Probing Supersymmetry with Parity-Violating Lepton Scatteringshufang/talk/ECT2010_Su.pdf · PVES...

S. Su

Probing Supersymmetry with Parity-Violating Lepton Scattering

Shufang Su • U. of Arizona

based on work with A. Kurylov, M. Ramsey-Musolf

Tuesday, November 9, 2010

S. Su 2

Precision measurements vs. direct detection-

LEP EWWG July 2010

Direct vs. indirect detection

● provide complementary

information

● success of SM

● consistency check of any

new physics scenarioLEP EWWG

(direct)(indirect)

8 0.3

8 0.4

8 0.5

1 5 0 1 75 2 00

mH [G eV]1 1 4 300 1 000

mt [G eV]

mW

[G

eV]

6 8 % CL

!"

LEP1 and SLD

LEP2 and Tevatron (prel.)

July 2 01 0


S. Su 3

Low energy precision measurements• address questions difficult to study at high energy weak interactions (parity violation)

• high precision low energy experiment available

- muon g-2: M=mµ , δnew ∼ 2x10-9, δexp < 10-9

- β-decay, π-decay: M=mW , δnew ∼ 10-3, δexp ∼ 10-3

- parity-violating electron scattering: M=mW , δnew ∼ 10-3

1/QWe,p ≈10 more sensitive to new physics

need δexp ∼ 10-2 “easier” experiment

-

QWe,p ∼ 1-4 sin2θW ∼ 0.1

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

size of loop effects from new physics: (α/π)(M/Mnew)2


S. Su 4

Outline-

Neutral current experiments

• Determination of sin2θeff

• Neutral current measurements➡ PVES ➡ PVDIS➡ APV ➡ NuTeV


S. Su 4

Outline-

Neutral current experiments

• Determination of sin2θeff

• Neutral current measurements➡ PVES ➡ PVDIS➡ APV ➡ NuTeV

William J. Marciano, “Overview of the weak mixing angle”Michael J. Ramsey-Musolf, “Physics bryond the SM and the Precision Frontier”Wally Melnitchouk, “SM correction to parity-violating electron scattering”Ian C. Cloet, “Theoretical Interpretation of neutrino/antineutrino scattering”Weifu Chang, “Physics beyond the SM; Sensitivities of PVLS”

Krishna S. Kumar, “Low energy test of SM: experimental overview”Roger D. Carlini, “QWEAK”, David Armstrong, “MOLLER”, Paul E. Reimer, “PVDIS”APV talks by Andrei Derevianko, Justin Torgerson, Lorenz Willmann, Eduardo Gomez-Garxia, Maarten de Kieviet, Thomas Stoehlker。。。


S. Su 5

e e

γ

ee

Z

Møller Scattering

• Purely Leptonic

e e

γ Z

Q-Weak (JLab)

• Coherent quarks in p• in operation now• 2(2C1u+C1d)

e γ

ZCs133

Atomic Parity Violation

• Coherent quarks in entire nucleus• Nuclear structure uncertainties• -376 C1u – 422 C1d

e eγ Z

p

n

DIS-Parity

•Isoscaler quark scattering• (2C1u-C1d)+Y(2C2u-C2d)

ν µ

W

ν ν

Z+

Neutrino Scattering

•Quark scattering (from nucleus)•Weak charged and neutral current difference

Courtesy of P. Reimer and R. Arnold


S. Su 6

Test of sin2θW running -

g sinθW = g’ cosθW = eWeak mixing angle sinθW

Standard Model PredictionErler, Kurylov & Ramsey-Musolf,Phys. Rev. D 72, 073003 (2005)

NuTeV SLAC E158

Jlab MollerQWe

PVDIS

Qweak

Cs APVPlot you have seen 10 timesin this meeting


S. Su 7

Measurement Δsin2θW/sin2θW Δsin2θW

Z-pole 0.07% 0.00017

0.5% Qw(Cs) 0.6% 0.0013

NuTeV 0.7% 0.0016

13.1% Qw(e)SLAC 0.5% 0.0013

4% QW(p) 0.3% 0.00072

2.1% Qw(e)Jlab 0.1% 0.00026(on par with Z pole)

0.76% (0.5%)PVDIS 0.45% (0.28%) 0.0011 (0.0006)

reactor based νee scattering

1% 0.0025

Precision of sin2θW determination-

-


S. Su 8

Sensitivity to new physics scale-

Take δQWp=4%

Λ: new physics scale O(1)Ramsey-Musolf(1999)

courtesy of Carlini

● probe new physics scale comparable to LHC

● confirmation of LHC discovery (couplings, charges)


S. Su 9

Experiment Z’M(ZΧ) M(ZLR) (TeV) (TeV)

LeptoquarksMLQ(up) MLQ(down)

(TeV) (TeV)

Compositeness (LL)

e-q e-e(TeV) (TeV)

direct limits .69 .63 0.3 0.3 --- ---

EW fit 0.78 0.86 1.5 1.5 11-26 8-10

0.5% Qw(Cs) 1.2 1.3 4.0 3.8 28 ---

13.1% Qw(e) .66 .34 --- --- --- 13

4% Qw(p) .95 .45 3.1 4.3 28 ----

2.5% Qw(e) 1.5 .77 --- --- --- 29

scaled from R-Musolf, PRC 60 (1999), 015501 Collider limits from Erler and Langacker, hep-ph/0407097

Misc. model sensitivities (non-SUSY)- Courtesy of D. Mack


S. Su 10

NC exp as a indirect probe of new physics

• SUSY: minimal Supersymmetric extension of SM (MSSM)

each SM particle superpartner - with R-parity : loop corrections

- without R-parity: tree-level contribution

• extra Z’

- exists in extension of SM

- constraints from Z-pole observable (mix with Z)

• leptoquark

• extra-dimension …

-

SM is a low energy approximation of a more fundamental theory

spin differ by ½


S. Su 11

Moller and Qweak -

A

V

weak charge QWf = 2gf

V = 2 If3 -4Qfs2


S. Su 12

Moller and Qweak -

QWp (Qweak) QW

e (SLAC) QWe (Jlab)

QWe,p

tree 1-4s2 -(1-4s2)QW

e,p loop 0.0713 -0.0449

q2 0.03 GeV2 0.026 GeV2 0.008 GeV2

ALR -0.29 ppm -0.131 ppm -0.04 ppm exp precision 4% 13% 2.1% δ sin2θW 0.0007 0.0013 0.00026

clean environment: Hydrogen target theoretically clean: small hadronic uncertainties tree level ∼ 0.1 ⇒ sensitive to new physics


S. Su 13

SUSY contributions-


S. Su 13

SUSY contributions-

universal


S. Su 13

SUSY contributions-

universal universal


S. Su 13

SUSY contributions-

universal universal

flavordependent


S. Su 14

MSSM correction to weak charge-

δ (QWp)SUSY / (QW

p)SM < 4%, δ (QWe)SUSY / (QW

e)SM < 8%

• QWe and QW

p

correlated

QWf = ρ (2Tf

3 - 4Qf κ s2) + λf

dominant : δκ (<0)⇒

negative shift in sin2θW

Kurylov, Ramsey-Musolf, Su (2003)

MSSM


S. Su 15

SUSY contributions-

! "!! #!! $!! %!! &!!!!"'(

!"

!&'(

!&

!!'(

!)*&!

!+

,-..*/0123

451

*

*

.67-89

.:1;<=>

?@>=

A@BB.@>=

C@>=MSUSYother=1 TeV


S. Su 16

SUSY contributions-

!"#$%&'()

!"*$$%&'()

!+,+++-

!+,+++-

!+,+++.

!+,+++.

!+,++/-

!+,++/-

!+,++/0

/++ -++ 1++ 2++ 3++ .++ 4++ 0++ 5++ /+++-++

1++

2++

3++

.++

4++

0++

5++

/+++

!"#$%&'(

)*+$,-

!./('))*+$,-

!010002

!010002

!010003

!010003

!010042

400 200 500 600 700 300 800 900 :00 4000400

200

500

600

700

300

800

900

:00

4000

MSUSYother=1 TeV


S. Su 17

R-parity violating (RPV) -

• RPV operators contribute to QWe,p at tree level

δQpW Gµ

Quantity !!11k(d

kR) !!

1k1(qkL) !12k(ek

R) !!21k(d

kR) !!

2k1(dkL) Value Discussion

!|Vud|2/|Vud|2 2 0 -2 0 0 !0.0032 ± 0.0014(a) Sec. IV

!0.0002 ± 0.0015(b) Sec. IV

!QCsW /QCs

W -4.82 5.41 0.05 0 0 !0.0040 ± 0.0066 Sec. V

!Re/µ 2 0 0 -2 0 !0.0042 ± 0.0033 Sec. IV

!Gµ/Gµ 0 0 1 0 0 0.00025 ± 0.001875 Sec. V

!QeW /Qe

W 0 0 -29.8 0 0 0.14 ± 0.11 Sec. V

!R! 0 0 -0.21 0.22 0.08 !0.0033 ± 0.0007 Sec. V

!R! 0 0 -0.077 0.132 0.32 !0.0019 ± 0.0016 Sec. V

TABLE III: PR-violating contributions to !|Vud|2/|Vud|2, !QCsW /QCs

W , !Re/µ, !Gµ/Gµ, !QpW /Qp

W ,!Qe

W /QeW , R! and R! . Here !|Vud|2/|Vud|2 means the possible correction to the value of |Vud|2 ex-

tracted from beta-decay that is allowed by first row CKM unitarity tests. See text for descriptionof scenario (a) and (b) for !|Vud|2/|Vud|2. Columns give the coe"cients of the various corrections

from !!ijk and !12k to the di#erent quantities. Next to last column gives the value of the cor-

responding quantity extracted from experiment assuming only Standard Model contributions tothe relevant process. Final column gives section of this review containing relevant discussion..

(a) large Nc QCD (b)lattice QCD

!!11k(d

kR) 0 ! 0.0020 0 ! 0.0024

!!1k1(q

kL) 0 ! 0.0017 0 ! 0.0019

!12k(ekR) 0.0013 ! 0.0039 0.0006 ! 0.0031

!!21k(d

kR) 0 ! 0.0015 0 ! 0.0014

!!2k1(d

kL) 0 ! 0.0013 0 ! 0.0009

TABLE IV: 95% C.L. ranges for the !(!)ijk obtained from fitting to the low energy observables

listed in Table III.

G. SUSY Searches

Both direct and indirect searches for superparticles have been carried out in variousexperiments [27]. Sparticles can be pair produced at e+e", pp and pp colliders via theintermediate !#, Z#, gluon or sparticles. Each sparticle subsequently decays into energeticlepton, jets plus an LSP for R-parity conserving scenarios. In most cases, the LSP is aneutral weakly interacting particle (e.g., a neutralino) which travels through the detec-tor without depositing significant energy. Therefore, typical signatures consist of somecombination of jets, leptons, possibly photons, and large missing energy.

The large electron-position (LEP) collider at CERN has completed its running at centerof mass energy more than twice the mass of Z boson with a few hundred pb"1 integratedluminosity. No events inconsistent with the SM have been reported and all visible sparticleswith mass up to half the Z mass have been excluded. Data taken at center of mass energy

16


S. Su 18

SUSY contributions- Kurylov, Ramsey-Musolf, Su (2003)

RPV 95% CL

MSSMloop

I) Obtain 95% CL allowed region in RPV coefficients

II) Evaluate δ QWe and δ QW

p

!0.2 !0.15 !0.1 !0.05 0 0.05 0.1

!0.1

!0.05

0

0.05

0.1

0.15

! (QW

e)SUSY

/(QW

e)SM

! (

QWp

) SU

SY/(

QWp

) SM

(b)

(a)

FIG. 9: Relative shifts in electron and proton weak charges due to SUSY e!ects (updated plot

from Ref. [142]). Dots indicate MSSM loop corrections for ! 3000 randomly-generated SUSY-breaking parameters. Interior of truncated elliptical regions (a) and (b) give possible shifts due

to R-parity non-conserving SUSY interactions (95% confidence), using value of !|Vud|2/|Vud|2 (a)and (b) in Table. III, respectively.

The arrows indicate correlated e!ects. For example, while both the superpartner loops andleptoquark exchange give a positive contribution to the proton weak charge, only MSSMgive rise to a sizable e!ect on the electron weak charge [134, 136]. for the general classof Z ! theories based on E6 gauge group, with neutral gauge bosons having mass <

" 1000GeV, the e!ects on Qp

W and QeW also correlate, but !Qe,p

W /Qe,pW can have either sign in this

case [134, 136]. In the case when E6 Z ! models and MSSM have similar e!ects on theelectron and proton weak charge, measurement of the cesium weak charge using atomicparity violation can further tell these two apart, as explained in Sec. VD below.

If we relax the assumption of R-parity conservation, tree level corrections to the weakcharges are generated RPV interactions. In this manner one obtains the following e!ectivefour-fermion Lagrangian, using the notation of "(!)

ijk as defined in Eq. (48):

LEFFRPV = ""!

1k1(qkL)dR"µdReL"µeL + "!

11k(dkR)uL"µuLeL"µeL

""12k(ekR) [#µL"µµLeL"µ#eL + h.c.] , (166)

where we have taken |q2| # m2f

and have retained only the terms relevant for the PVESscattering. The last term contributes to the muon decay, which a!ects the extraction ofthe fermi constant from the muon decay lifetime. Note the absence from Eq. (166) ofthe parity-violating contact four-electron interaction. This is because the superpotential inEq. (12) can only produce parity-conserving contact interactions between identical leptons.

61


S. Su 18


RPV 95% CL

MSSMloop

4% Qweak



p

!0.2 !0.15 !0.1 !0.05 0 0.05 0.1

!0.1

!0.05

0

0.05

0.1

0.15

! (QW

e)SUSY

/(QW

e)SM

! (

QWp

) SU

SY/(

QWp

) SM

(b)

(a)











LEFFRPV = ""!






61


S. Su 18


RPV 95% CL

MSSMloop

Future 2.1% Moller

4% Qweak



p

!0.2 !0.15 !0.1 !0.05 0 0.05 0.1

!0.1

!0.05

0

0.05

0.1

0.15

! (QW

e)SUSY

/(QW

e)SM

! (

QWp

) SU

SY/(

QWp

) SM

(b)

(a)











LEFFRPV = ""!






61


S. Su 19

Correlation between QWp

, QWe

-

Distinguish new physics

• exp

• MSSM

• extra Z’

• RPV SUSY

• leptonquark

Δ QWp Δ QW

e

SM

± 0.0029

SM

± 0.001

Erler, Kurylov and Ramsey-Musolf (2003)

Distinguish via APV QW

Cs


S. Su 19

Correlation between QWp

, QWe

-


• exp

• MSSM

• extra Z’

• RPV SUSY

• leptonquark

Δ QWp Δ QW

e

SM

± 0.0029

SM

± 0.001

Combinations of NC exps could be used to distinguish various new physics


Distinguish via APV QW

Cs


S. Su 20

Sensitivity to new physics-


• exp• MSSM • extra Z’

δ QWCs

small

sizable

δ QWp

SM

± 0.0029δ QW

e

SM

± 0.001

• δ QW (Z,N)=(2Z+N) δ QWu +(2N+Z) δ QWd

δ QWu >0

δ QWd <0


MSSM ⇒ δ QW(Z,N) / QW(Z,N) < 0.2 % for Cs


S. Su 21

Longitudinally polarized electrons on unpolarized deuterium targetCahn and Gilman (1978)

PVDIS: eD scattering - e e

δ Ad/Ad = 0.76% → δ sin2 θW/sin2θW = 0.45%

δ Ad/Ad = 0.5% → δ sin2 θW/sin2θW = 0.28%


S. Su 22

Ranges of C1u, C1d, C2u, C2d -

Courtesy of P. Reimer

(0.76%)


S. Su 23

SUSY contributions -

Kurylov, Ramsey-Musolf, SS (2003)


S. Su 23


PVDIS 0.76%



S. Su 23


PVDIS 0.76%


PVDIS 0.5%


S. Su 24

NuTeV experiment-

NC

• exp fit: (gLeff)2=0.3005±0.0014, (gR

eff)2=0.0310±0.0011

• SM EW fit: (gLeff)2=0.3042, (gR

eff)2=0.0301

gL,R2=(εu

L,R)2+(εdL,R)2

CC

δRν=-0.0033 ± 0.0015 δRν=-0.0019 ± 0.0026 -


S. Su 25

NuTeV anomaly-

• nuclear shadowing Miller and Thomas (2002), Zeller et. Al. (2002), Kovalenkov, schmidt and Yang (2002)

• asymmetry in strange sea distribution Davidson, Forte, Gambino, Rius and Strumia (2002), Goncharov et. al. (2001)

• isospin symmetry breaking Bodek et. al. (1999), Zeller et. Al. (2002)

• QCD corrections Dobrescu and Ellis (2003), Kretzer et. al. (2003), Davidson et. al. (2002)

…

SM QCD effects:

As we have heard this morning ...


S. Su 26

New physics explanation-

Difficult !● Supersymmetry: δ Rν, ν > 0 Kurylov, Ramsey-Musolf, Su (2003), Davidson, Forte, Gambino, Rius and Strumia (2002)

● Extra Z’ : family non-universal, finetuning Langacker and Plumacher (2000)

● Leptoquark: tune mass splitting Davidson, Forte, Gambino, Rius and Strumia (2002)

● νµ mixing with extra heavy neutrino: constraints from other observables Babu and Pati (2002), Loinaz et. al. (2003)

−


S. Su 26






−

MSSM RPV



S. Su 26






−


S. Su 27

Conclusion-

Precision measurements played an important role in developing and testing SMThey will be a crucial tool in probing new physics beyond the SMLow energy precision measurement can probe new physics not mix with Z (comparing with Z-pole precision observables)

precision frontierComplementary to what we may learn from LHC Opportunities and challenges for both experimentalists and theorists


Probing Supersymmetry with Parity-Violating Lepton Scatteringshufang/talk/ECT2010_Su.pdf · PVES...

Documents

Transcript of Probing Supersymmetry with Parity-Violating Lepton Scatteringshufang/talk/ECT2010_Su.pdf · PVES...