probing supersymmetry with neutral current scattering experiments

Probing Supersymmetry with Neutral Current Scattering

Experiments

Probing Supersymmetry with Neutral Current Scattering

Experiments

Shufang Su • Shufang Su • U. of ArizonaU. of ArizonaShufang Su • Shufang Su • U. of ArizonaU. of Arizona

S. Su LOOPFESTIII 2

Sub-Z precision measurements Sub-Z precision measurements

• neutral current scatteringneutral current scattering• hheavy quark physicseavy quark physics• CP violation, EDMCP violation, EDM• RRare K-decay, CKM unitarityare K-decay, CKM unitarity• mmuon g-2uon g-2• llepton flavor violationepton flavor violation

… …

• polarized ee scattering (SLAC E158) • polarized ep scattering (JLab Qweak) • neutrino-nucleus scattering (NuTeV)

A. Kurylov, M. Ramsey-Musolf, SS

S. Su LOOPFESTIII 3

Outline Outline

• motivationmotivation• parity-violating electron scattering parity-violating electron scattering

experiments experiments

• radiative corrections to weak charge radiative corrections to weak charge QQWW

• analysis of SUSY contributions to Qanalysis of SUSY contributions to QWW – MSSM contributionsMSSM contributions– RPV analysisRPV analysis– distinguish various new physics / SUSYdistinguish various new physics / SUSY

• NuTeV experimentNuTeV experiment– MSSM contributions MSSM contributions – RPV analysisRPV analysis

• conclusionconclusion

S. Su LOOPFESTIII 4

Motivation Motivation

• high precisionhigh precision low energy experiment low energy experiment availableavailable

- muon g-2: M=m- muon g-2: M=m , , new new 2x10 2x10-9-9, , expexp < 10 < 10-9 -9

-decay, -decay, -decay: M=m-decay: M=mWW , , new new 10 10-3-3, , expexp 10 10-3-3

– parity-violating electron scattering: M=mparity-violating electron scattering: M=mWW , , new new 10 10--

33,,

1/Qe,pW 10 more sensitive to new physics

need exp 10-2 “easier” experiment

• indirect+direct: complementary information indirect+direct: complementary information – consistency test of theory at loop levelconsistency test of theory at loop level

QQe,pe,pWW 1-4 sin 1-4 sin22WW 0.1 0.1

• probe new physics probe new physics offoff the Z-resonance the Z-resonance- sensitive to new physics not mix with Z- sensitive to new physics not mix with Z

size of loop effects from new physics: (size of loop effects from new physics: (//)(M/M)(M/Mnewnew))22

S. Su LOOPFESTIII 5

Test of sin2W running Test of sin2W running

• sinsin22WW(0) - sin(0) - sin22WW(m(mZZ22) = +0.007) = +0.007

– QQCsCsww: agree : agree QQ22=0 =0

– NuTeV: +3NuTeV: +3 QQ22=20 (GeV)=20 (GeV)22

• parity-violating electron parity-violating electron

scattering (PVES)scattering (PVES) ee Moller scattering (SLAC) ee Moller scattering (SLAC) QQee

WW

ep elastic scattering (J-lab)ep elastic scattering (J-lab) QQppWW

--

clean environment: clean environment: Hydrogen targetHydrogen target theoretically clean:theoretically clean: small hadronic uncertainties small hadronic uncertainties tree level tree level 0.1 0.1 sensitivesensitive to new physics to new physics

-- sinsin22W W 0.0007 at Q 0.0007 at Q22=0.03 (GeV)=0.03 (GeV)22

S. Su LOOPFESTIII 6

Goal Goal

• minimal Supersymmetric extension of SM (MSSM)minimal Supersymmetric extension of SM (MSSM)

SUSY: most promising candidate for new physicsSUSY: most promising candidate for new physics– solution to Hierarchy problem– gauge coupling unification– provide a natural electroweak symmetry breaking– dark matter candidate ? (PVES) with R-parity : loop correctionswith R-parity : loop corrections without R-parity: tree-level contributionwithout R-parity: tree-level contribution

• low-energy precision measurementslow-energy precision measurements

– PVES: PVES: weak charge Qweak charge QeeWW , Q , Qpp

WW , ( Q , ( QCsCsW W ) ) - NuTeV: - NuTeV: RR(())

Develop consistency checks for theories of new physicsDevelop consistency checks for theories of new physicsusing the low energy precision measurementsusing the low energy precision measurements

--

S. Su LOOPFESTIII 7

Weak charge QW Weak charge QW

NN++-N-N--

NN+++N+N--

AALRLR Q QffWW

AA

VVggee

A A = I= Iee33

ep Qep Qweakweak exp exp QQppWW ee Moller exp ee Moller exp QQee

WW

QQe,pe,pW W treetree 1-4s1-4s22 -(1-4s-(1-4s22))

QQe,pe,pWW looploop 0.07210.0721 -0.0449-0.0449

exp precisionexp precision 4%4% 8%8% sinsin22WW 0.00070.0007 0.00090.0009SM runningSM running 10 10 8 8 QQCsCs

WW : : sin sin22W W = 0.0021= 0.0021 NuTeV:NuTeV: sin sin22W W = 0.0016= 0.0016

weak chargeweak charge Q QffWW = 2g = 2gff

V V = 2 I= 2 Iff33 -4Q -4Qffss22

S. Su LOOPFESTIII 8

General structure of radiative corrections to QfW General structure of radiative corrections to QfW

Including radiative corrections:Including radiative corrections:

,, : universal, : universal, ff: depend on fermion species: depend on fermion species

= 1+= 1+SMSM++SUSYSUSY, , = 1+ = 1+SMSM++SUSYSUSY, , ff= = ffSMSM++ff

SUSYSUSY

correction to muon life time

QQffWW = = (2I (2Iff

33 - 4 - 4 Q Qf f ss22) + ) + ff

S. Su LOOPFESTIII 9

Radiative contributions Radiative contributions

QQffWW = = (2I (2Iff

33 - 4 - 4 Q Qf f ss22) + ) + ff

ff

correction to , G and mZs2

S. Su LOOPFESTIII 10

MSSM particle contents MSSM particle contents

SM particle superpartnerSM particle superpartner Spin differ by 1/2Spin differ by 1/2

mass parameter mass parameter

mmqLqL22,,

mmlRlR22,,mmlLlL

22,,

mmqLRqLR22mmqRqR

22,,

mmlLRlLR22

, tan, tan=v=vuu/v/vdd

MM33MM22MM11


One loop SUSY contributions to PVESOne loop SUSY contributions to PVES

• gauge boson gauge boson self-energies self-energies

• external leg correctionsexternal leg corrections • vertex correctionsvertex corrections

• box diagramsbox diagrams


Numerical analysis Numerical analysis

• MSSM parameter range: random scanMSSM parameter range: random scan

hard to impose bounds on certain MSSM parameter show the possible range of MSSM corrections

– impose exp search limit on SUSY particles impose exp search limit on SUSY particles – impose S-T 95% CL constraintsimpose S-T 95% CL constraints– impose g-2 constraints (2nd slepton LR mixing)impose g-2 constraints (2nd slepton LR mixing)

50 GeV < m50 GeV < mqq, m, mll, M, M1,21,2, , < 1000 GeV < 1000 GeV 1.4 < tan1.4 < tan < 60 < 60

~~ ~~

Model-independent analysisModel-independent analysis


Correction to weak charge Correction to weak charge

(Q(QppWW))SUSYSUSY / (Q / (Qpp

WW))SMSM < 4%, < 4%, (Q (QeeWW))SUSYSUSY / (Q / (Qee

WW))SMSM < 8% < 8%

QQeeW W andand QQpp

W W

correlatedcorrelated

QQffWW = = (2T (2Tff

33 - 4Q - 4Qf f s s22) + ) + ff

dominant : dominant : (<0) (<0)

negativenegative shift in sin shift in sin22WW


Dominant contributions Dominant contributions

QQffWW = = (2T (2Tff

33 - 4Q - 4Qf f s s22) + ) + ff

• non-universal non-universal corrections corrections

– vertex + wavefunction : vertex + wavefunction : cancelcancel– box diagrams numerically box diagrams numerically suppressed suppressed

• contribution contribution suppressed by (1-4 ssuppressed by (1-4 s22))

• dominant dominant contribution from contribution from

(<0)(<0) negativenegative shift in sin shift in sin22WW


R-parity R-parity

• General MSSM, including General MSSM, including B,L-violatingB,L-violating operators operators

ijkijk

’’ijkijk

• dangerous dangerous introduce proton decay introduce proton decay• R-parity R-parity SM particle:SM particle: even even superparticle: superparticle: oddodd

– stable LSP as dark matter candidatestable LSP as dark matter candidate• RPV: RPV: only look at L-violating operatoronly look at L-violating operator

L = - 1L = - 1


R-parity violating (RPV) R-parity violating (RPV)

• RPV operators contribute to QRPV operators contribute to Qe,pe,pWW

at tree levelat tree level

Exp constraintsExp constraints

• decay:decay: |Vud| = |Vud| = -0.00145 -0.00145 0.0007 0.0007• APV(Cs):APV(Cs): Q QWW

Cs Cs = = -0.0040 -0.0040 0.0066 0.0066

• RRe/e/ :: R Re/e/ = = -0.0042 -0.0042 0.0033 0.0033

• GG:: G G = = 0.00025 0.00025 0.00188 0.00188

QQppWW

GG

I) Obtain 95% CL allowed region I) Obtain 95% CL allowed region in RPV coefficientsin RPV coefficientsII) Evaluate II) Evaluate Q QWW

e e andand QQWWpp

RPVRPV95% CL95% CL

MSSMMSSMlooploop

No SUSY dark No SUSY dark mattermatter


Correlation between QpW and Qe

W Correlation between QpW and Qe

W

• QQWW (Z,N)=(2Z+N) (Z,N)=(2Z+N) Q QuuWW +(2N+Z) +(2N+Z) Q Qdd

WW

QQuuWW >0 >0

QQddWW <0 <0

SUSY correction to heavy nuclei SUSY correction to heavy nuclei QQWW

• MSSM: MSSM:

• extra Z’: extra Z’:

• leptoquark: leptoquark:

• RPV SUSYRPV SUSY

QQppWW QQee

WW QQCsCsWW

smallsmall

sizablesizable

QQWW(Z,N) / Q(Z,N) / QWW(Z,N) < 0.2 % for Cs(Z,N) < 0.2 % for Cs

Distinguish new physicsDistinguish new physics


sin2W

(GeV)

SLAC SLAC E158 (ee)E158 (ee)

ee++ee-- LEP, SLD LEP, SLD

N deep inelastic N deep inelastic

DIS-Parity, DIS-Parity, JLabJLab

JLabJLab Moller (ee)Moller (ee)

DIS-Parity, SLACDIS-Parity, SLAC

Czarnecki, Marciano ， Erler et al.

Linear Collider eLinear Collider e--ee--

Additional PV electron scattering ideasAdditional PV electron scattering ideas

APVAPV

JLab Q-Weak JLab Q-Weak (ep)(ep)


NuTeV experiment NuTeV experiment

NCNC CCCC

((N N X)X)

((N N l l-(+)-(+)X)X)RR(()) --

((--))

wrongwrong-sign contribution!-sign contribution!Davidson et. al., JHEP 02, 037, 2002

MSSMMSSM

RR==--0.0033 0.0033 0.0015 0.0015RR==--0.0019 0.0019 0.0026 0.0026

--


R-parity violating (RPV) R-parity violating (RPV)

• RPV operators contribute to RRPV operators contribute to R(() ) at tree levelat tree level--

NCNC

CCCC

either wrong sign or too smalleither wrong sign or too small hard to explain NuTeV deviationhard to explain NuTeV deviation


ConclusionConclusion

• Parity-violating ee and ep scattering Parity-violating ee and ep scattering – could be used to test SM and probe new physicscould be used to test SM and probe new physics– MSSM contribution to QMSSM contribution to Qee

W W andand QQppW W is 8% and 4% is 8% and 4% 1 1

expexp need higher exp precision to constrain SUSYneed higher exp precision to constrain SUSY– correlation between Qcorrelation between Qee

W W andand QQppW W

• distinguish various new physics distinguish various new physics • distinguish various SUSY scenario distinguish various SUSY scenario

whether dark matter is SUSY particle ? whether dark matter is SUSY particle ?

• SUSY contribution to NuTeV resultSUSY contribution to NuTeV result– MSSM with R-parity: wrong sign /smallMSSM with R-parity: wrong sign /small– negative gluino contribution:negative gluino contribution:

– size constrained by other considerationssize constrained by other considerations – hard to explain NuTeV in RPVhard to explain NuTeV in RPV

SUSY is not responsible for the NuTeV deviationSUSY is not responsible for the NuTeV deviation– other new physics ? other new physics ?

– hadronic effects ?hadronic effects ?

probing supersymmetry with neutral current scattering experiments

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