Sushant Raut
Complementarity between current and future
oscillation experiments
Sushant Raut
NuHorizons2018, Allahabad
IBS - Center for Theoretical Physics of the Universe, Daejeon, South Korea
NuHorizons 2018, Allahabad 21 February 2018
Sushant Raut
Standard three-flavour oscillation framework:
Three mixing angles, two independent mass-squared differences, one CP-violating phase
Neutrino Oscillations
NuHorizons2018, Allahabad
Atmospheric + LBL Solar + reactor Reactor + LBL
Dm231 Dm2
21
February 2018
Sushant Raut
Known measurements
NuHorizons2018, Allahabad
1708.01186: de Salas, Forero, Ternes, Tortola, Valle
February 2018
Sushant Raut
Known measurements
NuHorizons2018, Allahabad
1708.01186: de Salas, Forero, Ternes, Tortola, Valle
February 2018
Sushant Raut
Known measurements
NuHorizons2018, Allahabad
1708.01186: de Salas, Forero, Ternes, Tortola, Valle
NH or IH?
LO or HO?
dCP=?
February 2018
Sushant Raut
Beyond standard oscillations
NuHorizons2018, Allahabad February 2018
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...
Sushant Raut
Measuring the unknowns
NuHorizons2018, Allahabad
22 2 2
13 12 2
13 12 23
2 2 2 2
21 31
2
2
2 2
23 23
31 31
ˆsin ( )4sin sin 2
ˆ
2 sin sin 2 si
ˆsin ((1 ) )
ˆ(1 )
ˆ
sin cos
ˆsin((1 ) ) sin( )
ˆ ˆ(1n 2 cos( )
ˆwhere = / , / 4 , /
)CP
e
AP
A
m m m L
A
A
E A
A
m
A A
A
A
d
D
D DD
D
D D D D D
Measurements of the mass hierarchy, octant of 23 and dCP are affected by parameter degeneracies
February 2018
Sushant Raut
Parameter degeneracies:
Pe(NH, dCP) = Pe(IH, dCP’) ; P(23) = P(90-23)
Why do we not know what we don’t know?
NuHorizons2018, Allahabad
See, for example: 1504.06283: Ghosh, Ghoshal, Goswami, Nath, SR 1406.2551: Coloma, Minakata, Parke
February 2018
Sushant Raut
Degeneracies in neutrino parameter space
NuHorizons2018, Allahabad
dCP
0o
90o
270o
180o
February 2018
Sushant Raut NuHorizons2018, Allahabad
dCP
0o
90o
270o
180o
Degeneracies in neutrino parameter space
February 2018
Sushant Raut NuHorizons2018, Allahabad
dCP
0o
90o
270o
180o
Dm231>0
dCP
0o
90o
270o
180o Dm231<0
Degeneracies in neutrino parameter space
February 2018
Sushant Raut NuHorizons2018, Allahabad
dCP
0o
90o
270o
180o
Dm231>0
dCP
0o
90o
270o
180o Dm231<0
NH, LO = IH, HO
Degeneracies in neutrino parameter space
February 2018
Sushant Raut NuHorizons2018, Allahabad
dCP
0o
90o
270o
180o
Dm231>0
dCP
0o
90o
270o
180o Dm231<0
NH, LO = IH, HO NH, UHP = IH, LHP
Degeneracies in neutrino parameter space
February 2018
Sushant Raut NuHorizons2018, Allahabad
dCP
0o
90o
270o
180o
Dm231>0
dCP
0o
90o
270o
180o Dm231<0
NH, LO = IH, HO NH, UHP = IH, LHP No degeneracy
Degeneracies in neutrino parameter space
February 2018
Sushant Raut NuHorizons2018, Allahabad
dCP
0o
90o
270o
180o
Dm231>0
dCP
0o
90o
270o
180o Dm231<0
NH, HO = IH, LO NH, UHP = IH, LHP No degeneracy
Degeneracies in antineutrino parameter space
February 2018
Sushant Raut
Summary of degeneracies
NuHorizons2018, Allahabad
Neutrinos Antineutrinos
February 2018
Sushant Raut
Summary of degeneracies
NuHorizons2018, Allahabad
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 dCP or is insensitive to dCP .
February 2018
Sushant Raut
Summary of degeneracies
NuHorizons2018, Allahabad
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 dCP or is insensitive to dCP .
current best-fit
February 2018
Sushant Raut
Different experiments have different L,E dependence, therefore their functional dependence on a given parameter p is different.
Synergies between experiments
NuHorizons2018, Allahabad
two degenerate values for expt 1
two degenerate values for expt 2
February 2018
Sushant Raut
Different experiments have different L,E dependence, therefore their functional dependence on a given parameter p is different.
Synergies between experiments
NuHorizons2018, Allahabad
two degenerate values for expt 1
two degenerate values for expt 2
true solution
February 2018
Sushant Raut
Combined c2 much higher than sum of the individual c2 : Synergy!
NuHorizons2018, Allahabad
1308.5979: Ghosh, Ghoshal, Goswami, SR
February 2018
Sushant Raut
Current + future experiments
NuHorizons2018, Allahabad
deca
y a
tmos
pheric
react
or
supe
rbeam
February 2018
DUNE ESSnSB
MOMENT DAR
JUNO
PINGU
HK ICAL@INO
T2HK
T2HKK
<~20 km 200-2000 km 20-200 km O(1000-10000 km)
T2K NOvA
Daya Bay D-Chooz
RENO
SK IceCube
Sushant Raut
Matter effects help to break the hierarchy-CP degeneracy
Mass hierarchy
NuHorizons2018, Allahabad
22 2 2
13 12 2
13 12 23
2 2 2 2
21 31
2
2
2 2
23 23
31 31
ˆsin ( )4sin sin 2
ˆ
2 sin sin 2 si
ˆsin ((1 ) )
ˆ(1 )
ˆ
sin cos
ˆsin((1 ) ) sin( )
ˆ ˆ(1n 2 cos( )
ˆwhere = / , / 4 , /
)CP
e
AP
A
m m m L
A
A
E A
A
m
A A
A
A
d
D
D DD
D
D D D D D
February 2018
Sushant Raut
Mass hierarchy
NuHorizons2018, Allahabad
For favourable combinations of parameters, NOvA and T2K can determine the hierarchy very well
1208.3644: Agarwalla, Prakash, SR, Uma Sankar
February 2018
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
Sushant Raut
Mass hierarchy
NuHorizons2018, Allahabad
Additional data from an experiment that is (a) insensitive to CP
1212.1305: Choubey, Ghosh, Thakore
Also see 1203.3388: Blennow, Schwetz
1305.5539: Winter
February 2018
Sushant Raut
Mass hierarchy
NuHorizons2018, Allahabad
1307.2519: Barger et al.
DUNE
February 2018
Additional data from an experiment that (b) has more matter effects to break the degeneracy
Sushant Raut
Mass hierarchy
NuHorizons2018, Allahabad
1307.2519: Barger et al.
DUNE
February 2018
Additional data from an experiment that (b) has more matter effects to break the degeneracy
1704.06116: Agarwalla, Ghosh, SR
or (c) has negligible matter effects in order to measure CP independently of the hierarchy
Sushant Raut
Mass hierarchy
NuHorizons2018, Allahabad February 2018
1611.06118: Abe et al.
T2HKK
T2HKK = T2HK (JD) + T2Kor (KD)
L = 295 km E = 0.6 GeV
L = 1100 km E = 0.6 GeV
Sushant Raut
Mass hierarchy
NuHorizons2018, Allahabad
1508.07166 (JUNO CDR)
February 2018
2 2 2 2
31 12 21sineem m mD D D
Effective mass-squared difference relevant for electron neutrino disappearance experiments
2 2 2 2
31 31 12 212sinIH NH
m m mD D D
JUNO
Sushant Raut
CP violation
NuHorizons2018, Allahabad
Hint from T2K, NOvA and SK for dCP around -90o
Favourable part of the parameter space if the hierarchy is normal
February 2018
Sushant Raut
CP violation
NuHorizons2018, Allahabad
Hint from T2K, NOvA and SK for dCP around -90o
Favourable part of the parameter space if the hierarchy is normal
February 2018
Sushant Raut
CP violation
NuHorizons2018, Allahabad
Hint from T2K, NOvA and SK for dCP around -90o
Favourable part of the parameter space if the hierarchy is normal
February 2018
Sushant Raut
CP violation
NuHorizons2018, Allahabad
Synergy between NOvA and T2K helps constrain the wrong-hierarchy solution
Atmospheric neutrino expts which are typically insensitive to CP, can also improve CP measurement further by eliminating the wrong-hierarchy solution
1504.06283: Ghosh, Ghoshal, Goswami, Nath, SR
February 2018
Sushant Raut
CP violation
NuHorizons2018, Allahabad
DUNE + NOvA + T2K + atmos
T2HK/T2HKK
1412.1744: Ghosh, Goswami, SR
1611.06118: Abe et al.
1703.07136: SR
T2HKK + DUNE
February 2018
Sushant Raut
CP violation
NuHorizons2018, Allahabad
1406.2219: Agarwalla, Choubey, Prakash
ESSnSB ˆ 0lim sin sin( )
e
AC
CP
P
dP
d
dd
D D D
CP sensitivity is greater at the second oscillation maximum (D=3p/2) than at the first one (D=p/2)
February 2018
Sushant Raut
CP violation
NuHorizons2018, Allahabad
1511.02859: Blennow, Coloma, Fernandez-Martinez
February 2018
Sushant Raut
CP violation
NuHorizons2018, Allahabad
1511.02859: Blennow, Coloma, Fernandez-Martinez
1704.06116: Agarwalla, Ghosh, SR
Combination of neutrino and antineutrino data helps in measuring dCP by breaking the degeneracy
February 2018
Sushant Raut
CP violation
NuHorizons2018, Allahabad
1511.02859: Blennow, Coloma, Fernandez-Martinez
1704.06116: Agarwalla, Ghosh, SR
Combination of neutrino and antineutrino data helps in measuring dCP by breaking the degeneracy
February 2018
1802.03677: Smirnov, Hu, Li, Ling
CPV at JUNO with new source of muons
Sushant Raut
Octant of 23
NuHorizons2018, Allahabad February 2018
n disapp
dCP
23
Sushant Raut
Octant of 23
NuHorizons2018, Allahabad February 2018
n disapp ne app
dCP
23
Sushant Raut
Octant of 23
NuHorizons2018, Allahabad February 2018
Larger value of 13
n disapp ne app
dCP
23
n disapp ne app
dCP
23
Sushant Raut
Octant of 23
NuHorizons2018, Allahabad
Synergy in octant measurement: Note the effect of reactor data (prior on 13)
1308.5979: Ghosh, Ghoshal, Goswami, SR
February 2018
Sushant Raut
Octant of 23
NuHorizons2018, Allahabad
DUNE
1307.2519: Barger et al.
February 2018
Sushant Raut
February 2018 NuHorizons2018, Allahabad
Octant of 23
1711.11107: Chakraborty, Deepthi, Goswami
T2HKK/T2HK/DUNE + current experiments
Sushant Raut
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?
Beyond standard oscillations
NuHorizons2018, Allahabad February 2018
Sushant Raut
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?
Beyond standard oscillations
NuHorizons2018, Allahabad
an opportunity to probe BSM physics!
February 2018
Sushant Raut
Sterile neutrinos
NuHorizons2018, Allahabad
1605.04299: Agarwalla, Chatterjee, Palazzo
DUNE: Expansion of the parameter space leads to octant-dCP-d14 degeneracy
February 2018
Also see 1704.07269: Choubey, Dutta, Pramanik
1711.07464: Choubey, Dutta, Pramanik
Sushant Raut
Non-standard interactions
NuHorizons2018, Allahabad
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
1507.02868: Blennow, Choubey, Ohlsson, SR
1705.09500: Tang, Zhang
February 2018
NC NSIs (in propagation) are best probed with large matter effects
Eg. DUNE, T2HKK, atmospheric neutrino experiments
Sushant Raut NuHorizons2018, Allahabad
Degeneracies in measuring CPV at DUNE, T2HK and T2HKK
1612.01443: Liao, Marfatia, Whisnant
February 2018
Also see 1711.04840:Deepthi, Goswami, Nath
Sushant Raut
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
Summary - 1
February 2018 NuHorizons2018, Allahabad
Sushant Raut
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 ne appearance helps to pinpoint the value of dCP
The synergy between reactor data , n disappearance and ne 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.
Summary - 2
February 2018 NuHorizons2018, Allahabad
Sushant Raut NuHorizons2018, Allahabad
THANK YOU
February 2018
Sushant Raut
February 2018 NuHorizons2018, Allahabad