Search for Supersymmetry

Outline Introduction to supersymmetry Phenomenology of the CMSSM Non-universal scalar masses? Non-universal Higgs masses (NUHM) Options for the LSP Gravitino dark matter New possibilities for collider phenomenology

Loop Corrections to Higgs Mass2 Consider generic fermion and boson loops: Each is quadratically divergent: ∫Λd4k/k2 Leading divergence cancelled if Supersymmetry! 2 ∙2

Other Reasons to like Susy It enables the gauge couplings to unify It predicts mH < 150 GeV As suggested by EW data Approved by Fabiola Gianotti JE, Nanopoulos, Olive + Santoso: hep-ph/0509331

Astronomers say that most of the matter in the Universe is invisible Dark Matter Lightest Supersymmetric particles ? We shall look for them with the LHC

Minimal Supersymmetric Extension of Standard Model (MSSM) Particles + spartners 2 Higgs doublets, coupling μ, ratio of v.e.v.’s = tan β Unknown supersymmetry-breaking parameters: Scalar masses m0, gaugino masses m1/2, trilinear soft couplings Aλ, bilinear soft coupling Bμ Often assume universality: Single m0, single m1/2, single Aλ, Bμ: not string? Called constrained MSSM = CMSSM Minimal supergravity (mSUGRA) predicts additional relations for gravitino mass, supersymmetry breaking: m3/2 = m0, Bμ = Aλ – m0

Lightest Supersymmetric Particle Stable in many models because of conservation of R parity: R = (-1) 2S –L + 3B where S = spin, L = lepton #, B = baryon # Particles have R = +1, sparticles R = -1: Sparticles produced in pairs Heavier sparticles  lighter sparticles Lightest supersymmetric particle (LSP) stable

Possible Nature of LSP No strong or electromagnetic interactions Otherwise would bind to matter Detectable as anomalous heavy nucleus Possible weakly-interacting scandidates Sneutrino (Excluded by LEP, direct searches) Lightest neutralino χ Gravitino (nightmare for astrophysical detection)

Constraints on Supersymmetry Absence of sparticles at LEP, Tevatron selectron, chargino > 100 GeV squarks, gluino > 250 GeV Indirect constraints Higgs > 114 GeV, b -> s γ Density of dark matter lightest sparticle χ: WMAP: 0.094 < Ωχh2 < 0.124 gμ - 2

Current Constraints on CMSSM Assuming the lightest sparticle is a neutralino Excluded because stau LSP Excluded by b  s gamma WMAP constraint on relic density Excluded (?) by latest g - 2 JE + Olive + Santoso + Spanos

Current Constraints on CMSSM Different tan β sign of μ Impact of Higgs constraint reduced if larger mt Focus-point region far up JE + Olive + Santoso + Spanos

Sparticles may not be very light Full Model samples ← Second lightest visible sparticle Detectable @ LHC Provide Dark Matter Dark Matter Detectable Directly Lightest visible sparticle → JE + Olive + Santoso + Spanos

Missing Energy Detection @ LHC Sensitive to missing transverse energy carried away by neutral particles: e.g., neutrinos, neutralinos

Supersymmetry Searches at LHC LHC reach in supersymmetric parameter space `Typical’ supersymmetric Event at the LHC Can cover most possibilities for astrophysical dark matter

Supersymmetric Benchmark Studies Lines in susy space allowed by accelerators, WMAP data Specific benchmark Points along WMAP lines Sparticle detectability Along one WMAP line Calculation of relic density at a benchmark point Battaglia, De Roeck, Gianotti, JE, Olive, Pape

Sparticle Signatures along WMAP lines Relatively small branching ratios in CMSSM Z h Average numbers of particles per sparticle event τ 3l Battaglia, De Roeck, Gianotti, JE, Olive, Pape

Summary of LHC Scapabilities … and Other Accelerators LHC almost `guaranteed’ to discover supersymmetry if it is relevant to the mass problem Battaglia, De Roeck, Gianotti, JE, Olive, Pape

Tests of Unification Ideas For gauge couplings For sparticle masses

Precision Observables in Susy Can one estimate the scale of supersymmetry? Precision Observables in Susy Sensitivity to m1/2 in CMSSM along WMAP lines for different A mW tan β = 10 tan β = 50 sin2θW Present & possible future errors JE + Heinemeyer + Olive + Weiglein

More Observables b → sγ Bs → μμ gμ - 2 tan β = 10 tan β = 50 JE + Heinemeyer + Olive + Weiglein

Global Fits to Present Data Including mW , sin2θW, b → sγ, gμ - 2 As functions of m1/2 in CMSSM for tan β = 10, 50 JE + Heinemeyer + Olive + Weiglein

Global Fits to Present Data χ χ2, χ ± Global Fits to Present Data χ3, χ2± τ1 Preferred sparticle masses for tan β = 10 e1 e2 JE + Heinemeyer + Olive + Weiglein

Global Fits to Present Data Preferred sparticle masses for tan β = 10 g A Within reach of LHC! JE + Heinemeyer + Olive + Weiglein

Beyond the CMSSM

More General Supersymmetric Models MSSM with more general pattern of supersymmetry breaking: non-universal scalar masses m0 and/or gaugino masses m½ and/or trilinear couplings A0 Nature of the lightest supersymmetric particle (LSP) Extended particle content: non-minimal supersymmetric model (NMSSM)

Non-Universal Scalar Masses Different sfermions with same quantum #s? e.g., d, s squarks? disfavoured by upper limits on flavour- changing neutral interactions Squarks with different #s, squarks and sleptons? disfavoured in various GUT models e.g., dR = eL, dL = uL = uR = eR in SU(5), all in SO(10) Non-universal susy-breaking masses for Higgses? No reason why not!

Non-Universal Higgs Masses (NUHM) Generalize CMSSM (+) mHi2 = m02(1 + δi) Free Higgs mixing μ, pseudoscalar mass mA Larger parameter space Constrained by vacuum stability

Sampling of (m1/2, m0) Planes in NUHM New vertical allowed strips appear JE + Olive + Santoso + Spanos

Low-Energy Effective Supersymmetric Theory Assume universality for sfermions with same quantum numbers (but different generations) Require electroweak vacuum to be stable (RGE not → negative mass2) up to GUT scale (LEEST) up to 10 TeV (LEEST10) Qualitatively similar to NUHM not much freedom to adjust squarks/sleptons

Sparticles may not be very light Full Model samples ← Second lightest visible sparticle Detectable @ LHC Provide Dark Matter Dark Matter Detectable Directly Lightest visible sparticle → JE + Olive + Santoso + Spanos

Gravitino Dark Matter?

Possible Nature of LSP No strong or electromagnetic interactions Otherwise would bind to matter Detectable as anomalous heavy nucleus Possible weakly-interacting scandidates Sneutrino (Excluded by LEP, direct searches) Lightest neutralino χ Gravitino (nightmare for astrophysical detection)

Possible Nature of NLSP NLSP = next-to-lightest sparticle Very long lifetime due to gravitational decay, e.g.: Could be hours, days, weeks, months or years! Generic possibilities: lightest neutralino χ lightest slepton, probably lighter stau Constrained by astrophysics/cosmology

Different Regions of Sparticle Parameter Space if Gravitino LSP masses χ NLSP stau NLSP Density below WMAP limit Decays do not affect BBN/CMB agreement JE + Olive + Santoso + Spanos

Minimal Supergravity Model (mSUGRA) More constrained than CMSSM: m3/2 = m0, Bλ = Aλ – 1 Excluded by b  s γ Neutralino LSP region stau LSP (excluded) LEP constraints On mh, chargino Gravitino LSP region tan β fixed by vacuum conditions JE + Olive + Santoso + Spanos

Light Nuclei: BBN vs CMB Good agreement for D/H, 4He: discrepancy for 7Li? Observations Calculations Cyburt + Fields + Olive + Skillman

Constraints on Unstable Relics 7Li < BBN? Effect of relic decays? Problems with D/H 3He/D too high! Interpret as upper limits on abundance of metastable heavy relics JE + Olive + Vangioni

Different Regions of Sparticle Parameter Space if Gravitino LSP χ NLSP stau NLSP Density below WMAP limit Decays do not affect BBN/CMB agreement JE + Olive + Santoso + Spanos

Regions Allowed in Different Scenarios for Supersymmetry Breaking CMSSM Benchmarks NUHM Benchmarks GDM Benchmarks with neutralino NLSP with stau NLSP De Roeck, JE, Gianotti, Moortgat, Olive + Pape: hep-ph/0508198

Spectra in NUHM and GDM Benchmark Scenarios Typical example of non-universal Higgs masses: Models with gravitino LSP Models with stau NLSP De Roeck, JE, Gianotti, Moortgat, Olive + Pape: hep-ph/0508198

Properties of NUHM and GDM Models Relic density ~ WMAP in NUHM models Generally < WMAP in GDM models Need extra source of gravitinos at high temperatures, after inflation? NLSP lifetime: 104s < τ < few X 106s De Roeck, JE, Gianotti, Moortgat, Olive + Pape: hep-ph/0508198

Neutralino Masses and Decay Modes χh, χZ may be large in NUHM χh, χZ small in CMSSM De Roeck, JE, Gianotti, Moortgat, Olive + Pape: hep-ph/0508198

Final States in GDM Models with Stau NLSP All decay chains end with lighter stau Generally via χ Often via heavier sleptons Final states contain 2 staus, 2 τ, often other leptons De Roeck, JE, Gianotti, Moortgat, Olive + Pape: hep-ph/0508198

Kinematic Distributions: Point ε Staus come with many jets & leptons with pT hundreds of GeV, produced centrally De Roeck, JE, Gianotti, Moortgat, Olive + Pape: hep-ph/0508198

Kinematic Distributions: Point ζ Staus come with many jets & leptons with pT hundreds of GeV, produced centrally De Roeck, JE, Gianotti, Moortgat, Olive + Pape: hep-ph/0508198

Stau Mass Measurements by Time-of-Flight Event-by-event accuracy < 10% < 1% with full sample De Roeck, JE, Gianotti, Moortgat, Olive + Pape: hep-ph/0508198

Numbers of Visible Sparticle Species At different colliders

Slepton Trapping at the LHC? If stau next-to-lightest sparticle (NLSP) may be metastable may be stopped in detector/water tank? Trapping rate Kinematics Hamaguchi + Kuno + Nakaya + Nojiri Feng + Smith

Stau Momentum Spectra βγ typically peaked ~ 2 Staus with βγ < 1 leave central tracker after next beam crossing Staus with βγ < ¼ trapped inside calorimeter Staus with βγ < ½ stopped within 10m Can they be dug out? De Roeck, JE, Gianotti, Moortgat, Olive + Pape: hep-ph/0508198

Extract Cores from Surrounding Rock? Very little room for water tank in LHC caverns, only in forward directions where few staus Extract Cores from Surrounding Rock? Use muon system to locate impact point on cavern wall with uncertainty < 1cm Fix impact angle with accuracy 10-3 Bore into cavern wall and remove core of size 1cm × 1cm × 10m = 10-3m3 ~ 100 times/year Can this be done before staus decay? Caveat radioactivity induced by collisions! 2-day technical stop ~ 1/month Not possible if lifetime ~104s, possible if ~106s? De Roeck, JE, Gianotti, Moortgat, Olive + Pape: hep-ph/0508198

Detect Staus in Mass Spectrometer? Each core ~ 1cm × 1cm × 10m ‘Region of interest’ ~ 1m long Contains ~ 2 × 1027 nucleons, i.e., 1027 protons Present best limits from water ~ 10-29/proton Sensitivity possible in principle How quickly could the volume be searched? Have at most a few weeks! De Roeck, JE, Gianotti, Moortgat, Olive + Pape: hep-ph/0508198

Detect Supersymmetric Decay Albedo? Look for staus stopping ~ 10m from detector Later decay → τ + gravitino τ → μ with branching ratio ~ 16% Characteristic energies ~ (1/6) mstau ~ 25 to 50 GeV Geometric acceptance for upward-going μ ~ 1/12 → ~ 1.3% of stau decays detectable → ~ 100 events/year in benchmark scenario ε De Roeck, JE, Gianotti, Moortgat, Olive + Pape: hep-ph/0508198

Caveat Cosmic-Ray Background Background of cosmic-ray μ ~ 100 events/year Similar energy range Signal might be visible in benchmark scenario ε Not in scenarios ζ and η De Roeck, JE, Gianotti, Moortgat, Olive + Pape: hep-ph/0508198

Potential Measurement Accuracies Gravitino Dark Matter even more interesting than Neutralino Dark Matter! Measure stau mass to 1% Measure m½ to 1% via cross section, other masses? Distinguish points ζ, η De Roeck, JE, Gianotti, Moortgat, Olive + Pape: hep-ph/0508198

Summary The ‘C’ in CMSSM signifies ‘conservative’ Many more exotic supersymmetric phenomenologies are possible Gravitino dark matter is one example Not to mention breaking of R parity … … nor split supersymmetry Supersymmetry is the most ‘expected’ surprise at the LHC Expect it to appear in an unexpected way!

Elastic Scattering Cross Sections From global fit to accelerator data Latest experimental upper limit JE + Olive + Santoso + Spanos: hep-ph/0502001

Direct CDM detection in NUHM/LEEST Cross section similar in NUHM/LEEST Cross section depends on πN σ term Cross section depends on sign of μ Some NUHM/LEEST models already excluded JE + Olive + Santoso + Spanos