Is there a new physics between electroweak and Planck scale ? Mikhail Shaposhnikov Colloquium in the University of Nottingham Nottingham, 14 November 2012 – p. 1 Electroweak scale ≡ Fermi scale GF : energies E ∼ 100 GeV distances l ∼ 10−16cm time intervals δt ∼ 10−26s Domain of particle physics Planck scale is associated with Newton constant of gravitation GN : 19 energies E ∼ MP ∼ 10 GeV distances l ∼ 10−33cm time intervals δt ∼ 10−43s Domain of quantum gravity 17 orders of magnitude to go! Nottingham, 14 November 2012 – p. 2 If yes proton decay yes (?) Λ4 τ ∼ new p 5 mp 32 Current limit τp > 10 years; new physics at LHC yes (?) Electroweak scale solution to the hierarchy problem - stability of the weak scale against quantum radiative corrections. Supersymmetry, composite Higgs boson, large extra dimensions, etc. Scale of new physics hundreds of GeV. Nottingham, 14 November 2012 – p. 3 If yes searches for Dark Matter Weakly Interacting Massive Particles (WIMPS) yes (?) SUSY relic - neutralino searches for Dark Matter annihilation yes (?) SUSY relic - neutralino searches for axions yes (?) Axion is a hypothetic particle used for solution of the strong CP problem Nottingham, 14 November 2012 – p. 4 If no proton decay no 45 τp ≃ 10 years for Λnew ≃ MP Higgs and nothing else at LHC searches for Dark Matter Weakly Interacting Massive Particles (WIMPS) no searches for Dark Matter annihilation no searches for axions no Interacts too weakly if Λnew ≃ MP Nottingham, 14 November 2012 – p. 5 The answer to the question: Is there a new physics between electroweak and Planck scale ? Nottingham, 14 November 2012 – p. 6 The answer to the question: Is there a new physics between electroweak and Planck scale ? Is not known, Nottingham, 14 November 2012 – p. 6 The answer to the question: Is there a new physics between electroweak and Planck scale ? Is not known, and is not up to a theorist to deside! Nottingham, 14 November 2012 – p. 6 Outline Is there a new physics beyond Standard Model? Do we need an intermediate energy scale between MW and MP lanck? Higgs mass and new physics Cosmological inflation Neutrino masses, dark matter and baryogenesis Crucial tests and experiments Conclusions Nottingham, 14 November 2012 – p. 7 The Standard Model of particle interactions is in great shape: no convincing deviations from it were seen in any of accelerator experiments The evidence for the Higgs boson with the mass 125 − 126 GeV has been reported recently by Atlas and CMS collaborations at LHC. Nottingham, 14 November 2012 – p. 8 Is there a new physics beyond SM? Nottingham, 14 November 2012 – p. 9 Is there a new physics beyond SM? Yes: SM contradicts to experiments in neutrino physics and to a number of cosmological observations! Nottingham, 14 November 2012 – p. 9 Neutrino masses and oscillations Nottingham, 14 November 2012 – p. 10 CDHSW CHORUS NOMAD NOMAD NOMAD 0 KARMEN2 CHORUS Problem with solar neutrinos 10 LSND Bugey BNL E776 since late 60, R. Davis K2K SuperK Masses: CHOOZ –3 PaloVerde 10 Super-K+SNO ∆m2 Cl +KamLAND 21 ] = 7.65 ± 0.23 2 10−5 eV2 KamLAND 2 [eV 2 SNO ∆m32 –6 m 10 − = 2.40 ± 0.12 Super-K 10 3 eV2 ∆ Mixing matrix: Ga 0.79 − 0.88 0.47 − 0.61 < 0.20 –9 10 νe↔νX ν ↔ν 0.19 − 0.52 0.42 − 0.73 0.58 − 0.82 µ τ νe↔ντ 0 20 − 0 53 0 44 − 0 74 0 56 − 0 81 ν ↔ν . e µ SM: neutrinos are massless 10–12 10–4 10–2 100 102 tan2Nottingham,θ 14 November 2012 – p. 11 http://hitoshi.berkeley.edu/neutrino Dark matter in the universe Nottingham, 14 November 2012 – p. 12 Problem since 1933, F. Zwicky. Most of the matter in the universe is dark Evidence: Rotation curves of galaxies Big Bang nucleosynthesis Structure formation CMB anisotropies Supernovae observations Non-baryonic dark matter: ΩDM ≃ 0.22 SM: no particle physics candidate Nottingham, 14 November 2012 – p. 13 Baryon asymmetry of the universe Nottingham, 14 November 2012 – p. 14 Problem since 1930, P. Dirac. Observational evidence: no antimatter in the Universe. Required (Sakharov): T Baryon number non-conservation symmetric phase (OK) critical point CP-violation (OK) Higgs phase Substantial deviations from ther- MH mal equilibrium. Present for Higgs Electroweak theory masses larger than ≃ 73 GeV † 2 (first order electroweak phase hφ φi ≪ (250GeV ) T = 109.2 ± 0.8GeV , transition). MH = 72.3 ± 0.7GeV † 2 hφ φiT =0 ∼ (250GeV ) SM: Higgs mass > 114 GeV CP violation present but too small to accommodate observed BAU. Nottingham, 14 November 2012 – p. 15 Cosmological inflation Nottingham, 14 November 2012 – p. 16 Important cosmological problems: Horizon problem: Why the universe is so uniform and isotropic? t present horizon recombination horizon at recombination r Expected fluctuations at θ ∼ 1o: δT/T ∼ 1. Observed fluctuations: δT/T ∼ 1O−5 Nottingham, 14 November 2012 – p. 17 Flatness problem: Why ΩM +ΩΛ +Ωrad is so close to 1 now and was immensely close to 1 in the past? All this requires enormous fine-tuning of initial conditions (at the Planck scale?) if the Universe was dominated by matter or radiation all the time! Nottingham, 14 November 2012 – p. 18 Accelerated expansion of the Universe Nottingham, 14 November 2012 – p. 19 Nottingham, 14 November 2012 – p. 20 Theoretical problems Nottingham, 14 November 2012 – p. 21 Unification with gravity? 4 Cosmological constant problem: Why ǫvac/MPl ≪ 1? Dynamical Dark Energy or cosmological constant? Hierarchy problem: Why the Fermi scale is so much smaller than the Planck scale? Stability of the Higgs mass against radiative corrections. Strong CP-problem: Why θQCD ≪ 1? No CP-violation in strong interactions is seen. Fermion masses: Why me ≪ mt? ... Nottingham, 14 November 2012 – p. 22 Overwhelming point of view: these problems should find their solution by physics beyond the SM which contains some intermediate energy scale MW < Mnew < MPlanck Nottingham, 14 November 2012 – p. 23 Do we need an intermediate energy scale between MW and MP lanck? Nottingham, 14 November 2012 – p. 24 Do we need an intermediate energy scale between MW and MP lanck? No: the SM problems can be solved by new physics below the Fermi scale ! Nottingham, 14 November 2012 – p. 24 Our strategy Select the most important problems to solve (may be subjective). Most important for us: those where Standard Model is in conflict with observations: neutrino masses, dark matter, baryon asymmetry of the universe, inflation, accelerated expansion of the universe Use Ockham’s razor principle: “Frustra fit per plura quod potest fieri per pauciora” or ”entities must not be multiplied beyond necessity”. For particle physics: entities = new hypothetical particles and new scales different from Fermi and Planck scales. Nottingham, 14 November 2012 – p. 25 William of Ockham (Occam, Hockham,... ) 1288 - 1348 Nottingham, 14 November 2012 – p. 26 Higgs mass and new physics Nottingham, 14 November 2012 – p. 27 July 4, 2012, Higgs at ATLAS and CMS 3500 ATLAS Data Sig+Bkg Fit (m =126.5 GeV) 3000 H Bkg (4th order polynomial) CMS 2500 Events / 2 GeV 2000 1500 s=7 TeV, ∫Ldt=4.8fb-1 1000 s=8 TeV, ∫Ldt=5.9fb-1 γγ→ 500 H (a) 200100 110 120 130 140 150 160 100 0 -100 Events - Bkg (b) -200 100 110 120 130 140 150 160 Data S/B Weighted 100 Sig+Bkg Fit (m =126.5 GeV) H Bkg (4th order polynomial) 80 weights / 2 GeV Σ 60 40 20 (c) 8100 110 120 130 140 150 160 4 0 -4 (d) -8 Σ weights - Bkg 100 110 120 130 140 150 160 m γγ [GeV] Nottingham, 14 November 2012 – p. 28 July 4, 2012, Higgs at ATLAS and CMS According to CMS, MH = 125.3 ± 0.4(stat) ± 0.5(syst) GeV, According to ATLAS, MH = 126 ± 0.4(stat) ± 0.4(syst) GeV. Nottingham, 14 November 2012 – p. 29 July 4, 2012, Higgs at ATLAS and CMS According to CMS, MH = 125.3 ± 0.4(stat) ± 0.5(syst) GeV, According to ATLAS, MH = 126 ± 0.4(stat) ± 0.4(syst) GeV. What does it mean for high energy physics? Nottingham, 14 November 2012 – p. 29 Self-consistency of the SM Within the SM the mass of the Higgs boson is an arbitrary parameter which can have any value (if all other parameters are fixed) from mmeta ≃ 111 GeV (metastability bound) to mLandau ≃ 1 TeV (triviality bound) Nottingham, 14 November 2012 – p. 30 Triviality bound L. Maiani, G. Parisi and R. Petronzio ’77; Lindner ’85; T. Hambye and K. Riesselmann ’96;... The Higgs boson self-coupling has a Landau pole at some energy determined by the Higgs mass. For MH ≃ mLandau ≃ 1 TeV the position of this pole is close to the electroweak scale. ΛHΜL strong coupling Higgs mass 1 TeV ≃ M1 > M2 > M3 ≃ 175 GeV Μ Fermi Planck Nottingham, 14 November 2012 – p. 31 Triviality bound If mH < mmax ≃ 175 GeV the Landau pole appears at energies higher than the Planck scale E>MP . LHC: The Standard Model is weakly coupled all the way up to the Planck scale Nottingham, 14 November 2012 – p. 32 Metastability bound Krasnikov ’78, Hung ’79; Politzer and Wolfram ’79; Altarelli and Isidori ’94; Casas, Espinosa and Quiros ’94,’96;... If mH < mmin, there is a deeper vacuum with the Higgs vacuum expectation value larger than the EW vev. VHΦL VHΦL VHΦL mH > mmin mH = mmin mH < mmin Φ Φ Φ The life-time of our vacuum is smaller than the age of the Universe if mH < mmeta, with mmeta ≃ 111 GeV Espinosa, Giudice, Riotto ’07 Nottingham, 14 November 2012 – p. 33 Metastability bound If the Higgs mass happened to be smaller than mmeta ≃ 111 GeV, we would be forced to conclude that there must be some new physics beyond the SM, which stabilizes the SM vacuum.