1/24 Complementarity Between Hyperkamiokande and DUNE Osamu Yasuda Tokyo Metropolitan University August 24, 2016 WG1, NuFact 2016@ Quy Nhon, Vietnam Based on arxiv:1607.03758, Shinya Fukasawa, Monojit Ghosh & OY
1. Introduction Motivations for determination of mixing angles, mass hierarchy, CP phase Parameter degeneracy 2. Sensitivity of T2HK, ν atm @HK, DUNE Mass hierarchy Octant degeneracy CP Precision 3. Conclusion 2/24
1. Introduction Framework of 3 flavor ν oscillation Mixing matrix Functions of mixing angles θ 12, θ 23, θ 13, and CP phase δ ν ν ν e = μ τ U U U e1 μ1 τ1 U U U e2 μ2 τ2 U U U e3 μ3 τ3 All 3 mixing angles have been measured (2012): ν ν ν 1 2 3 Both hierarchy patterns are allowed Normal Hierarchy Inverted Hierarchy ν solar +KamLAND (reactor) θ π 6 2 5 2 12, m21 8 10 ev ν atm +K2K,MINOS(accelerators) π 2 3 2 DCHOOZ+Daya Bay+Reno (reactors), T2K+MINOS+Nova etc θ 23, m32 2.5 10 ev 4 θ 13 π / 20 3/24
4/24 Next things to do are to determine the following: sign(δm 2 31) π/4-θ 23 δ Both hierarchy patterns are allowed Normal Hierarchy Inverted Hierarchy m > 0 m2 < 0 2 32 32
Motivation for precise measurements of mixing angles From symmetry arguments there have been predictions for mixing angles -> Quark-lepton complementarity Minakata, Smirnov, PR D70 (2004) 073009 θ 12 +θ C = 45 deg θ 13 = 8.9 deg θ 12 = 35.4 deg θ 23 = 42.1 deg Dighe, Goswami, Roy PR D76 (2007) 096005 T symmetry Eby-Frampton, Phys.Rev. D86 (2012) 117304 π/4 - θ 23 = 2-1/2 θ θ 13 = 8.9 deg 13 θ 23 = 38.7 deg 5/24
6/24 Motivation for determining mass hierarchy (i) Guidelines for models (GUT etc.) (ii) Influence on the measurement of CP phase (iii) Implication for neutrinoless double β decay Motivation for determining the CP phase (i) Guidelines for models (GUT etc.) (ii) Leptogenesis?
7/24 Understanding degeneracy by appearance probabilities hierarchy - δ cp octant - δ cp Prakash, Raut, Sankar, PRD 86, 033012 (2012) Agarwalla, Prakash, Sankar, JHEP 1307, 131 (2013) T2HK E/GeV Due to uncertainty in δ, the appearance probabilities has finite width. -> Each border is approximately realized for δ = + π/2 or - π/2
Hierarchy T2HK NH-IH Separation is good only for δ ~ - π/2 E/GeV E/GeV For δ ~ π/2 degeneracy exists both in ν & ν 8/24
9/24 Octant T2HK HO-LO Separation is possible w/ ν & ν for most of δ NH o o NH E/GeV E/GeV Unlike hierarchy degeneracy, δ= π/2 lies on the same side for ν & ν
Hierarchy DUNE NH-IH Separation is good for any δ E/GeV E/GeV 10/24
11/24 Octant DUNE HO-LO Separation is possible w/ ν & ν for most of δ o o E/GeV E/GeV
12/24 Hierarchy ν atm @HK Hierarchy separation is excellent for cosθ = 0.9 (L=11500km)
2. Sensitivity of T2HK, ν atm @HK, DUNE arxiv:1607.03758, Shinya Fukasawa, Monojit Ghosh & OY The parameters assumed here: T2HK 0.56 Mton fiducial volume (old design) ν:anti-ν = 1:1 Total exposure: 1.56 x 10 22 POT ν atm @HK (old design) 0.56 Mton fiducial volume x 2000 days DUNE 34 kt LiAr detector, ν:anti-ν = 1:1 Total exposure: 10 X 10 21 POT 13/24
2.1 Sensitivity to Mass Hierarchy 14/24 Sensitivity of DUNE is excellent for any δ IH NH Sensitivity of T2HK is poor except for δ ~±π/2 Sensitivity of T2HK+ν atm @HK is improved for any δ
Sensitivity of ν atm @HK to Mass Hierarchy 15/24 WH: Wrong Hierarchy TH: True Hierarchy Sensitivity of ν atm @HK is worsen for IH (but still > 2.4σ) Sensitivity of T2HK+ν atm @HK is good
Dependence of #(events) for multi-gev in ν atm on δ, θ 23 NH, θ 23 =40 o etc e-like Variation in #(events) are in general larger for NH Variation in #(events) are in general smaller for NH μ-like If TH=IH (WH=NH), then there is more freedom to vary δ & θ 23 in χ 2 = χ 2 for TH=IH becomes smaller than χ 2 for TH=NH 16/24
2.2 Sensitivity to Octant degeneracy 17/24 HO-LO Separation is possible for T2HK & DUNE w/ ν & ν for most of δ IH NH
18/24 2.3 Sensitivity to CP Sensitivity of DUNE is excellent for sinδ =1 for both mass hierarchy IH NH Sensitivity of T2HK is poor for (NH, δ =+ π/2) & (IH, δ = - π/2), but T2HK+ν atm @HK has improvement for these regions
19/24 T2HK alone suffers from sign degeneracy for (NH, δ =+ π/2) & (IH, δ =-π/2), but DUNE, T2HK+ν atm @HK, T2HK+ν atm @HK+DUNE don t. NH IH
20/24 T2HK+ν atm @HK+DUNE has the best CP coverage. NH IH
2.4 Precision to oscillation parameters Precision of DUNE is slightly better than that of T2HK. DUNE T2HK θ 23 = (45 +1.4-0.7 ) o Δm 2 31 = (2.4 +0.01-0.01)x10-3 ev 2 Δm 2 31 = (2.4 +0.01-0.009)x10-3 ev 2 θ 23 = (45 +1.1-0.8 ) o 21/24
2.4 Precision to oscillation parameters Combination gives excellent precision. T2HK+natm@HK T2HK+natm@HK+DUNE 0.4% precision 1.3% precision θ 23 = (45 +1.0-0.6 ) o Δm 2 31 = (2.4 +0.006-0.008)x10-3 ev 2 Δm 2 θ 23 = (45 +0.6-0.4 ) o 31 = (2.4 +0.01-0.008)x10-3 ev 2 22/24
23/24 2.4 Precision to oscillation parameters Allowed region in (δ, θ 23 ) plane T2HK+ν atm @HK+DUNE 20% precision δ CP = (-90+8-17 ) o NH
24/24 3. Conclusion Precision measurements of mixing angles, mass hierarchy and CP phase are important for research on Physics Beyond the Standard Model. Resolution of parameter degeneracy can be only possible by combining T2HK + ν atm @HK, T2HK + DUNE or T2HK + ν atm @HK + DUNE. Combining all three, we will get excellent precision in θ 23 (1.3%), Δm 32 2 (0.4%), δ (20%).
Backup slides 25/24
Octant ν atm @HK 26/24
27/24 Sign degeneracy in ν atm Sign degeneracy is avoided if ν & ν are separated.
Sign degeneracy occurs if ν & ν are combined. 28/24
Variation in #(events) are in general larger for NH If True Hierarchy is IH, then there is more freedom to vary δ & θ 23 in χ 2 χ 2 for TN=IH becomes smaller than χ 2 for TN=NH 29/24
30/24 Allowed region in (δ, θ 23 ) plane T2HK NH T2HK+ν atm @HK
Allowed region in (δ, θ 23 ) plane 31/24 DUNE NH T2HK+ν atm @HK+DUNE
32/24 Allowed region in (δ, θ 23 ) plane T2HK IH T2HK+ν atm @HK
Allowed region in (δ, θ 23 ) plane 33/24 DUNE IH T2HK+ν atm @HK+DUNE