Complementarity between current and future oscillation experiments

Transcription

1 Complementarity between current and future oscillation experiments IBS - Center for Theoretical Physics of the Universe, Daejeon, South Korea NuHorizons 2018, Allahabad 21

2 Neutrino Oscillations Standard three-flavour oscillation framework: Atmospheric + LBL Reactor + LBL Solar + reactor Dm 2 31 Dm 2 21 Three mixing angles, two independent mass-squared differences, one CP-violating phase

3 Known measurements : de Salas, Forero, Ternes, Tortola, Valle

4 Known measurements : de Salas, Forero, Ternes, Tortola, Valle

5 Known measurements NH or IH? : de Salas, Forero, Ternes, Tortola, Valle LO or HO? d CP =?

6 Beyond standard oscillations Charged-current non-standard interactions (Production/detection NSIs): Additional 9+9 amplitudes, 9+9 phases Neutral-current non-standard interactions (Propagation NSIs): Additional 6 amplitudes, 3 phases Sterile neutrinos: Additional 3 angles, 2 phases, 1 mass-squared difference Non-unitary mixing: Additional 9 amplitudes, 9 phases Neutrino decoherence, neutrino decay, extra dimensions, new gauge interactions...

7 Measuring the unknowns ˆ ˆ P e 4sin sin 2 (1 Aˆ ) Aˆ sin((1 Aˆ ) D) sin( Aˆ D) 2 sin 13 sin 2 12 sin 2 23 cos( D dcp) (1 Aˆ) Aˆ sin ((1 A) D) sin ( AD) sin cos where = Dm / Dm, D Dm L / 4 E, Aˆ A / Dm Measurements of the mass hierarchy, octant of 23 and d CP are affected by parameter degeneracies

8 Why do we not know what we don t know? Parameter degeneracies: P e (NH, d CP ) = P e (IH, d CP ) ; P ( 23 ) = P (90-23 ) See, for example: : Ghosh, Ghoshal, Goswami, Nath, SR : Coloma, Minakata, Parke

9 Degeneracies in neutrino parameter space 90 o d CP 180 o 0 o 270 o

10 Degeneracies in neutrino parameter space 90 o d CP 180 o 0 o 270 o

11 Degeneracies in neutrino parameter space 90 o d CP 90 o d CP 180 o Dm 2 31<0 180 o Dm 2 31>0 0 o 0 o 270 o 270 o

12 Degeneracies in neutrino parameter space 90 o d CP 90 o d CP 180 o Dm 2 31<0 180 o Dm 2 31>0 0 o 0 o NH, LO = IH, HO 270 o 270 o

13 Degeneracies in neutrino parameter space 90 o d CP 90 o d CP 180 o Dm 2 31<0 180 o Dm 2 31>0 0 o 0 o NH, LO = IH, HO 270 o NH, UHP = IH, LHP 270 o

14 Degeneracies in neutrino parameter space 90 o d CP 90 o d CP 180 o Dm 2 31<0 180 o Dm 2 31>0 0 o 0 o 270 o 270 o NH, LO = IH, HO NH, UHP = IH, LHP No degeneracy

15 Degeneracies in antineutrino parameter space 90 o d CP 90 o d CP 180 o Dm 2 31<0 180 o Dm 2 31>0 0 o 0 o 270 o 270 o NH, HO = IH, LO NH, UHP = IH, LHP No degeneracy

16 Summary of degeneracies Neutrinos Antineutrinos

17 Summary of degeneracies Neutrinos Antineutrinos 0. If the best-fit value is in the green area, we are lucky 1. If we end up in the yellow unshaded area, lift the octant degeneracy by collecting data with the opposite polarity 2. If we are in the shaded area, we need to resolve the hierarchy degeneracy. This can only be done in conjunction with another experiment that measures d CP or is insensitive to d CP.

18 Summary of degeneracies Neutrinos Antineutrinos current best-fit 0. If the best-fit value is in the green area, we are lucky 1. If we end up in the yellow unshaded area, lift the octant degeneracy by collecting data with the opposite polarity 2. If we are in the shaded area, we need to resolve the hierarchy degeneracy. This can only be done in conjunction with another experiment that measures d CP or is insensitive to d CP.

19 Synergies between experiments Different experiments have different L,E dependence, therefore their functional dependence on a given parameter p is different. two degenerate values for expt 1 two degenerate values for expt 2

20 Synergies between experiments Different experiments have different L,E dependence, therefore their functional dependence on a given parameter p is different. true solution two degenerate values for expt 1 two degenerate values for expt 2

21 : Ghosh, Ghoshal, Goswami, SR Combined c 2 much higher than sum of the individual c 2 : Synergy!

22 Current + future experiments <~20 km km km O( km) Daya Bay D-Chooz RENO DAR NOvA T2HK T2K T2HKK DUNE ESSnSB JUNO MOMENT ICAL@INO IceCube HK SK PINGU decay atmospheric reactor superbeam

23 Mass hierarchy ˆ ˆ P e 4sin sin 2 (1 Aˆ ) Aˆ sin((1 Aˆ ) D) sin( Aˆ D) 2 sin 13 sin 2 12 sin 2 23 cos( D dcp) (1 Aˆ) Aˆ sin ((1 A) D) sin ( AD) sin cos where = Dm / Dm, D Dm L / 4 E, Aˆ A / Dm Matter effects help to break the hierarchy-cp degeneracy

24 Mass hierarchy For favourable combinations of parameters, NOvA and T2K can determine the hierarchy very well : Agarwalla, Prakash, SR, Uma Sankar For unfavourable combinations, we need to disentangle hierarchy and CP. For this we need data from an experiment that is either (a) insensitive to CP, (b) has more matter effects to break the degeneracy, or (c) has negligible matter effects in order to measure CP independently of the hierarchy

25 Mass hierarchy Additional data from an experiment that is (a) insensitive to CP : Choubey, Ghosh, Thakore Also see : Blennow, Schwetz : Winter

26 Mass hierarchy Additional data from an experiment that (b) has more matter effects to break the degeneracy DUNE : Barger et al.

27 Mass hierarchy Additional data from an experiment that (b) has more matter effects to break the degeneracy DUNE : Barger et al. or (c) has negligible matter effects in order to measure CP independently of the hierarchy : Agarwalla, Ghosh, SR

28 Mass hierarchy T2HKK = T2HK (JD) + T2Kor (KD) : Abe et al. T2HKK L = 295 km E = 0.6 GeV L = 1100 km E = 0.6 GeV

29 Mass hierarchy Dm Dm sin Dm ee Effective mass-squared difference relevant for electron neutrino disappearance experiments 2 IH 2 NH sin Dm Dm Dm (JUNO CDR) JUNO

30 CP violation Hint from T2K, NOvA and SK for d CP around -90 o Favourable part of the parameter space if the hierarchy is normal

31 CP violation Hint from T2K, NOvA and SK for d CP around -90 o Favourable part of the parameter space if the hierarchy is normal

32 CP violation Hint from T2K, NOvA and SK for d CP around -90 o Favourable part of the parameter space if the hierarchy is normal

33 CP violation Synergy between NOvA and T2K helps constrain the wrong-hierarchy solution : Ghosh, Ghoshal, Goswami, Nath, SR Atmospheric neutrino expts which are typically insensitive to CP, can also improve CP measurement further by eliminating the wronghierarchy solution

34 CP violation DUNE + NOvA + T2K + atmos : Ghosh, Goswami, SR : SR T2HK/ T2HKK T2HKK + DUNE : Abe et al.

35 CP violation dp e lim Dsin Dsin( D d ) Aˆ CP 0 dd CP : Agarwalla, Choubey, Prakash ESSnSB CP sensitivity is greater at the second oscillation maximum (D=3p/2) than at the first one (D=p/2)

36 CP violation : Blennow, Coloma, Fernandez-Martinez

37 CP violation : Blennow, Coloma, Fernandez-Martinez Combination of neutrino and antineutrino data helps in measuring d CP by breaking the degeneracy : Agarwalla, Ghosh, SR

38 CP violation : Blennow, Coloma, Fernandez-Martinez Combination of neutrino and antineutrino data helps in measuring d CP by breaking the degeneracy : Agarwalla, Ghosh, SR CPV at JUNO with new source of muons : Smirnov, Hu, Li, Ling

39 Octant of 23 n disapp d CP 23

40 Octant of 23 n disapp n e app d CP 23

41 Octant of 23 n disapp n e app n disapp n e app d CP d CP Larger value of 13

42 Octant of : Ghosh, Ghoshal, Goswami, SR Synergy in octant measurement: Note the effect of reactor data (prior on 13 )

43 Octant of 23 DUNE : Barger et al.

44 Octant of 23 T2HKK/T2HK/DUNE + current experiments : Chakraborty, Deepthi, Goswami

45 Beyond standard oscillations Beyond standard oscillation scenarios: CC NSIs (production/detection), NC NSIs (propagation), Sterile neutrinos, Non-unitarity,... Q1: How does the presence of new physics affect the measurement of the standard neutrino parameters? Q2: Can the new physics parameters be measured?

46 Beyond standard oscillations Beyond standard oscillation scenarios: CC NSIs (production/detection), NC NSIs (propagation), Sterile neutrinos, Non-unitarity,... Q1: How does the presence of new physics affect the measurement of the standard neutrino parameters? Q2: Can the new physics parameters be measured? an opportunity to probe BSM physics!

47 Sterile neutrinos : Agarwalla, Chatterjee, Palazzo DUNE: Expansion of the parameter space leads to octant-d CP -d 14 degeneracy Also see : Choubey, Dutta, Pramanik : Choubey, Dutta, Pramanik

48 Non-standard interactions To probe CC NSIs (at source and detector) without interference from the NC NSIs (in propagation), use a low-energy experiment to reduce matter effects Eg. ESSnuSB Eg. MOMENT : Blennow, Choubey, Ohlsson, SR : Tang, Zhang NC NSIs (in propagation) are best probed with large matter effects Eg. DUNE, T2HKK, atmospheric neutrino experiments

49 Degeneracies in measuring CPV at DUNE, T2HK and T2HKK : Liao, Marfatia, Whisnant Also see :Deepthi, Goswami, Nath

50 Summary - 1 The presence of parameter degeneracies makes it difficult to measure the oscillation parameters unambiguously These degeneracies can be lifted by a synergistic combination of experiments with different baselines, energies and channels If Nature has chosen a favourable combination of the parameters, a measurement of the mass hierarchy, octant and CPV may be around the corner with T2K+NOvA+SK data The next generation of experiments: DUNE, T2HK, T2HKK, ICAL@INO, etc will be able to determine the oscillation parameters accurately

51 Summary - 2 Matter effects play a crucial role in determining the mass hierarchy. Higher energy long-baseline and atmospheric neutrino data are useful in this regard The synergy between reactor data and n e appearance helps to pinpoint the value of d CP The synergy between reactor data, n disappearance and n e appearance (neutrino+antineutrino) helps to determine the octant of 23 In the case of new physics, many new degenerate solutions arise; new strategies will have to be devised to measure the parameters in such cases.

52 THANK YOU

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