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

Astrophysical neutrinos at Hyper-Kamiokande

Topics in Astroparticle and Underground Physics 2019

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Toyama, Japan 10 Sept. 2019

Takatomi Yano

ICRR, University of Tokyo For Hyper-Kamiokande Proto Collaboration

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D:68m Water Depth: 71 m

• Tot. Vol.

0.26Mt

H: 42m D:39m Tot.Vol. 0.05Mt Super-K

Our

• bservation

will be started at 2027.

Hyper-Kamiokande Project

Improved photo-sensors

Design Hyper-Kamiokande Super-Kamiokande

• No. of PMTs (ID/OD)

40,000 / 6,700 (Design Report) 11,129 / 1,885 Photocathode coverage 40% (×2 efficient p.e. detection) 40% Total / Fiducial V. 0.26 Mt / 0.19Mt (Design Report) 50 kt / 22.5 kt

Hyper-Kamiokande Project

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Cherenkov light Charged particle Neutrino

• The property of neutrinos could be measured with the charged

lepton generated by reactions in ultra pure water. e.g. : ν + e- → ν + e-.

• The energy, position, direction and type of the particle can be

identified at each event, with charge and time of PMT hits.

• “Real Time” and “Event by Event” measurement is possible.

Improved photo-sensors

Astrophysical Neutrino at HK

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HK

NASA, Chandra & Hubble 2007 NASA, Hubble 2009

Target energy: ~O(10) MeV. and DM annihilation, GRB ν (~GeV)…

Solar neutrino Supernova ν SN relic ν

• Burning processes,

modeling of the Sun

• Property of neutrino
• SN explosion

mechanism

• SN monitor
• Nucleosynthe

sis

• SN mechanism
• Star formation

history

• Extraordinary

SNe

kpc ~ Mpc Mpc ~ ~5μpc

wikimedia

Solar neutrino

p + p → 2H + e+ + νe (99.75%) p + e- + p → 2H + νe (0.25%)

2H + p → 3He + γ 3He + 3He → 4He + 2p 3He + 4He → 7Be + γ 3He + p → 4He + e+ + νe 7Be + e- → 7Li + νe 7Be + p → 8B + γ 8Be* → 2 4He 7Li + p → 2 4He

85% 2×10

• 5%

14% 99.85% 0.15%

pp-chain & ν Energy specturm

• The Sun is burning

with nuclear fusion reactions, i.e. pp-chain and CNO-cycle, emitting neutrinos.

• Only neutrinos can

bring out the information of “today’s” status of solar center.

• With Hyper-K, a large

statistics is expected : 130 νev./day/tank,

Evis>4.5MeV

(15 ν ev./day in SK-I ~ IV)

8B → 8Be* + e+ + νe

Visible with Hyper-K

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Solar neutrino observation

Yearly ν variation & Sun spots (SK)

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• Y. Nakano ICRC2015
• Importance of solar nu meas. in

particle physics and astrophysics

• Precision measurement, Δm221
• Day/Night asymmetry
• Solar nu spectrum up-turn
• Discovery of Hep neutrino
• Variation of solar ν flux

Day-Night asymmetry in SK

sin2θ12=0.314, sin2θ13=0.025

1σ KamLAND 1σ Solar SK-I,II,III,IV combined 1σ range expected

PRL 112, 091805 (2014)

• Nonzero D/N asymmetry of

solar ν caused by terrestrial matter effect is indicated by SK.

[PRL 1212, 091805(2014)]

• The D/N asymmetry leads

smaller Δm221 value in solar neutrino analysis, comparing to reactor neutrino analysis (~2σ).

sin2(Θ13)=0.0219±0.0014 sin2(Θ12)=0.308±0.013 ∆m2

• 0.36) 10-5eV2

∆m2 in eV2 x10

• 5

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 2 4 6 810121416182022242628

1σ 2σ 3σ 4σ 5σ

∆χ2 sin2(θ) 0.1 0.2 0.3 0.4 0.5 2 4 6 8 10 12 14 16 18 20 22 24 26 28

1σ 2σ 3σ 4σ 5σ

∆χ2

Solar global + HK 20y 3σ

sin

sin

∆m

• 0.17) 10
• 5eV

sin

∆m

• 0.60) 10
• 5eV

sin

• 0.026

∆m

• 0.18) 10
• 5eV

∆m2

21 in 10-5eV2

5 10 15 2 4 6 8

1σ 2σ 3σ

∆χ2 sin2(θ12) 0.1 0.2 0.3 0.4 0.5 2 4 6 8

1σ 2σ 3σ

∆χ2 Very Preliminary

KamLAND 3σ Combined 3σ Solar global 3s

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April 2018 (SK) + HK 20years

• The D/N asymmetry leads smaller Δm221 value in solar neutrino

analysis, comparing to reactor neutrino analysis. (~2σ tension)

• With Hyper-K statistics, we can separate solar best Δm221 and

KamLAND best above 4σ.

• 10 years with 1 tank, 0.3% sys. Err.

→ CPT violation test, difference between Pνe -> νx and Pνe -> νe. → Precise Δm221 also contributes to CPV test in HK long-baseline.

Precision oscillation measurement

Reactor best Δm2

sin

sin

∆m

• 0.17) 10
• 5eV

sin

∆m

• 0.60) 10
• 5eV

sin

• 0.026

∆m

• 0.18) 10
• 5eV

∆m2

21 in 10-5eV2

5 10 15 2 4 6 8

1σ 2σ 3σ

∆χ2 sin2(θ12) 0.1 0.2 0.3 0.4 0.5 2 4 6 8

1σ 2σ 3σ

∆χ2 Very Preliminary

KamLAND 3σ Combined 3σ Solar global 3s

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April 2018 (SK)

• The D/N asymmetry leads smaller Δm221 value in solar neutrino

analysis, comparing to reactor neutrino analysis. (~2σ tension)

• With Hyper-K statistics, we can separate solar best Δm221 and

KamLAND best above 4σ.

• 10 years with 1 tank, 0.3% sys. Err.

→ CPT violation test, difference between Pνe -> νx and Pνe -> νe. → Precise Δm221 also contributes to CPV test in HK long-baseline.

Precision oscillation measurement

Year 2 4 6 8 10 12 14 16 18 20 Sensitivity (sigma) 2 4 6 8 10

Separation with non-D/N Separation with KamLAND best

• - - : 0.1% sys.err.

: 0.3% sys.err.

Δm2 separation w/ HK

10 12 14 16 18 20 22 24 [MeV]

visible

E

2

• 10

1

• 10

1 10

2

10

3

10

4

10

5

10 Number of events / 0.5 MeV

Solar 8B + hep spectrum, HK 10 years, 73% signal eff.

8B+hep (BP2004 SSM)

• nly 8B

Data points w/ stat. err. (sqrt(N))

Solar 8B + hep spectrum, HK 10 years, 73% signal eff.

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Other solar ν topics

Hep process neutrino

• Undiscovered solar neutrino,

with small branching ratio.

• With Hyper-K 10 years, there is

chance to discover.

• → To test the solar models.
• 1.8 ~ 3 σ, 10y

Energy spectrum up-turn

• Verification of neutrino
• scillation, or to search new

physics beyond the SM. → Non-standard interaction, sterile neutrinos …

• Separable w/ up-turn from w/o

up-trun with ~3(4)σ.

• 4.5 (3.5) MeV threshold, 10y

0.1 0.5 1 2 3 5 7 10 14 Eν [MeV] 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 〈P

ee〉 = ΦCC / ΦNC

Brx (pp) Brx (

7Be)

Brx (pep) pp KL (

7Be)

Borexino (

8B)

Super-K SNO Sterile Standard NSI-up NSI-dw

Maltoni et al. Arxiv:1507.05287 Hyper-K Optimization of Detector & software

8B and Hep nu spectrum, HK 10 years

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Supernova Neutrino

Core collapse supernova emits all kinds of neutrinos.

• 11 neutrino events by

Kamiokande from SN1987A at 50kpc (LMC).

• 50 ~ 80k events/tank are

expected in HK from SN at 10kpc (galactic center). Physics Motivation

• Core collapse SN physics

– Explosion mechanism – Proto-neutron star formation – Black hole formation

• Neutrino Physics
• Multi-messenger analysis

– With gravitational wave, gamma-ray, X-ray, telescope…

1 10 10 2 10 3 10 4 10 5 10 6 10 7 10 8 10 9 10

• 1

1 10 10

2

10

3

ν

– e+p

νe+16O ν

– e+16O

ν+e-

Betelgeuse Antares Galactic center LMC M31

distance(kpc) events/0.22Mega-ton

500 1000 1500 2000 2500 3000 0.05 0.1 0.15 0.2 0.25 0.3

Time (sec) events/0.22Mt/20msec

Nakazato et al. (2015),1D,30M,BH Nakazato et al. (2015),1D,20M 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

10kpc

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Features

• Precise SN neutrino time profile
• Energy spectrum measurement

– Investigation of the SN mechanism (SASI/Rotation/Convection)

• Proving dim supernova/BH

formation

100 200 300 400 500 50 100 150 Time [ms] Counts / 0.22 Mt / 2 ms

Sekiguchi ApJ, 737.6.2 (2011) Horiuchi et al. AstroP.J769,113 (2013)

SASI model, 10kpc BH formation Dim SN

nu Flux from I. Tamborra PRL 111, 121104 (2013)

Supernova Relic Neutrino

1 Billion years from Bigbang 14 Billion years from Bigbang

• Supernova Relic Neutrino (SRN)

is diffused neutrinos coming from all past supernovae.

• Not discovered but promising

source of extra-galactic neutrino.

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SRN with HK

Physics of SRN

• Test of star formation rate

– Factor ~2 discrepancy between rates of formations and SNe.

• Energy spectrum of supernova

burst neutrinos

– Temperature inside the SN

• Extraordinary SN

– BH formation, dim supernova

[MeV]

vis

E 5 10 15 20 25 30 35 40 45 50 Events/MeV/0.187Mt/10y 5 10 15 20 25

SRN 4MeV 100% SRN 4MeV 70% + BH 30% SRN 6MeV 100% SRN 6MeV 70% + BH 30%

Horiuchi (2009, 2017)

10 20 30 40 50 60 10 15 20 25 30 35 40 45 50

Energy (MeV) Events/2MeV/0.187Mton/10years

SRN+B.G.(inv.mu 1/5) total B.G. i n v . m u ( 1 / 5 )

• atmsph. ν

– e

spallation B.G.

Energy spectrums with BH formation

SRN with Hyper-K

• SRN can be observed by HK in

10y with ~70±17 events.

• It is > 4σ for SRN signal.
• We will go beyond the

discovery and aim to measurement of SRN.

Summary

• Hyper-K project is a next generation large water

Cherenkov detector. – Design Report is ready. The update is being prepared. – Our observation will be started at 2027. – HK is on the list of MEXT’s budget request for FY2020.

• Astrophysical neutrino measurements is one of the

features of Hyper-Kamiokande. – Solar neutrino

• Hep neutrino, seasonal variation, up-turn etc…

– Supernova neutrino

• Energy and time spectrum measurement, SN

alarming etc.. – Supernova Relic Neutrino

• Supernova and SFR models, extraordinary SN

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Year 2 4 6 8 10 12 14 16 18 20 Sensitivity (sigma) 2 4 6 8 10

Solar Day/Night asymmetry

Day-Night asymmetry in SK

sin2θ12=0.314, sin2θ13=0.025

1σ KamLAND 1σ Solar SK-I,II,III,IV combined 1σ range expected

PRL 112, 091805 (2014)

• Nonzero D/N asymmetry of

solar ν caused by terrestrial matter effect is indicated by SK.

[PRL 1212, 091805(2014)]

• The D/N asymmetry leads

smaller Δm221 value in solar neutrino analysis, comparing to reactor neutrino analysis.

Separation with non-D/N Separation with KamLAND best

• - - : 0.1% sys.err.

: 0.3% sys.err.

• With Hyper-K statistics, we can

separate solar best Δm221 and KamLAND best above 4σ.

• 10 years with 1 tank, 0.3% sys. Err.

→ CPT violation test, difference between Pνe -> νe and Pνe -> νe. → Precise Δm221 also contributes to CPV test in HK long-baseline.

WIMP search

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Earth WIMP, SI Galactic WIMP

Solar neutrino upturn

Maltoni et al. http://arxiv.org/pdf/1507.05287.pdf

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0.1 0.5 1 2 3 5 7 10 14

Eν [MeV]

0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

〈P

ee〉 = ΦCC / ΦNC

Brx (pp) Brx (

7Be)

Brx (pep) pp KL (

7Be)

Borexino (

8B)

Super-K SNO Sterile Standard NSI-up NSI-dw

Solar neutrino fluxes of models.

J.N. Bahcall and A.M. Serenelli, Astro. Phys. J. 621, 85 (2005)

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Table 2: Predicted solar neutrino fluxes from seven solar models. The table presents the predicted fluxes, in units of 1010(pp), 109( 7Be), 108(pep, 13N,15 O), 106( 8B,17 F), and 103(hep) cm−2s−1 for the same solar models whose characteristics are summarized in Table 1. Model pp pep hep

7Be 8B 13N 15O 17F

BP04(Yale) 5.94 1.40 7.88 4.86 5.79 5.71 5.03 5.91 BP04(Garching) 5.94 1.41 7.88 4.84 5.74 5.70 4.98 5.87 BS04 5.94 1.40 7.86 4.88 5.87 5.62 4.90 6.01 BS05(14N) 5.99 1.42 7.91 4.89 5.83 3.11 2.38 5.97 BS05(OP) 5.99 1.42 7.93 4.84 5.69 3.07 2.33 5.84 BS05(AGS,OP) 6.06 1.45 8.25 4.34 4.51 2.01 1.45 3.25 BS05(AGS,OPAL) 6.05 1.45 8.23 4.38 4.59 2.03 1.47 3.31

Neutrino, Messenger from Nature

Source of Neutrinos

• Neutrino Mixing
• Mixing angles, Mass

differences

• Difference between ν&ν
• CPV, CPTV (Leptogenesis)
• Tiny neutrino masses
• Mass hierarchy (See-saw

mechanism)

• Astrophysics
• Prove of supernova, Sun,

Earth and our universe.

• ν’s role in nature
• ν heating in supernova

Physics of Neutrinos Atmospheric Supernova Solar Accelerator (J-PARC)

(Geo & Reactor)

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