Sensitivity Study for Astrophysical Neutrinos at Hyper-Kamiokande Pos(ICHEP2020)191

Home , ANTARES (telescope), Kamioka Observatory

PoS(ICHEP2020)191 https://pos.sissa.it/ ∗ 0, [email protected] Speaker ∗ Kamioka Observatory, ICRR, The University ofJAPAN Tokyo, 456 Higashi-Mozumi, Kamioka, Hida, Gifu, E-mail: Hyper-Kamiokande (Hyper-K) is a next generation undergroundThe large detector water is Cherenkov filled detector. with ultra-pureIt water will and provide surrounded the with fiducial newly volume developed of photodetectors. Super-Kamiokande. 0.187 Mt, The which is energies, 8 positions, times directions largerby than and neutrino preceding interactions types experiment can of be identified charged using particles itswill Cherenkov produced light be in located water. The at Hyper-K deep detector undergroundwhich to is reduce a the dominant cosmic background muon forits flux the fruitful physics and low research energy its programs, astrophysical Hyper-K spallation will neutrino products, playfrontier. measurements. a critical It role With will in also the provide next neutrino important physics solar information neutrino, via supernova astrophysical neutrino burst neutrinos measurements, i.e., andphysics supernova potential relic of neutrino. Hyper-K neutrino Here, astrophysics. we will discuss the Copyright owned by the author(s) under the terms of the Creative Commons 0 © Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0). 40th International Conference on High EnergyJuly physics 28 - - ICHEP2020 August 6, 2020 Prague, Czech Republic (virtual meeting) Takatomi Yano for Hyper-Kamiokande Proto-Collaboration Sensitivity Study for Astrophysical Neutrinos at Hyper-Kamiokande PoS(ICHEP2020)191 . These 4 2a + + 24 Takatomi Yano for + U → 4? 650 meters of rock, which is ∼ octant with beam and atmospheric 23 \ 2 71 m (H) for each, our cylindrical water tanks provide the fiducial × Schematic view of one Hyper-Kamiokande water Cherenkov detector [1]. Figure 1: The Sun is burning and emitting neutrinos with the nuclear fusion reactions, which are called as Hyper-Kamiokande (Hyper-K, HK) is a next generation water Cherenkov detector planned 2. Solar Neutrino the pp-chain and the CNO cycle. They can be summarized as follows: (total) volume of 0.187 (0.26) millionof metric Super-K. tons After1). (figure the They budget are approvalHyper-K 8 is from (5) started the toward times the Japanese observation larger which than government will those start atwill at 2020, 2027. be the Our separated construction cylindrical to detector of structure innerdiameter 40,000 and photodetectors. outer 8-inch detectors. diameter 6,700 photodetectorsveto The will be detector inner installed detector for to the will outer remove bedynode cosmic-ray surrounded photo-multiplier muon by tube backgrounds. 20-inch Hamamatsu R12860,better The is photon 20-inch detection newly developed efficiency, photodetector, the for Box&Line superior HK.the photon It photodetector counting achieved and used twice timing in resolution SK comparedthe (Hamamatsu to R3600) usage [3]. below 70 It m alsoThe depth has detector of the will water. high-pressure be tolerance The located for multiple-photosensor underground unit with is an also overburden in of our R&D [3,4]. in Japan [1], asdimensions a of successor the of 64 m the (D) Super-Kamiokande (Super-K, SK) experiment [2]. With the Sensitivity Study for Astrophysical NeutrinosHyper-Kamiokande at Proto-Collaboration Hyper-Kamiokande 1. Introduction equivalent to 1,750 meters of water. Charged particles,are such detected as the with products the of neutrino emitted interactions, on Cherenkov photons. the photodetectors The are number usedHyper-K of has photons to various and physics reconstruct topics: their the arrival searchoscillations energy for times including CP and violation determination vertex in of of neutrinos, mass precise the hierarchy study and particle, of neutrino respectively. neutrinos, search for nucleon decay and observations of astrophysical neutrinos. PoS(ICHEP2020)191 2 28 26 5 24 22 20 18 16 4 lines and 14 12 10 f 8 3 6 4 -e scattering 2 2 a 1 ) ( 0.5 2 s [7] tension between sin r 2 Takatomi Yano for f 20y eV 0.4 2 and the mass squared 5 ∼ 0.0014 − ± [9] 12 \ 10 2 )=0.0219 0.3 13 ( 2 × eV sin 2 5 eV -5 − 0.8 1.5 ) 10 + − 0.2 +0.45 -0.36 10 Solar global + HK parameter given by KamLAND. =(4.85 2 21 × 4.8 m 2 21 Neutrino oscillation parameter allowed re- = < 0.1 0.013 ± Δ 0.20 0.21 , with its high energy above our analysis events/day are observed at SK-IV. 2 21 )=0.308 + − 4 12 ( a < 2 a sin 5 4 3 2 1 area are shown here. The red dashed line shows Δ -5

8 6 4 2 +

28 26 24 22 20 18 16 14 12 10 9 8 7 6 5 4 3 2 1

in eV in

18 17 m 16 15 14 13 12 11 10 7.58 f x10

2 2 2 + 3 the best Figure 3: gion, with all solar neutrino experimentsand at Hyper-K 2018[10] 20 years observation. 1 to 5 4 = + 3 0.023 2 21 0.027 ∗ + − 2 25 2 < 8 8 015. Δχ Be . Δχ 6 Δ 6 0 lines 8 , 4 4 2σ3σ 2σ3σ ± f 0.334 2 2 → 1σ 1σ B ) 028 = 0.09 0.14 ) . 12 8 is constrained + − θ θ ( ( 2 2 12 0.5 13 =0 0.0014 \ ± θ sin tan 2 13 0.56 10 0.0014 θ ± )=0.0219 2 = B neutrino is observed through neutrino-electron elastic scattering, 13 sin Θ ( 8 2 )=0.0219 sin 12 )spectral+day/nightdata 0.4 13 1 Θ \ ( 2 sin 2 2 2 2 MeV. 2 eV eV eV from solar neutrino data (green), -5 -5 -5 -1 eV tan -5 ) 10 ) 10 ) 10 , favoring sin 10 12 ) 10 0.3 θ +0.19 -0.18 +1.33 -0.59 +0.19 -0.18 σ +1.5 -0.8 is the visible energy of the neutrino event in water Cherenkov detector, which is 2 > 4.5 =(7.54 =(4.85 =(7.49 =(4.8 -2 from all solar neutrino experiments, as well as the reactor neutrino experiment is consistent between solar and reactor neutrinos, we see 2 21 2 21 2 21 2 21 E8B m m m m Δ Δ Δ Δ 10 confidence levels. The filled regions give the 2 21 12 E8B vs. sin B neutrino, produced by .E \ σ < 0.2 0.014 increases in the solar+KamLAND data com- results. The tension is mainly derived from the asymmetry of the solar neutrino flux 8 2 21 4 +0.034 -0.026 ± +0.013 -0.012 +0.027 -0.023 -3 Δ m 13 + Neutrino oscillation parameter allowed re- 10 θ 2 21 )=0.316 )=0.308 )=0.307 )=0.334 a 12 12 12 12 area are7]. shown[ The green dashed line is Θ Θ Θ Θ < ( ( ( ( 2 2 2 2 Solar combined results: Reactor results: -4 confidence level results, the other contours shown are at 3σ 2σ 1σ sin sin sin 3σ 2σ 1σ sin Δ f → 0.1 The solar neutrino measurement is capable of determining the neutrino oscillation parameters Though

8 6 4 2 σ -4 -5 -6 -7 -8 -9 8 6 4 2 9 8 7 6 5 4 3 2 1

10 • •

18 17 16 15 14 13 12 11 10 .

Δχ Δ

in eV in

m 2

Δχ 10 Δ 10 10 10 10 10 eV 10 in

m arison, the almost identical result of the SK+SNO combined

bined fit to about two anti-correlation for low energy neutrinos.actor neutrino KamLAND re- data haslow the energy same solar anti-correlation neutrinosectseff as because play the in a bothnon-zero minor cases matter role. Therefore the significance of

2 2 2

2 2 -5 " 2 + confidence level contours are also displayed). the 3 a and 3 the combined results of SK and SNO. gion from all solar experiments (green),(blue) and KamLAND Solar+KamLAND (red) from 1 to 5 between neutrino mass eigenstates.performed the neutrino Super-K oscillation [7], measurementresults SNO on of the [8] the solar and allowed neutrinos. neutrino several oscillation2 Figure experiments parameters,shows have the the mixing latest been angle Figure 2: 2.1 Solar Neutrino Oscillation KamLAND [9]. events will be observed with Hyper-K per day, while 21 difference these during day and night (day-night asymmetry),try which would was indicated arises by from Super-K the]. [11 through terrestrial MSW The matter asymme- matter effect effect, in i.e.in the the Earth.The the nighttime, effect regeneration than can of that be the seen in electron as neutrinos the a daytime few [11]. percent more With event rate Hyper-K, the day-night asymmetry effect equivalent to the scattered electron kinematic energy in the reaction above. About 130 Sensitivity Study for Astrophysical NeutrinosHyper-Kamiokande at Proto-Collaboration Hyper-Kamiokande processes are well described withtarget is the the standard solar modelthreshold (SSM) of [5,6]. E Our main observation rmination of the SK and SNO combined analysis (red) to the σ 2 2 0219 . 8 8 0 Δχ Δχ 6 6 − 0014 owed contours of ∆ . 13 4 4 0 2σ3σ 2σ3σ θ 2 2 2 sec) at the 1, 2, 3, 4 and 5 1σ 1σ sin 2 ) ) ) is about ! θ θ ( ( 2 2 Be 0.0014 0.0014 /(cm ± ± 7 tan tan 6 10 10

)=0.0219 )=0.0219

13 13

from the SK-IV (left panel) and SK-I/II/III/IV (right panel

× Θ Θ

(

( 2

sin

. 1

1 0

2 ± is constrained by 2 2 25 -1 -1 eV eV . 13 -5 -5 θ vs. tan ) while the MSWect eff causes 10 10 ) 10 ) 10 13 +1.3 -0.6 +2.8 -0.2 2 21 θ ( m ) for high energy neutrinos and an =(4.8 =(3.2 -2 -2 4 2 21 2 21 ). This results in a correlation of 13 m m Δ Δ . 10 10 θ 13 2 ( B) solar neutrino survival probability θ 2 " 8 ( )) cos 4 0.014 ± +0.026 -0.031 -3 -3 12 confidence level (for the solar analyses, 4 and 5 0219 θ . 10 10 0 σ )cos )=0.310 )=0.327 (2 − 12 12 2 0014 Θ Θ . 12 ( ( 13 2 2 0 θ ) and sin θ Bfluxconstraintof5 -4 -4 1σ sin 3σ 2σ 1σ sin 3σ 2σ ( sin 8 2 2 12 8 6 4 2 6 4 2 8 1 2

-9 -4 -5 -6 -7 -8 -6 -7 -8 -9 -4 -5

10 10

θ sin

( conﬁdence level results.

Δ Δχ Δχ Δ in eV in m in eV in

m !

2 10 10 10 10 10 10 10 10 10 10 10 10

− 2 2 2 2 2 2 σ (1 by with a about one standard deviationlar because neutrinos for the low survival energy probability so- (e.g FIG. 34: Left:oscillation constraints comparison of of SNO by the itself oscillation (blue). parameter Right: dete all FIG. 33: Contours of ∆ sin of sin a high energy ( 3 the 1 and 2 KamLAND data (blue), andfit the is combined shown result by (red). the For dashed comp dotted lines. The filled regions give PoS(ICHEP2020)191 8 2 21 > < after Δ O CC B solar f in solar 16 8 + 4 4 a a → 4 a Takatomi Yano for ergs and 99% of the energy is 53 10 × 3 ∼ -e scattering events, 80-4,100 a 4 after the 10 years solar neutrino measurement with f reaction is an undiscovered solar neutrino. Though it 4 a + + 4 ). For each full volume of two inner detectors, we expect to see + 40%) and the non-zero significance will be 1.8 (2.3) = ∼ + He 4 + in reactor neutrino will introduce the test of new physics, e.g. CPT 4 4 → ¯ a 60% ( ? → O CC events, in total 52,000-79,000 events for a supernova explosion at → 4 ∼ + ¯ 16 ? a + + He 4 ¯ 4 3 a ¯ a with 10 (20) years observation (figure3). The difference of P f Another motivations of solar neutrino observation is the test of the SSM predictions. Hep solar Core collapse supernova explosions are the last process in the evolution of massive stars ( The first and direct observation of supernova neutrinos is about the supernova burst neutrinos, ). The energy released by a supernova is estimated to be

halfway across our galaxy (10 kpc,several figure4). SN models, The and statistical so error Hyper-K should will giveRecent be crucial simulations data small suggest for that enough further the to model shock compare predictions wave will (figure5). to be heated the efficiently physical by motions neutrinos in to a revival, due supernova,rotation Standing of Accretion Shock supernova Instability are (SASI) ormodulation the convection, of examples. neutrino flux, These due towill models the prove also motions the predict in neutrino supernovae. the as The characteristic the detection frequency of driver these of modulation supernova explosions. Other topics for astrophysics and events, and 650-3,900 Sensitivity Study for Astrophysical NeutrinosHyper-Kamiokande at Proto-Collaboration Hyper-Kamiokande can be measured precisely withparameter, our large our detector measurement volume. will Assuming bevalue the possible about current to 4 solar separate (5) best itselfneutrino from oscillation and the P current KamLAND best about 49,000-68,000 inverse beta events, 2,100-2,500 2.2 Hep Solar Neutrino Search neutrino, produced by violation of neutrinos. The solar neutrino energy spectrumMSW-LMA upturn hypothesis is] [7 also and the interesting possiblynon-standard physics affected interaction target. [12], by mass-varying It physics neutrino is beyond oscillation predicted the [13]non-zero by upturn and standard sterile sensitivity model, will neutrino be [14]. such about The as 34.5 (4) MeV (3.5 MeV) threshold. has the highest energy in solar neutrinos, most of the energy spectrum overlaps with that of which are released in several seconds afterinverse beta its reaction onset ( of a burst. About 90% of signals at Hyper-K is neutrinos. So far, onlyhep upper neutrino limits flux were will reported10 be by (20)15].The SNO[ years uncertainty observation in of Hyper-K. the measured 3. Supernova Neutrinos M carried out by all three typesgives of direct neutrinos and information anti-neutrinos. of The energyIMB, detection flow of and during supernova the neutrinos Baksan explosions. experimentssupernova observed From explosion 25 SN1987a, was correct. neutrino the Kamiokande, events. However, closeexplosions to is It three still decades proved not later known. the the The basicdesired. detailed observation scenario mechanism of The of new of multi-messenger supernova observation the with with theand visible large Hyper-K light, neutrino will detector gamma-ray, also x-ray, is gravitational reveal wave the supernova explosion in details. PoS(ICHEP2020)191 Time (sec) Takatomi Yano for Inverse beta event rate predicted by su- 0 0.05 0.1 0.15 0.2 0.25 0.3 Nakazato et al. (2015),1D,30M,BH Nakazato et al. (2015),1D,20M Nakazato et al. Takiwaki et al. (2014),3D,11.2M Bruenn et al. (2016),2D,20M Dolence et al. (2015),2D,20M Pan et al. (2016),2D,21M Tamborra et al. (2014),3D,27M Totani et al. (1998),1D,20M 0

and enough for conﬁrming the discovery. 500 3000 2500 2000 1500 events/0.22Mt/20msec 1000 f Figure 5: pernova simulations for the ﬁrst 0.3 secondsonset after of the a 10kpc distantthe burst. statistic error. The error bars shows 70 SRN events are expected at 16-30 MeV with ∼ 5 /sec. SRN contains the information of its origins, 2 ) c

p M31 k ( 10

2 LMC 10

distance center +p

– - Galactic ν e

O 10 +e 16 ν – + e ν 16 O + ν e

1 Antares

Expected number of supernova burst Betelgeuse -1 8 7 6 5 4 3 2 9 10

Another observation target is about the supernova relic neutrinos (SRN), produced by all past Hyper-Kamiokande is a next generation large water Cherenkov detector. Several studies 10 10 10 10 10 10 10 10 10 events/0.22Mega-ton i.e. the starstrange formation supernova rate, explosions like energy dim spectrumfor supernovae SRN of or have supernova black been burst holeyet conducted neutrinos, formations. been at and obtained, large Although the because underground searches of fractionSuper-Kamiokande detectors, the (SK-Gd) of can small no be flux evidence the of discoverer ofwill of SRN. SRN SRN. be With The 0.8-5 signals incoming number events/year detector has of above update, eventsmeasure 10 in and Gd-loaded MeV. Even their determine though, detector the it precise is flux of still SRN. very interesting physics theme to Figure 4: supernova explosions since the beginning ofand the their universe and flux diffused. is estimated They must to fill be the a universe few tens/cm are being performed, e.g.measurement is photosensor one of R&D, the designwould be features and possible of with physics Hyper-K. Hyper-K and optimization. Several its precisefor high physics measurements statistics, Solar beyond e.g. of the the neutrino solar standard solar model, neutrinos neutrino the oscillation, the first search measurement of hep process neutrino and also the events for each interaction astance to a a function supernova. of Thethe the band variation dis- due of to each the color neutrino shows oscillation cases. particle physics also can behierarchy examined, of e.g. neutrinos. direct observation of black hole formations and mass 10 years observation. TheFurther studies significance for will astrophysics and be particle physics 4.2 topics will be performed. 4. Summary Sensitivity Study for Astrophysical NeutrinosHyper-Kamiokande at Proto-Collaboration Hyper-Kamiokande PoS(ICHEP2020)191 , . Phys. Rev. ]. , Search for hep ]. Takatomi Yano for ]. 1805.04163 , ]. ]. Nucl. Instrum. Meth. , 1109.0763 ]. ]. hep-ph/0307266 1312.5176 (2018) 325. (2020). astro-ph/0402114 213 102 astro-ph/0511337 0801.4589 (2013) 025501[ Solar neutrinos as probes of neutrino matter ]. (2004) 113002[ New 50 cm Photo-Detectors for 10,000 standard solar models: a Monte Carlo R&D Studies of New Photosensors for the C88 6 ]. hep-ph/0402266 (2014) 091805[ D69 (2017) 303. Homestake result, sterile neutrinos and low-energy What do we (not) know theoretically about solar 112 Solar mass-varying neutrino oscillations (2006) 400[ (2004) 121301[ Hyper-Kamiokande Design Report First Indication of Terrestrial Matter Effects on Solar Solar Neutrino Measurements in Super-Kamiokande-IV The Super-Kamiokande detector , June, 2018. 10.5281/zenodo.1286858. B neutrino flux. The unique high statistics information for 8 92 (2008) 221803[ Phys. Rev. 165 1606.07538 Physical Review D , (2004) 347[ Springer Proc. Phys. , collaboration, , collaboration, 100 Phys. Rev. Precision Measurement of Neutrino Oscillation Parameters with , ICHEP2016 hep-ph/0502196 B594 collaboration, Phys. Rev. Lett. collaboration, collaboration, collaboration, PoS , Combined Analysis of all Three Phases of Solar Neutrino Data from the , Phys. Rev. Lett. , (2016) 052010[ Phys. Lett. collaboration, Phys. Rev. Lett. , Astrophys. J. Suppl. , D94 , Superkamiokande (solar) (2005) 211802[ (2003) 418. collaboration, 95 Neutrino Oscillation interactions Lett. Sudbury Neutrino Observatory Super-Kamiokande SNO KamLAND KamLAND solar neutrino experiments Phys. Rev. solar neutrinos and the diffuse supernovasudbury neutrino neutrino background using observatory all three phases of the Hyper-Kamiokande proto Hyper-Kamiokande Detector Super-Kamiokande A501 Hyper-Kamiokande Proto Hyper-Kamiokande neutrino fluxes? simulation Super-Kamiokande Hyper-Kamiokande [8] [9] [4] [5] J. N. Bahcall and M. H. Pinsonneault, [6] J. N. Bahcall, A. M. Serenelli and S. Basu, [7] [3] [2] [1] [13] V. Barger, P. Huber and D. Marfatia, [10] M. Ikeda, [11] [12] A. Friedland, C. Lunardini and C. Pena-Garay, [14] P. C. de Holanda and A. Yu. Smirnov, [15] B. Aharmim, S. Ahmed, A. Anthony, N. Barros, E. Beier, A. Bellerive et al., Sensitivity Study for Astrophysical NeutrinosHyper-Kamiokande at Proto-Collaboration Hyper-Kamiokande seasonal variation measurement of the supernova burst and supernova relicwill neutrinos play a will crucial role be in also theastrophysics. next available. neutrino physics As frontier for a both conclusion, of particle Hyper-K physics and neutrino References