1. DUNE as the Next-Generation Solar Neutrino Experiment
Shirley Li
Collaborators: Francesco Capozzi, Guanying Zhu, John Beacom
NUFACT, August 2018

2. Why haven’t we resolved this?
Outline
Data from SK 2016
DUNE comes to rescue!
What is this?
Why haven’t we resolved this?
Shirley Li (SLAC)
2/28

3. Why haven’t we resolved this?
Outline
Data from SK 2016
DUNE comes to rescue!
What is this?
Why haven’t we resolved this?
Shirley Li (SLAC)
3/28

4. Solar neutrino spectra
0.1 MeV
1 MeV
10 MeV
Borexino 2014
8B: used for oscillation study
hep: haven’t been detected
Shirley Li (SLAC)
4/28

5. Solar neutrino oscillation
The survival probability
Vacuum oscillation
1− sin 2 2 𝜃 12
Matter effect
sin 2 𝜃 12
Borexino 2014
Good agreement?
Shirley Li (SLAC)
5/28

6. Oscillation phenomena
Two matter-induced effects
Upturn
Day-night effect
Vissani 2017
Both effects depend on neutrino energy
Shirley Li (SLAC)
6/28

7. Current status Solar & reactor tension Reactor: vacuum oscillation
Data from SK 2016
Reactor: vacuum oscillation
Solar: matter effect
Capozzi et al, in prep
Tension driven by day-night effect
Shirley Li (SLAC)
7/28

8. New physics?
Maltoni & Smirnov, 2015
Shirley Li (SLAC)
8/28

9. Why haven’t we resolved this?
Outline
Data from SK 2016
DUNE comes to rescue!
What is this?
Why haven’t we resolved this?
Shirley Li (SLAC)
9/28

10. 𝜙 𝜈 𝑒 / 𝜙 𝜈 as a function of neutrino energy
What we want to measure
𝜙 𝜈 𝑒 / 𝜙 𝜈 as a function of neutrino energy
Upturn
Day-night effect
Vissani 2017
Shirley Li (SLAC)
10/28

11. SNO: 1999 -- 2006 Both NC and CC channel 𝜈 𝑥 +𝑑→ 𝜈 𝑥 +𝑝+𝑛 𝜈 𝑒 +𝑑→𝑒+𝑝+𝑝
sno.phy.queensu.ca
𝜈 𝑥 +𝑑→ 𝜈 𝑥 +𝑝+𝑛
𝜈 𝑒 +𝑑→𝑒+𝑝+𝑝
𝜈 𝑥 +𝑒→ 𝜈 𝑥 +𝑒
Provides 8B 𝜈 flux: 4%
Shirley Li (SLAC)
11/28

12. SNO: 1999 -- 2006 Both NC and CC channel Provides 8B 𝜈 flux: 4% 12/28
sno.phy.queensu.ca
Provides 8B 𝜈 flux: 4%
Shirley Li (SLAC)
12/28

13. ES channel only: 𝜈 𝑥 +𝑒→ 𝜈 𝑥 +𝑒
Super-K: present
ES channel only: 𝜈 𝑥 +𝑒→ 𝜈 𝑥 +𝑒
𝜈 𝑒 𝑒
𝜈 𝑒, 𝜇, 𝜏
𝜈 𝑒, 𝜇, 𝜏 𝑊 𝑍 𝑒
𝜈 𝑒 𝑒 𝑒
Shirley Li (SLAC)
13/28

14. Super-K: 1996 -- present ES channel only: 𝜈 𝑥 +𝑒→ 𝜈 𝑥 +𝑒
Li 2017
𝑓 𝑒 +1/6( 𝑓 𝜇 + 𝑓 𝜏 )
sin 2 𝜃 limited by SNO flux
Shirley Li (SLAC)
14/28

15. Super-K: 1996 -- present ES channel only: 𝜈 𝑥 +𝑒→ 𝜈 𝑥 +𝑒
Li 2017
Neutrino energy dependence washed out
Smear 𝛿 𝑚 2
Shirley Li (SLAC)
15/28

16. Why haven’t we resolved this?
Outline
Data from SK 2016
DUNE comes to rescue!
What is this?
Why haven’t we resolved this?
Shirley Li (SLAC)
16/28

17. 4 10-kton liquid argon TPC module
DUNE
4 10-kton liquid argon TPC module
Trigger
𝑇 𝑒 >5 MeV
Energy resolution 7%
Angular resolution 25∘
sciencemag.org
Shirley Li (SLAC)
17/28

18. Unique advantage of DUNE
CC channel: 𝜈 𝑒 +Ar→𝑒+ K ∗
𝜈 𝑒 𝑒 𝑊 Ar K* 𝛾
Shirley Li (SLAC)
18/28

19. Unique advantage of DUNE
CC channel: 𝜈 𝑒 +Ar→𝑒+ K ∗
Combine with:
𝜈 𝑥 +𝑒→ 𝜈 𝑥 +𝑒
Improve on sin 2 𝜃
Capozzi et al, in prep
Shirley Li (SLAC)
19/28

20. Unique advantage of DUNE
CC channel: 𝜈 𝑒 +Ar→𝑒+ K ∗
𝐸 𝑒 = 𝐸 𝜈 −𝑄−ΔE
Improve on 𝛿 𝑚 2
Shirley Li (SLAC)
20/28

21. Event rate in DUNE 100 kton-year exposure 21/28 Capozzi et al, in prep
Shirley Li (SLAC)
21/28

22. In addition, 8B flux 2.5%, hep flux 10%
Results
Capozzi et al, in prep
In addition, 8B flux 2.5%, hep flux 10%
Shirley Li (SLAC)
22/28

23. Solar neutrino in DUNE
Program
Shirley Li (SLAC)
23/28

24. Trigger
Shirley Li (SLAC)
24/28

25. Backgrounds Three options: ~ 40 cm of water/plastic shielding
Capozzi et al, in prep
Three options:
~ 40 cm of water/plastic shielding
Double the exposure
Separating gamma from electron
Shirley Li (SLAC)
25/28

26. Threshold Depends on reconstruction & background level
Capozzi et al, in prep
Can be compensated by larger exposure
Shirley Li (SLAC)
26/28

27. Current uncertainty: a few %
Cross section
Current uncertainty: a few %
Capozzi et al, in prep
Shirley Li (SLAC)
27/28

28. Conclusions
Shirley Li (SLAC)
28/28

29. Back up

30. Measured metallicities
Shirley Li (SLAC)
24/24

31. Cross section
Shirley Li (SLAC)
24/24

32. Cross section
Shirley Li (SLAC)
24/24

33. Cross section
Shirley Li (SLAC)
24/24

34. Mass square sensitivity
Shirley Li (SLAC)
24/24