New Models. Savas Dimopoulos. with. Nima Arkani-Hamed

Transcription

1 New Models Savas Dimopoulos with Nima Arkani-Hamed

2 Small numbers and hierarchy problems GeV M PL Gauge Hierarchy Problem 10 3 GeV M W GeV ρ 1 4 vac Cosmological Constant Problem Program of the last 30 years: Seek Natural explanations of these numbers

3 Outline M weak M weak ρ vacuum in theories with few vacua in theories with many vacua in theories with many vacua: Split Supersymmetry

4 Approaches to the gauge hierarchy problem Stages: Philosophy (1974) Technicolor (1978) Supersymmetric Standard Model (1981) Low Scale Gravity (1998) Warped Gravity (1999) Little Higgs (2001) [Wilson] [Susskind, Weinberg] [S.D., Georgi] [Antoniadis, Arkani-Hamed, S.D., Dvali] [Randall, Sundrum] [Arkani-Hamed, Cohen, Georgi]

5 Supersymmetric Standard Model Introduces Superpartners at the weak scale Successes Uni f ication Dark Matter Shortcomings Higgs? Sparticles? FCNC ; CP Proton Decay Fermions Gravitino Moduli Problem Scalars Hierarchy Problem Cosmological Constant

6 Strategy for the last 30 years m weak Focus on this ρvacuum Ignore this This could be flawed

7 In theories with few vacua ρ vacuum Getting ρ vacuum (10 15 M W ) 4 Looks like divine intervention! Since any bigger value would rip apart galaxies However... (Weinberg 1987)

8 In theories with many vacua Therefore, if there are enough vacua with different ρ the structure principle can explain why we live in a universe with small, but nonzero, ρ vacuum vacuum,

9 This reasoning correctly predicted a small ρ vacuum and has recently gained momentum because string theory may well have a vast landscape of metastable vacua s Bousso, Polchinski; Kachru et.al.; Douglas et.al.; Susskind Similarly, if there are enough vacua with different M the atomic principle can explain the value of M Weak Weak Donoghue et.al. 1998

10 New approach The mechanism solving the cosmological constant problem, may also solve the hierarchy problem Can we preserve the successes of the low energy SUSY?

11 Split Supersymmetry M Pl TeV Scalars (Squarks, sleptons,...) M susy?{ 10 9 TeV 10 TeV Fermions (Higgsinos, gauginos) +SM Higgs M weak 1 TeV Preserves gauge unification and DM candidate!

12 Particles and Couplings H B W g H u Hd Higgs Gauginos Higgsinos m 1 B2 + m 2 W 2 + m 3 g 2 + µ H u Hd λ H 4 m 2 H 2 κ u H H u W + κd H Hd W κ uh H B u + κ d H Hd B Gaugino Higgs Quartic Yukawas λ = κ 1 8( u = g 2 sin + g β 2) cos κ 2 d = 2β g cos β 5 Couplings from 1 parameter!

13 Unification in MSSM α 1 1 α 1 2 α 1 3 E (GeV)

14 Gauge Coupling Unification Squarks and Sleptons don t alter unification α Split Susy M susy MSSM 40 α α E(GeV)

15 The heavy Higgs of Split SUSY Higgs Mass GeV } } tan β tan β = Log 10 M s GeV A. Arvanitaki, et al hep-ph/

16 Long-Lived Light Gluinos Must decay through squarks q j g q q j B E/ T τ g 2 sec. ( 350 GeV m g ) 5 ( MSusy 10 6 TeV ) 4

17 Gluino Phenomenology LHC: Gluino Factory, ~1 gluino/sec! (350 GeV) Bound States: Charged and intermittent tracks Displaced gluinos gg, gq q, gqqq Stopped, late-decaying gluinos! (R-Hadrons)

18 Post-LHC A long lived strongly interacting particle A few electroweakinos Doesn t match SUSY traditional models signatures Doesn t look natural... What is it?

19 Yukawa Couplings Unification Msusy tan β λ κ u κ d κ u κ d % Change from Susy value 30% % λ κ κ 0 10 TeV A. Arvanitaki, et al hep-ph/

20 ILC Measurements 8 parameters + CP violating phases (M 1,M 2,µ,κ u,κ d,κ u,κ d,λ) Charged masses measured through threshold scans Mass differences through electroweak decays all couplings measurable in multiple ways Split SUSY: clean environment (free of scalar pollution) Kilian et.al. 2004

21 Gauginos and Higgsinos Long-lived Gluinos Split SUSY in colliders Yukawa Unification Window to the Landscape?