Non oscillation flavor physics at future neutrino oscillation facilities

Transcription

1 Non oscillation flavor physics at future neutrino oscillation facilities Tokyo Metropolitan University Osamu Yasuda 2 July (SM+m ν ) + (correction due to New physics) which can be probed through oscillations

2 1. Motivation for research on New Physics 2. A word on origin of New Physics 3. New Physics in oscillation experiments 4. New Physics at source and detector 5. New Physics in propagation (matter effect) 6. Violation of unitarity 7. Summary Notations throughout this talk: ΔE jk =Δm 2 jk /2E A= 2 1/2 G F N e (matter effect)

3 1. Motivation for research on New Physics Just like at B factories, high precision measurements of ν oscillation in future experiments can be used also to probe physics beyond SM by looking at deviation from SM+massive ν In this talk I will discuss phenomenologically new physics which is described by 4-fermi exotic interactions: ν α ν β ν α λ β f f f f neutral current charged current

4 2. A word on the origin of New Physics If we have New Physics at higher energy scale, there can be higher dimensional operators: These operators are supposed to be SU(2) invariant before symmetry breaking of SM. The lower dimensional operators relevant to neutrino oscillation experiments are of dim 6 and dim 8. dim 6 operators such as ( H + Lα ) γ idμ ( HLβ ) turn out to be strongly constrained by charged lepton processes. dim 8 operators such as do not have strong constraints. To justify the discussions below, dim 8 operators will be assumed. μ

5 Constraints on dimension-6, 8 operators dim-6 operators ( H +L α ) γ f μ id μ ( HL W - β f SM NP dim-8 operators ) ν α λ β strong constraints from charged lepton processes, e.g., μ + e + e + e - λ ν α α μ γ λ γ μ λ β β f γ f μ f γ f μ ν β ν α f NP f little constraints from charged lepton

6 The coefficient of the operator is usually normalized in terms of G F : where etc Theoretically the coefficients αβ of the exotic interactions are expected to be suppressed by ratio (M W /Λ NP ) n << 1 (n=2 for dim 6, n=4 for dim 8). In phenomenological analysis, however, we take into account only the constraints from the experiments, and we do not worry about the magnitude of the coefficients αβ which may be unnaturally large from a theoretical view point.

7 3. New Physics in oscillation experiments NP at source Grossman, Phys. Lett. B359, 141 (1995) Effective eigenstate

8 NP at detector Grossman, Phys. Lett. B359, 141 (1995) Effective eigenstate

9 NP in propagation (NP matter effect) SM potential due to W exchange is modified by NP SM NP

10 Oscillation probability w/o and w/ NP SM+m ν NP

11 NB o NP effects at production and at detection becomes important when L is smaller P ν α ν β U d ( ) U s -1 βα 2 i.e., no BG from ν osc. in the limit of L 0 Experiments with a shorter baseline are advantageous o NP effects in propagation becomes important when L is larger because AL αβ ~ αβ (L/2000km) Experiments with a longer baseline are advantageous Sato: ISS 2 nd KEK

12 o History of analysis of sensitivity 1. Statistics only 2. Statistics + systematic errors 3. Statistics + systematic errors + correlations of errors 4. Statistics + systematic errors + correlations of errors + degeneracies (Just for illustration) sin 2 2θ or αβ t Unless new ideas appears, sensitivity to unknown parameters is monotonically decreasing as a function of time.

13 4. New Physics at source and detector Grossman, Phys. Lett. B359, 141 (1995) Optimistic bounds on αβ are obtained by s d* ( να ν β ) αβ max s d P αβ ~ αβ, αβ < P( ν and typically are of order 10-2 α ν β ) upper bound s eμ, d eμ < MiniBooNE s d μτ, μτ < NOMAD s eτ d eτ, < 0.1 NOMAD

14 Sensitivity to eμ at ν factory A CP P P eμ eμ + P P eμ eμ Statistics only; naïve arguments s eμ < a few 10 4 Gonzalez-Garcia, Grossman, Gusso, Nir, Phys. Rev. D64, (2001)

15 Sensitivity to eμ, eτ, μτ at ν factory ν ν μ ν μ ν Ota-Sato-Yamashita, PRD65:093015, 02 s = eμ s, m = 3 10 e s = eτ μτ τ Sato: ISS 2 nd KEK Statistics + some correlations of errors Required data size in unit of μ 100kt

16 Sensitivity by Noνa + DC-200kt Kopp, Lindner, Ota, Sato, PRD77:013007,2008 = s ee s μe d* ee = s μe s μμ d* μe = s eτ s μτ d* τ e Statistical + systematic errors + correlations of errors + degeneracies T2K + DCHOOZ s μe < = s eμ d* μ e = d s* μμ μμ = d s* τμ μτ Noνa + DC-200kt s μe <

17 5. New Physics in propagation (matter effect) 5.1 Constraints from various ν experiments (CHARM, LEP, LSND, NuTeV) Davidson, Pena-Garay, Rius, Santamaria, JHEP 0303:011,2003 See also Berezhiani and A. Rossi, PLB535 ( 02) 207; Barranco et al., PRD73 ( 06) ; Barranco et al., arxiv: Because of the relation contribution comes from the quantities with largest errors., the dominant ee, eτ, ττ ~O(1) are consistent with accelerator experiments data

18 update of JHEP 0303:011,2003 on July 1, 2008 courtesy by Sacha Davidson Only the bound on eμ is modified:

19 5.2 Phenomenology with ee, eτ, ττ ~O(1) Constraints from ν atm ee, eτ, ττ ~O(1) are consistent with atmospheric neutrino data, provided that Friedland-Lunardini-Maltoni, PRD70:111301, 04; Friedland- Lunardini, PRD72:053009, 05 95%CL 99%CL 3σCL

20 Exact analytical formula for the oscillation probability with ee, eτ, ττ in the limit Δm OY arxiv: [hep-ph] Eigenvalues can be exactly obtained in the limit Δ m : This includes corrections to all orders in θ13, ee, e τ, ττ. The assumptions are Δ m2 21 =0 and ττ = e τ 2 /(1+ ee ) Corrections in Δ m2 21 and other αβ can be also obtained to first order.

21 Once the eigenvalues are known, we can easily get the analytical formula for the oscillation probability by KTY s method Kimura, Takamura, Yokomakura (PLB537:86,2002) The problem of obtaining the exact analytical oscillation probability is reduced to obtaining only the eigenvalues!

22 ν e appearance probability ν μ disappearance probability

23 At first sight NP with ee, eτ, ττ ~O(1) seems to be inconsistent with ν atm, but it is not the case: At high energy limit, matter effect becomes dominant, but because the two eigenvalues of matter potential matrix turn out to be zero, the scenario is reduced to vacuum oscillation which is consistent with the high energy atmospheric neutrino data. A>> ΔE jk In the limit θ 13 0 Friedland-Lunardini, PRD72:053009, 05

24 At low energy or at shorter baseline (such as K2K & MINOS), matter effect is negligible compared to ΔE jk, so the sub-gev atmospheric and K2K + MINOS data are supposed to give us the true value for Δm 2 23 and sin 2 2θ 23 c 2 β >0.45. Friedland-Lunardini, PRD72:053009, 05 The multi-gev atmospheric data should in principle give us a signature for NP, but statistics is so low that we can t say anything conclusive. Will HK improve the situation? Thus NP with ee, eτ, ττ ~O(1) is consistent with ν atm for the moment.

25 So, as approximation, we can eliminate ττ by ττ = eτ 2 /(1+ ee ) and we can reduce the problem in ( ee, eτ, ττ ) to the allowed region in ( ee, eτ ). eτ =tanβ(1+ ee ) (β stands for the gradient of the line), c 2 β >0.45 tan2 β<1.2 degeneracy: (1+ ee ) -(1+ ee ) Δm Δm2 31

26 ν e appearance Region testable by ν e appearance at MINOS If eτ is very large then we may be able to prove the existence of NP from ν e appearance at MINOS Sugiyama, [hep-ph]; OY, Acta Phys.Polon.B38:3381, 07 Blennow-Ohlsson-Skrotzki, PLB660:522, 08

27 ν e appearance at T2K(K) T2K(T2KK) is insensitive (sensitive) to eτ, so if eτ is very large then we may be able to prove the existence of NP from ν e appearance by T2K-T2KK complex. T2K T2KK

28 ν μ disappearance Region testable by ν μ disappearance at MINOS Friedland, Lunardini, PRD74:033012, 06 Because of the two constraints due to ν atm, sin 2 2θ 23 and Δm 2 23 are correlated: The allowed region before (left) and after (right) the first MINOS results

29 Speculation on ν μ disappearance at T2K Determination of ee, eτ, ττ from future long baseline experiments with P μμ : 0.94< sin 2 2θ atm <=1 (Raaf@ν2008) Δm 2 atm =( ) 10-3 ev 2 (Raaf@ν2008) is determined by T2K precisely in the future, if the Even if Δm 2 31 central values are the same as in ν atm, then the errors in sin 2 2θ atm (+-6%) and Δm 2 atm (+-20%) will remain and will be dominant. In the case where the central values are the same as in ν atm from sin 2 2θ 23 tan 2 β<0.79 from Δm 2 23 tan 2 β<0.77 The constraint may not improve very much.

30 Analysis of solar neutrinos with NP Friedland, Lunardini, Pena-Garay Phys.Lett.B594:347,2004 degeneracy: (1+ ee ) -(1+ ee ) θ 12 π/2-θ 12

31 The survival probability for solar neutrino can be obtained by KTY formalism SM+m ν For simplicity the nonadiabatic corrections are neglected NP This agrees with the analytical formula in Friedland, Lunardini, Pena-Garay Phys.Lett.B594:347, 04

32 Solar ν may give a strong constraint on the allowed region in ( ee, eτ ) n : 4 points studied in detail by Friedland, Lunardini, Pena-Garay : =1 : =1 If and, then by adjusting the free parameter arg ( eτ ) in such a way that θ 12 =θ 12, we have Thus on the region in the red circles fit is expected to be good. However, off these lines fit may not be good. Scanning the whole region may give a new constraint.

33 Summary of possibility with ee, eτ, ττ ~O(1) ν e appearance at present/near future LBL: With longer baseline length (L> ~ 1000km), it may be possible to see the effect of NP if eτ is very large. ν μ disappearance at present/near future LBL : Because of dominant errors of atmospheric neutrino data, even if T2K measures sin 2 2θ 23 and Δm 2 32 precisely, it is difficult to give a strong constraint on ee, eτ, ττ. ν factory will be necessary to pin down eτ to <<1.

34 Gago-Guzzo-Nunokawa-Teves-Zukanovich Funchal, Phys.Rev.D64:073003,2001 Sensitivity at ν factory ττ eτ ττ μτ Statistics only + = ττ τ τ * e e ee A A = ττ μτ μμ μτ * A A 5.3 Sensitivity to αβ (<<1) in future experiments

35 Degeneracy between θ 13 and eτ ν ν ν e μ Degeneracy between θ 13 and eτ may be removed by combining two baselines sin 2 2θ 13 Huber, Schwetz, Valle, Phys. Rev. Lett. 88, (2002)

36 Sensitivity at ν factory ν ν e τ Campanelli-Romanino, PRD66:113001, 02 Statistics only high energy behavior eτ

37 Davidson, Pena-Garay, Rius, Santamaria, JHEP 0303:011,2003 Sensitivity at near detectors of ν factory leptonic s 2 W f ee < O( 10 3) f μμ < O( 10 3) ( 10 2 f < O ) < O( 10 2) f μτ at ν factory s2 eτ W in DIS at ν factory f = e, u, d Sensitivity of KamLAND and SNO/SK f ττ < 0.3

38 Sensitivity at ν factory Ribeiro-Minakata-Nunokawa- Uchinami-Zukanovich- Funchal, JHEP 0712:002,2007. Statistics + some correlations of errors A eτ 1 = A + 0 * eτ ee eτ ττ 0 < a few 10 3

39 Sensitivity by superbeam + reactor Kopp, Lindner, Ota, Sato, PRD77:013007,2008 Statistics + systematic errors + correlations of errors + degeneracies m eμ m eτ m μτ T2K + DCHOOZ m eμ < 0.5 m eμ m μτ Noνa + DC-200kt m eμ < 0.1 m eτ

40 Sensitivity to μτ and ττ at T2KK truncation Statistical + systematic errors some correlations of errors ττ μτ ττ < 0.03 < 0.3 Ribeiro-Kajita-Ko-Minakata-Nakayama- Nunokawa, PRD77:073007, 08 μτ

41 Sensitivity of MINOS+OPERA+DCHOOZ Does OPERA help to resolve θ 13 - eτ degeneracy? Statistics at OPERA: too small to be significant to constrain e τ Esteban-Pretel, Valle, Huber, arxiv: [hep-ph]

42 Sensitivity at ν factory Statistical + systematic errors + some correlations of errors + some correlations of errors m ee m eτ m μτ m ττ (@ 3σ ) m αβ Kopp-Ota-Winter, v1 [hep-ph]

43 Sensitivity at OPERA Blennow-Meloni-Ohlsson-Terranova- Westerberg, v1 [hep-ph] μτ : important at shorter baseline length ( ) Im μτ ( ) Re μτ ν only Re( μτ ) ν +ν

44 6. Violation of unitarity w/o light ν s Antusch, Biggio, Fernandez-Martinez, Gavela, Lopez-Pavon, JHEP0610,084, 06 In generic see-saw models, after integrating out ν R, the kinetic term gets modified, and unitarity is expected to be violated. L rescaling ν = 1 2 L c g + μ ( iν / K ν ν α M ν ) ( W l γ Pν + h. c. ) +... = α 1 2 αβ g ( / c + μ iν ν ν im ν ) ( W l γ P N ν ) +... i β i αβ ii The nontrivial issue is the magnitude of violation. Some of see-saw models (e.g., inverse see-saw) do have two scales, one to produce small neutrino mass and another which may not be extremely different from M W. Then magnitude of violation may not be extremely small. Unitarity of the lepton sector is worth checking. i β 2 2 μ μ α α L L α αi i N: non-unitary

45 Oscillation probability is similar to but different from that of NP: N HU H: close to identity NN 1: deviation from unitarity Constraints from weak decays turned out to be more stringent than ν oscillation: NN ± < < < ± < < < ± Deviation from unitarity < O(1%) mostly from rare decays 90% C.L.

46 Sensitivity at ν factory 4kt OPERA-like near m ν e ν τ ν ν μ τ N ei N τ *i i i N * μ i N τ i < < (present (present Antusch et al, JHEP0610,084, 06 : 0.016) : 0.013) 5kt OPERA-like far km ν ν μ Fernandez-Martinez, et al, PLB649:427, 07 H 1+η τ arg(η μτ ) Present bound from τ μγ Sensitivity to arg(η μτ ) For non-trivial arg(η μτ ), one order of magnitude improvement for η μτ η μτ Sensitivity to η μτ

47 7. Summary New physics Current bounds on αβ are typically of order 10-3 for production and detection αβ for propagation have bounds typically of order 10-2 but ee, eτ, ττ <~O(1) and it is difficult to give strong constraints on these three from the present data. ν factory may be able to improve bounds on αβ for propagation dramatically. Violation of 3 flavor unitarity Deviation from unitarity is expected in generic models (e.g., see-saw) but phenomenologically its magnitude is less than O(1%). Further studies are necessary.

48 There are a lot of problems to be worked out: Correlations of errors, degeneracies, etc. in the presence of all new physics parameters αβ Distinction between the new physics effects (e.g., 4-fermi interactions vs. unitarity violation due to modification in the kinetic term)

49 Backup slides

50 In the present case 1-P μμ can be expressed as

51 Analytical formula for the oscillation probability in matter 2 with New Physics in the limit 0 Δm 21 OY arxiv: [hep-ph] A 1 = A + 0 * eτ ee eτ ττ 0 depends only on arg( eτ )+δ

52 Features of the probability 2 ( in the limit Δm 21 0) A) It depends only on arg( eτ )+δ. 2 This is approximately the case also for Δm21 0. B) Each term gives a large contribution (See Fig. below). Interpretation of behavior of probability is not obvious. cf In standard 3 flavor case, only one term dominates: