1987A 6

However, proton decay was not observed. IMB group paper in 1983. 2017/6/19 M. Nakahata: 30 years after SN1987A 7

Upgrade to Kamiokande- ＩＩ (1984-1985) Thanks to large photo-coverage, it was found that the detector is sensitive to low energy events. So, the detector was upgraded for solar neutrinos.  Upgrade electronics for readout of timing information. It improved vertex reconstruction.  Made outer detector to shield external gamma rays 8

Upgrade of IMB detector Increased light collection efficiency in order to improve physics analysis. One of the main motivations was to improve the particle identification capability.  IMB-1: 5-inch PMT Photo-coverage(1.3%)  IMB-2: Added WLS plates for a factor of ~1.5 increase  IMB ‐ 3: In 1986 shut down to add 8-inch PMTs to bring coverage to effectively about 5%. Also added a WWVB clock to get IMB-3 detector absolute time to better than 50 milliseconds. 2017/6/19 M. Nakahata: 30 years after SN1987A 9

Kamiokande data 12 events within 13sec. 11 of them are higher energy events. Vertical axis: Number of hit PMTs for each event, at 7:35:35( ± 1min)(UT) on Feb.23, which is almost proportional to energy 1987 2017/6/19 M. Nakahata: 30 years after SN1987A 10

Kamiokande events From 7:35:35(UT)( ± 1min.) Feb.23, 1987 T=0 s T=0.303 s T=0.324 s T=0.107 s 20.0 MeV 7.5 MeV 9.2 MeV 13.5 MeV event #1 T=0.686 s T=1.541 s T=0.507 s T=1.728 s 6.3 MeV 35.4 MeV 12.8 MeV 21.0 MeV T=9.219 s T=12.439 s T=1.915 s T=10.433 s 8.6 MeV 8.9 MeV 19.8 MeV 13.0 MeV 2017/6/19 M. Nakahata: 30 years after SN1987A 11

IMB events SN 1987A Events in IMB Detector February 23, 1987 UT 7:35:41.4 UT 7:35:42.0 UT 7:35:41.8 UT 7:35:42.5 UT 7:35:42.9 UT 7:35:44.1 UT 7:35:46.4 UT 7:35:46.9 2017/6/19 M. Nakahata: 30 years after SN1987A 12

The Baksan underground scintillation telescope (Russia)  3184 segmented liquid scintillator detectors  330 tons total target mass Each detector 5 events in Baksan detector 2017/6/19 M. Nakahata: 30 years after SN1987A 13

Adjusting the 1 st events from Kamiokande, IMB and Baksan Detection efficiency Kam-II (11 evts.) IMB-3 (8 evts.) Baksan (5 evts.) 24 events total Energy threshold (at 50% eff.) ~8.5 MeV @ Kamiokande ~28 MeV @ IMB ~10 MeV @ Baksan 2017/6/19 M. Nakahata: 30 years after SN1987A 14

What we have learned from SN1987A Binding energy (X10 53 erg) (gravitational mass) Sato and Suzuki, Phys.Lett.B196 (1987) 267 Jegerlehner, Neubig & Raffelt, PRD 54 (1996) 1194  Total energy released by ν ̅ e was measured to be ~5x10 52 erg.  Assuming equipartition, binding energy was estimated to be ~3x10 53 erg.  This binding energy was consistent with core-collapse scenario. However, no detailed information of burst process was observed because of low statistics. 2017/6/19 M. Nakahata: 30 years after SN1987A 15

History of supernova detectors 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 9 0 0 1 1 1 1 1 1 1 1 8 8 8 8 8 8 8 8 8 8 9 9 9 9 9 9 9 9 9 9 0 0 0 0 0 0 0 0 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 BAKSAN (330t liq.sci.) IMB (7000t water) Kamiokande (2140t water) LSD(90t liq. sci.) MACRO(560t liq.sci.) LVD (330  1000t liq. sci.) Super-Kamiokande (32000t water) SN1987a Amanda/IceCube SNO (1000t D 2 O) SNO+ KamLAND(1000t liq.sci.) Borexino(300t liq.sci.) No galactic supernova in HALO(76t Pb, 3 He counter) last 37 years. Daya Bay(160t liq.sci.) NOvA(14kt liq.sci.) 16

Supernova burst detectors in the world now Liquid scintillator Super-Kamiokande Water, Ice Borexino Baksan Other LVD target mass SNO+ 0.3 kt 0.3 kt 1 kt 32 kt 1 kt KamLAND HALO Pb 76 t 1 kt NOvA Daya Bay IceCube 1 gt 0.16 kt surface 14 kt 17

IceCube (South pole) IceCube detector • Number of Optical modules: 5160 • 25cm diameter PMTs in each optical module • Number of strings: 86 • Instrumented volume: 1 km 3 Supernova neutrinos coherently increase single rates of PMTs. From L.Koepke 18

High frequency signal variation by SASI SASI=standing accretion shock instability 2-D(axially symmetric) simulation with luminosity PROMETHEUS-VERTEX code Supernova at 10kpc IceCube “event” rate energy T.Lund et al., Phys. Rev. D82, 063007(2010). 2017/6/19 M. Nakahata: 30 years after SN1987A 19

Super-K: Number of events Number of events vs. distance 32kton water Cherenkov For each interaction Livermore Nakazato ν ̅ e p  e + n 7300 3100 ν +e -  ν +e - 320 170 16 O CC 110 57 Directional information Supernova at 10 kpc Ethr=3.5MeV(kin) 32kton SK volume 4.5MeV(kin) threshold No oscillation case. Livermore simulation T.Totani, K.Sato, H.E.Dalhed and J.R.Wilson, ApJ.496,216(1998) Nakazato et al. K.Nakazato, K.Sumiyoshi, H.Suzuki, T.Totani, H.Umeda, and S.Yamada, ApJ.Suppl. 205 (2013) 2, (20M sun , trev=200msec, z=0.02 case) 20

Sensitivity of Super-K for the model discrimination For 10kpc supernova Time variation of event rate Time variation of mean energy High statistics enough to discriminate models Cooperation: H. Suzuki 21 M. Nakahata: 30 years after SN1987A 2017/6/19

Super-K: directional information Reconstructed direction Distance vs. pointing accuracy (Simulation of a 10kpc supernova) ν ̅ e +p ν +e Livermore Model 3.1-3.8 deg. for 10kpc Nakazato model ν +e ν ̅ e +p 4.3-5.9 deg. for 10kpc 2017/6/19 M. Nakahata: 30 years after SN1987A 22

Single volume liquid scintillator detectors KamLAND Borexino SNO+ (Kamioka, Japan) (Gran Sasso, Italy) (SNO Lab.,Canada) 300ton liq.sci. Running since 2007. 1000ton liq.sci. 1000ton liq.sci. Running since 2002. 2017/6/19 M. Nakahata: 30 years after SN1987A 23

Energy spectrum expected at the liquid scintillation detectors Expected energy spectrum (10kpc) ν x parameter measurement with ν p elastic scattering events (3000t eqv.) 1000ton, Nakazato-model Phys. Rev. D 86, 125001 (2012 ） From K. Ishidoshiro ν ̅ e p  e + n ν -e scattering ν p elastic NC gamma 2.2MeV gamma ν ̅ e C  e + B ν e C  e - N scattering Determine luminosity and mean energy of ν x Expected number of for 1kton, 10kpc events ( ν x : ν µ , ν τ at the source) ν ̅ e p  e + n ~300 ν +e -  ν +e - ~20 ν +p  ν +p ~80 (>200keV) 12 C CC 60 24

Supernova signals by Dark Matter detectors Coherent elastic neutrino-nucleus scattering XENON1T DEAP3600 CE ν NS cross section (Xe 1ton) (Ar 3.6ton) P. C. Divari High Energy Phys. (2012) 379460 Ar Xe  XMASS (Xe 0.83ton) K. Abe et al., Astr.Phy.89 (2017) 51-56 ◦ >300eV threshold Total # for SN at 10 kpc Livermore Nakazato 15 3.5 ~ 21 K. Hiraide from 15:40 on June 21 25 M. Nakahata: 30 years after SN1987A 2017/6/19

Future Large Volume Detectors Hyper-Kamiokande JUNO(China) DUNE/LBNF (US) (440 kton Water) (20kton Liq. Sci.) (40 kton Liq. Ar) ~120k ν ̅ e p ,~5k ν +e events ν e + 40 Ar → e - + 40 K* Precise measurement for 10 kpc supernova. is the dominant of average energy and Precise measurement of interaction. luminosity for all time variation. neutrino flavors. ~4000 events for 10kpc ~1 deg. pointing accuracy. SN. ~60 events for from ~1% for <E> for ν ̅ e neutronization burst for Detection of supernova ~10% for <E> for ν e IH case (~0 for NH). neutrinos at nearby ~5% for <E> for ν X galaxies. H. Li from 16:50 J.Reichenbacher from S.Nakayama from on June 21 17:10 on June 21 14:50 on June 20 26 M. Nakahata: 30 years after SN1987A 2017/6/19