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M.J. Ramsey-Musolf. J. Erler Kurylov S. Su. Sub Z 0 Supersymmetry. Precision Electroweak Physics Below the Z 0 Pole. An evolving story: New K e3 data & analyses; neutron b -decay. Outline. Precision measurements & radiative corrections. The Standard Model & SUSY.
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M.J. Ramsey-Musolf J. Erler Kurylov S. Su Sub Z0 Supersymmetry Precision Electroweak Physics Below the Z0 Pole
An evolving story: New Ke3 data & analyses; neutron b-decay Outline • Precision measurements & radiative corrections The Standard Model & SUSY • Charged Current Universality Is SUSY-breaking flavor neutral ? • Neutral currents Is there SUSY dark matter ? • Some QCD Issues How well do we know the Standard Model predictions ?
I.Radiative Corrections & Precision Measurements: SM & SUSY Why we love the Standard Model
The Fermi theory and QED corrections QED radiative corrections: finite
The Fermi theory and higher order weak contributions Weak radiative corrections: infinite Can’t be absorbed through suitable re-definition of GFin HEFF
Re-define g Finite All radiative corrections can be incorporated in the Standard Model with afinitenumber of terms g g g
g g GFencodes the effects of all higher orderweak radiative corrections Drm depends on parameters of particles inside loops
g g Comparingradiative corrections in differentprocesses canprobeparticle spectrum Drm differs from DrZ
Comparingradiative corrections in different processes canprobeparticle spectrum
Precision measurements predicted a range for mt before top quark discovery • mt >> mb ! • mt is consistent with that range • It didn’t have to be that way Radiative corrections Direct Measurements Stunning SM Success Comparingradiative corrections in different processes canprobeparticle spectrum J. Ellison, UCR
Can we place analogous constraints on new physics using low-energy precision measurements ? This talk: SUSY
LSM LSM + LSUSY sfermions gauginos Higgsinos Charginos, neutralinos tan Minimal Supersymmetric Standard Model (MSSM)
LSM LSM + LSUSY + Lsoft Minimal Supersymmetric Standard Model (MSSM) Lsoft gives contains 105 new parameters How is SUSY broken?
mWEAK ~ 250 GeV GF ~ 10-5/MP2 l The Fermi constant is too large
=0 if SUSY is exact SUSY protectsGFfrom shrinking
Visible Sector: Hidden Sector: SUSY-breaking MSSM Flavor-blind mediation How is SUSY broken? Gravity-Mediated (mSUGRA)
Visible Sector: Hidden Sector: SUSY-breaking MSSM messengers How is SUSY broken? Flavor-blind mediation Gauge-Mediated (GMSB)
ln gaugino mass group structure increases as decreases increases faster than at the weak scale Mass evolution
Qf < 0 Qf > 0 Sfermion Mixing
MSSM and R Parity SM Particles: Superpartners: Matter Parity: An exact symmetry of the SM
MSSM and R Parity MSSM conserves vertices have even number of superpartners • Lightest SUSY particle is stable viable dark matter candidate • Proton is stable • Superpartners appear only in loops Consequences
Precision Measurements: SUSY Sensitivity Muon (g-2): Weak processes: M=m~ 2 x 10-9 exp ~ 1 x 10-9 M=MW ~ 10-3
Visible Sector: Hidden Sector: SUSY-breaking MSSM II. Charged Current Processes Is SUSY-breaking mediation flavor blind?
Fermi Constants m decay b decay is universal Universality obscured by Charged Current (non) Universality
GeV-2 GeV-2 Radiative Corrections ~ ~ 0.2% SM ~ modulo log enhancements Fermi Constants, Cont’d SUSY
GeV-2 GeV-2 Status in early ‘04 Require Fermi Constants, Cont’d CKM Unitarity = 1 SM Data + SM
Universal SUSY Radiative Corrections
Non-universal SUSY Radiative Corrections
Non-universal Vertex Corrections (Dominant)
mt , MH Other Inputs 1. Muon (g-2): Size of error bar crucial 2. W Mass: 3. Superpartner Masses: Start analysis with collider lower bounds and vary later
Assume a model for SUSY-breaking mediation • Assume most general SUSY-breaking sector 105 parameters 105 parameters a few parameters (M1/2, M0, A0, …) random scan of parameter space This study: • Assume most general SUSY-breaking sector 105 parameters analytic exploration of parameter space Model-independent Analysis Usual approaches:
Maximal L-R Mixing No solution muon g-2 2. Increase M Changes sign of r-runless ,no solution CKM ‘04 3. Increase Alleviates (g-2)problem but shrinks allowed region W mass 4. Reduce L-R Mixing Allowed solution but conflict with flavor-blind SUSY-breaking 5. Non-universal squarks Allowed solution, large gluino effects, but conflict with flavor-blind SUSY-breaking 6. Heavy gluinos, GeV Model Independent Analysis
Flavor-blind SUSY-breaking Maximal L-R Mixing No solution 2. Increase M Changes sign of r-runless ,no solution CKM ‘04 3. Increase Alleviates (g-2)problem but shrinks allowed region 4. Reduce L-R Mixing Allowed solution but conflict with flavor-blind SUSY-breaking 5. Non-universal squarks Allowed solution, large gluino effects, but conflict with flavor-blind SUSY-breaking 6. Heavy gluinos, GeV Model Independent Analysis
muon g-2 Maximal L-R Mixing No solution W Mass 2. Increase M Changes sign of r-runless ,no solution 3. Increase Alleviates (g-2)problem but shrinks allowed region CKM ‘04 4. Reduce L-R Mixing Allowed solution but conflict with flavor-blind SUSY-breaking 5. Non-universal squarks Allowed solution, large gluino effects, but conflict with flavor-blind SUSY-breaking Inconsistent with Higgs mass bounds, flavor-blind SUSY-breaking, color neutral vacuum 6. Heavy gluinos, GeV Model Independent Analysis
LANSCE UCN SUSY irrelevant to low energy observables See end of talk Better control of non-pQCD Exp’t: n decay, Ke3 decay ??? Break R-parity But NuTeV CC (non) universality & the MSSM Data appeared to conflict with MSSM & models having flavor-blind SUSY-breaking mediation Possible resolutions: MSUSY > TeV 2. Hadronic effects in SM predictions 3. Something is wrong with exp’t 4. New models of SUSY-breaking 5. Go beyond the MSSM
Vus Ke3decays: recent developments V. Cirigliano
O(p6) Ke3decays: current status G. Isidori, CKM 2005
Quenched LQCD Vus O(p6) Large NC Ke3decays: current status G. Isidori, CKM 2005
SUSY irrelevant to low energy observables Better control of non-pQCD Exp’t: n decay, Ke3 decay ??? Break R-parity CC (non) universality & the MSSM Data appeared to conflict with MSSM & models having flavor-blind SUSY-breaking mediation Possible resolutions: MSUSY > TeV 2. Hadronic effects in SM predictions 3. Something is wrong with exp’t 4. New models of SUSY-breaking 5. Go beyond the MSSM
III. Neutral Current Processes Is there SUSY dark matter?
~ sin2 LPV Weak Charge Weak Neutral Currents at Low Energies Parity-violating electron scattering
Weak Charges QWp = 1 - 4 sin2W ~ 0.1 QWe = -1 + 4 sin2W ~ -0.1 Need~ few percent to probe SUSY
Atomic PV N deep inelastic sin2W e+e- LEP, SLD SLAC E158 (ee) JLab Q-Weak (ep) (GeV) Weak Mixing Angle: Scale Dependence Czarnecki, Marciano Erler. Kurylov, MR-M
Flavor-dependent sin2 Normalization Scale-dependence of weak mixing Flavor-independent QW and SUSY Radiative Corrections Tree Level Radiative Corrections
Universal corrections muon decay gauge boson propagators
SM fit only No SUSY effects Oblique Parameters
SUSY loops 3000 randomly chosen SUSY parameters but effects are correlated Negligible SUSY loop impact on cesium weak charge Effects in sin2qW dominate Comparing Qwe and QWp SUSY loops