Can we distinguish among different models for mass in the near future? Carla Biggio Max-Planck-Institut für Physik, München, Germany Convegno informale.

Can we distinguish among different models for mass in the near future? Carla Biggio Max-Planck-Institut für Physik, München, Germany Convegno informale di fisica teorica – Sestri Levante 2008 Based on collaborations with: A. Abada, S. Antusch, F. Bonnet, E. Fernández-Martínez, B. Gavela, T. Hambye, J. López-Pavón

Sestri Levante 08Carla Biggio, MPI, Germany The “problem” of masses in 6 lines… are exactly massless in the Standard Model (SM) Experimentally: they oscillate → they are massive there is leptonic flavour mixing m  « m l : m  < O(eV) → we need new physics (NP) beyond the SM to describe their masses → we’d like this new physics to explain their smallness

Sestri Levante 08Carla Biggio, MPI, Germany The “problem” of masses in 6 lines… are exactly massless in the Standard Model (SM) Experimentally: they oscillate → they are massive there is leptonic flavour mixing m  « m l : m  < O(eV) → we need new physics (NP) beyond the SM to describe their masses → we’d like this new physics to explain their smallness Explaining the smallness of masses with new physics at high energy: → the seesaw mechanism

Sestri Levante 08Carla Biggio, MPI, Germany The “problem” of masses in 6 lines… are exactly massless in the Standard Model (SM) Experimentally: they oscillate → they are massive there is leptonic flavour mixing m  « m l : m  < O(eV) → we need new physics (NP) beyond the SM to describe their masses → we’d like this new physics to explain their smallness The “bansigo” mechanism… Explaining the smallness of masses with new physics at high energy: → the seesaw mechanism

Sestri Levante 08Carla Biggio, MPI, Germany Effective field theory approach the effects of high energy NP @ low energy encoded in higher dimensional operators

Sestri Levante 08Carla Biggio, MPI, Germany Effective field theory approach the effects of high energy NP @ low energy encoded in higher dimensional operators Many O d>4 op.s with SM fields but O d=5 is UNIQUE!

Sestri Levante 08Carla Biggio, MPI, Germany Effective field theory approach D=5 operator violates lepton number → must be Majorana  depends on the model  ~O(1), M~M GUT, v=v EW → m ~10 -3 →   vv the effects of high energy NP @ low energy encoded in higher dimensional operators Many O d>4 op.s with SM fields but O d=5 is UNIQUE!

Sestri Levante 08Carla Biggio, MPI, Germany Effective field theory approach D=5 operator violates lepton number → must be Majorana  depends on the model  ~O(1), M~M GUT, v=v EW → m ~10 -3 →   vv the effects of high energy NP @ low energy encoded in higher dimensional operators Many O d>4 op.s with SM fields but O d=5 is UNIQUE! In how many ways can I obtain this O d=5 ?

Sestri Levante 08Carla Biggio, MPI, Germany Tree-level realisations of seesaw mechanism Type I See-Saw N R fermionic singlet Minkowski, Gell-Mann, Ramond, Slansky, Yanagida, Glashow, Mohapatra, Senjanovic, …

Sestri Levante 08Carla Biggio, MPI, Germany Tree-level realisations of seesaw mechanism Type I See-Saw N R fermionic singlet Type II See-Saw  scalar triplet Minkowski, Gell-Mann, Ramond, Slansky, Yanagida, Glashow, Mohapatra, Senjanovic, … Magg, Wetterich, Lazarides, Shafi, Mohapatra, Senjanovic, Schecter, Valle, …

Sestri Levante 08Carla Biggio, MPI, Germany Tree-level realisations of seesaw mechanism Type I See-Saw N R fermionic singlet Type II See-Saw  scalar triplet Type III See-Saw  R fermionic triplet Minkowski, Gell-Mann, Ramond, Slansky, Yanagida, Glashow, Mohapatra, Senjanovic, … Magg, Wetterich, Lazarides, Shafi, Mohapatra, Senjanovic, Schecter, Valle, … Foot, Lew, He, Joshi, Ma, Roy, …, Bajc, Nemevsek, Senjanovic, Dorsner, Fileviez-Perez

Sestri Levante 08Carla Biggio, MPI, Germany Tree-level realisations of seesaw mechanism Type I See-Saw N R fermionic singlet Type II See-Saw  scalar triplet Type III See-Saw  R fermionic triplet Minkowski, Gell-Mann, Ramond, Slansky, Yanagida, Glashow, Mohapatra, Senjanovic, … Linearly prop to Y  suppressed by  /M 2 Magg, Wetterich, Lazarides, Shafi, Mohapatra, Senjanovic, Schecter, Valle, … Foot, Lew, He, Joshi, Ma, Roy, …, Bajc, Nemevsek, Senjanovic, Dorsner, Fileviez-Perez

Sestri Levante 08Carla Biggio, MPI, Germany How can we distinguish among them?

Sestri Levante 08Carla Biggio, MPI, Germany How can we distinguish among them? not from the d=5 operator: it’s the same! either we are able to produce heavy states or from the d=6 operator → which are the d=6 operators associated to these seesaw models?

Sestri Levante 08Carla Biggio, MPI, Germany D=6 operators Broncano, Gavela, Jenkins 02 Type I:

Sestri Levante 08Carla Biggio, MPI, Germany D=6 operators Broncano, Gavela, Jenkins 02 Type I: Type III: Abada, CB, Bonnet, Gavela, Hambye 07

Sestri Levante 08Carla Biggio, MPI, Germany D=6 operators Broncano, Gavela, Jenkins 02 Type I: Type III: Type II: Abada, CB, Bonnet, Gavela, Hambye 07 Abada, CB, Bonnet, Gavela, Hambye 07 It is not suppressed by 

Sestri Levante 08Carla Biggio, MPI, Germany D=6 operators Broncano, Gavela, Jenkins 02 Type I: Type III: Type II: D=6 operators do not violate Lepton Number It is not suppressed by  Abada, CB, Bonnet, Gavela, Hambye 07 Abada, CB, Bonnet, Gavela, Hambye 07

Sestri Levante 08Carla Biggio, MPI, Germany Phenomenological effects Type I: non-unitary mixing in CC FCNC for Broncano, Gavela, Jenkins 02 Antusch, CB, F.dez-M.nez, Gavela, López-Pavón 06

Sestri Levante 08Carla Biggio, MPI, Germany (D=6 op and non-unitarity in type I seesaw) Kinetic terms → diagonalized and normalized → unitary transf. + rescaling m ab → diagonalized → unitary transformation U N is not unitary (O(  )) Antusch, CB, F.dez-M.nez, Gavela, López-Pavón 06

Sestri Levante 08Carla Biggio, MPI, Germany Phenomenological effects Type I: non-unitary mixing in CC FCNC for Broncano, Gavela, Jenkins 02 Antusch, CB, F.dez-M.nez, Gavela, López-Pavón 06

Sestri Levante 08Carla Biggio, MPI, Germany Phenomenological effects Type I: Type III: non-unitary mixing in CC FCNC for non-unitary mixing in CC FCNC for FCNC for charged leptons Broncano, Gavela, Jenkins 02 Antusch, CB, F.dez-M.nez, Gavela, López-Pavón 06 Abada, CB, Bonnet, Gavela, Hambye 07

Sestri Levante 08Carla Biggio, MPI, Germany Phenomenological effects Type I: Type III: Type II: LFV 4-fermions interactions non-unitary mixing in CC FCNC for non-unitary mixing in CC FCNC for FCNC for charged leptons Broncano, Gavela, Jenkins 02 Antusch, CB, F.dez-M.nez, Gavela, López-Pavón 06 Abada, CB, Bonnet, Gavela, Hambye 07 Abada, CB, Bonnet, Gavela, Hambye 07

Sestri Levante 08Carla Biggio, MPI, Germany Can we really use d=6 ops to distinguish?

Sestri Levante 08Carla Biggio, MPI, Germany Can we really use d=6 ops to distinguish? Generically if Y≈O(1) → c d=6 ≈ (c d=5 ) 2 → very suppressed (fermionic)

Sestri Levante 08Carla Biggio, MPI, Germany Can we really use d=6 ops to distinguish? Generically if Y≈O(1) → c d=6 ≈ (c d=5 ) 2 → very suppressed Is it possible to have a LARGE effect coming from c d=6 still with SMALL c d=5 ( mass) without fine-tuning? (fermionic)

Sestri Levante 08Carla Biggio, MPI, Germany Can we really use d=6 ops to distinguish? Generically if Y≈O(1) → c d=6 ≈ (c d=5 ) 2 → very suppressed We need to decouple d=5 op. from d=6 Is it possible to have a LARGE effect coming from c d=6 still with SMALL c d=5 ( mass) without fine-tuning? - d=5 operator violates lepton number - d=6 operators conserve it → natural from the point of view of symmetries… (fermionic)

Sestri Levante 08Carla Biggio, MPI, Germany Direct Lepton Number Violation Scheme  assume L-conserving setup with small M ( M~1TeV ) and large Y ( Y~O(1) ): large L conserved Abada, CB, Bonnet, Gavela, Hambye 07

Sestri Levante 08Carla Biggio, MPI, Germany Direct Lepton Number Violation Scheme  assume L-conserving setup with small M ( M~1TeV ) and large Y ( Y~O(1) ): large L conserved  assume L broken by small perturbation  : Neutrino mass directly proportional to a small source of L violation rather than inversely proportional to a large one Abada, CB, Bonnet, Gavela, Hambye 07

Sestri Levante 08Carla Biggio, MPI, Germany Direct Lepton Number Violation Scheme  assume L-conserving setup with small M ( M~1TeV ) and large Y ( Y~O(1) ): large L conserved  assume L broken by small perturbation  : Neutrino mass directly proportional to a small source of L violation rather than inversely proportional to a large one Is this possible? Abada, CB, Bonnet, Gavela, Hambye 07

Sestri Levante 08Carla Biggio, MPI, Germany Seesaw at low scale YM2YM2 c d=5 ≈ Y † Y M 2 c d=6 ≈ Type II seesaw:

Sestri Levante 08Carla Biggio, MPI, Germany Seesaw at low scale YM2YM2 c d=5 ≈ Y † Y M 2 c d=6 ≈ González-García, Valle 89 … Kersten, Smirnov 07 Inverse/Double type I (III) seesaw: Ex.) 2 generations (  L,  L, N c 1R, N c 2R ): Type II seesaw: If Y~O(1) and M~1TeV → large c d=6 L is conserved → m =0 Abada, CB, Bonnet, Gavela, Hambye 07

Sestri Levante 08Carla Biggio, MPI, Germany Seesaw at low scale YM2YM2 c d=5 ≈ Y † Y M 2 c d=6 ≈ González-García, Valle 89 … Kersten, Smirnov 07 Inverse/Double type I (III) seesaw: Ex.) 2 generations (  L,  L, N c 1R, N c 2R ): Type II seesaw: If Y~O(1) and M~1TeV → large c d=6 L is broken by  → Abada, CB, Bonnet, Gavela, Hambye 07

Sestri Levante 08Carla Biggio, MPI, Germany Seesaw at low scale YM2YM2 c d=5 ≈ Y † Y M 2 c d=6 ≈ González-García, Valle 89 … Kersten, Smirnov 07 Inverse/Double type I (III) seesaw: Ex.) 2 generations (  L,  L, N c 1R, N c 2R ): Type II seesaw: If Y~O(1) and M~1TeV → large c d=6 L is broken by  → Direct Lepton Number Violation can be realised in any seesaw model → low scale seesaw is possible and its effects can be observed in the near future Abada, CB, Bonnet, Gavela, Hambye 07

Sestri Levante 08Carla Biggio, MPI, Germany Testing the seesaws… Type II: LFV 4-fermions interactions  → eee,  → lll,  → e ,  → l  bounds on various combinations of Scalar seesaw:

Sestri Levante 08Carla Biggio, MPI, Germany Testing the seesaws… Type II: LFV 4-fermions interactions  → eee,  → lll,  → e ,  → l  bounds on various combinations of Scalar seesaw: Fermionic seesaws: non-unitarity 3x3 non-unitary unitary

Sestri Levante 08Carla Biggio, MPI, Germany Testing the seesaws… Type II: LFV 4-fermions interactions  → eee,  → lll,  → e ,  → l  bounds on various combinations of Scalar seesaw: Fermionic seesaws: non-unitarity Type I: non-unitary mixing in CC FCNC for analogous for NC W, Z, (semi)leptonic decays → (NN † )  unsuppressed  → e ,  → l  → (NN † ) 

Sestri Levante 08Carla Biggio, MPI, Germany Testing the seesaws… Type II: LFV 4-fermions interactions  → eee,  → lll,  → e ,  → l  bounds on various combinations of Scalar seesaw: Fermionic seesaws: non-unitarity Type I: Type III: non-unitary mixing in CC FCNC for non-unitary mixing in CC FCNC for FCNC for charged leptons analogous for NC W, Z, (semi)leptonic decays → (NN † )  unsuppressed  → e ,  → l  → (NN † )  Similar to type I but  → eee,  → lll at tree-level → stronger bounds

Sestri Levante 08Carla Biggio, MPI, Germany Bounds on (Y † Y/M 2 ) in type II Upper bounds from LFV 4-fermions processes: indep. of  or stronger Partly from: Barger et al. 82, Pal 83, Bernabeu et al. 84, 86, Bilenky, Petcov 87, Gunion et al. 89, 06, Mohapatra 92 Abada, CB, Bonnet, Gavela, Hambye 07

Sestri Levante 08Carla Biggio, MPI, Germany Bounds on (Y † Y/M 2 ) in type II Upper bounds from LFV 4-fermions processes: indep. of  or stronger Partly from: Barger et al. 82, Pal 83, Bernabeu et al. 84, 86, Bilenky, Petcov 87, Gunion et al. 89, 06, Mohapatra 92 Abada, CB, Bonnet, Gavela, Hambye 07 Best signature of this model at LHC: dileptons Kadastic, Raidal, Rebane 07, Garayoa, Schwetz 07, …

Sestri Levante 08Carla Biggio, MPI, Germany Bounds on (Y † Y/M 2 ) in type I and III No deviations from unitarity measured so far → only upper bounds TYPE I TYPE III Bounds are a bit stronger for type III. In particular we have better bounds on off-diag elements due to tree-level  →eee and  →3l due to FCNC for charged leptons General trend: or smaller Abada, CB, Bonnet, Gavela, Hambye 07 Antusch, CB, F.dez-M.nez, Gavela, López-Pavón 06

Sestri Levante 08Carla Biggio, MPI, Germany  → e  and  → l  in type III @ O(  ) and M  >>M W Observation of radiative decays and no tree level decays → the type III seesaw cannot be the only source of lepton flavour violating new physics worst bounds with respect to tree-level decays l → 3l; But: Abada, CB, Bonnet, Gavela, Hambye 08

Sestri Levante 08Carla Biggio, MPI, Germany Conclusions Can we distinguish among different models for mass in the near future?

Sestri Levante 08Carla Biggio, MPI, Germany Conclusions Can we distinguish among different models for mass in the near future? YES, IF… …if the new physics scale is low enough…

Sestri Levante 08Carla Biggio, MPI, Germany Conclusions d=6 effective operators crucial to distinguish among different models Can we distinguish among different models for mass in the near future? YES, IF… …if the new physics scale is low enough

Sestri Levante 08Carla Biggio, MPI, Germany Conclusions d=6 effective operators crucial to distinguish among different models d=6 ops are usually suppressed but not necessarily: Can we distinguish among different models for mass in the near future? YES, IF… …if the new physics scale is low enough

Sestri Levante 08Carla Biggio, MPI, Germany Conclusions d=6 effective operators crucial to distinguish among different models d=6 ops are usually suppressed but not necessarily: Direct Lepton Violation pattern: d=5 op. suppressed by small scale d=6 ops. unsuppressed Can we distinguish among different models for mass in the near future? YES, IF… …if the new physics scale is low enough

Sestri Levante 08Carla Biggio, MPI, Germany Conclusions d=6 effective operators crucial to distinguish among different models d=6 ops are usually suppressed but not necessarily: Direct Lepton Violation pattern: d=5 op. suppressed by small scale d=6 ops. unsuppressed this pattern is the same in all models: natural in the scalar case, inverse seesaw for fermionic seesaws Can we distinguish among different models for mass in the near future? YES, IF… …if the new physics scale is low enough

Sestri Levante 08Carla Biggio, MPI, Germany Conclusions d=6 effective operators crucial to distinguish among different models d=6 ops are usually suppressed but not necessarily: Direct Lepton Violation pattern: d=5 op. suppressed by small scale d=6 ops. unsuppressed this pattern is the same in all models: natural in the scalar case, inverse seesaw for fermionic seesaws rich phenomenology associated to low scale seesaws: Can we distinguish among different models for mass in the near future? YES, IF… …if the new physics scale is low enough

Sestri Levante 08Carla Biggio, MPI, Germany Conclusions d=6 effective operators crucial to distinguish among different models d=6 ops are usually suppressed but not necessarily: Direct Lepton Violation pattern: d=5 op. suppressed by small scale d=6 ops. unsuppressed this pattern is the same in all models: natural in the scalar case, inverse seesaw for fermionic seesaws rich phenomenology associated to low scale seesaws: - provides bounds on high energy theory parameters Can we distinguish among different models for mass in the near future? YES, IF… …if the new physics scale is low enough

Sestri Levante 08Carla Biggio, MPI, Germany Conclusions d=6 effective operators crucial to distinguish among different models d=6 ops are usually suppressed but not necessarily: Direct Lepton Violation pattern: d=5 op. suppressed by small scale d=6 ops. unsuppressed this pattern is the same in all models: natural in the scalar case, inverse seesaw for fermionic seesaws rich phenomenology associated to low scale seesaws: - provides bounds on high energy theory parameters - stay tuned!!! Maybe interesting results in the near future… Can we distinguish among different models for mass in the near future? YES, IF… …if the new physics scale is low enough

Sestri Levante 08Carla Biggio, MPI, Germany Back-up

Sestri Levante 08Carla Biggio, MPI, Germany D=6 op and non-unitarity in type I seesaw Kinetic terms → diagonalized and normalized → unitary transf. + rescaling m ab → diagonalized → unitary transformation U N is not unitary neutrino oscillations CC interactions unsuppressed l  → l   neutrino oscillations in matter invisible Z decay ABFGL 06

Sestri Levante 08Carla Biggio, MPI, Germany D=6 op and non-unitarity in type III seesaw N is not unitary new processes: ex.  → eee @ tree level ABBGH 07

Sestri Levante 08Carla Biggio, MPI, Germany Rare leptons decays in type I From rare leptons decays: Infos on (NN † )   e conversion in nuclei  → e + e - e (only @ 1 loop): suppressed by a factor  SM → GIM suppression: Now → no suppression: → constant term leading W i ll ll  NiNi N*  i

Sestri Levante 08Carla Biggio, MPI, Germany are massless in the Standard Model No Dirac mass: because no fermionic singlet R → No Majorana mass: because - no scalar triplet  → - SM is renormalizable  → - global U(1) B-L not anomalous → not radiatively generated

Sestri Levante 08Carla Biggio, MPI, Germany Present status of parameters From oscillations experiments (2  ) : Solar Atmospheric Bounds on absolute mass scale (2  ) : –Tritium  decay – 0  decay –Cosmology: → Open questions: hierarchy, absolute mass scale,  13, , (  1,  2 ) Fogli et al. 06 CMB CMB + LSS CMB + LSS + Lyman-a Mainz, Troitsk Heidelberg-Moscow model dependent

Can we distinguish among different models for mass in the near future? Carla Biggio Max-Planck-Institut für Physik, München, Germany Convegno informale.

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Can we distinguish among different models for mass in the near future? Carla Biggio Max-Planck-Institut für Physik, München, Germany Convegno informale.

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Presentation on theme: "Can we distinguish among different models for mass in the near future? Carla Biggio Max-Planck-Institut für Physik, München, Germany Convegno informale."— Presentation transcript:

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