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Leptogenesis

… a personal review on. Leptogenesis. (CERN). TH-Institute on Flavor, CERN, 08/05/08. Based on some works with: V.Cirigliano, A.De Simone, G.Isidori, F.R. Joaquim, A.Riotto, C.A.Savoy. FOR A RECENT GENERAL REVIEW : Davidson Nardi Nir, arXiv:0802.2962.

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Leptogenesis

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  1. … a personal review on Leptogenesis (CERN) TH-Institute on Flavor, CERN, 08/05/08 Based on some works with: V.Cirigliano, A.De Simone, G.Isidori, F.R. Joaquim, A.Riotto, C.A.Savoy FOR A RECENT GENERAL REVIEW: Davidson Nardi Nir, arXiv:0802.2962

  2. …leptogenesis is maybe the most promising mechanism to explain B-asymmetry BUT WHY A TALK ABOUT IT IN A “FLAVOR AS A WINDOW TO NEW PHYSICS AT LHC” WORKSHOP? New Physics necessary because (even postponing the problem of unification with gravity) it must account for: astro particle • n masses&mixings • hierarchy problem (th) • flavour&CP problem (th) • …. • baryon asymmetry • dark matter • dark energy • …. esp’lly if NP@TeV!!!  leptogenesis and flavor are both related to New Physics bSM, so that flavor might play an important role in the generation of B-asymmetry

  3. PLAN 1- What is and how to measure the B asymmetry 2- Dynamical mechanisms for Baryogenesis (beyond SM)  leptogenesis 3- Various leptogenesis  seesaw type I, II, III, ... 4- Leptogenesis via type I seesaw a- effects: flavor, resonant, quantum b- related phenomenology i- connection with CPV in n masses ii- range of RH n masses iii- embedding in susy: gravitino problem iv- embedding in susy: LFV, EDM, …. v- embedding in GUT/flavor models: 2 examples 5- Conclusions

  4. Baryon asymmetry of the universe nX= # density of X @68% How to measure? BBN - Historically CMB - At present more precise

  5. Today BBN CMB

  6. A NAIVE estimation of the B asymmetry of the universe TODAY 1.5 x 1079 Hatoms in observed universe = 1.25 1011 galaxies x 1011 stars/galaxy x 1.2 1057 Hatoms/star Hubble Space Telescope as in our galaxy as in the Sun 2x1030 kg/star 1.67x10-27 kg/Hatom 3.6 x 1080 m3= volume of observed universe Hatom density =4.2 x 10-2 /m3 = 10-10 number density of gas of photons in th eq at T=2.73K =4.1 x 108 /m3

  7. Baryon asymmetry of the universe A non-trivial value! If the universe were B-antiB symmetric ….annihilation catastrophe! From fine-tuned (1/109) initial conditions? No: with inflation, any preexisting B-asymm is diluted to a negligible value, due to entropy production during reheating Need a dynamical mechanism to generate B-asymmetry after inflation!

  8. Baryogenesis Sakharov’s3 conditions[‘67]to dynamically create the asymmetry 1- B Violation 2- C & CP Violations 3- out of thermal equil’m

  9. Baryogenesis Sakharov’s3 conditions[‘67]to dynamically create the asymmetry SM 1- B Violation 2- C & CP Violations 3- out of thermal equil’m  at quantum-level (triangle anomaly) possess all ingredients but does not work…  maximal & TOOtiny  NOT so STRONG 1° EWPT [Gavela Hernandez Orloff Pene] Topological trans’n: sphalerons B-L conserved: [Kuzmin Rubakov Shaposhnikov ‘85]

  10. Mechanisms for Baryogenesis Sakharov’s3 conditions[‘67]to dynamically create the asymmetry 1- B Violation 2- C & CP Violations 3-out of thermal equil’m bSM • out of eq decay (3-) of heavy particles whose int’s violate C, CP (2-) • and B-L (1-) so that SM sphalerons do not erase the B asymmetry : • GUT leptoquarks ; RH neutrinos ; etc GUT baryogenesis leptogenesis B) OTHERS: EW baryogenesis (modification of EWPT): 2HDM, MSSM; spontaneous baryogenesis; Affleck-Dine; gravitational leptogenesis; etc

  11. Various Leptogensis …according to type of seesaw inducing from now on

  12. [P.Minkowski ‘77] The seesaw (I) Dirac-Yukawa Majorana-mass if complex  CPV DL=2 Mass eigenstates: (where M1< M2< M3) Heavy: with Light: with MNS mixing matrix mn =O(eV)  Mn= O(1015GeV) , near SUSY g.c.u.!

  13. Leptogenesis [Fukugita Yanagida ‘86] > 0.  tipically T>MR In the thermal bath with decays & inverse decays are in thermal equilibrium YNeq =z

  14. Leptogenesis [Fukugita Yanagida ‘86] < 1.  tipically T<MR In the thermal bath when decays & inverse decays are no more effective in diluting YN go out of equilibrium! sooner (i.e. N’s more abundant) the more YN =z

  15. Leptogenesis [Fukugita Yanagida ‘86] < 1.  tipically T<MR In the thermal bath when decays & inverse decays are no more effective in diluting YN go out of equilibrium! sooner (i.e. N’s more abundant) the more YN HOWEVER: laterN’s decay =z Boltzmann eq’n

  16. Leptogenesis [Fukugita Yanagida ‘86] 2. Violating C&CP Y* Y Y Y* Y* Y* Y* Y Y* Y Y* Y Y Y lepton asymm

  17. Leptogenesis [Fukugita Yanagida ‘86] 2. Violating C&CP vertex lepton asymm most important for hierarchical RH n’s  lower limit on M1

  18. Leptogenesis 2. Violating C&CP self-energy j j i i i j i j i i lepton asymm resonantly enhanced for Resonant effects (i-decays, j-internal) [Pilaftsis, Covi Roulet,Flanz… ‘97]  M1 as low as TeV relevant for nearly deg RH n’s

  19. Leptogenesis i a i a lepton asymm eia 3. BV- Sphaleron conserve YDa=B/3-La a

  20. Leptogenesis b i k a inverse decayswash outeiaonly ifb=a b k i a lepton asymm eia 3. BV- Sphaleron conserve YDa=B/3-La Flavor effects a Boltzmann eq’n: eia a a [Barbieri et al; Abada et al;… ] Aaa depend on which Ych.lept inter’ns are in equil’m a

  21. Leptogenesis z=MR/T time j j i i i previous scattering j CTP i j i i lepton asymm from solving quantum Boltzmann eq’n eia (z) z Quantum effects typical timescale 1/DMij [De Simone & Riotto ‘07] relevant if t’scale-eia> t’scale-YNi namely

  22. Leptogenesis-related phenomenology

  23. From seesaw: given MR, reconstruction of Yn ambiguous up to R (^=diag) I-Connection with CPV in n masses Casas-Ibarra parameterization

  24. From seesaw: given MR, reconstruction of Yn ambiguous up to R (^=diag) I-Connection with CPV in n masses Casas-Ibarra parameterization (hierarchical case) function of R and mn only! Neglecting flavor: [Davidson Ibarra, Branco IM et al, etc] introduce dep on U Including flavor: [Davidson, Ibarra, Petcov et al, etc]

  25. II-Range for RH n masses Neglecting flavor: efficiency factor k<0.1 

  26. II-Range for RH n masses Neglecting flavor: efficiency factor k<0.1  Hierarchical (enough) Nearly degenerate [Davidson Ibarra ‘02] <O(1) Including flavor: lower bound on M1 relaxed in general by O(2)

  27. III-Embedding in SUSY: gravitinos TRH has to be small enough to avoid overproduction of gravitinos during reheating. Being only gravitationally coupled to MSSM particles, they decay late destroying successful BBN. gravitino bound [Moroi, etc] For > • thermal production of RH n’s is inefficient Tension with lower bound on M1 for hier RH n’s WAYS OUT: non-thermal production, e.g. via flat directions in scalar potential [Giudice etc]; stable gravitinos (but then model dependence); resonant leptogenesis; etc etc

  28. IV-Embedding in SUSY: LFV & EDM Loops w/ Sleptons & Gauginos LFVdecays EDMs

  29. IV-Embedding in SUSY: LFV & EDM [BorzumatiMasiero ‘86] FV FC [EllisHisanoLolaRaidalShimizu ‘01] [IM ‘03] From mSUGRA at MPl,susy seesaw induce FV and CPV at l.e. via RGE Loops w/ Sleptons & Gauginos LFVdecays EDMs

  30. IV-Embedding in SUSY: LFV & EDM From mSUGRA at MPl,susy seesaw induce FV and CPV at l.e. via RGE Loops w/ Sleptons & Gauginos at present (future) strong impact on see-saw models LFVdecays BR(me g) < 10-11(-13) C21 < 10-1(-2) [Buchmuller et al; Sato, Tobe, Yanagida; Casas Ibarra; King et al; Lavignac I.M. Savoy; Masiero et al; .......... ] seesaw contribution to de observable in future only if tgb large, RH n’s are Hi and various yukawas are O(1) EDMs de < 10-27(-30) e cm  [IM’04] e.g. Th leptogenesis & observable seesaw-induced de M1 > 1011 GeV  can’t explain both with seesaw [IM Riotto Joaquim, ph/0701270]

  31. To look for correlations among observables: 2 examples with A) hierarchicalB) degenerate RH n’s V-Embedding in flavor models/GUTs A SU(5)XU(1)F with q>0 [Froggatt Nielsen] hB : M1 = O(1011) GeV M3£5x1012-13 GeV x 1/30 in future m e g :  WHOLE CLASS could be TESTED!! [IM Savoy ‘05] B Minimal Lepton Flavor Violation Quantum effects might be as large as O(103) [DeSimone Riotto Blanchet DiBari Raffelt] [Cirigliano De Simone Isidori IM Riotto ‘07] …despite “Minimal”, not a very predictive model for hB

  32. Conclusions New TeV-scale physics should not Violate too much F&CP New physics must explain B-asymmetry  e.g. via leptogenesis New Phys = seesaw As happens for leptogenesis (and depending on the details of the model), the flavor structure of New Physics can play a significant role in the generation of the B-asymmetry

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