* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Mass hierarchy and physics beyond the Standard Theory
Tensor operator wikipedia , lookup
Oscillator representation wikipedia , lookup
Symmetry in quantum mechanics wikipedia , lookup
Nuclear structure wikipedia , lookup
History of quantum field theory wikipedia , lookup
Kaluza–Klein theory wikipedia , lookup
Canonical quantization wikipedia , lookup
An Exceptionally Simple Theory of Everything wikipedia , lookup
Quantum chromodynamics wikipedia , lookup
Relativistic quantum mechanics wikipedia , lookup
Scale invariance wikipedia , lookup
Introduction to gauge theory wikipedia , lookup
Strangeness production wikipedia , lookup
Yang–Mills theory wikipedia , lookup
Higgs boson wikipedia , lookup
Weakly-interacting massive particles wikipedia , lookup
Theory of everything wikipedia , lookup
ALICE experiment wikipedia , lookup
Renormalization wikipedia , lookup
Elementary particle wikipedia , lookup
Faster-than-light neutrino anomaly wikipedia , lookup
ATLAS experiment wikipedia , lookup
Search for the Higgs boson wikipedia , lookup
Peter Kalmus wikipedia , lookup
Higgs mechanism wikipedia , lookup
Compact Muon Solenoid wikipedia , lookup
Mathematical formulation of the Standard Model wikipedia , lookup
Scalar field theory wikipedia , lookup
Renormalization group wikipedia , lookup
Grand Unified Theory wikipedia , lookup
Supersymmetry wikipedia , lookup
Standard Model wikipedia , lookup
Technicolor (physics) wikipedia , lookup
Minimal Supersymmetric Standard Model wikipedia , lookup
Mass hierarchy and physics beyond the Standard Theory I. Antoniadis Why mH = 126 GeV? IFT UAM/CSIC, Madrid, 25-27 September 2013 Low energy SUSY and 126 GeV Higgs Live with the hierarchy Low scale strings and extra dimensions I. Antoniadis (CERN) 1 / 36 Entrance of the Higgs Boson in the Particle Data Group 2013 particle listing I. Antoniadis (CERN) 2 / 36 Entrance of the Higgs Boson in the Particle Data Group 2013 summary tables I. Antoniadis (CERN) 3 / 36 Couplings of the new boson vs SM exclusion : spin 2 and pseudoscalar at > ∼ 95% CL Agreement with Standard Model expectation at ∼ 2 σ I. Antoniadis (CERN) 4 / 36 Remarks on the value of the Higgs mass ∼ 126 GeV consistent with expectation from precision tests of the SM favors perturbative physics 2 /v 2 ≃ 1/8 quartic coupling λ = mH 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 / 36 6 5 incertitude théorique ∆α (5) ∆αhad = 0.02761±0.00036 ∆χ2 4 3 95% CL 2 0 région exclue 20 100 260 1 400 mH [GeV] I. Antoniadis (CERN) 6 / 36 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 I. Antoniadis (CERN) ‘little’ hierarchy problem 7 / 36 I. Antoniadis (CERN) 8 / 36 I. Antoniadis (CERN) 9 / 36 What to do? Physics is an experimental science We must fully explore the multi TeV energy range I. Antoniadis (CERN) 10 / 36 We must fully explore the 10-100 TeV energy range ILC project The future of LHC I. Antoniadis (CERN) 11 / 36 I. Antoniadis (CERN) 12 / 36 I. Antoniadis (CERN) 13 / 36 I. Antoniadis (CERN) 14 / 36 I. Antoniadis (CERN) 15 / 36 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 / 36 126 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) 17 / 36 Fine-tuning in MSSM Upper bound on the lightest scalar mass: " 4 mt̃2 3 A2t m t 2 2 mh2 < ∼ mZ cos 2β + (4π)2 v 2 ln m2 + m2 t t̃ A2t 1− 12mt̃2 !# 2 < ∼ (130GeV ) mh ≃ 126 GeV => mt̃ ≃ 3 TeV or At ≃ 3mt̃ ≃ 1.5 TeV => % to a few %0 fine-tuning minimum of the potential: mZ2 = 2 RG evolution: m22 = m22 (MGUT ) − m11 − m22 tan2β tan2 β − 1 ∼ −2m22 + · · · 3λ2t 2 MGUT + ··· m ln 4π 2 t̃ mt̃ [27] ∼ m22 (MGUT ) − O(1)mt̃2 + · · · I. Antoniadis (CERN) 18 / 36 Reduce the fine-tuning minimize radiative corrections MGUT → Λ : low messenger scale (gauge mediation) δmt̃2 = Λ 8αs 2 M ln + ··· 3π 3 M3 increase the tree-level upper bound => extend the MSSM see Graham’s talk extra fields beyond LHC reach → effective field theory approach ··· I. Antoniadis (CERN) 19 / 36 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: Z 1 L(5) = d 2 θ (η1 + η2 S) (H1 H2 )2 M η1 : generated for instance by a singlet W = λσH1 H2 +Mσ 2 → Weff = λ2 (H1 H2 )2 M Strumia ’99 ; Brignole-Casas-Espinosa-Navarro ’03 Dine-Seiberg-Thomas ’07 η2 : corresponding soft breaking term I. Antoniadis (CERN) spurion S ≡ mS θ 2 20 / 36 Physical consequences of MSSM5 : Scalar potential 2 g22 + gY2 |h1 |2 − |h2 |2 8 1 η2 (h1 h2 )2 + h.c. + |h1 |2 + |h2 |2 (η1 h1 h2 + h.c.) + 2 V = m12 |h1 |2 + m22 |h2 |2 + Bµ(h1 h2 + h.c.) + + η12 |h1 h2 |2 (|h1 |2 + |h2 |2 ) 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 last term ∼ η12 : guarantees stability of the potential but requires addition of dim-6 operators I. Antoniadis (CERN) 21 / 36 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) / => large tan β expansion: δ6 mh2 = f v 2 + · · · ր constant receiving contributions from several operators f ∼ f0 × µ2 /M 2 , mS2 /M 2 , µmS /M 2 , v 2 /M 2 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) 22 / 36 Can the SM be valid at high energies? Degrassi-Di Vita-Elias Miró-Espinosa-Giudice-Isidori-Strumia ’12 Instability of the SM Higgs potential => metastability of the EW vacuum see Misha’s talk I. Antoniadis (CERN) 23 / 36 SUSY : λ = 0 => tan β = 1 HSM = sin β Hu − cos β Hd∗ λ = 18 (g22 + g ′2 ) cos2 2β λ = 0 at a scale ≥ 1010 GeV => mH = 126 ± 3 GeV Ibanez-Valenzuela ’13 #$ (# ) * + %#& ' !" ,#& ' ,#& ' ,#& ' ,#& e.g. for universal I. Antoniadis (CERN) √ 2m = M = MSS , A = −3/2M 24 / 36 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 [27] 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) 25 / 36 An extra U(1) can also cure the instability problem Anchordoqui-IA-Goldberg-Huang-Lüst-Taylor-Vlcek ’12 usually associated to known global symmetries of the SM: B, L, . . . B anomalous and superheavy B − L massless at the string scale (no associated 6d anomaly) but broken at TeV by a scalar VEV with the quantum numbers of NR L-violation from higher-dim operators suppressed by the string scale U(3) unification, Y combination => 2 parameters: 1 coupling + mZ ′′ perturbativity => 0.5 < ∼ gU(1)R < ∼1 interesting LHC phenomenology and cosmology I. Antoniadis (CERN) 26 / 36 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 = 1032 l n (R ∼ .1 − 10−13 mm for n = 2 − 6) Ms ∼ 1 TeV => volume R⊥ ⊥ s - 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 [18] 2 = a loop factor × Λ2 Λ ∼ a few TeV and mH But unification has to be probably dropped New Dark Matter candidates e.g. in the extra dims I. Antoniadis (CERN) 27 / 36 Origin of EW symmetry breaking? possible answer: radiative breaking I.A.-Benakli-Quiros ’00 V = µ2 H † H + λ(H † H)2 µ2 = 0 at tree but becomes < 0 at one loop non-susy vacuum simplest case: one scalar doublet from the same brane => tree-level V same as susy: λ = 81 (g22 + g ′2 ) D-terms µ2 = −g 2 ε2 Ms2 ← effective UV cutoff e −πl ց ր Z 1 X 2 −2πn2 R 2 l R 3 ∞ 3/2 θ24 2 ε (R) = il + dll n e 2π 2 0 16l 4 η 12 2 n ր ց IR 1 UV I. Antoniadis (CERN) 28 / 36 0.20 0.15 ε 0.10 0.05 0.00 0.25 1.00 1.75 2.50 3.25 4.00 4.75 R R → 0 : ε(R) ≃ 0.14 large transverse dim R⊥ = ls2 /R → ∞ R → ∞ : ε(R)Ms ∼ ε∞ /R ε∞ ≃ 0.008 UV cutoff: Ms → 1/R Higgs scalar = component of a higher dimensional gauge field => ε∞ calculable in the effective field theory λ = g 2 /4 ∼ 1/8 => MH ≃ v /2 = 125 GeV Ms or 1/R ∼ a few or several TeV I. Antoniadis (CERN) 29 / 36 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 Mj2 = M02 + Ms2 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 Mk2 = M02 + k 2 /R 2 ; k = ±1, ±2, . . . experimental limits: R −1 > ∼ 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) [32] 30 / 36 I. Antoniadis (CERN) 31 / 36 Extra U(1)’s and anomaly induced terms masses suppressed by a loop factor usually associated to known global symmetries of the SM (anomalous or not) such as (combinations of) Baryon and Lepton number, or PQ symmetry Two kinds of massive U(1)’s: - 4d anomalous U(1)’s: I.A.-Kiritsis-Rizos ’02 MA ≃ gA Ms - 4d non-anomalous U(1)’s: (but masses related to 6d anomalies) MNA ≃ gA Ms V2 ← (6d→4d) internal space => MNA ≥ MA or massless in the absence of such anomalies I. Antoniadis (CERN) 32 / 36 Standard Model on D-branes : SM++ 1-Right 2-Left gluon U(3) 3-Baryonic QL UR , D R W #-Leptonic U(1) L LL Sp(1) ≡ SU(2) ER ! " U(1) R U(1)3 ⇒ hypercharge + B, L I. Antoniadis (CERN) 33 / 36 TeV string scale Anchordoqui-IA-Goldberg-Huang-Lüst-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 no Lepton number => B, L => extra Z ′ s 1 Ms LLHH → Majorana mass: hHi2 Ms LL տ ∼ GeV with possible leptophobic couplings leading to CDF-type Wjj events Z ′ ≃ B lighter than 4d anomaly free Z ′′ ≃ B − L I. Antoniadis (CERN) 34 / 36 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) 35 / 36 The LHC timeline LS1 Machine Consolidation !"#$%&'()*'$ 7FFP% !"#$"%&'%()*% +,-%./%012%345/%678% 9.%:-";%<,=:% LS2 Machine upgrades for high Luminosity 7F.EH.I% >$4?#$4%()*%'&$% @4A:B-%!%C%<,=:% • Collimation • Cryogenics • Injector upgrade for high intensity (lower emittance) • Phase I for ATLAS : Pixel upgrade, FTK, and new small wheel LS3 Machine upgrades for high Luminosity • Upgrade interaction region • Crab cavities? • Phase II: full replacement of tracker, new trigger scheme (add L0), readout electronics. Europe’s top priority should be the exploitation of the full potential of the LHC, including the high-luminosity upgrade of the machine and detectors with a view to collecting ten times more data than in the initial design, by around 2030. I. Antoniadis (CERN) !"#$ *&<<4D"%6EF%9.%?4$% G4#$%#"%.EH.I%345%% 7F.2% >J#A4K.%,?B$#@4%% !"%$ ,<L=#"4%<,=:% 3M:D4%-&=:-#<%<,=:% #"%.I%345/%% 6.FF%9.%?4$%G4#$% 67F77% >J#A4K7%,?B$#@4% !"&$ "&%)(K()*% 6EFF%9.%?4$%G4#$/% $,-%,?%"&%N%E%#O.% D&<<4D"4@% 67FEF% E2% ##### # 36 / 36