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December 4, 2009 MOLLER Physics Case 1

MOLLER Physics CaseElements of the “Dry Run”

Krishna KumarUniversity of Massachusetts, Amherst

December 4, 2009

MOLLER Collaboration Meeting

Measurement of Lepton-Lepton Electroweak Reaction

Nuclear/Atomic systems address several topics; complement the LHC:• Neutrino mass and mixing 0νββ decay, θ13, β decay, long baseline neutrino expts

• Rare or Forbidden Processes EDMs, charged LFV, 0νββ decay

• Dark Matter Searches

• Low Energy Precision Electroweak Measurements:

December 4, 2009 MOLLER Physics Case

Worldwide Experimental Thrust in the 2010s: New Physics Searches

2

Lower Energy: Q2 << MZ2Large Hadron Collider as well as

A comprehensive search for clues requires:Compelling arguments for “New Dynamics” at the TeV Scale

Nuclear/Atomic systems address several topics; complement the LHC:• Neutrino mass and mixing 0νββ decay, θ13, β decay, long baseline neutrino expts

• Rare or Forbidden Processes EDMs, charged LFV, 0νββ decay

• Dark Matter Searches

• Low Energy Precision Electroweak Measurements:


Worldwide Experimental Thrust in the 2010s: New Physics Searches

2

Lower Energy: Q2 << MZ2Large Hadron Collider as well as

• Neutrons: Lifetime, Asymmetries (LANSCE, NIST, SNS...)

• Muons: Lifetime, Michel parameters, g-2 (BNL, PSI, TRIUMF, FNAL, J-PARC...)

• Parity-Violating Electron Scattering Low energy weak neutral current couplings, precision weak mixing angle (SLAC, JLab)

Complementary signatures to decipher LHC new physics signals

A comprehensive search for clues requires:Compelling arguments for “New Dynamics” at the TeV Scale


Comprehensive Search for New Neutral Current Interactions

Many new physics models give rise to non-zero Λ’s at the TeV scale: Heavy Z’s, compositeness, extra dimensions…

One goal of neutral current measurements at low energy AND colliders: Access Λ > 10 TeV for as many f1f2 and L,R combinations as possible

Important component of indirect signatures of “new physics”

€

Lf1 f2=

4πΛ ij2 ηij

i, j= L ,R∑ f 1iγµ f1i f 2 jγ

µ f2 j

Consider

€

f1 f 1→ f2 f 2

€

f1 f2 → f1 f2orΛ’s for all f1f2 combinations and L,R combinations

Eichten, Lane and Peskin, PRL50 (1983)


Comprehensive Search for New Neutral Current Interactions

Many new physics models give rise to non-zero Λ’s at the TeV scale: Heavy Z’s, compositeness, extra dimensions…

One goal of neutral current measurements at low energy AND colliders: Access Λ > 10 TeV for as many f1f2 and L,R combinations as possible


LEPII, Tevatron access scales Λ’s ~ 10 TeVe.g. Tevatron dilepton spectra, fermion pair production at LEPII

- L,R combinations accessed are parity-conservingLEPI, SLC, LEPII & HERA accessed some parity-violating combinations but precision dominated by Z resonance measurements: ~ few TeV sensitivity

€

Lf1 f2=

4πΛ ij2 ηij

i, j= L ,R∑ f 1iγµ f1i f 2 jγ

µ f2 j

Consider

€

f1 f 1→ f2 f 2

€

f1 f2 → f1 f2orΛ’s for all f1f2 combinations and L,R combinations

Eichten, Lane and Peskin, PRL50 (1983)


Colliders vs Low Q2

Window of opportunity for weak neutral current measurements at Q2<<MZ2

2

Consider known weak neutral current interactions mediated by Z Bosons


Colliders vs Low Q2

Window of opportunity for weak neutral current measurements at Q2<<MZ2

2

Processes with potential sensitivity: - neutrino-nucleon deep inelastic scattering - Atomic parity violation (APV) - parity-violating electron scattering

NuTeV at Fermilab 133Cs at Boulder

Consider known weak neutral current interactions mediated by Z Bosons


Published MeasurementsRunning of sin2θW established to 6σ

T

6σ•Czarnecki and Marciano •Erler and Ramsey-Musolf•Sirlin et. al.•Zykonov

Precision Standard Model Tests

PDG 200416 TeV17 TeV

0.8 TeV 1.0 TeV (Zχ)

0.01•GF

95% C.L.

Limits on “New” Physics

102

103

0.23 0.232 0.234

sin2!

lept

eff

mH [G

eV]

"2/d.o.f.: 11.8 / 5

Al(SLD) 0.23098 ± 0.00026

A0,b

fb 0.23221 ± 0.00029

Average 0.23153 ± 0.00016

had= 0.02758 ± 0.00035(5)

mt= 172.7 ± 2.9 GeV


Future Measurements

6

102

103

0.23 0.232 0.234

sin2!

lept

eff

mH [G

eV]

"2/d.o.f.: 11.8 / 5

Al(SLD) 0.23098 ± 0.00026

A0,b

fb 0.23221 ± 0.00029

± 0.00029

Average 0.23153 ± 0.00016

had= 0.02758 ± 0.00035(5)

mt= 172.7 ± 2.9 GeV


Future Measurements

6

MOLLERthe MOLLER proposal is precise enough to affect the central value of sin2θW and its implications for mH

102

103

0.23 0.232 0.234

sin2!

lept

eff

mH [G

eV]

"2/d.o.f.: 11.8 / 5

Al(SLD) 0.23098 ± 0.00026

A0,b

fb 0.23221 ± 0.00029

± 0.00029

Average 0.23153 ± 0.00016

had= 0.02758 ± 0.00035(5)

mt= 172.7 ± 2.9 GeV


Future Measurements

6


A

V

V

A

102

103

0.23 0.232 0.234

sin2!

lept

eff

mH [G

eV]

"2/d.o.f.: 11.8 / 5

Al(SLD) 0.23098 ± 0.00026

A0,b

fb 0.23221 ± 0.00029

± 0.00029

Average 0.23153 ± 0.00016

had= 0.02758 ± 0.00035(5)

mt= 172.7 ± 2.9 GeV


Future Measurements

6


€

δ(C1q )∝ (+ηRLeq +ηRR

eq −ηLLeq −ηLR

eq )

€

δ(C2q )∝ (−ηRLeq +ηRR

eq −ηLLeq +ηLR

eq )PV elastic e-p scattering, APV

PV deep inelastic scattering

A

V

V

A

102

103

0.23 0.232 0.234

sin2!

lept

eff

mH [G

eV]

"2/d.o.f.: 11.8 / 5

Al(SLD) 0.23098 ± 0.00026

A0,b

fb 0.23221 ± 0.00029

± 0.00029

Average 0.23153 ± 0.00016

had= 0.02758 ± 0.00035(5)

mt= 172.7 ± 2.9 GeV


Future Measurements

6


€

δ(C1q )∝ (+ηRLeq +ηRR

eq −ηLLeq −ηLR

eq )

€

δ(C2q )∝ (−ηRLeq +ηRR

eq −ηLLeq +ηLR

eq )PV elastic e-p scattering, APV

PV deep inelastic scattering

A

V

V

A

SoLID proposal

Qweak experiment


MOLLER Parameters

7

•Comparable to the two best measurements at colliders•Unmatched by any other project in the foreseeable future•At this level, one-loop effects from “heavy” physics

Compelling opportunity with the Jefferson Lab Energy Upgrade:

Ebeam = 11 GeV

APV = 35.6 ppb

δ(APV) = 0.73 ppb

δ(QeW) = ± 2.1 (stat.) ± 1.0 (syst.) %

75 μA 80% polarized

δ(sin2θW) = ± 0.00026 (stat.) ± 0.00012 (syst.) ~ 0.1%

~ 38 weeks(~ 2 yrs)

not just “another measurement” of sin2θW


EW Physics at One-Loop

8

Three fundamental inputs needed: αem, GF and MZOther experimental observables predicted at 0.1% level: sensitive to heavy particles via higher order quantum corrections

4th and 5th best measured parameters: sin2θW and MW



8



AFB(b)

ALR(had)

102

103

0.23 0.232 0.234

sin2!

lept

eff

mH [G

eV]

"2/d.o.f.: 11.8 / 5

Al(SLD) 0.23098 ± 0.00026

A0,b

fb 0.23221 ± 0.00029

Average 0.23153 ± 0.00016

had= 0.02758 ± 0.00035(5)

mt= 172.7 ± 2.9 GeV



8



AFB(b)

ALR(had)

102

103

0.23 0.232 0.234

sin2!

lept

eff

mH [G

eV]

"2/d.o.f.: 11.8 / 5

Al(SLD) 0.23098 ± 0.00026

A0,b

fb 0.23221 ± 0.00029

± 0.00029

Average 0.23153 ± 0.00016

had= 0.02758 ± 0.00035(5)

mt= 172.7 ± 2.9 GeV



8



AFB(b)

ALR(had)

This proposal

102

103

0.23 0.232 0.234

sin2!

lept

eff

mH [G

eV]

"2/d.o.f.: 11.8 / 5

Al(SLD) 0.23098 ± 0.00026

A0,b

fb 0.23221 ± 0.00029

± 0.00029

Average 0.23153 ± 0.00016

had= 0.02758 ± 0.00035(5)

mt= 172.7 ± 2.9 GeV



8



AFB(b)

ALR(had)

This proposal

AFB(b) measures product of e- and b-Z couplingsALR(had) measures purely the e-Z couplings

102

103

0.23 0.232 0.234

sin2!

lept

eff

mH [G

eV]

"2/d.o.f.: 11.8 / 5

Al(SLD) 0.23098 ± 0.00026

A0,b

fb 0.23221 ± 0.00029

± 0.00029

Average 0.23153 ± 0.00016

had= 0.02758 ± 0.00035(5)

mt= 172.7 ± 2.9 GeV



8



AFB(b)

ALR(had)

This proposal


Proposed APV measures purely the e-Z couplings at a different energy scale

102

103

0.23 0.232 0.234

sin2!

lept

eff

mH [G

eV]

"2/d.o.f.: 11.8 / 5

Al(SLD) 0.23098 ± 0.00026

A0,b

fb 0.23221 ± 0.00029

± 0.00029

Average 0.23153 ± 0.00016

had= 0.02758 ± 0.00035(5)

mt= 172.7 ± 2.9 GeV



8



This proposal


Proposed APV measures purely the e-Z couplings at a different energy scale

The moment one adds “new physics”, sin2θW becomes process-dependent (initial and final state fermion type), and Q2-dependent


Off the Z Resonance

9


Off the Z Resonance

9

!!|g2

RR ! g2LL|

= 7.5 TeVLe1e2 =!

i,j=L,R

g2ij

2!2ei!µeiej!

µej

APV


Off the Z Resonance

9

Many new physics models give rise to neutral ‘contact’ (4-Fermi) interactions: Heavy Z’s, compositeness, SUSY, doubly charged scalars, extra dimensions…


!!|g2

RR ! g2LL|

= 7.5 TeVLe1e2 =!

i,j=L,R

g2ij

2!2ei!µeiej!

µej

APV

!!|g2

RR + g2LL|

= 4.4 TeV !gRL

= 5.2 TeV |g2RR ! g2

LL|


insensitive toOR


Off the Z Resonance

9

Many new physics models give rise to neutral ‘contact’ (4-Fermi) interactions: Heavy Z’s, compositeness, SUSY, doubly charged scalars, extra dimensions…


!!|g2

RR ! g2LL|

= 7.5 TeVLe1e2 =!

i,j=L,R

g2ij

2!2ei!µeiej!

µej

APV

!!|g2

RR + g2LL|

= 4.4 TeV !gRL

= 5.2 TeV |g2RR ! g2

LL|


insensitive toOR

If new contact interactions are to be folded in with the Standard Model processes, disentangling them requires several measurements of different processes off the Z resonance


Example I: Supersymmetry

10

RPVSUSY

MinimalSUSY

This proposal

Does Supersymmetry provide a candidate for dark matter?•B and/or L need not be conserved (RPV): neutralino decay

•neutralino then no longer viable dark matter candidate

•Qweak and PVDIS are additional complementary measurements

MSSM sensitivity if light super-partners, large tanβ

PR = (!1)3(B!L)+2s

Ramsey-Musolf and Su (2007)

•Virtually all GUT models predict new Z’s: LHC reach ~ 5 TeV•With high luminosity at LHC, 1-2 TeV Z’ properties can be extracted•APV can help separate left- and right-handed couplings

!2GF!(Qe

W) =1

(7.5 TeV)2

=|g2

RR ! g2LL|

!2=

e2R ! e2

L

M2Z!


Example II: Heavy Z

11

Suppose a 1 to 2 TeV heavy Z’ is discovered at the LHC•What are its vector- and axial-vector coupling?

This proposal

LHC data can extract the mass, width and AFB(s)

constraint on eR/eL

Z’

e-

e-

e-

e-

Courtesy F. Petriello et al


Doubly Charged Scalars

e-

H-- e

-

e-

e-∆L = 2

!2GF!(Qe

W) =1

(7.5 TeV)2 MPV !|hee

L,R|2

2M2!L

eL!µeLeL!µeL

M!L

|heeL | ! 5.3 TeV

Sensitivity better than LEP20012


Input from Mike R-M

13

• Working with Shufeng Su on quantifying specific SUSY scenarios– What are the scenarios for LHC SUSY searches that allows

interesting discovery phase space for MOLLER?

• Three classes: squarks, sleptons, gauginos– If LHC discovers light squarks, expect greater than 2 sigma

deviation in MOLLER

– If LHC doesnt find squarks, then they are heavy. If winos are relatively light, then MOLLER reach of slepton masses exceeds LHC reach

– If Winos also heavy, then MOLLER doesnt have SUSY reach

• Will provide plots to illustrate these points


Input from Jens Erler• How much error degradation can MOLLER

tolerate and still be worth doing? Answer: 3.2% instead of 2.3% still VERY compelling– Consider that error on QW(e) will be ±0.0015. In the

language of Ci’s, this will be ±0.00075. The best C1q combination from APV is ±0.0011. NuTeV at face value in the best case is ±0.001.

– New scale sensitivity is 6.4 TeV, still better than LEPII

– Weak mixing angle error would be ±0.0004. The LEP/SLD raw difference is 0.00126, so this error still has considerable discriminative power.

– Z’ limits will continue to be complementary to LEP measurements

14

MOLLER Physics Case - hallaweb.jlab.orghallaweb.jlab.org/...2009Dec4_5/kumar_physicscase.pdfMany new...

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