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1) “Plaquette Invariants and the Flavour-Symmetric…” P.F. Harrison, D. R. J. Roythorne,

A FLAVOUR-SYMMETRIC. P.F. Harrison (U. of Warwick), W. G. Scott (PPD Rutherford) HEP Forum, 17 April 2008. PERSPECTIVE ON NEUTRINO MIXING. “ Tri-Bimaximal Lepton Mixing and the Neutrino Oscillation Data” P.F. Harrison,

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1) “Plaquette Invariants and the Flavour-Symmetric…” P.F. Harrison, D. R. J. Roythorne,

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  1. A FLAVOUR-SYMMETRIC P.F. Harrison (U. of Warwick), W. G. Scott (PPD Rutherford) HEP Forum, 17 April 2008 PERSPECTIVE ON NEUTRINO MIXING “Tri-Bimaximal Lepton Mixing and the Neutrino Oscillation Data” P.F. Harrison, D. H. Perkins, W. G. Scott, Phys. Lett. B. 530 (2002) 167. hep-ph/0202074 (see also: HPS hep-ph/9904297 ) NOW OFFICIALLY A “FAMOUS” PAPER ( > 250 CITES). “A TREMENDOUS ACHIEVEMENT!” T. D. LEE AT CERN - 30 AUG 2007 (CERN indico video min. 42!!) OF COURSE IT IS ACTUALLY THE EXPERIMENTSWHICH ARE TREMENDOUS! OUTLINE OF TODAYS TALK: (emphasis on Flavour-Symmetry) 1) “Plaquette Invariants and the Flavour-Symmetric…” P.F. Harrison, D. R. J. Roythorne, and W. G. Scott, Phys. Lett. B 657 (2007) 210. arXive:0709.1439 [hep-ph] 2)“Real Invariant Matrices and Flavour-Symmetric…” P.F. Harrison, W. G. Scott and T. J. Weiler, Phys. Lett. B 641 (2006) 372. hep-ph/0607336 3)“Simplified Unitarity Triangles for the Lepton Sector…” J. D. Bjorken, P.F. Harrison, and W. G. Scott, Phys. Rev D 74 (2006) 073012. hep-ph0511201 4)“Covariant Extremisation of Flavour-Symmetric Jartlskog Invariants…” P.F. Harrison, and W. G. Scott Phys. Lett. B 628 (2005) 93. hep-ph/0508012 5) “The Simplest Neutririo Mass Matrix” P. F. Harrison and W. G. Scott Phys Lett. B B594 (2004) 324. hep-ph/0403278. …….. “Review” of past few years 2004-2007 of HS… Presented by: W. G. Scott, PPD/RAL.

  2. 1) “Plaquette Invariants and the Flavour-Symmetric …” P.F. Harrison, D. R. J. Roythorn, and W. G. Scott, Phys. Lett. B 657 (2007) 210. arXive:0709.1439 [hep-ph] The Principles which guide us: 1) Flavour Symmetry:A fundamental theory of flavour should surely be Flavour-Symmetric (ie. it should make no reference to explicit flavour indices). 2) Jarlskog Invariance:A fundamental theory should be weak-basis independent (i.e. it should make no reference to any preferred weak-basis). Use Flavour-Symmetric Jarlskog Invariant variables!! The Architypal example: The Jarlskog CP-Invariant: The Jarlskogian J is “odd-odd” under separate l and ν flavour permutations: Independent, of plaquette choice l,ν hence “Plaquette Invariant” We define 6 New Flavour-Symmetric Jarlskog-Invariant mixing variables : with odd/even symmetry under: (functions only of mixing angles) spanning the Invariant polynomial ring An `elemental” set - not all independent, e,g, Presented by: W. G. Scott, PPD/RAL.

  3. 2)“Real Invariant Matrices and Flavour-Symmetric…” P.F. Harrison, W. G. Scott and T. J. Weiler, Phys. Lett. B 641 (2006) 372. hep-ph/0607336 The “P-matrix”: “T-matrix” Moment Transform: (invertible) The “K-matrix” ”permanent” “Q-matrix” Moment Transform: (invertible) Presented by: W. G. Scott, PPD/RAL.

  4. 3)“Simplified Unitarity Triangles for the Lepton Sector…” J. D. Bjorken, P.F. Harrison, and W. G. Scott, Phys. Rev D 74 (2006) 073012. hep-ph/0511201 From the Plaquette Products: Form the Matrix of Plaquette Products: We define the Matrix of Unitarity Triangle Angles:* *Footnote [42] hep-ph/0511201 Presented by: W. G. Scott, PPD/RAL.

  5. 4)“Covariant Extremisation of Flavour-Symmetric….” Extremising: Extremising: P.F. Harrison, and W. G. Scott Phys. Lett. B 628 (2005) 93. hep-ph/0508012 The Jarlskog Commutator: Characteristic Equationn: † We extremise wrt Mass Matrices theselves: † 3 x 3 Max (=ΣPrincipal Minors C) 2 x 2 Max et perms. Extremising: “The Simplest Neutrino Mass Matrix” P. F. Harrison and W. G. Scott PLB 594 (2004) 324. hep-ph/0403278 Presented by: W. G. Scott, PPD/RAL.

  6. 5)”The Simplest Neutrino Mass Matrix” P. F. Harrison and W. G. Scott Phys Lett. B B594 (2004) 324. hep-ph/0403278. In the charged-lepton flavour basis, ie. where Is diagonal, we impose: “Democracy Symmetry” the “democracy operator” Ie. commutes with “Mu-Tau Reflection Symmetry” (“mutautivity”) the “μτ-exchange operator” Note definition includes a complexconjugation Finally, implementing the “Simplest” Condition: y=0 z=0 Presented by: W. G. Scott, PPD/RAL.

  7. T. D. LEE LECTURE AT CERN 30 AUG 2007 CERN video: http://indico.cern.ch/conferenceDisplay.py?confId=19674 (min. 42) Presented by: W. G. Scott, PPD/RAL.

  8. WE DID “ACHIEVE” SOMETHING HOWEVER: WEPREDICTED TWO (E)SMPARAMETERS!!: Tri-Bi-Maximal (HPS 1999/2002) Tri-Maximal (HS/HPS 1994/1995) CHOOZ EXPT. SAYS < 0.03 (not HS/HPS!!) HS/BHS (2002-2006) via Tri-Phi-Maximal & Tri-Chi-Maximal (HS 2002) “S3 Group Mixing” “Magic-Square Mixing” “Tri-χφ-Maximal” There was never a prediction from HPS/HS of exact Ue3≡0! Presented by: W. G. Scott, PPD/RAL.

  9. HPS “Derivation” of TriBimaximal Mixing: Harrison, Perkins, Scott, Phys. Lett. B. 530 (2002) 167.hep-ph/0202074 In the “circulant basis”: * 3 x 3 circulant (by definition of the * basis) 2 x 2 circulant (determines the physics) † † A popular choice: Presented by: W. G. Scott, PPD/RAL.

  10. Symmetries of TriBimaximal Mixing: 1) “CP symmetry” Zero CP violation J=0 (hopefully approximate!) 2) “μτ-reflection symmetry” “Two rows equal” (=Max CPV!) |Uμi|=|Uτi| for all i=1-3. 3) “democracy symmetry” one trimaximal eigenvector |Uαi|=|1/3 for all α for some i. Presented by: W. G. Scott, PPD/RAL.

  11. “Symmetries and Generalisations of Tri-Bimaxiaml Mixing” P.F. Harrison, and W. G. Scott Phys. Lett. B 535 (2002) 163. hep-ph/0203029 “Tri-χ-Maximal Mixing” “Tri-Φ-Maximal Mixing” Exact μτ - Refl. Symm., J≠0 J=0, Break μτ-Symmetry Φ→0 Χ→0 “Permutation Symmetry, Tri-Bimaximal Mixing and the S3 Group ...” P.F. Harrison, and W. G. Scott Phys. Lett. B 557 (2003) 76. hep-ph/0302025 “S3 Group Mixing”, “Magic-Square Mixing”, “BHS-Mixing”… . “Tri-χφ-Maximal Mixing” Presented by: W. G. Scott, PPD/RAL.

  12. Nature Plays Sudoku !! “Magic-Square”/”S3 Group Mixing” “Democracy Symmetry” Experiment tells us that the neutrino mass matrix² in the (charged-lepton) flavour basis is essentially a 3 x 3 Magic Square !! Symmetric Group S3 (natural representation): All row/column sums equal !! The most general such (hermitian) matrix may be constructed as an “S3 Group Matrix” in the natural representation of the S3 group ring Any “S3 Group Matrix” clearly has (at least) one trimaximal eigenvector: “circuant” “retro-circuant” Presented by: W. G. Scott, PPD/RAL.

  13. τ e μ Uτ3 1σ Simplified Unitarity Traingles in the Lepton Sector “BHS” Mixing (=“Tri-χφ-Mixing”) “ν2.ν3”=“the ν1-triangle” Ue3 Uμ3 The Matrix of Unitarity Triangles: Notice the natural “complementary” labelling of angles and triangles each angle Φαiappears in one row-based triangle and one column-based triangle J. D. Bjorken, P.F. Harrison, and W. G. Scott, Phys. Rev D 74 (2006) 073012. hep-ph0511201 Presented by: W. G. Scott, PPD/RAL.

  14. “d.b”=“the s-triangle” “t.u”=“the c-triangle” (in SM - see F. Muheim “Flavour in the Era of LHC” HEP Forum 21 June 2007) α d α t u b β+χ γ β γ -χ χ c s UNITARITY TRIANGLES IN THE QUARK SECTOR THE MATRIX OF UNITARITY TRIANGLES IN THE QUARK SECTPR EQUIVALENT INFO. TO CKM MATRIX !! Presented by: W. G. Scott, PPD/RAL.

  15. SYMMETRIES OF “HPS” MIXING e.g. M = 0 SUBSET OF CLEBSCH- GORDAN COEFFS. COULD PERHAPS BE A USEFUL REMARK ?!! See: J. D. Bjorken, P. F. Harrison and W.G. Scott. hep-ph/0511201 Presented by: W. G. Scott, PPD/RAL.

  16. Jarlskog Invariance: (Also known as Weak-Basis Invaraince) In any “weak” (“gauge”) basis the weak interaction is diagonal and universal (i.e proportional to the identity matrix) We often seem to choose to blame the mixing on the “down” quarks! weak basis But we could equally choose to blame it on the “up”-type quarks! weak basis CC weak int. U(3) Elsewhere in the Lagrangian: (i.e in the yukawa sector) Mass² Matrices Mu is diagonal (Md is non-diagonal) Md is diagonal (Mu is non-diagonal) All observables are Jarlskog Invariant: e.g. masses, mixing angles: Note that the Jarlskogian J is (moreover) also Flavour-Symmetric !! Presented by: W. G. Scott, PPD/RAL.

  17. † † FLAVOUR-SYMMETRIC JARLSKOG INVARIANT MASS PARAMETERS Charged-Leptons: Mass Matrix: Neutrinos: Mass Matrix: Presented by: W. G. Scott, PPD/RAL.

  18. THE CHARACTERISTIC EQUATION e.g. For the Charged-Lepton Masses: where: The Disciminant: All are Flavour-Symmetric and Jarlskog Invariant!! Presented by: W. G. Scott, PPD/RAL.

  19. Flavour-Symmetric Mixing Observables… 2 x 2 of P.F. Harrison, D. R. J. Roythorn, and W. G. Scott, Phys. Lett. B 657 (2007) 210. arXive:0709.1439 [hep-ph] Six New FS Variables (“Plaquette Invariants”) A, B, C, D, F, G, analogous to Jarlskog J, order (n) with odd/even symmetry under - scalar or pseudoscalar. B, D are notl ↔ν symmetric Not all independent Presented by: W. G. Scott, PPD/RAL.

  20. Plaquette Invariance (= Invariance) “PLAQUETTE INVARIANT”!!! Presented by: W. G. Scott, PPD/RAL.

  21. Flavour-Symmetric Weak-Basis-Invariant Constraints on Mixing: Democracy Symmetry ie. one column=(1/3,1/3.1/3), iff: “ μ–τ ” - Reflection Symmetry, ie. two rows (or columns) equal, iff: Tri-Bi-Maximal Mixing, iff: Solving more generally for the P-matrix in the limit F, A, C → 0 and 0 < G < 1/6, gives: Presented by: W. G. Scott, PPD/RAL.

  22. Ansatz F G C A Symm. 18J B D Tri-Bi-Max. 0 1/6 0 0 Dem., μτ, CP 0 0 1/12√3 Tri-Max. Mix. 0 0 0 0 Dem., μτ1/6 0 0 Tri-χφ-Max. 0 - 0 - Dem.(ocracy) - 0 - 2 Rows Eq. 0 - - 0 e.g. μ-τ - 0 - 2 Cols. Eq. 0 - - 0 e.g. 1-2 - - 0 Alt.-Feruglio 0 - (6G-1)/8 0 μτ, CP 0 0 - Tri-χ-Max. 0 - 0 0 Dem., μτ - 0 - Tri-φ-Max. 0 1/6 0 - Dem., CP 0 0 - Orig. Bi-Max. 0 1/8 -1/32 0CP, μ-τ,1-2 0 0 0 No Mixing 1 1 1 1 CP 0 0 0 Jarlskog J measures CP-violation (J=0 protects against violation of CP). F measures the acoplanarity of the P-vectors in the flavour space (F=0 => Det <P(∞)> = 0, i.e. protects distant source against flavour analysis) G = 3<<Pll(∞)>>-1 measures the flavour-averaged asymptotic survival prob…. Presented by: W. G. Scott, PPD/RAL.

  23. Directly in Terms of Mass Matrices: † † The Jarlskog Commutator: controls CP violation: Generalised Jarlskog Commutators: And Anti-Commutators: The Matrix of Cubic Commutator Traces The Matrix of Anti-Commutator Traces (traces of mass-matrix products): For example, F: In terms of Mass Matrices only Presented by: W. G. Scott, PPD/RAL.

  24. Expressed as Traces entirely in terms of Mass Matrices Two quadratic variables G,F No l↔ν asymmetric quadratic variables: Two l↔ν symmetric cubic variables C,A: Two l↔ν asymmetric cubic variables B,D: Presented by: W. G. Scott, PPD/RAL.

  25. Flavour-Summed Loop Amplitudes 4-Plaquette Usual Plaquette Product: Hexaplaquette Product: 6-Plaquette even odd purely real Presented by: W. G. Scott, PPD/RAL.

  26. More Flavour-Symmetric Constarints: Completely Symmetric CKM P-matrix: Extremise a “Potential”, e.g.: Tri-Bi-Maximal Mixing !!! Presented by: W. G. Scott, PPD/RAL.

  27. EXTREMISATION: A TRIVIAL EXAMPLE In the SM: Yukawa couplings Add to SM Action, the determinant : (taken here to be dimensionless) i. e. e.g. i.e. 2 zero mass 1 non-zero! NOT BAD!! This notion appeared in: P.F. Harrison and W. G. Scott Phys. Lett. B 333 (1994) 471. hep-ph/9406351 Presented by: W. G. Scott, PPD/RAL.

  28. Extremise Det C = Tr C³ /3 (wrt mixing angles, fixed masses) 3 x 3 Max Mix. !! Extremise the sum of The Principal Minors Tr C² /2 (wrt mixing angles) (use hierachical approx.): 2 x 2 Max Mix. !! Presented by: W. G. Scott, PPD/RAL.

  29. Extremise wrt the Mass matrices themselves! Exploit Matrix Calculus Theorem Where Ais any constant matrix andX is a variable matrix. Apply to Extremise Tr C³ Weak-Basis Covariant !! Apply to Extremise Tr C² Presented by: W. G. Scott, PPD/RAL.

  30. The “Epsilon” Phase Convention* The usual (charged-lepton) flavour basis has not been completely defined. There remains the freedom to re-phase the fields such that all the imaginary parts of the neutrino mass matrix are equal Incredible but true!! † Now the 7 parameters a, b, c, d, x, y, z encode directly the 3 neutrino masses and the usual 4 mixing parameters. *See Footnote 1 of: P. F. Harrison and W. G. Scott Phys Lett. B B594 (2004) 324.hep-ph/0403278 Presented by: W. G. Scott, PPD/RAL.

  31. Extremise Tr C³ Eq. 1 Off-Diagonal Real Parts: Magic-Square Constraint!! Eq. 1 Off-Diagonal Imag. Parts: Circulant mass matrix i.e. 3 x 3 Maximal Mixing!! Maximal CPV (J=1/(6√3) Presented by: W. G. Scott, PPD/RAL.

  32. Differentiate the Mass Constraints Our Equations get modified: (i.e. must add-in Lagrange multipliers λ) but still Jarlskog Covariant Incredibly, all the remaining equations are either redundant or serve only to fix the Lagrange multipliers: Always True??? Solving explicitly: Jarlskog Scalars!! If the action were the “right” one, the Lagrange multipliers would vanish for the experimental mass values! Koide relation e.g. Presented by: W. G. Scott, PPD/RAL.

  33. Now Extremise Tr C² Eq. 1 the of-diagonal Real Parts: Easy Solution: Eq. 1 the of-diagonal Imag Parts: Zero CPV! 2 x 2 Max. Mix In any sector!! Non-trivial Mass-Dependent Solution: d = 0 Fit a, b, c to “observed” Presented by: W. G. Scott, PPD/RAL.

  34. Absolute neutrino masses not yet measured, but with the “minimalist” assumption of a normal classic fermionic neutrino spectrum we may make a unique prediction for the MNS mixing: The only operative parameter then becomes: (b-a)/(a-c) and setting: In clear disagreement with experiment. All the the right numbers in all the wrong places!! Presented by: W. G. Scott, PPD/RAL.

  35. Try a simple linear combination of the two: Take r to be a constant with dimensions of (mass)² With the “Magic-Square constraint” imposed there are analytical solutions: In practice: In general, for sufficiently extreme hierarcy h → 0, we are close to the pole at X →0, i.e. x→∞ and we have |x| >> y, z, whereby the “Simplest” assumption must hold. In this sense this V(C) above points to the “Simplest Neutrino Mass Matrix” despite that in practice (in actuality!) the hierarchy h is too large!! Presented by: W. G. Scott, PPD/RAL.

  36. ”The Simplest Neutrino Mass Matrix” P. F. Harrison and W. G. Scott Phys Lett. B B594 (2004) 324. hep-ph/0403278. In the charged-lepton flavour basis, ie. where Is diagonal, we impose: “Democracy Symmetry” “Mu-Tau Reflection Symmetry” (“mutativity”) |x|>> y, z Finally, implementing the “Simplest” Condition: Presented by: W. G. Scott, PPD/RAL.

  37. CONCLUUSIONS Sorry! - Bill Scott doesn’t do conclusions! Instead, T. D. Lee’s lecture again (a 2nd clip- from earlier in his talk) Inspirational for anyone working on fermion mixing and flavour etc. : “….these two 3 x 3 matrices (CKM and MNS) are the cornerstones of particle physics… ….but do we understand them???” Presented by: W. G. Scott, PPD/RAL.

  38. T. D. Lee CERN colloquium Aug 2007 Presented by: W. G. Scott, PPD/RAL.

  39. CONCLUUSIONS Sorry! - Bill Scott doesn’t do conclusions! Instead, T. D. Lee’s lecture again (a 2nd clip- from earlier in his talk) Inspirational for anyone working on fermion mixing and flavour etc. : “….these two 3 x 3 matrices (CKM and MNS) are the cornerstones of particle physics… ….but do we understand them???” My personal view: Not yet! – but we are all (experimenters & theorists) working very hard on the problem and one day (hopefully) we will !! Presented by: W. G. Scott, PPD/RAL.

  40. SPARE SLIDES AND SLIDES IN PROGRESS Presented by: W. G. Scott, PPD/RAL.

  41. Presented by: W. G. Scott, PPD/RAL.

  42. THE “5/9-1/3-5/9” BATHTUB Presented by: W. G. Scott, PPD/RAL.

  43. UP-TO-DATE FITS A. Strumia and F. Vissani Nucl.Phys. B726 (2005) 294. hep-ph/0503246 IS THE BEST MEASURED MIXING ANGLE !!! Presented by: W. G. Scott, PPD/RAL.

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