Aspects of string phenomenology in the LHC era I. Antoniadis Pre-SUSY 2014, Manchester, 15-18 July 2014 I. Antoniadis (CERN) 1 / 91 Outline 1 LHC: where do we stand? where do we go? 2 Supersymmetry: is it alive? 3 String phenomenology: what for? main issues 4 High string scale - heterotic string 5 High string scale - type IIA/B and intersecting/magnetized branes 6 Low string scale and large extra dimensions 7 Experimental predictions 8 Warped spaces and holography I. Antoniadis (CERN) 2 / 91 Bibliography Topics on String Phenomenology I. Antoniadis e-Print: arXiv:0710.4267 [hep-th] An Introduction to perturbative and nonperturbative string theory Ignatios Antoniadis, Guillaume Ovarlez e-Print: hep-th/9906108 String theory and particle physics: An introduction to string phenomenology Luis E. Ibanez, Angel M. Uranga Published in Cambridge, UK: Univ. Pr. (2012) 673 p I. Antoniadis (CERN) 3 / 91 Entrance of a Higgs Boson in the Particle Data Group 2013 particle listing I. Antoniadis (CERN) 4 / 91 Combined mass measurement 37 [CMS-PAS-HIG-14-009] ! Float 3 signal strengths to not depend on yields. ! %%% and HZZ 4 results compatible at 1.6 / level. [email protected] @CMSexperiment @ICHEP2014 I. Antoniadis (CERN) 5 / 91 +=);5A+B+LR'E>'RF='&.::;'IE;E,'B);;' l9L<'QGEL9J'QRP=LERFQm' ) 4 ATLAS Combined γγ +ZZ* s = 7 TeV Ldt = 4.5 fb -1 H → γγ 3.5 ∫ H → ZZ* → 4 l s = 8 TeV ∫Ldt = 20.3 fb -1 Best fit =125.36 GeV) 3 H 68% CL TEK+'B+);5A+'-<),,+*;' (m 95% CL 2.5 SM QGEL9J'QRP=LERF' σ / σ 2 µγγ =1.29 ± 0.30 1.5 (mH =125.98GeV ) ZZ +0.45 1 µ =1.66 (m =124.51 ) −0.38 Signal yield ( H GeV 0.5 0 123 123.5 124 124.5 125 125.5 126 126.5 127 127.5 88'9L<' γγ '-EB0)LI.K6' m [GeV] -J<'P=QXJRc' H +0.5 ∆ = 2.3± 0.9 -JD' m 125.5 ± 0.2 (stat) −0.6 (syst) GeV T+Wc' '"EB0)LI.*.K6''1c9 σ'' 125.36 ± 0.37 (stat) ± 0.18 (syst) GeV ∆m =1.47± 0.72 "EB0)LI.*.K6''8c3l σ'' 7caq'%A+-.;.E,'B+);5A+B+,K'F;K)L;L-)*'5,-+AK).,K6'DEB.,),KG' 8m' I. Antoniadis (CERN) 6 / 91 @).,'O+-)6'),D'%AED5-SM,'@ED+;' ATLAS σ(stat.) Prelim. sys inc. Total uncertainty σ( ) m = 125.5 GeV theory H σ(theory) ± 1 σ on µ + 0.23 H → γγ - 0.22 + 0.24 +0.33 - 0.18 µ = 1.57 + 0.17 -0.28 - 0.12 + 0.35 - 0.32 H → ZZ* → 4l + 0.20 +0.40 - 0.13 µ = 1.44 + 0.17 -0.35 - 0.10 + 0.21 - 0.21 H → WW* → l νlν + 0.24 +0.32 - 0.19 µ = 1.00 + 0.16 -0.29 - 0.08 + 0.14 Combined - 0.14 H γγ→ , ZZ*, WW* + 0.16 +0.21 - 0.14 µ = 1.35 + 0.13 -0.20 - 0.11 W,Z H → b b ±0.5 ±0.4 µ = 0.2 +0.7 -0.6 <0.1 + 0.3 H → ττ (8 TeV data only) - 0.3 + 0.4 +0.5 - 0.3 µ = 1.4 + 0.2 -0.4 - 0.1 + 0.24 Combined - 0.24 + 0.27 H→bb, ττ +0.36 - 0.21 µ = 1.09 + 0.08 -0.32 - 0.04 + 0.12 =;;5B+;'/@'IA),-<.,:'JA)-LE,;' - 0.12 Combined + 0.14 +0.18 - 0.11 µ = 1.30 + 0.10 ),D'0AED5-LE,'BED+;' -0.17 - 0.08 = 7 TeV s = 7 TeV ∫Ldt = 4.6-4.8 fb -1 -0.5 0 0.5 1 1.5 2 !MKN9S:J='ZGRF'1+'l9R'uxÅm'' = 8 TeV s = 8 TeV ∫Ldt = 20.3 fb -1 Signal strength ( µ) µ =1.30 ± 0.12 (stat) ± 0.10 (th) ± 0.09 (syst) =**'-<),,+*;'-E50*.,:;'50D)K+D';EE,' /K)6'K5,+D'U'' a1' I. Antoniadis (CERN) 7 / 91 Signal strength 53 [CMS-PAS-HIG-14-009] ! Grouped by production tag and dominant decay: ! 12/dof = 10.5/16 ! p-value = 0.84 (asymptotic) Same sign dimuons ! ttH-tagged 2.0 / above SM. ! Driven by one channel. [email protected] @CMSexperiment @ICHEP2014 I. Antoniadis (CERN) 8 / 91 Fran¸cois Englert Peter Higgs Nobel Prize of Physics 2013 ↓ ↓ I. Antoniadis (CERN) 9 / 91 The value of its mass 125 GeV ∼ consistent with expectation from precision tests of the SM favors perturbative physics quartic coupling λ = m2 /v 2 1/8 H ≃ 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) 10 / 91 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) 11 / 91 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) 12 / 91 I. Antoniadis (CERN) 13 / 91 I. Antoniadis (CERN) 14 / 91 What is next? I. Antoniadis (CERN) 15 / 91 What is next? Physics is an experimental science Exploit the full potential of LHC • Go on and explore the multi TeV energy range • I. Antoniadis (CERN) 16 / 91 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. 67F77% "/'7+BH%;5.6'*+% ! &$ 84% !B! *% Europe’s top priority should be the exploitation of the full potential of the LHC, including the CIFF%- .%?4$%G4#$/% high-luminosity upgrade of the machine and 6;3%;5%84%P%I%'( .% detectors with a view to collecting ten times )411+)8+*% more data than in the initial design, by around 67FEF% 2030. #####E2%#### I. Antoniadis (CERN) 17 / 91 We must fully explore the 10-100 TeV energy range ILC project The future of LHC I. Antoniadis (CERN) 18 / 91 I. Antoniadis (CERN) 19 / 91 I. Antoniadis (CERN) 20 / 91 I. Antoniadis (CERN) 21 / 91 I. Antoniadis (CERN) 22 / 91 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) 23 / 91 I. Antoniadis (CERN) 24 / 91 I. Antoniadis (CERN) 25 / 91 126 GeV Higgs compatible with supersymmetry 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 3 TeV or At 3m 1.5 TeV ≃ ˜t ≃ ≃ ˜t ≃ => % 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 M m [31] RG evolution: 2 = 2( GUT) 2 ˜t ln + − 4π m˜t · · · 2 2 m (MGUT) (1)m + ∼ 2 − O ˜t · · · I. Antoniadis (CERN) 26 / 91 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 → Low scale SUSY breaking => extend MSSM with the goldstino Non linear MSSM → · · · I. Antoniadis (CERN) 27 / 91 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) 28 / 91 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 ( m ) ∼ 3/2 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) 29 / 91 Giudice-Strumia ’11 I. Antoniadis (CERN) 30 / 91 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 l (R⊥ .1 10 mm for n =2 6) ∼ ⊥ 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 [26] Λ a few TeV and m2 = a loop factor Λ2 ∼ H × But unification has to be probably dropped New Dark Matter candidates e.g.