Neutrino oscillation phenomenology

Transcription

1 Neutrino oscillation phenomenology Tokyo Metropolitan University Osamu Yasuda INO-KEK meeting 7 November 007@KEK

2 Contents 1. Introduction. Future long baseline experiments 3. Deviation from the standard scenario 4. Summary

3 1. Introduction Framework of 3 flavor ν oscillation Mixing matrix ν ν ν e U e1 = U µ µ1 U τ τ1 U e U µ U τ U e3 U µ3 U τ3 ν ν ν 1 3 Functions of mixing angles θ 1, θ 3, θ 13, and CP phase δ Information we have obtained so far: ν solar +KamLAND (reactor) θ π 6 5 1, m ev ν atm +KK,MINOS(accelerators) π 3 θ3, m ev 4 CHOOZ (reactor) θ 0.15/ 13

4 U U e1 = U µ1 U τ1 U e U µ U τ U e3 U µ3 U τ3 c1 s / 1 s / 1 s1 c / 1 c / ε / / n Both mass hierarchies are allowed n θ 13 :only upper bound is known n δ :undetermined 3 1 Next task is to measure θ 13, sign( m 31) and δ. 1 normal hierarchy 3 inverted hierarchy m > 0 m < 0 3 3

5 n Theoretical prediction for θ 13 Chen: ISS 3 rd plenary ( RAL

6 Winter: Okayama Systematic generation of ν mass matrices by extended QLC Parameter space analysis based on realizations Large θ 13 preferred Compared to the GUT literature: Some realizations with very small sin θ 13 ~ (Plentinger, Seidl, Winter, hep-ph/061169)

7 hep-ex/ All kinds of values of θ 13 are predicted by theory, and it doesn t look like illuminating. Theory is not yet developed enough to say something on mass & mixing of quarks & leptons.

8 . Future LBL (Long BaseLine experiments) Most realistic way to measure θ 13, sign( m 31) and δ is long base line experiments by accelerators or reactors. Matter effect contributes in LBL in most cases n Two points to be taken into account for precise measurements: (1) Correlation of errors () Parameter degeneracy

9 (1) Correlation of errors If uncertainties of other parameters (such as density of matter ρ A) mimic the dependence on δ, then we cannot determine δ (correlation of errors) We have take into account the uncertainties of other parameters to reject δ=0

10 (Example) There is correlation of errors at a neutrino factory: large correlation E µ =50GeV, L=3000km correlation of errors in ρ and δ is serious for sin θ 13 ~0.1 small correlation sensitivity to sin θ 13 a ν factory is poor for sin θ 13 ~0.1 of small correlation correlation of errors in ρ and δ is not serious for sin θ 13 <0.01

11 () Parameter degeneracy ( ) ( ) Even if we know Pν μ ν e and Pν μ ν e in a long baseline accelerator experiments with approximately monoenergetic neutrino beam, precise determination of θ 13, sign( m 31 )andδ is difficult because of the 8-fold parameter degeneracy. intrinsic (δ, θ 13 ) degeneracy m 31 - m 31 degeneracy θ 3 π/ - θ 3 degeneracy

12 If parameter degeneracy exists, then the errors of the parameters become unnecessarily large. Resolution of parameter degeneracy is important. error w/o degeneracy error w/ degeneracy

13 Future LBL experiments To perform precise measurements of θ 13 and δ, one has to have a lot of numbers of events to improve statistical errors. We need high intensity beam Candidates for high intensity beam in the future: (conventional) superbeam neutrino factory beta beam µ in a storage ring RI in a storage ring μ + μ π + μ + + π μ ν μ e + ν e + ν μ 6 He Li 3 18 Ne 9 ν μ e + ν e + ν μ + e +ν e + F + e +ν e ν ν μ e νμ νe ν e νe νe ν e ν μ νμ νμ ν μ

14 Future LBL exp. (under construction / proposed ) superbeam TK phase I (009-, 0.75MW, E~1GeV, L=95km) TK phase II (4MW+HK, E~1GeV, L=95km) TKK (JAERI HK&Korea, E~1GeV, L=95km&1000km) NOvA (FNAL Ash River (MN), E~GeV, L=810km) VBLNO (BNL DUSEL*, E~GeV, L>500km) (*Deep Underground Science and Engineering Laboratory: Homestake(SD), Icicle Creek(WA), San Jacinto(CA), Soudan(MN), Kimballton(VA), Henderson(CO)) SPL (CERN Frejus, E~0.5GeV, L=130km) neutrino factory (E ν <50GeV, L~3000km) beta beam (E ν = GeV, L~130km) Proposed reactor experiments (E~4MeV, L~km) Double CHOOZ (France), Daya Bay (China), Reno (Korea), Angra (Brazil)

15 sensitivity to the CP phase δ of future experiments 1 error of δ THK = Tokai to HyperKamiokande CP Fraction of δ SPL THK WBB NF BB True value of sin θ 13 arxiv: [hep-ph] GLoBES 006

16 TKK vs. NOνA; CP NOνA II: II: hepex/ thick: 3σ, thin: σ σ nd TKK workshop ( 06)

17 June 005 ~ Aug Evaluate the physics case for the facility Study options for the accelerator complex and neutrino detection systems Physics Group Y. Nagashima Detector Group A. Blondel Accelerator Group M. Zisman Theory Subgroup S.F. King Phenomenology Subgroup OY Experiment Subgroup K. Long Muon Subgroup L. Roberts

18 Theory Subgroup Model building for neutrino mass & mixing Phenomenology Subgroup Deviation from SM with massive neutrinos Experiment Subgroup Estimation of sensitivity and resolution of degeneracy for ν factories and β beams Final report of Physics Group : arxiv: [hep-ph]

19 Accelerator Group Detector Group Physics and Performance Evaluation Group 007 ~ Tentative plan of PPEG - provide sensitivity estimates as requested - track new developments like low E NF - understand optimization in the context of non-standard physics - establish a physics case for all values of θ 13 - keep track of competitors to the NF - near detector, both at a SB and NF - status of cross-sections - muon physics

20 3. Deviation from standard 3 flavor framework (1) New physics (NP) (exotic interactions) () violation of unitarity (like at a B factory) (3) Sterile neutrinos

21 (1) New physics (NP) (exotic interactions) Flavors are not necessarily conserved: ν α ν β ν α l β f NC f f CC f

22 Effects of New Physics on ν oscillations with source s s s (U s -1) αβ < O(10 - ) propagation ε ee, ε eτ, ε ττ ~O(1) detection (U d -1) αβ < O(10 - ) d d d

23 (i) Effects of New Physics at source and detector Deviation from the standard form is small: Grossman (PLB359:141,1995) (U s -1) αβ < O(10 - ), (U d -1) αβ < O(10 - ) (ii) New Physics effects in propagation 1. Constraints from various ν experiments: Davidson et al (JHEP 0303:011,003). Constraints from atmospheric neutrinos: Friedland-Lunardini (Phys.Rev.D7:053009,005) ε ee, ε eτ, ε ττ ~O(1) are consistent with ν atm data, provided

24 In general: NP effects at production and at detection becomes important when L is smaller ε αβ < O(10 - ) P ν α ν β U d ( U s ) -1 βα i.e., no BG from osc. in the limit of L 0 Experiments with a shorter baseline are advantageous NP effects in propagation becomes important when L is larger ε αβ can be of O(1) because AL ε αβ ~ ε αβ (L/000km) Experiments with a longer baseline (e.g., INO) are advantageous

25 MINOS (ν e appearance) ν ν μ e TKK (ν e appearance) ν ν μ e NK,HS,OY, hep-ph/

26 ν factory ( channel) ν e ν μ ν factory ( channel) ν e ν τ NK,HS,OY, hep-ph/

27 () Unitarity violation due to heavy ν U N (non-unitary) NN NN 1: deviation from unitarity ± < < < ± < < < ± mostly from rare decays W NP ν α l β minimal nonunitary model 90% C.L. Constraints on unitary violation are strong: (NN 1) αβ < O(10 - ) Minimal case: Antusch, Biggio, Fernandez-Martinez, Gavela, Lopez-Pavon, JHEP 0610:084,006. Non-minimal case: Abada, Biggio, Bonnet, Gavela, Hambye, arxiv: [hep-ph] Even stronger constraints more difficult to detect

28 Unitarity violation is similar to NP effects at production and at detection becomes important when L is smaller P )]U -1 (1 η) -1 ν (1 η)uexp[-i diag(e α ν + β j + βα η (NN 1) / η αβ < O(10 - ) U s 1+η/, U d 1+η/ Experiments with a shorter baseline are advantageous

29 Neutrino factory with a baseline L=130km Fernandez-Martinez, Gavela, Lopez-Pavon, OY, Phys.Lett.B649:47-435,007 Phase of N ν ν µ τ arg(η µτ ) Present bound from τ µγ For non-trivial arg(η µτ ), one order of magnitude improvement for η µτ Sensitivity to arg(η µτ ) Sensitivity to η µτ

30 (3A) Sterile neutrinos assuming LSND m sol ~ 10 4 ev m atm ~ 10 3 ev m LSND ~ O(1) ev LSND( ν at least one ν s is required µ MiniBOONE( ν ν e ): affirmative µ ν ):negative e difference between ν & anti-ν may offer a promising fit (3+)-scheme w/ CP phase δ

31 φ 54 best = 1.64π Karagiorgi@nufact07 χ /ndf = 146.7/156 gof=69% φ 54 best = 1.74π

32 (3B) Sterile neutrinos w/o assuming LSND Without assuming LSND and imposing all the negative constraints one can still consider (3+1)-scheme 3+1 sterile neutrinos at the CNGS Donini, Maltoni, Meloni, Migliozzi, Terranova, arxiv: v [hep-ph] θ θ θ θ 4 θ 14, θ 4, θ 34 : angles which appear only in 4ν scenario

33 Signatures of heavy sterile neutrinos at long baseline experiments Dighe, Ray, arxiv: [hep-ph]

34 In either case (3A) or (3B), sterile neutrino oscillations will exhibit enhancement/suppression for ν or anti- ν, and experiments with a longer baseline (such as INO) are expected to have good sensitivity to sterile neutrinos.

35 3. Summary A brief review was given on the known parameters in SM+massive ν. Efforts to determine the unknown parameters (θ 13, δ,sign( m 31) ) in the future experiments were described. The future neutrino experiments with high precision will be able to see deviation from SM such as non-std. interactions, unitarity violation, sterile neutrinos, etc. Experiments with longer baselines (such as INO) are advantageous to search for NP in propagation and sterile neutrinos.