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Mass Hierarchy and Physics Beyond the Standard Theory

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Mass Hierarchy and Physics Beyond the Standard Theory Mass hierarchy and physics beyond the Standard Theory I. Antoniadis HEP 2014 - Conference on Recent Developments in High Energy Physics and Cosmology Naxos, Greece, 8-10 May 2014 Low energy SUSY and 126 GeV Higgs Live with the hierarchy Low scale strings and extra dimensions I. Antoniadis (CERN) 1 / 35 Entrance of a Higgs Boson in the Particle Data Group 2013 particle listing I. Antoniadis (CERN) 2 / 35 Couplings of the new boson vs SM Higgs Agreement with Standard Model Higgs expectation at 1.5 σ Most compatible with scalar 0+ hypothesis Measurement of its properties and decay rates currently under way I. Antoniadis (CERN) 3 / 35 Fran¸cois Englert Peter Higgs Nobel Prize of Physics 2013 ↓ ↓ I. Antoniadis (CERN) 4 / 35 Remarks on the value of the Higgs mass ∼ 126 GeV consistent with expectation from precision tests of the SM 2 2 favors perturbative physics quartic coupling λ = mH /v ≃ 1/8 1st elementary scalar in nature signaling perhaps more to come triumph of QFT and renormalized perturbation theory! Standard Theory has been tested with radiative corrections Window to new physics ? very important to measure precisely its properties and couplings several new and old questions wait for answers Dark matter, neutrino masses, baryon asymmetry, flavor physics, axions, electroweak scale hierarchy, early cosmology, . I. Antoniadis (CERN) 5 / 35 6 incertitude théorique ∆α 5 ∆α(5) ± had = 0.02761 0.00036 4 2 3 ∆χ 2 95% CL 1 région exclue 0 20100 400 260 [ ] mH GeV I. Antoniadis (CERN) 6 / 35 Beyond the Standard Theory of Particle Physics: driven by the mass hierarchy problem Standard picture: low energy supersymmetry Natural framework: Heterotic string (or high-scale M/F) theory Advantages: natural elementary scalars gauge coupling unification LSP: natural dark matter candidate radiative EWSB Problems: too many parameters: soft breaking terms MSSM : already a % - %0 fine-tuning ‘little’ hierarchy problem I. Antoniadis (CERN) 7 / 35 I. Antoniadis (CERN) 8 / 35 I. Antoniadis (CERN) 9 / 35 What to do? Physics is an experimental science • Exploit the full potential of LHC • Go on and fully explore the multi TeV energy range I. Antoniadis (CERN) 10 / 35 We must fully explore the 10-100 TeV energy range ILC project The future of LHC I. Antoniadis (CERN) 11 / 35 I. Antoniadis (CERN) 12 / 35 I. Antoniadis (CERN) 13 / 35 I. Antoniadis (CERN) 14 / 35 I. Antoniadis (CERN) 15 / 35 VHE-LHC: location and size A circumference of 100 km is being considered for cost-benefit reasons 20T magnet in 80 km / 16T magnet in 100 km → 100 TeV I. Antoniadis (CERN) 16 / 35 I. Antoniadis (CERN) 17 / 35 I. Antoniadis (CERN) 18 / 35 126 GeV Higgs and SUSY compatible with supersymmetry (even with MSSM) although it appears fine-tuned in its minimal version but early to draw a general conclusion before LHC13/14 I. Antoniadis (CERN) 19 / 35 Fine-tuning in MSSM Upper bound on the lightest scalar mass: 3 m4 m2 A2 A2 m2 < m2 cos2 2β + t ln ˜t + t 1 − t < (130GeV )2 h ∼ Z 2 v 2 2 2 2 ∼ (4π) " mt m˜t 12m˜t !# mh ≃ 126 GeV => m˜t ≃ 3 TeV or At ≃ 3m˜t ≃ 1.5 TeV => % to a few %0 fine-tuning m1 − m2 tan2 minimum of the potential: m2 = 2 1 2 β ∼−2m2 + · · · Z tan2 β − 1 2 2 2 2 3λt 2 MGUT m m MGUT m [29] RG evolution: 2 = 2( ) − 2 ˜t ln + · · · 4π m˜t 2 2 ∼ m2(MGUT) − O(1)m˜t + · · · I. Antoniadis (CERN) 20 / 35 Reduce the fine-tuning minimize radiative corrections MGUT → Λ : low messenger scale (gauge mediation) 2 8αs 2 Λ δm˜t = M3 ln + · · · 3π M3 increase the tree-level upper bound => extend the MSSM extra fields beyond LHC reach → effective field theory approach · · · I. Antoniadis (CERN) 21 / 35 MSSM with dim-5 and 6 operators I.A.-Dudas-Ghilencea-Tziveloglou ’08, ’09, ’10 parametrize new physics above MSSM by higher-dim effective operators relevant super potential operators of dimension-5: 1 L(5) = d 2θ (η + η S) (H H )2 M 1 2 1 2 Z η1 : generated for instance by a singlet 2 2 λ 2 W = λσH H +Mσ → Weff = (H H ) 1 2 M 1 2 Strumia ’99 ; Brignole-Casas-Espinosa-Navarro ’03 Dine-Seiberg-Thomas ’07 2 η2 : corresponding soft breaking term spurion S ≡ mS θ I. Antoniadis (CERN) 22 / 35 Physical consequences of MSSM5: Scalar potential 2 2 g + g 2 V = m2|h |2 + m2|h |2 + Bµ(h h + h.c.)+ 2 Y |h |2 − |h |2 1 1 2 2 1 2 8 1 2 1 + |h |2 + |h |2 (η h h + h.c.)+ η (h h )2 + h.c. 1 2 1 1 2 2 2 1 2 2 2 2 2 + η1 |h1h2| (|h1| + |h2| ) η1,2 => quartic terms along the D-flat direction |h1| = |h2| tree-level mass can increase significantly bigger parameter space for LSP being dark matter Bernal-Blum-Nir-Losada ’09 2 last term ∼ η1 : guarantees stability of the potential but requires addition of dim-6 operators I. Antoniadis (CERN) 23 / 35 MSSM Higss with dim-6 operators dim-6 operators can have an independent scale from dim-5 Classification of all dim-6 contributing to the scalar potential (without SUSY)/ => 2 2 large tan β expansion: δ6mh = f v + · · · ր constant receiving contributions from several operators 2 2 2 2 2 2 2 f ∼ f0 × µ /M , mS /M , µmS /M , v /M mS = 1 TeV, M = 10 TeV, f0 ∼ 1 − 2.5 for each operator => mh ≃ 103 − 119 GeV => MSSM with dim-5 and dim-6 operators: possible resolution of the MSSM fine-tuning problem I. Antoniadis (CERN) 24 / 35 Can the SM be valid at high energies? Degrassi-Di Vita-Elias Mir´o-Espinosa-Giudice-Isidori-Strumia ’12 Instability of the SM Higgs potential => metastability of the EW vacuum I. Antoniadis (CERN) 25 / 35 SUSY : λ =0=> tan β = 1 ∗ 1 2 ′2 2 HSM = sin β Hu − cos β Hd λ = 8 (g2 + g ) cos 2β 10 λ = 0 at a scale ≥ 10 GeV => mH = 126 ± 3 GeV Ibanez-Valenzuela ’13 $ ;#A!+ + #+ ,G; 'E 'F H B@C";D! # -./01 " ' < >"+ ' ! ,#C;D# '())*+,**+ ,#C;D! ,#C";D# ,#C; ! # % ! # 232456/,7(8)*9,:/; 22 -./01 e.g. for universal √2m = M = M , A = 3/2M SS − I. Antoniadis (CERN) 26 / 35 If the weak scale is tuned => split supersymmetry is a possibility Arkani Hamed-Dimopoulos ’04, Giudice-Romaninio ’04 natural splitting: gauginos, higgsinos carry R-symmetry, scalars do not main good properties of SUSY are maintained gauge coupling unification and dark matter candidate also no dangerous FCNC, CP violation, ... experimentally allowed Higgs mass => ‘mini’ split mS ∼ few - thousands TeV gauginos: a loop factor lighter than scalars (∼ m3/2) natural string framework: intersecting (or magnetized) branes IA-Dimopoulos ’04 D-brane stacks are supersymmetric with massless gauginos intersections have chiral fermions with broken SUSY & massive scalars I. Antoniadis (CERN) 27 / 35 Giudice-Strumia ’11 I. Antoniadis (CERN) 28 / 35 Alternative answer: Low UV cutoff Λ ∼ TeV - low scale gravity => extra dimensions: large flat or warped - low string scale => low scale gravity, ultra weak string coupling n 32 n −13 Ms ∼ 1 TeV => volume R⊥ = 10 ls (R⊥ ∼ .1 − 10 mm for n =2 − 6) - spectacular model independent predictions - radical change of high energy physics at the TeV scale Moreover no little hierarchy problem: radiative electroweak symmetry breaking with no logs [20] 2 2 Λ ∼ a few TeV and mH = a loop factor × Λ But unification has to be probably dropped New Dark Matter candidates e.g. in the extra dims I. Antoniadis (CERN) 29 / 35 Accelerator signatures: 4 different scales Gravitational radiation in the bulk => missing energy present LHC bounds: M∗ ∼> 3 − 5 TeV Massive string vibrations => e.g. resonances in dijet distribution 2 2 2 Mj = M0 + Ms j ; maximal spin : j + 1 higher spin excitations of quarks and gluons with strong interactions present LHC limits: Ms ∼> 5 TeV Large TeV dimensions => KK resonances of SM gauge bosons I.A. ’90 2 2 2 2 Mk = M0 + k /R ; k = ±1, ±2,... −1 experimental limits: R ∼> 0.5 − 4 TeV (UED - localized fermions) extra U(1)’s and anomaly induced terms masses suppressed by a loop factor from Ms [??] I. Antoniadis (CERN) 30 / 35 I. Antoniadis (CERN) 31 / 35 Standard Model on D-branes : SM++ 2-Left 1-Right gluon U(3) 3-Baryonic Q L U , D R R W #-Leptonic U(1) L L E ! " L R ≡ SU(2) U(1) Sp(1) R U(1)3 ⇒ hypercharge + B, L I. Antoniadis (CERN) 32 / 35 TeV string scale Anchordoqui-IA-Goldberg-Huang-L¨ust-Taylor ’11 B and L become massive due to anomalies Green-Schwarz terms the global symmetries remain in perturbation - Baryon number => proton stability - Lepton number => protect small neutrino masses 2 no Lepton number => 1 LLHH → Majorana mass: hHi LL Ms Ms տ ∼ GeV B, L => extra Z ′s with possible leptophobic couplings leading to CDF-type Wjj events Z ′ ≃ B lighter than 4d anomaly free Z ′′ ≃ B − L I. Antoniadis (CERN) 33 / 35 Conclusions Confirmation of the EWSB scalar at the LHC: important milestone of the LHC research program Precise measurement of its couplings is of primary importance Hint on the origin of mass hierarchy and of BSM physics natural or unnatural SUSY? low string scale in some realization? something new and unexpected? all options are still open LHC enters a new era with possible new discoveries Future plans to explore the 10-100 TeV energy frontier I. Antoniadis (CERN) 34 / 35 The LHC timeline ! #$%%"()*"$ 7FFP% $8'68%4,%! *% LS1 Machine Consolidation +,-%./%012%345/%678% 9.%038@%1;20% LS2 Machine upgrades for high Luminosity 7F.EH.I% "6+5'6+%! *%,46% • Collimation ! #$ • Cryogenics @4A0.3% !%C%1;20% • Injector upgrade for high intensity (lower emittance) *411+)8%CIF%- .%546% • Phase I for ATLAS : Pixel upgrade, FTK, and new small wheel G4#$%#"%.EH.I%345%% 7F.2% "/'7+BG%;5.6'*+%% LS3 Machine upgrades for high Luminosity ;192'8+%1;20% ! %$ • Upgrade interaction region • Crab cavities? %<0)+%34203'1%1;20% #"%.I%345/%% • Phase II: full replacement of tracker, new trigger scheme (add L0), readout 6.FF%9 .%?4$%G4#$% electronics.
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