Neutrino-nucleus interactions relevant to atmospheric neutrinos & …shima/NDM12/talk/Sakuda.pdf ·...

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Neutrino-nucleus interactions relevant to atmospheric neutrinos & neutrino oscillation experiments Makoto Sakuda (Okayama) 14 June, 2012 @NDM12 (Nara) In collaboration with I.Oh, T.Mori, A.Ankowski, and O.Benhar Outline 0. New Phase After Neutrino 2012 (θ 13 =9±1°Established) 1. Importance of NC ν-A γ-ray production 2. Process to produce γ-ray production in NC ν-A reactions 3. E<200MeV 4. E>200MeV 5. Proposed experiment to measure the relevant branching ratios (Br(A* γ)) 6. Summary

Transcript of Neutrino-nucleus interactions relevant to atmospheric neutrinos & …shima/NDM12/talk/Sakuda.pdf ·...

Page 1: Neutrino-nucleus interactions relevant to atmospheric neutrinos & …shima/NDM12/talk/Sakuda.pdf · 2012. 6. 26. · Neutrino-nucleus interactions relevant to atmospheric neutrinos

Neutrino-nucleus interactions relevant to atmospheric neutrinos & neutrino oscillation experiments

Makoto Sakuda (Okayama)

14 June, 2012 @NDM12 (Nara)In collaboration with I.Oh, T.Mori, A.Ankowski, and O.Benhar

Outline0. New Phase After Neutrino 2012 (θ13 =9±1°Established)1. Importance of NC ν-A γ-ray production 2. Process to produce γ-ray production in NC ν-A reactions3. E<200MeV4. E>200MeV5. Proposed experiment to measure the relevant branching

ratios (Br(A* γ))6. Summary

Page 2: Neutrino-nucleus interactions relevant to atmospheric neutrinos & …shima/NDM12/talk/Sakuda.pdf · 2012. 6. 26. · Neutrino-nucleus interactions relevant to atmospheric neutrinos

1. New Phase of ν-A Interactions After Neutrino2012 (θ13 =9±1°Established)

A few % accuracy of the neutrino cross sections is required for the determination of precise value of θ13 , MH(mass hierarchy) and CP-phase δ. Understanding of the overlapping region among Quasi-elastic(QE), Resonance(RES) and Deep-inelastic scattering (DIS) becomes important. In addition, a forward region (low Q2) in QE,1π and DIS is uncertain, ~20%. See Itow, McFarland at Neutrino2012, Okumura@NDM.

Page 3: Neutrino-nucleus interactions relevant to atmospheric neutrinos & …shima/NDM12/talk/Sakuda.pdf · 2012. 6. 26. · Neutrino-nucleus interactions relevant to atmospheric neutrinos

1. Importance of γ rays in NC ν-O or ν-C interactions

This process is very important to both Supernova (SN) physics and neutrino oscillation experiments. The x-section is sizable, ~30-40% of that of Elastic (coherent) or QE reaction.

1) SN DetectionSupernova neutrino bursts in Our Galaxy: The events containing γ rays from NC ν-O (ν-C) interactions comprise 5-10% of the total events. They will give us flux (Temperature), independent of the neutrino oscillations.

Supernova Relic Neutrino (SRN) detection: Though we are about toreach the sensitivity to SRN, the γ-rays from Atmospheric NC ν-O (ν-C) interactions at high energy may make serious background in 5-20 MeV region.

2) Neutrino Oscilation Experiments at Beam Dump or LBNEBD: KARMEN experiment measured the 15.1MeV γ rays from NC ν-C reactions at 29.8MeV. No experiments exist for oxygen at low energy. LBNE: The number of γ-ray events from NC ν-A interaction is independent of neutrino oscillations.

Page 4: Neutrino-nucleus interactions relevant to atmospheric neutrinos & …shima/NDM12/talk/Sakuda.pdf · 2012. 6. 26. · Neutrino-nucleus interactions relevant to atmospheric neutrinos

Status of γ-ray production study of NC ν-O (-C) reactions

Theoretical Calculations1) Eν<100MeV: Langanke et al., Phys.Rev.Lett.76(1996).

Inelastic scattering (Giant resonances):νO νO* , O* γ

2) Eν>100MeV: Ankowski,Benhar,Mori,Yamaguchi and MS,Phys.Rev.Lett.108(2012)052505

Nucleon knockout: νO ν+p/n+15N*/15O*(Excitation of residual nucleus)

Experiments1) Eν<100MeV:No experiments exists for Oxygen. Karmen for

C*(15.1MeV) only We are preparing the experiment!2) Eν>100MeV: K2K. T2K, RCNP E148 O(p,2pγ)

ν16O

ν16O* 16O

ν ν

p15N*γ

γ

1) Eν<100MeV: Elastic and Inelastic 2) Eν>100MeV: Quasi-elastic (1N knock-out)

Page 5: Neutrino-nucleus interactions relevant to atmospheric neutrinos & …shima/NDM12/talk/Sakuda.pdf · 2012. 6. 26. · Neutrino-nucleus interactions relevant to atmospheric neutrinos

Feature of the energy dependence

NC Elastic(Coherent)ν+16O→ν+16O

NC quasi-elastic ν+16O→ν+p/n+X

NC Elastic only

Page 6: Neutrino-nucleus interactions relevant to atmospheric neutrinos & …shima/NDM12/talk/Sakuda.pdf · 2012. 6. 26. · Neutrino-nucleus interactions relevant to atmospheric neutrinos

γ-production in nucleon decayEjiri,PRC48,1442(1993)

SUSY Golden Mode P K+ν

Residual 15N sometimes emits γ−rays.

All we need is the spectroscopic factors Sp(p1/2,p3/2,s1/2,,,,)

16OP K+ν

16O P K+ν, 15N* 15N+γ

15N

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1) Supernova Physics

SN bursts from SN explosion@10kpcWith about 8000 events, we expect to clarify the Supernova explosion mechanism every msec over 10 seconds. NC events (oscillation indep.) are very important. We may solve θ13 and Mass Hierarchy. –Kajino@NDM12

(SN1987a:Only 12 events ( Nobel Prize))

Supernova Relic Neutrinos(SRN,or DSNB): SN flux from the past (z).

K.Bays et al.(SK),PRD85,052007(2012) has the best sensitivity to SRN.

.sec)/(7.1

)3.17(%90@sec)/(9.22

2

predictediscmwhile

MeVECLcmFlux

e

e

>⋅<

ν

ν ν

τμ νννν

,e

e

0 10 20 40MeV

SRN flux

(Sec)

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1) Neutrino bursts from SN explosion at 10kpc, expected for H2O detector (22.5kton)

CC e±

NC γ

400 γ-ray events (5%) out of total 8000 events (H2O) above E>5 MeV.

NC γ-ray Calculations by Langanke,Vogel,Kolbe,PRL76,2629,’96; Beacom-Vogel,PRD58,053010,’98.

M.Ikeda et al (SK collab), APJ669,619(‘07): Evis>18MeV.

)7(%)6/%5(),(: τμ νννγννγ =++→+ xxx XONC

CC:

5MeV

18MeV

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Neutrino bursts from SN at 10kpc with Liq.scint(KamLAND)

1000-ton Liq.Scinti.Detector (C+H) observes ~60 NC 15.1MeV γ-ray events.

•P.Vogel :http://sn1987a-20th.physics.uci.edu/, Feb.2007, Hawaii, -KamLAND.US.Proposal(March,1999

νe-bar+p→e++n : ~300 eventsνe+12C→e+12N(12B): ~30 eventsν+e-→ ν+e- : ~20 eventsNC ν+12C→ν+12C+γ (15.1MeV): ~60 events

ν+p→ ν+p: ~300 events

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2) NC ν+A ν+γ+X in neutrino oscillation experiment at Short- and Long-baseline (Eν=30MeV or >200 MeV)

-independent of ν-oscillations-

KARMEN at Short Baseline ν+12C ν+12C+γ(15.11MeV)

Detailed Fig Later.

K2K 1ktonWC measuredνμ+O νμ+γ(6MeV)+X.

-Kameda@NuInt05 Proceedings.-Spectrum shape is consistent with NC

6.3MeV γ-ray production.0 10 20 30

Evis (MeV)

K2K: ν+H2O γ + nothing

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16O

(ν,ν’)

6.049 , 0+6.130 , 3-7.117 , 1+8.872 , 2-9.585 , 1-

10.356 , 4-10.957, 4-11.097 , 4+11.520 , 2+12.049, 0+12.440, 1-

13.090 , 2-13.129 , 3-

12.796 , 0-12.996 , 2-

17.090 , 1-

18.800 , 1+19.000 , 1+19.470 , 1-20.400 , 2-

22.000 , 1-

24.000 , 1-25.000 , 1-

T=0 T=1

Sn:15.66

Sp:12.127

14.815 , 6+15.196 , 2-16.200, 2-

17.775 , 2-

5

10MeV

15

20

25

γ

15N+p

5.270 , 5/2+5.298 , 1/2+6.323 , 3/2-7.155 , 5/2+7.300 , 3/2+7.567 , 7/2+8.312 , 1/2+8.572 , 3/2+9.049 , 1/2+15N*

15O+n

5.183 , 1/2+5.249 , 5/2+6.176 , 3/2-6.793 , 3/2+6.859 , 5/2+7.275 , 5/2+

γ

15O* 9.152 , 3/2-9.155 , 5/2+

Sp=7.296MeV9.222 , 1/2-9.760 , 5/2-9.829 , 7/2-9.925 , 3/2-

SP=10.02MeV

3. NC ν-O γ-production (E<100MeV, Inelastic) νx+16O νx+16O* ;16O* 15N*+p, 15O*+n ; 15N*, 15O* γ

0+,T=0

1/2-

1/2-

Langanke,Vogel,Kolbe,PRL96,’96 Kolbe,Langanke,Vogel,PRD66,’02•Br(NC 15N* γ)=25%, Br(NC 15O* γ)=6%At <E>=25MeV, using SMOKER code.

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11C

11B

g.s.

g.s.

25MeV

20MeV

10MeV

5MeV

0MeV

Sn:18.751

Sp:15.957

Sp=8.6869 Sp=11.227

11C*

11B*

12C

T=0 T=1

15.44 , 2+

14.08 , 4+

13.35 , 2-

12.71 , 1+

11.83 , 2-

11.16 , 2+

10.84 , 1-

10.30 , 0+

9.641 , 3-

7.654 , 0+

4.438 , 2+

g.s. ,0+

28.20, 1-

25.40, 1-

23.52 1-

22.65, 1-

22.40, 1-

22.00, 1-

20.27, 1+

18.80, 2+

18.35, 3-

18.16, 1+

17.76, 0+

17.23, 1-

16.57, 2-

16.11, 2+

15.11, 1+

11.0, 5/2-

10.6, 7/2+10.3, 5/2-

9.88, 3/2+9.82, 1/2+9.27, 5/2+9.19, 7/2+8.92, 5/2-8.56, 3/2-7.98, 3/2+7.29, 5/2+6.79, 1/2+6.74, 7/2-5.02, 3/2-4.44, 5/2-2.12, 1/2-

8.66, 7/2+

8.42, 5/2-8.10, 3/2-7.50, 3/2+6.90, 5/2-6.48, 7/2-6.34, 1/2+4.80, 3/2-4.32, 5/2-2.00, 1/2-

g.s. 3/2-

g.s. 3/2-

0+

15MeV

Except for γ−rays from C*(15.11MeV), no measurements exists.

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E<200MeV: ν+12C ν+12C+γ(15.11MeV)Donnelly-Pecci,Phys.Rep.50,1,’79.

• 15.11MeV (JP=1+, T=1 Giant M1 Resonance) of 12C exists below proton separation energy (Sp=15.96MeV) and it decays to the ground state, emitting a single 15.11MeV γ-ray (Br~80%) andother cascade γ-rays.

• KARMEN measurement @Eν=29.8MeV(3.2±0.5±0.4)x10-42cm2

In good agreement with the calculation, 2.8x10-42cm2.

•Cross section saturates above 100MeV.

Karmen

10 20 30 E(MeV)

15.11MeV γ-ray

ν

ν

θw=28.7°

0 100 200 E(MeV)

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Total and partial NC ν-O/-C cross sections calculated for a Fermi-Dirac ν-spectrum (T=8MeV, μ=0MeV)

-Kolbe et al.,NPA540,599,’92;PRD66,013007,’02

T=8MeV, μ=0<Eν>=24MeV.For oxygen,

16O(νx, νxpγ)15N is dominant.

νx-16O (νx=νμ , ντ) σ(10-42cm2)16O(νx, νx)X 5.19

16O(νx, νxpγ)15N 1.2916O(νx, νxnγ)15O 0.35

• For Carbon target, the γ production is dominated by 15.11 MeV γ emission. But, how dominant is not shown in the paper.

ν-12C (averaged over all

flavors)σ(10-42cm2)

12C(ν, ν’) 6.8412C(ν, ν’γ)

(including 15.11MeV γ) 3.0

Br~32%

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Axial vector dominant

JP=1-,2- dominant, 0-,1+ small.Langanke1996,2002, Janowitz03Contribution of vector current –smaller by 2 orders

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4. E>200MeV(QE)

can be calculated using the spectral function for O.

can be calculated as follows:

is estimated by using Spectroscopic factors of Oxygen and some data.

( ) NW

VNNCV FFF 12

1;

1 sin221 θ−=

( ) NW

VNNCV FFF 22

2;

2 sin221 θ−±= ( )22

22QM

FMFNC

ANCpseudo +

ANC

A FF21

±=NC Form factor:

μμ JjG

NC 2=Η

( ) ( ) ( ) τμμτμμμμμμμ νγγννγγννγγν +++++= 111 eejem

WV JJJ μμμ θ23; sin2−=

emS

emV

em JJJ ,3, μμμ += 21 VV iJJJ μμμ ±=±

( )⎟⎠

⎞⎜⎝

⎛ +=Η +−−+ μμ

μμ

)()()()(

2JjJjG

CC

Hadronic current:

Electromagnetic current:

2/1.1 cGeVM A =

Leptonic current:

( )( ) ( γννσ

γννσ

+→×++→+=

+++→+

XXBrXnpO

XnpO

NC

NC**16

16

/

/

( )XnpONC ++→+ /16 ννσ

( )XNnpNNC ++→+ ννσ ),(

( )γ+→XXBr *

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30MeV

25MeV

20MeV

15MeV

10MeV

5MeV

15O

14O+n

14N+p

7.55

4.635.17

13.2 g.s.

7.30

3.95

29.0

5.18

0

28.0

2.31

4.925.115.695.836.206.457.03

Sp=4.63

1s1/2

1p3/2

1p1/2

proton neutron

ν ν

14N+n 14C+p

15N

30MeV

25MeV

20MeV

15MeV

10MeV

5MeV

10.8

2.31

3.954.925.115.695.836.206.457.03

10.2

6.096.596.736.907.017.34 8.18

0

5.275.30

26.825.524.8

7.55

1s1/2

1p3/2

1p1/2

proton neutron

ν ν

Eν>200MeV: NC QE process producing γ-raysν+O ν+n+15O*, ν+p+15N*

- -Ejiri, PRC48,1442 (1993).

6.18 P3/2

s1/2

6.32 P3/2

s1/2

9.93 P3/2

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S(p,E) for 16O, O.Benhar,MS et al., PRD72,053005,2005,will give a spectroscopic factor for p,s shells (Fig) when a proton or neutron is kicked out by a neutrino.

S

p3/2state

Scorr(p,E)

p1/2state

O(e,e’p)

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NC quasi-elastic cross section and γ-production cross section- Ankowski, MS et al., PRL.108(2012) 052505

Br=40%XNO ++→+ νν

XNO ++→+ νν

GeVatbySmallerInelasticNCetalKolbebyXOO

)0.1(5.0)15(10).(*

−++→+→+ γννν

Page 20: Neutrino-nucleus interactions relevant to atmospheric neutrinos & …shima/NDM12/talk/Sakuda.pdf · 2012. 6. 26. · Neutrino-nucleus interactions relevant to atmospheric neutrinos

Branching ratio Br(15N*,15O* γ ,Eγ>5MeV)

Br~41% dominated by p3/2, only Br~2% from s1/2

s1/2 cross section, ie Br too, is much suppressed below 200MeV, due to its large binding energy.

18 June, 2009 Makoto Sakuda@LOWE

Page 21: Neutrino-nucleus interactions relevant to atmospheric neutrinos & …shima/NDM12/talk/Sakuda.pdf · 2012. 6. 26. · Neutrino-nucleus interactions relevant to atmospheric neutrinos

We used the following numbers for Br(S1/2 g, E>5MeV):15N Br=15.6% (E148), 15O Br=16% (Kamyshkov et al.,PRD67)

s1/2: Br(15N s1/2 γ)=2/8x0.422x0.16=0.02p3/2:Br(15N p3/2 γ)=4/8x0.703x1.0=0.352If the cross sections for s1/2 and p3/2 are the same, we simply obtain Br=0.352+0.02=0.37.

Since the binding energy of s1/2 is larger, the cross section of p3/2 is larger and Br of γ-production is dominated by p3/2. We obtain Br~41%.

Page 22: Neutrino-nucleus interactions relevant to atmospheric neutrinos & …shima/NDM12/talk/Sakuda.pdf · 2012. 6. 26. · Neutrino-nucleus interactions relevant to atmospheric neutrinos

5. Preparing for O,C(p,p’γ),(He,tγ) at 0 degrees at RCNP

This proposal is relevant to supernova physics (E<100MeV). We would like to measure γ-rays from excited states including giant resonances in 5<Ex<20MeV.

Particle beam: p or 3He (max E=400MeV)Target: 16O and 12C Grand Raiden: Measure excitation energy

Ex with scattered p or t at ~0 degrees.ΔEx=20keV(@Ep=295MeV)

γ-ray detector: Placed nearby the target

Page 23: Neutrino-nucleus interactions relevant to atmospheric neutrinos & …shima/NDM12/talk/Sakuda.pdf · 2012. 6. 26. · Neutrino-nucleus interactions relevant to atmospheric neutrinos

Eγ(MeV)

•6MeV γ rays from p3/2 hole are clearly observed.•Br(15N*(s-hole) 15Nγ)=15.6+-1.3%, Eγ>6MeV.

Excitation energy Ex (MeV)Eγ

E148 16O(p,2p)15N* measured Br(15N* γ) Tag Ex (ΔEx=20KeV) and Eγ. Kobayashi et al.,nucl-ex/0604006 (@NuInt04)

NaI

Ice target

5MeV

6.3MeV

Page 24: Neutrino-nucleus interactions relevant to atmospheric neutrinos & …shima/NDM12/talk/Sakuda.pdf · 2012. 6. 26. · Neutrino-nucleus interactions relevant to atmospheric neutrinos

Target and γ detector array (Photo from E148)

We designed one 5x5 NaI(Tl) array (25x25x15cm), using inner 3x3 array as active counters and outer 16 counters as veto (Compton suppression) counters. Downstream Veto counters (CsI) will be installed too. We have 27 NaIs from RCNP E148 O(p,2p)N.

18 June, 2009 Makoto Sakuda@LOWE

γ

15cm

Veto

Active

25cm

Target point

Page 25: Neutrino-nucleus interactions relevant to atmospheric neutrinos & …shima/NDM12/talk/Sakuda.pdf · 2012. 6. 26. · Neutrino-nucleus interactions relevant to atmospheric neutrinos

We like to measure O, C(p,p’γ) and O,C(He,tγ) near 0 degrees at RCNP

16O(p,p’) T.Kawabata

Excitation energy[MeV]

•We like to measure γ-rays in the forward direction of O,C(p,p’). No Systematic study has been done.

•Similar motivation: H.Ejiri et al., Ga(He,tγ)Ge, Phys.Lett.B433,257,1998.

Excitation energy[MeV]

12C(p,p’) H.Matsubara, 2010

Page 26: Neutrino-nucleus interactions relevant to atmospheric neutrinos & …shima/NDM12/talk/Sakuda.pdf · 2012. 6. 26. · Neutrino-nucleus interactions relevant to atmospheric neutrinos

Super-K search for SRN (Zhang@ν2012)

(1) Single tag analysis: K.Bays et al.,Phys.Rev.D85 052007,2012) used SK-I,SK-II and SK-III data

*SRN Flux< 1.7*(LMA Flux) (90%CL) for Ee>16MeV

(2) Double tag analysis using SK-IV data

*SRN Flux< 6.5*(LMA Flux) (90%CL) for Ee=12-30 MeV

Cf.KamLAND flux <14*LMA flux

26

nepe +→+ +ν

)2.2(,

MeVdpnnepe

γν

+→++→+ +

Page 27: Neutrino-nucleus interactions relevant to atmospheric neutrinos & …shima/NDM12/talk/Sakuda.pdf · 2012. 6. 26. · Neutrino-nucleus interactions relevant to atmospheric neutrinos

Other experimental searches for (SRN) -All these liq.scinti detectors have delayed coincidence (double tag) for a signal.

KamLAND: (8.3MeV<Eν<30.8MeV)

A.Gando etal.,ApJ745,193(2012)

SNO:

Aharmim etal., PRD70,093014(2004).

Aharmim etal., APJ653,1545(2006)

Borexino :

G.Bellini etal.,PLB696,191(2011)

Even KamLAND (4.53kton year) limit is still 2 orders of magnitude above SRN.

)( γν +→++→+ + dpnnepe

)8.144())25.6((

MeVEMeVdnnnede

<<→+++→+ +

ν

γν

)3521( MeVEe << νν

)( γν +→++→+ + dpnnepe

SRN

Page 28: Neutrino-nucleus interactions relevant to atmospheric neutrinos & …shima/NDM12/talk/Sakuda.pdf · 2012. 6. 26. · Neutrino-nucleus interactions relevant to atmospheric neutrinos

KamLAND 25 and MC prediction

They concluded that “Atmospheric ν NC background will be a challenge for future Large Liq.Scintillator detectors”. Fig. from KamLAND paper.

A.Gando etal.,ApJ745,193(2012)).

28

Candidateseν

Page 29: Neutrino-nucleus interactions relevant to atmospheric neutrinos & …shima/NDM12/talk/Sakuda.pdf · 2012. 6. 26. · Neutrino-nucleus interactions relevant to atmospheric neutrinos

SummaryWe reviewed the γ-ray production from excited nuclei in NC ν-O or -C interactions for both E<100MeV and E>200MeV.

Neutrinos from SN explosion in our galaxy Supernova Relic Neutrinos (SRN, DSNB)Shrot or Long Baseline ν-oscillation experiments

We calculated the γ-production from NC QE cross section using the spectral function for the first time. We find that this cross section is larger at E>100MeV than the γ-production based on the excitation of O* which saturates above 200 MeV. This cross section is dominated by p3/2 and Br(NC γ)~40%.We plan to measure both the excitation energy (Ex) and the energy of γ-rays (Eγ) in the O,C (p,p’γ) and (He,tγ) experiment at ~0 degrees, and thus we will measure the branching ratios of γ−ray emission as functions of Ex from giant resonances for Eγ>5 MeV. This experiment will provide essential information for γ-ray production in NC γ-O,C reactions.

Page 30: Neutrino-nucleus interactions relevant to atmospheric neutrinos & …shima/NDM12/talk/Sakuda.pdf · 2012. 6. 26. · Neutrino-nucleus interactions relevant to atmospheric neutrinos

Backup

18 June, 2009 Makoto Sakuda@LOWE

Page 31: Neutrino-nucleus interactions relevant to atmospheric neutrinos & …shima/NDM12/talk/Sakuda.pdf · 2012. 6. 26. · Neutrino-nucleus interactions relevant to atmospheric neutrinos

Apology: I skip the recent progress in improved shell model calculation (E<100MeV)

JPS Journal “Buturi” (January 2012).

SFO model: