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THE PHYSICS OF THE ELECTROWEAK SCALE

 1 . THE PHYSICS OF THE ELECTROWEAK SCALE. Tomislav Prokopec (ITP & Spinoza Institute, Utrecht U.). WHEPP-XI, PRL, Ahmedabad 4 Jan 2010.  2 . OUTLINE. ◙ STANDARD MODEL. ● particle content. ◙ ELECTROWEAK TRANSITION. ● equilibrium considerations.

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THE PHYSICS OF THE ELECTROWEAK SCALE

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  1.  1 THE PHYSICS OF THE ELECTROWEAK SCALE TomislavProkopec (ITP & Spinoza Institute, Utrecht U.) WHEPP-XI, PRL, Ahmedabad 4 Jan 2010

  2.  2 OUTLINE ◙ STANDARD MODEL ● particle content ◙ ELECTROWEAK TRANSITION ● equilibrium considerations ● dynamics of 1st order transition ◙ ELECTROWEAK BARYOGENESIS ● measurements ● tests ● particle models ● calculational techniques ◙ GRAVITATIONAL WAVES ● characteristic frequency and spectrum ◙ MAGNETIC FIELDS ●

  3.  3 STANDARD MODEL MATTER CONTENT & INTERACTIONS ● matter: 3 generation of chiral fermions (quarks & leptons): max. violate parity ● interactions: gauge fields: gluons, Ws, Zs, hypercharge field symmetry: SU(3)c x SU(2)L x U(1)Y ● spontaneous symmetry breaking by Higgs: SU(3)c x SU(2)L x U(1)Y  SU(3)c x U(1)EM H  fermions and gauge bosons acquire masses

  4.  4 ELECTROWEAK TRANSITION

  5.  5 EQUILIBRIUM ASPECTS OF THE TRANSITION ● Higgs potential at T=0:  LEP bound: mH > 114 GeV • LHC ?? ● Higgs potential at T0:  E: regulates the strength of the transition: bosons  Shaposhnikov’s condition: /Tc>1  bubbles of 1st order transition form @ Tc>Tn>Tb

  6.  6 EQUILIBRIUM CONSIDERATIONS EW TRANSITION in MSM Kajantie. Laine, Rummukainen, Shaposhnikov 1996  for Higgs mass >72GeV transition is acrossover  Experimental (LEP) Higgs mass bound >114GeV:rules out BAU in MSM Strong first order phase transition in MSSM  allowed “triangle” forMSSM: Carena, Quiros, Seco, Wagner, 2000; Quiros 2001 weak transition : T  the “triangle” extends by ~5GeV for large mQ >>TeV R-stop mass strong transition: T Carena, Nardini, Quiros, Wagner, 2008 color breaking phase Higgs mass

  7.  7 EQUILIBRIUM IN MODELS WITH SINGLETS ♦ singlet model without discrete symmetries nMSSM Huber,Schmidt 2000 Menon, Morrissey, Wagner 2004 Huber, Konstandin, Prokopec, Schmidt 2006

  8.  8 DYNAMICS OF THE TRANSITION  at Tc the two minima are degenerate  bubbles begin to nucleate at Tn<Tc  nucleation rate:  the bubble energy (saddle point):  basic parameters of the transition: bubble wall velocity vw& thickness Lw  for standard model: vw=0.35-0.45c; Lw ~20/Tc(Moore, Pokopec 1995)  for MSSM: vw~0.05c [not all contributions accounted for!](John, Schmidt 2000)  other models, e.g. NMSSM, nMSSM, NOT KNOWN!  recent developments: runaway wall (if supersonic can become ballistic) Bodeker, Moore 2009 (important both for BG & GW creation)

  9.  9 TRANSITION DYNAMICS IN THE SM:A MICROSCOPIC MODEL Moore, Prokopec 1995  pressure difference vs. plasma friction  HIGGS FIELD EQUATION: deviation from equilibrium + FLUID EQUATIONS FOR f (for each relevant species):  classical forces:  Can be derived from Boltzmann equations: with a fluid ansatz for DISTRIBUTION FUNCTION:

  10.  10 ELECTROWEAK BARYOGENESIS Sakharov 1967; Kuzmin, Rubakov, Shaposhnikov 1985

  11.  11 OBSERVED MATTER-ANTIMATTER ASYMMETRY The ratio of the baryon and photon number densities: - nucleosynthesis constraint, cmbr+LSS measurements baryons: increase compression (odd) peaks, decrease rarefaction peaks Based on temperature anisotropies in CMB (WMAP 2008)

  12.  13 NUCLEOSYNTESIS (BBN) • synthesis of nucleons in the Universe:yields a constraint on B in a reasonable agreement with CMB • some tension with: Li6, Li7 and He4 Olive & Sarkar, PDG

  13.  14 SAKHAROVS CONDITIONS • Sakharov (1967) establisheed criteria for dynamical baryogenesis: • B-violation • C & CP violation • - processes including baryons and antibaryons are not equally fast • Out of equilibrium • - CPT symmetry implies equal number of particles and antiparticles.

  14.  15 SPHALERON PROCESSES • Adler, Bell & Jackiw: • - chiral anomaly of the standard model: `large’ gauge transformations violate leptonic and baryonic currents •  each transition over the barier adds 9 quarks & 3 leptons

  15.  16 WHY IS ELECTROWEAK BARYOGENESIS INTERESTING? MODELS ARE TESTABLE AT ACCELERATORS (LHC, ILC) ◙ New (scalar) particles at LHC (Higgs, ..) ◙ New sources of CP violation (EDM exsperiments) ◙ Gravitational waves produced at EW phase transition ◙ Magnetic fields produced at EW phase transition (indirect) CENTRAL QUESTION: Does the explanation for the origin of matter-antimatter asymmetry lies atenergies ~1TeV accessible by LHC, ILC?

  16.  17 ELECTROWEAK BARYOGENESIS AT A STRONG 1st ORDER TRANSITION Cohen,Kaplan,Nelson 1991  diffusion: ink in water 8 expanding bubbles of higgs phase 8 CP violation on bubble walls 8 B violation in symmetric phase

  17.  18 SUPERSIMETRY & MSSM ●each particle of the standard model has a supersymmetric partner with a different spin (& statistic): charginos & neutralinos NB:in contrast to SM, MSSM has 2 complex Higgs doublets

  18.  19 SEMICLASSICAL FORCE Joyce, Prokopec, Turok, 1994 Kainulainen, Prokopec, Schmidt, Weinstock 2001; Rangarajan 2003 ●semi-classical force: consequence of a difference in energy between fermionic particles & anti-particles (s = spin = ± , m=|m|eiθ, c=1): Fs ●semi-classical force : ●semi-classical force in kinetic theory: NB: applicable for energetic particles for which gradient expansion applies: met for typical thermal particles with E~T, since and LwT>>1.

  19.  20 SEMICLASSICAL FORCE FOR CHARGINOS Joyce, Prokopec, Turok, 1994 Kainulainen, Prokopec, Schmidt, Weinstock 2001; Rangarajan 2003 LAGRANGIAN Fs ●The presence of a propagating bubble wall (Higgs condensate) induces chargino flavour oscillations (1st order in gradients), analogous to neutrino flavour oscillations, and semiclassical force (2nd order in gradients)

  20.  21 CHARGINOS MEDIATED BARYOGENESIS Carena, Moreno, Quiros, Seco, Wagner (2000) Cline, Joyce, Kainulainen (2000) Konstandin, Prokopec, Schmidt, Seco (2005) ● Charginos decay into quarks & leptons via weak strength interactions: ● Sphalerons bias production of net baryon number, which diffuses into broken phase We solve the relevant diffusion equations. We use the system of equations initially proposed by Huet and Nelson 1995, and refined in the work of Carena, Moreno, Quiros, Seco, Wagner 2000; Balazs et al 2004.

  21. CHARGINO BARYOGENESISINMSSM  22 Konstandin, Prokopec, Schmidt, Seco (2005) Baryon productionb=nb/nsas a function of mc & mA

  22.  23 CHARGINO BARYOGENESISINMSSM (2) Baryon productionb=nb/n as a function ofc,tan & mA=150GeV

  23.  24 ELECTRIC DIPOLE MOMENTS IN M(S)SM The current measurement bound of the electron electric dipole moment (EDM) Regan et al, Phys. Rev. Lett. 88:071805, 2002 The standard model (MSM) value for eEDM (4 loop) Pospelov, Khriplovich, Sov.J.Nucl.Phys.53:638-640,1991, Yad.Fiz.53:1030-1033,1991 The standard model (MSM) value for neutron EDM (2 loop penguin) The MSSM 2 loop Higgs contribution for electron EDM

  24.  25 CHARGINO BARYOGENESISINMSSM (3) Konstandin, Prokopec, Schmidt, Seco (2005) black regions mean Baryon asymmetry from charginos with maximum CP violation assumed The current measurements of the electron electric dipole moment Regan et al, Phys. Rev. Lett. 88:071805, 2002 Romalis et al., 2002 constrain the CP violating phase to be < 0.1, implying that charginos cannot produce enough baryons to explain the BAU (unless there are fortuitious cancellations of the MSSM contributions to the EDM).

  25.  26 CHARGINO BARYOGENESIS IN nMSSM Menon, Morrissay, Wagner (2004) W = λH1H2 –mS/λ+.. Huber, Konstandin, Prokopec, Schmidt (2006) BG (~50%) BG+EDM Baryogenesis in nMSSM is efficient (η10|obs=0.9)! - Because of the additional scalar singlet S, PT transition and CP violation are much stronger than in the MSSM

  26.  27 COLD EW BG WITH SM CP VIOLATION Tranberg, Hernandez, Konstandin, Schmidt 2009 Hernandez, Konstandin, Schmidt 2008  CP VIOLATING OPERATOR IN SM:  much bigger than the Jarlskog CP violation (nonpertrbative in masses) • can produce (within the cold BG scenario) about 4 orders of magnitude larger asymmetry from the observed: Q: What about near equilibrium baryon production?

  27.  28 GRAVITATIONAL WAVES

  28.  29 SOURCES OF GWs AND MEASUREMENT PROSPECTS LIGO, LISA: ~2020, BBO? SOURCES: (1) direct bubble collisions (2) turbulence (3) magnetic fields STRENGHT OF THE TRANSITION: BUBBLE SIZE AT COLLISION:  ~1/(duration of transition) NB: Need a very strong transition (~1) and relativistic bubbles (vb~c) Grojean, Servant 2006

  29.  30 TYPICAL GW FREQUENCY  agrees reasonably well with Grojean, Servant and others

  30.  31 GWs FROM BUBBLE COLLISIONS Kosowsky, Turner, Watkins 1992 Kamionkowski, Kosowsky & Turner 1993 [see also Caprini, Durrer & Servant 2007-08] Konstandin, Huber 2008  f-1  f-1.8  f3  f3 [see also Caprini, Durrer, Konstandin & Servant 2009]  Konstandin & Huber get enhanced high frequency power: • potentially observable by LISA & BBO (for relativistic bubbles)  GWs from turbulence & EWPT Caprini, Durrer & Servant 2009 NB: GWs from preheating: too high frequency [Dufaux, Bergman, Felder, Kofman & Uzan 2006]

  31.  32 MAGNETIC FIELDS  from bubble collisions: Kibble, Vilenkin 1990s; Vashaspati 1990s-2000s  as a source of GWs: Caprini & Durrer 2001

  32.  33 HIGGS FIELD AS THE INFLATON Bezrukov, Shaposhnikov 2007

  33.  34 HIGGS FIELD AND NONMINIMAL INFLATION Bezrukov, Shaposhnikov 2007  Add to the standard model a negative nonminimal coupling:  R=Ricci scalar, ~-50000, ~0.1 • during inflation, when the Higgs acquires a large expectation value, the tree level Higgs mass can be neglected. In Einstein frame, the model behaves as a light massive inflaton, with a mass making the model viable. • initial calculation of quantum corrections suggests: the model is viable for mH=120-140GeV Bezrukov, Shaposhnikov 2009 Barvinsky et al 2008

  34.  35 DISCUSSION & CONCLUSIONS strength of the transition understood:  strong transition: light stop & negative mH² (MSSM), singlets (nMSSM, NMSSM), 2HDM, effective theories withdim 6 operators, [open Q: lattice for the 2HDM?] wall velocity & thickness: known in SM, roughly known in MSSM (slow); poorly known in most of other cases Q: non-perturbative effects of infrared gauge fields: Moore; Schmidt, Zahlten Baryon production: (1) well understood from semiclassical force and flavor mixing (charginos) in gradient expansion; (2) poor understanding of sources from quantum reflection Koksma, Prokopec & Schmidt 2009 + in progress (3) more realistic set of fluid equations Chung, Garbrecht, Ramsey-Musolf & Tulin 2009 (4) baryogenesis for supersonic walls, and (5) with transitional CP violation

  35.  36 DISCUSSION & CONCLUSIONS 2 MODEL BUILDING:  current EDM bounds strongly disfavour electroweak scale baryogenesis in the MSSM  in a model with scalar singlet in the Higgs sector (n/NMSSM) BAU can be generated with CP violation consistent with EDM bounds  BAU in 2HDMs, in effective models with6 model (CP violation consistent with EDM bouds) • BAU in NMSSM, models with extra U(1)’s, E6SSM, extra dimensional models, little Higgs models:  should be studied in more detail U(1)’s:Kang, Langacker, Li & Liu 2009  Lepton mediated EW baryogenesisChung, Garbrecht, Ramsey-Musolf & Tulin 2009 importance of collider signatures: new particles, CP violation and other signatures: EDM, CMB,..

  36.  37 DISCUSSION & CONCLUSIONS 3 GRAVITATIONAL WAVES FROM EW TRANSITION: From bubble collisions, turbulence or magnetic fields; for very strong transition and relativisitic bubbles: potentially observable at LISA and BBO  useful for testing the nature of the EW transition • MAGNETIC FIELDS FROM EW TRANSITION: • most likely not observable/relevant for LS magnetic fields (but may produce GWs)

  37. 38 Grandunified scale baryogenesis Yoshimura 1978 Toussaint, Treiman, Wilczek, Zee 1979 Barr 1979; Weinberg 1979

  38. 39 GRANDUNIFIED SCALE BARYOGENESIS  out of equilibrium CP violating decay of heavy GUT gauge bosons X and/or higgses Y  Modern version: inflaton or GUT Higgs decay (parametric resonance)  CP-violation: interference of tree-level and 1 loop decays Y Kolb, Wolfram 1981  Mechanism that involves tree level interactions only: coherent baryogenesis Garbrecht, Prokopec, Schmidt 2003, 2005  GUT Higgs decays resonantly into fermion flavours & violates CP & B-L: separation of charge among fermion flavours results in baryogenesis  realised in supersymmetric Pati-Salam & SO(10) models

  39. 40 INFLATION Van der Post, Prokopec (2006) Garbrecht, Prokopec (2007)  Similarly to the amplification of matter fluctuations by which cosmological perturbations are generated, inflation can amplify quantum charge fluctuations SCALAR FIELD LAGRANGIAN:  CP violation in complex phases of ω and μ:  charge density is produced during inflation (by amplification of vacuum fluctuations): H dH/dt  charge density depends on the parameters of the model only (no initial condition dependence)  qcontains non-perturbative enhancement ~|μ|²dH/dt/[(m²+|μ|²)(m²-|μ|²)]  If  is charged under B, qgets converted into B  links inflation and baryogenesis

  40. 41 Baryogenesis via Leptogenesis Fukugita, Yanagida 1986

  41. 42 MAJORANA νLEPTOGENESIS MAJORANA LAGRANGIAN: Fukugita, Yanagida 1986  Naturally embedded into GUTs (SO(10), etc.) Chen, Mahanthappa 2003  Sea-saw: mass matrix: = =  neutrino masses: = =  Heavy RH Majorana neutrino decays as (H=SU(2) Higgs doublet): TREE LEVEL – 1 LOOP INTERFERENCE EFFECT   Thus created leptons are processed via EW sphalerons (B+L=0) into baryons  CP violation of the LH neutrino mass matrix has 3 (1) CP violating parameters if the mass term is Majorana (Dirac), while the heavy neutrino sector has 6 phases  in general: NO DIRECT RELATION between CP violation in heavy & light sectors

  42. 43 Thermal leptogenesis: R-neutrino bound Buchmüller, Di Bari & Plümacher 2003  Maximum CP violation in the heavy RH Majorana sector assumed Davidson-Ibarra bound (2002): _  conflict with the gravitino bound:  From the BBN abundance of D+ ³He: Buchmüller, Peccei & Yanagida 2005  From hardronic decay modes into gluon+gluino: Kawasaki, Khori & Moroi 2005 Pradler, Steffen 2006

  43. 44 DIRAC νLEPTOGENESIS Dick, Lindner, Ratz, Wright 2000 DIRAC LAGRANGIAN:  Some process produces at a high T a negative initial LH lepton number:  below T~10^12 GeV this is processed by the EW sphalerons (B+L=0) into: B1=-L1/2=-LL0/3  below LR equlibration temperature T<TLR < 100GeV (LL=LR)this becomes: B=L=-LL0/3, LR=LL=-LL0/6  these survive up to today: a prediction of the model  Similar to electrogenesis: initial eR converted by sphalerons to B & L at T~100GeV Joyce, Prokopec 1998

  44. 45 ALTERNATIVE MODELS Lazarides, Shafi 1991 1. NONTHERMAL LEPTOGENESIS Kumekawa, Moroi, Yanagida 1994 Giudice, Peloso, Riotto, Tkachev 1999  RH Majorana neutrinos are produced nonthermally (e.g. at (pre)heating after inflation)  via Affleck-Dine mechanism Affleck, Dine 1985  inflaton Ф decays either perturbatively or nonperturbatively (parametric resonance) into M1: >> BARYON ASYMMETRY: = = NB: Treh can be as low as 10^6 GeV: no tension with the gravitino bound(as of yet!)

  45. 46 ALTERNATIVE MODELS (2) Flanz, Paschos, Sarkar 1996 2. RESONANT LEPTOGENESIS Covi, Roulet 1997 Pilaftsis, Underwood 2003 Heavy Majorana masses nearly degenerate:  self-energy diagram dominates  condition on the lightest Majorana ν relaxed: M1~M2 > 1TeV NB: Fine tuning of masses M1≈M2required

  46. 47 ALTERNATIVE MODELS (3) Grossman, Kashti, Roulet 2003 3. SOFT LEPTOGENESIS D’Ambrosio, Giudice, Raidal 2003 Boubekeur, Hambye, Senjanović 2003  If there is a mismatch between physical and CP R-(s)neutrino eigenstates, CP eigenstates oscillate (recall oscillations in KL & KS mesons) MODEL: soft susy breaking for RH sneutrino (with A term) + superpotential: CP RH-sneutrino eigenstates oscillate when Im(A) != 0  LEPTOGENESIS BARYON ASYMMETRY: NB: Model can be also realised in GUTs, e.g. SO(10)

  47. 48 CP VIOLATION & LEPTOGENESIS  when Yukawa matrix y‘ has 2 zeros: 1 heavy phase  observable  when one Majorana νis very heavy: 3 phases  2 are observable  3 bimaximal mixing model: hint for symmetry: solar mixing angle: sin²(θ)~1/3 Mohapatra, Nasri, Yu 2006 Mohapatra, Yu 2006 Pascoli Petcov Riotto 2006  Lepton mixing matrix: • S3: permutation symmetry of 3 lepton generations  the origin of the symmetry not known BARYON ASYMMETRY: Mohapatra, Yu 2006 =  tanβ=10  φ1= Majorana CP phase  η ~ 5/1000 = efficiency factor NB: When S3 is approximate: BAU depends on the Dirac CP phase as well: ×√(∆m²atm/2)

  48. 49 AFFLECK DINE BARYOGENESIS Affleck, Dine 1985 Murayama, Yanagida 1994  (scalar) flat directions of supersymmetric theories can carry L and/or B charge Dine, Randall, Thomas 1996  As flat directions roll towards their true minimun and decay, B & L can be generated

  49.  50 CONCLUSIONS current EDM bounds strongly disfavour electroweak scale baryogenesis in the MSSM In a model with scalar singlet in the Higgs sector (nMSSM) BAU can be generated with CP violation consistent with EDM bounds Inflation does not necessarily wash out initial B or L asymmetry; instead it can be used to amplify charged vacuum fluctuations akin to cosmological perturbations: links inflation and BAU! Thermal leptogenesis is excluded in SUGRA unless gravitino is LSP or it is very light (<<1GeV) or very heavy (>100TeV) Nonthermal leptogenesis is still viable (it requires Treh > 10^6 GeV) Resonant and soft leptogenesis are viable alternatives; require some (fine) tuning Models with S³symmetry in the lepton sector link leptogenesis and CP violation in the SM neutrino sector Affleck Dine mechanisms are viable; one is often promted to invoke Planck scale physics however

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