Mass hierarchy and CP violation with upgraded NOA and T2K...
Transcript of Mass hierarchy and CP violation with upgraded NOA and T2K...
Mass hierarchy and CP violation with upgradedNOνA and T2K in light of large θ13
Suprabh Prakash
Department of PhysicsIndian Institute of Technology Bombay
Mumbai, India
September 26, 2012
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 1 / 39
This talk is based on the following works:
SP, S. K. Raut, S. U. Sankar, Getting the best out of T2K and NOνA ,Phys. Rev. D 86, 033012 (2012) arXiv:1201.6485
S. K. Agarwalla, SP, S. K. Raut, S. U. Sankar, Potential of optimizedNOνA for large θ13 and combined performance with a LArTPC and T2K,arXiv:1208.3644
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 2 / 39
Outline
Introduction
Recent reactor neutrino results
The superbeam experiments: Pµe channel
Hierarchy-δCP degeneracy
Reoptimized NOνA, for large θ13 and NOνA upgrades
Mass hierarchy sensitivity
Leptonic CP violation sensitivity
Results and Summary
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 3 / 39
The physics of neutrino oscillations
Neutrinos are massive and they mix
As they travel, they can oscillate from one flavor to another
The physics of flavor oscillations can solely be explained by quantummechanics Quant. Mech. description
Neutrino oscillations are sensitive to 6 parameters:
3 mixing angles: θ12, θ13 and θ23
A leptonic CP violating phase: δCP
2 mass squared differences between the 3 mass eigenvalues:∆21 = m2
2 − m21 and ∆31 = m2
3 − m21
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 4 / 39
Present status of neutrino oscillations
Best fit points, 1σ & 3σ ranges for various neutrino parameters (after Neutrino2012):
[Gonzalez-Garcia,Maltoni,Salvado,Schwetz, arXiv:hep-ph/1209.3023v2]Global sin2 2θ13 best-fit: 0.089Best final precision on sin2 2θ13: Daya Bay: ∼5%
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 5 / 39
The unknowns in neutrino oscillations physics
Mass hierarchy
We do not know whether the hierarchyis
Normal: m1 < m2 � m3 or
Inverted: m3 � m1 < m2 ?
Leptonic CP violation
Whether CP is violated in the leptonic sector?i.e. is P(α→ β) 6= P(α→ β) ?
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 6 / 39
Recent θ13 measurements by reactor neutrino experiments
Updated results from Reactor Neutrino Experiments (reported at Neutrino2012):
Daya Bay: sin2 2θ13 = 0.089± 0.011(stat)± 0.005(syst) , 7.7σ fornon-zero θ13
RENO: sin2 2θ13 = 0.113± 0.013(stat)± 0.019(syst) , 4.9σ fornon-zero θ13
Double CHOOZ: sin2 2θ13 = 0.109± 0.030(stat)± 0.025(syst) , 3.1σfor non-zero θ13
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 7 / 39
Implications of a large θ13
Nature has been very friendly to us with θ13
Present and future generation Superbeam experiments have a very goodscope of performing well
With present generation superbeam experiments, one can get significanthints about both hierarchy and δCP
And, if we are lucky with δCP also, the present generation superbeamexperiments will be able to establish hierarchy as well
However, establishing CP violation and measuring the phase δCP mightnot be possible even with such a large θ13
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 8 / 39
The superbeam experiments
An intense beam of neutrinos directed towards a detector
Most experiments plan to run in both ν as well as ν mode
The beams primarily consists of the µ-type ν/ν; contaminations are alsopresent which lead to backgrounds
The beam is directed towards a detector which in general is locatedfar-off and the beam travels entirely through the earth which leads tomatter effects
The distance that the beam travels i.e. the baseline, is important
The beam profile i.e. the Eν at which the flux peaks, is also important
Finally, in the detector, one looks for electron appearance i.e. νµ whichhave oscillated to νe
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 9 / 39
The Pµe oscillation channel
νµ → νe oscillation probability, expanded perturbatively in α = ∆21/∆31:
Pµe = sin2 2θ13 sin2 θ23sin2 ∆(1− A)
(1− A)2
+α cos θ13 sin 2θ12 sin 2θ13 sin 2θ23 cos(∆ + δCP)sin ∆A
A
sin ∆(1− A)
1− A
+α2 sin2 2θ12 cos2 θ13 cos2 θ23sin2 ∆A
A2
where
∆ = ∆31L/4E
A = A/∆31
Wolfenstein matter term: A(eV2) = 0.76× 10−4ρ(gm/cc)E(GeV).
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 10 / 39
Dependence of Pµe on the baseline
Pµe(as a band in δCP) vs. EnergyLeft panel: L=295 km & Right panel: L=810 km
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sin22θ13 = 0.1
295 km
NHIH
δCP = +90o
δCP= -90o
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sin22θ13 = 0.1
810 km
NHIH
δCP = +90o
δCP= -90o
The value of Pµe scales with LThe position of 1st Oscillation maxima also scales with L
Go Back
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 11 / 39
Various LBL superbeam experiments
Present generation LBL superbeam experiments
MINOS: 735 km
T2K: 295 km
NOνA: 810 km
Next generation LBL superbeam experiments
CERN-Frejus: 130 km
T2HK: 295 km
CERN-Canfranc: 630 km
CERN-Gran Sasso: 730 km
CERN-Homestake: 1300 km
CERN-Pyhasalmi: 2300 km
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 12 / 39
The Pµe oscillation channel: degeneracies
The Pµe channel
Has sensitivity to all the neutrino parameters
Pros: This feature, in principle, makes measurement of all neutrinoparameters possible using superbeam
Cons: This very feature handicaps it of various degeneracies
A measurement of Pµe will have
Intrinsic or (δCP, θ13)-degeneracy
Hierarchy or sign(∆31)-degeneracy
Octant or θ23-degeneracy
This leads to an eight-fold degeneracy in determination of θ13 and δCP.[Barger et. al., hep-ph/0112119]
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 13 / 39
The Pµe oscillation channel: degeneracies
But, the reactor neutrino experiments are independent of these degeneraciesas they are independent of δCP and matter-effects (hence hierarchy) andtherefore, they have provided a very clean measurement of θ13.
In this work, we have assumed a precise information of θ13. Hence thedegeneracies relevant for us are:
hierarchy-δCP degeneracy
Octant or θ23-degeneracy
We further assume the maximal value of sin2 2θ23 = 1 and, for the moment,ignore the octant degeneracies. So, the degeneracy relevant for this work is
hierarchy-δCP degeneracy
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 14 / 39
Hierarchy-δCP degeneracy
Pµe(as a band in δCP) vs. EnergyLeft panel: Neutrinos & Right panel: Anti-neutrinos
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sin22θ13 = 0.1
810 km
NHIH
δCP = +90o
δCP= -90o
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sin22θ13 = 0.1
810 km
NHIH
δCP = +90o
δCP= -90o
Lower half plane (−180◦ ≤ δCP ≤ 0): favourable plane for NH
Upper half plane (0 ≤ δCP ≤ 180◦): favourable plane for IH
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 15 / 39
Resolving the hierarchy-δCP degeneracy
The hierarchy-δCP degeneracy can be resolved in following ways:1 Including atmospheric data2 The Magic baseline proposal [Barger et. al., hep-ph/0112119; Huber and
Winter, hep-ph/0301257]3 By combining data from more that one channels like: νe → νµ orνe → ντ [Donini et. al., hep-ph/0206034]
4 The Bimagic baseline proposal5 By combining data from more than one LBL superbeam experiments
[Barger et. al., hep-ph/0112119]
Option 1 is a free source, but for a good hierarchy sensitivity, huge statisticsare required.While options 2 and 3 are futuristic and challenging to implement, options 4and 5 are more feasible
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 16 / 39
The Bimagic baseline
Pµe(as a band in δCP) vs. Energy for 2540 kmLeft panel: Neutrinos & Right panel: Anti-neutrinos
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sin22θ13 = 0.1
2540 km
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δCP = +90o
δCP= -90o
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sin22θ13 = 0.1
2540 km
NHIH
δCP = +90o
δCP= -90o
Clean separation between NH and IH around 1st Osc. maximaOne of the hierarchy loses its δCP dependence around 3 GeV and theother is amplified
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 17 / 39
The Bimagic baseline
References for 2540 km:[Raut et. al. arXiv:0908.3741, Phys.Lett.B696:227-231,2011][Dighe et. al. arXiv:1009.1093, Phys.Rev.Lett.105:261802,2010][Joglekar et. al. arXiv:1011.1146, Mod.Phys.Lett.A26:2051-2063,2011]
CERN-Pyhasalmi (L=2300 km), one strong contender for the LBLsuperbeam experiment in Europe, is very close to the bimagic baseline
Very good sensitivity to mass hierarchy even with very moderateexposures [Dusini et. al. arXiv:1209.5010]
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 18 / 39
NOνA and T2K
Characteristic NOνA T2KBaseline
810 km 295 kmLocation Fermilab-Ash River J-PARC-KamiokaBeam NuMI beam 0.8◦ off
- axisJHF beam 2.5◦ off -axis
Beam power 0.7 MW 0.75 MWBeam peaks at
2 GeV 0.6 GeVPµe 1st Osc. Maximum 1.5 GeV 0.55 GeVDetector TASD, 14 kton Water Cerenkov,
22.5 ktonRuntime
3 in ν+3 in ν 5 in ν
Simulation Details
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 19 / 39
Hierarchy sensitivity of NOνA
NOνA with various design statisticsLeft panel: NH is true & Right panel: IH is true
-180
-120
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60
120
180
0 0.05 0.1 0.15 0.2
δC
P(t
rue)
sin2 2θ13(true)
True:NH / Test:IH, 90% C.L.
NOνA1.5*NOνA
3*NOνA
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-120
-60
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60
120
180
0 0.05 0.1 0.15 0.2
δC
P(t
rue)
sin2 2θ13(true)
True:IH / Test:NH, 90% C.L.
NOνA1.5*NOνA
3*NOνA
For the bestfit, 90% C.L. hint for the whole of favourable half planeAlmost no sensitivity in the unfavourable half plane, even with largerstatistics
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 20 / 39
Hierarchy sensitivity of NOνA + T2K
NOνA + T2K with nominal design statisticsLeft panel: NH is true & Right panel: IH is true
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-120
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60
120
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0 0.05 0.1 0.15 0.2
δC
P(t
rue)
sin2 2θ13(true)
True:NH / Test:IH, 90% C.L.
NOνA+T2K
-180
-120
-60
0
60
120
180
0 0.05 0.1 0.15 0.2
δC
P(t
rue)
sin2 2θ13(true)
True:IH / Test:NH, 90% C.L.
NOνA+T2K
Adding the T2K data helps in the unfavourable half plane; butinsufficient for the bestfitNo difference in the favourable half plane
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 21 / 39
Resolving hierarchy-δCP degeneracy using two differentLBL experiments
Event sample observed in the detector has to be analyzed assuming a truemass hierarchy. If the assumption is right, we get a right estimate of δCP
(∆χ2min occuring at right δCP). If the assumption is wrong, we get a wrong
estimate of δCP (∆χ2min occuring at wrong δCP).
measurement has degenerate solutions: (hierright, δCPright) and
(hierwrong, δCPwrong)
For a given experiment, (sin δCPright − sin δCP
wrong) ∝ A ∝ E ∝ L forthat experiment [O. Mena and S. Parke, arXiv:hep-ph/0408070]
E810 kmpeak flux ' 3 · E295 km
peak flux
(sin δCPright − sin δCP
wrongNOνA) ' 3 · (sin δCP
right − sin δCPwrongT2K )
δCPwrong predicted by two LBL experiments with different matter effects
are different (also evident from the Pµe vs. E plots )
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 22 / 39
Resolving hierarchy-δCP degeneracy using two differentLBL experiments
[∆χ2min]NOνA at (hierright, δCP
right) and (hierwrong, δCPwrongNOνA)
[∆χ2min]T2K at (hierright, δCP
right) and (hierwrong, δCPwrongT2K )
[∆χ2]NOνA not minimal at (hierwrong, δCPwrongT2K )
[∆χ2]T2K not minimal at (hierwrong, δCPwrongNOνA)
[∆χ2min]NOνA+T2K not at (hierwrong, δCP
wrongNOνA) or (hierwrong, δCP
wrongT2K )
=⇒ wrong solutions excluded
Caveat: In order to have reasonable excluding sensitivity, ∆χ2min value at
(hierwrong, δCPwrong) should be much larger than ∆χ2
min value at (hierright,δCP
right). Therefore, the experiments must have enough statistics.
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 23 / 39
How does combining data from two LBL help?
χ2 vs. δCP(test) plots for NOνALeft panel: favourable half plane & Right panel: unfavourable half plane
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χ2
δCP(test)
1.5*NOνA True sin22θ13 : 0.1
True:NH / Test:IH
True δCP = -180o
True δCP = -135o
True δCP = -90o
True δCP = -45o
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χ2
δCP(test)
1.5*NOνA True sin22θ13 : 0.1
True:NH / Test:IH
True δCP = 0
True δCP = 45o
True δCP = 90o
True δCP = 135o
χ2min always occurs around −90◦
χ2min large for fav. half plane, very small for unfav. half plane
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 24 / 39
How does combining data from two LBL help?
χ2 vs. δCP(test) plots for T2KLeft panel: favourable half plane & Right panel: unfavourable half plane
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χ2
δCP(test)
2*T2K True sin22θ13 : 0.1
True:NH / Test:IH
True δCP = -180o
True δCP = -135o
True δCP = -90o
True δCP = -45o
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5
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χ2
δCP(test)
2*T2K True sin22θ13 : 0.1
True:NH / Test:IH
True δCP = 0
True δCP = 45o
True δCP = 90o
True δCP = 135o
Right panel: large χ2 where χ2min of NOνA was almost 0
Right panel: χ2min occurs at test δCP different from that of NOνA
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 25 / 39
How does combining data from two LBL help?
χ2 vs. δCP(test) plots for 1.5*NOνA +2*T2KLeft panel: 1.5*NOνA only & Right panel: 1.5*NOνA +2*T2K
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χ2
δCP(test)
True (sin22θ13, δCP) = (0.1, 90
o)
1.5*NOνA
χ2 = 2.71, 90% C.L.
True:NH / Test:NHTrue:NH / Test:IH
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χ2
δCP(test)
True (sin22θ13, δCP) = (0.1, 90
o)
1.5*NOνA+2*T2K
χ2 = 2.71, 90% C.L.
True:NH / Test:NHTrue:NH / Test:IH
Left panel: A large range of wrong δCP compatible with wrong hierarchyRight panel: Adding T2K data almost eliminates this wrong δCP range
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 26 / 39
How does combining data from two LBL help?
χ2 vs. δCP(test) plots for 1.5*NOνA +2*T2KLeft panel: 1.5*NOνA only & Right panel: 1.5*NOνA +2*T2K
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10
15
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25
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35
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χ2
δCP(test)
True (sin22θ13, δCP) = (0.1, -90
o)
1.5*NOνA
χ2 = 2.71, 90% C.L.
True:IH / Test:NHTrue:IH / Test:IH
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5
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15
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χ2
δCP(test)
True (sin22θ13, δCP) = (0.1, -90
o)
1.5*NOνA+2*T2K
χ2 = 2.71, 90% C.L.
True:IH / Test:NHTrue:IH / Test:IH
Left panel: A large range of wrong δCP compatible with wrong hierarchyRight panel: Adding T2K data almost eliminates this wrong δCP range
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 27 / 39
Reoptimization and upgrades in NOνA, post-large θ13
We study the physics reach of the reoptimized NOνA (in conjunctionwith T2K) to determine the mass hierarchy and CP violation
There is considerable enthusiasm in the NOνA and LBNE collaborationsfor an additional small liquid argon detector at the Ash River site
We consider the possiblility of such a module
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 28 / 39
Reoptimized NOνA
Previous optimization: done under the assumption sin2 2θ13 = 0 withobjective to have least background
New optimization: for moderately large θ13 with relaxed cuts for eventselection criteria which allow more signal and background [talk by R.Patterson in NuFACT 12]
The main differences between the old criteria and new criteria are:
The signal efficiencies for new NOνA are higher than that of old one byroughly a factor of 2 for neutrino events
The background acceptance has also increased
The NC spectrum shift to the measured energies is implemented throughmigration matrices. [LBNE Collaboration, T. Akiri et al. arXiv:1110.6249]
We have taken care of the neutrino contamination in the anti-neutrinobeam
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 29 / 39
Liquid Argon TPC
A 10 kt liquid argon time projection chamber (LArTPC) constructedclose to NOνA
A signal efficiency of 80% for e± compared to 45% for TASD [LBNECollaboration, T. Akiri et al. arXiv:1110.6249]
The energy resolution and background rejection for the LArTPC andTASD are comparable
Such a detector will come on line much later than NOνA
In considering NOνA + LArTPC, we assume equal 6 years ν and ν runsfor NOνA and equal 3 years ν and ν runs for LArTPC
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 30 / 39
Mass hierarchy sensitivity with upgraded NOνA and T2K
Hierarchy discovery for various set-upsLeft panel: TASD vs. LArTPC for NH true & Right panel: Combined set-upfor NH true
Mass Hierarchy Discovery, NH true
δ
χ
(true)CP
∆
95% C.L.
90% C.L.
2
0
8
10
12
14
16
−180 −90 0 90 180
NOvA (3+3)
5 kt LAr (3+3)
10 kt LAr (3+3)
14 kt LAr (3+3)
4
2
6
Mass Hierarchy Discovery, NH true
χ
CP
∆2
δ
90% C.L.
95% C.L.
(true)
NOvA (6+6) + T2K (5) + 5 kt LAr (3+3)
20
25
30
−180 −90 0 90 180
10
5
0
NOvA (6+6) + T2K (5) + 10 kt LAr (3+3)
NOvA (3+3) + T2K (5+0)
15
Left panel: LArTPC of mass 10 kt can be as effective as 14 kton TASDRight panel: With the addition of a 10 kt LArTPC, close to 95% C.L.hierarchy discrimination becomes possible for all the values of δCP
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 31 / 39
Mass hierarchy sensitivity with upgraded NOνA and T2K
Hierarchy discovery for various set-upsLeft panel: TASD vs. LArTPC for IH true & Right panel: Combined set-upfor IH true
90% C.L.
δ (true)CP
∆ χ
Mass Hierarchy Discovery, IH true
95% C.L.
2
0
8
10
12
14
16
−180 −90 0 90 180
4
2
6
Mass Hierarchy Discovery, IH true
(true)CP
∆ χ2
90% C.L.
95% C.L.
δ
0
20
25
30
−180 −90 0 90 180
10
5
15
Left panel: LArTPC of mass 10 kt can be as effective as 14 kton TASDRight panel: With the addition of a 10 kt LArTPC, close to 95% C.L.hierarchy discrimination becomes possible for all the values of δCP
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 32 / 39
Sensitivity of upgraded NOνA and T2K for CP violation
Leptonic CP violation discovery for various set-upsLeft panel: TASD vs. LArTPC for NH true & Right panel: Combined set-upfor NH true
95% C.L.
(true)CP
∆2
δ
CP Violation Discovery, NH true
90% C.L.χ
0
4
5
6
−180 −90 0 90 180
NOvA (3+3)
5 kt LAr (3+3)
10 kt LAr (3+3)
14 kt LAr (3+3)
2
1
3
90% C.L.
χ∆2
δ (true)
CP Violation Discovery, NH true
95% C.L.
CP
0
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−180 −90 0 90 180
4
2
NOvA (3+3) + T2K (5+0)
NOvA (6+6) + T2K (5+0) + 5 kt LAr (3+3)
NOvA (6+6) + T2K (5+0) + 10 kt LAr (3+3)
6
Left panel: LArTPC of mass 10 kt can be as effective as 14 kton TASDRight panel: Addition of a 10 kt LArTPC significantly improves range oftrue δCP for which CP conservation can be ruled out at 95% C.L.
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 33 / 39
Sensitivity of upgraded NOνA and T2K for CP violation
Leptonic CP violation discovery for various set-upsLeft panel: TASD vs. LArTPC for IH true & Right panel: Combined set-upfor IH true
90% C.L.
CP
∆ χ2
δ
CP Violation Discovery, IH true
95% C.L.
(true)
0
4
5
6
−180 −90 0 90 180
2
1
3
CP Violation Discovery, IH true
2
δ (true)CP
χ
95% C.L.
90% C.L.
∆
0
8
10
12
14
16
−180 −90 0 90 180
4
2
6
Left panel: LArTPC of mass 10 kt can be as effective as 14 kton TASDRight panel: Addition of a 10 kt LArTPC significantly improves range oftrue δCP for which CP conservation can be ruled out at 95% C.L.
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 34 / 39
Can hier-δCP degeneracy be resolved by first measuring δCP?
Can a short LBL experiment such as T2K(295 km) or CERN-Frejus(130km) measure the δCP phase independent of hierarchy with electronappearance channel?
A short baseline has small matter effects and therefore is relatively freeof hierarchy-δCP degeneracy. Therefore, it is expected that it can providea clean δCP measurement.
But it cannot!!
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 35 / 39
Can hier-δCP degeneracy be resolved by first measuring δCP?
Allowed δCP plots for T2K[3+3]Left panel: Hierarchy known & Right panel: Hierarchy not known
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-120
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δC
P (
test
)
δCP (true)
True:NH/Test:NH, 90% C.L.
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-120
-60
0
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120
180
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δC
P (
test
)
δCP (true)
True:NH/Test:IH, 90% C.L.
Left panel: allowed range of test δCP is around true δCP
Right panel: large region of the wrong half-plane alsoSuprabh Prakash (IITB) INFN, Padova visit - Sep 2012 36 / 39
Can hier-δCP degeneracy be resolved by first measuring δCP?
Allowed δCP plots for CERN-Frejus(130 km)Left panel: Hierarchy known & Right panel: Hierarchy not known
-180
-120
-60
0
60
120
180
-180 -120 -60 0 60 120 180
δC
P (
test
)
δCP (true)
True:NH/Test:NH, 90% C.L.
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-120
-60
0
60
120
180
-180 -120 -60 0 60 120 180
δC
P (
test
)
δCP (true)
True:NH/Test:IH, 90% C.L.
Left panel: allowed range of test δCP is around true δCP
Right panel: large region of the wrong half-plane alsoSuprabh Prakash (IITB) INFN, Padova visit - Sep 2012 37 / 39
δCP phase measurement with upgraded NOνA and T2K
δCP phase measurementLeft panel: NOνA +T2K & Right panel: NOνA +T2K+LArTPC
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-60
0
60
120
180
-180 -120 -60 0 60 120 180
δC
P (
test
)
δCP (true)
True:NH/Test:NH 90% C.L.
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-120
-60
0
60
120
180
-180 -120 -60 0 60 120 180
δC
P (
test
)
δCP (true)
True:NH/Test:NH 90% C.L.
A precise δCP phase measurement will require a future facility
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 38 / 39
Summary
A 10 kt LArTPC is found to be equivalent to new NOνA in its ability toexclude the wrong hierarchy and CP violation discovery
For increased exposure for NOνA, the combination of data from NOνA,LArTPC and T2K (nominal) can determine hierarchy at almost 2σ levelfor all the values of δCP
NOνA by itself can discover CP violation only for a small fraction of thefavourable half-plane, and only at 90% C.L.
Addition of data from T2K causes a remarkable increase in the range ofδCP for which CP violation can be established
With the combination of additional data from the LArTPC detector withboosted NOνA and nominal T2K, CP violation can be discovered at 95%confidence level for around 60% of the entire δCP range
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 39 / 39
Suprabh Prakash (IITB) INFN, Padova visit - Sep 2012 40 / 39
n flavor eigenstates |να〉; connected to n mass eigenstates |νi〉 through unitaryPMNS mixing matrix U.
|να〉 =∑
i
Uαi|νi〉
νe
νµντ
= U
ν1ν2ν3
U =
Ue1 Ue2 Ue3Uµ1 Uµ2 Uµ3Uτ1 Uτ2 Uτ3
U = U23 (θ23)× U13 (θ13, δ)× U12 (θ12)× UMaj
Schroedinger’s Eq. in matter : i ddt |να〉 = Hflav
matt|να〉
P (α→ β) =
δαβ − 4<∑
j>i U∗αiUβiUαjU∗
βj sin2 ∆jiL4E + 2=
∑j>i U∗
αiUβiUαjU∗βj sin ∆jiL
2E
∆ji = m2j − m2
i
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