Muon Physics Overview(A Muon Collider Roadmap)

William J. Marciano

July 23, 2009

Chicago, ILL

OUTLINE1. Great Muon Expectations2. Recent Muon Results (PSI)

i) Muon Lifetime G=1.166367(5)x10-5 GeV-2

S Parameter: New Heavy Chiral Doublets? Extra Dimensions? ii) Muon-H Capture gP=7.71.2 (Agrees with PT) • Muon Anomalous Magnetic Moment (BNL E821)

aexp-a

SM=307(63)exp(53)SMx10-11 3.7sigma (SUSY?)

1. LFV: e PSI (10-13) 2e Fermilab/JPARC (2x10-17)• Muon Collider(2TeV)/Neutrino Factory

• Outlook/Vision

Apologies For Incompleteness

Not enough time to discuss TRIUMF (TWIST),

Muon Cooling, -EDM, JPARC plans…

1. Great Muon Expectations

• Muons are very special: ≈2.2x10-6sec!

m=105.66MeV ( heavy electron, light proton)

• Decay: ee()

100%Polarized-P.V. Decay Ang. Dist. Tracks Pol.

SR (condensed matter), Muon g-2 (Garwin et al.)

Copious Production: 1p(8GeV)+N1

Intense Muon Source 1013-1014/sec possible!

(Currently 108+/sec, 107-/sec at PSI)

Muon Collider , Neutrino Factory, Nanoscience…

CF? DTHe(4MeV)+n(14MeV)+ (1020p/s!!)

Muon Collider: Produce 1013/sec, Collect, Cool,

Accelerate, Store, Collide at s≥mZ, …2TeV!

Challenging! Neutrino Radiation Problem?

(Plan B Muon SR-Neutrino Factory +e+e)

Muon Technology Needs To Be Nurtured!

(Pursue Fundamental Muon Physics Aggressively!)

Build Muon Community

2. Recent Muon Results (PSI)

Standard Model Natural Relations:

e02/g0

2=sin20W=1-(m0

W/m0Z)2

Radiative Corrections (Loops) Finite & Calculable

mt prediction160-180GeV, mH160GeV (95%CL)!

(Relatively light Higgs suggests Supersymmetry)

Deviation”New Physics”: SUSY, Technicolor, W*…

* MUON LIFETIME PARTICULARLY IMPORTANT G

eg. G(1-r(mZ)MS)=/2mW2sin2W(mZ)MS

r(mZ)MS=0.0696+0.0085S + (1)(mW/mW*)2+ …

S=ND/6, ND= No. of new heavy doublets

eg. (4th generation), 12 (mirror fermions), Technifermions…

W* excited W (extra dimensions, compositeness…)

i) Muon () Lifetime

MuLAN & FAST experiments at PSI:

World Ave. =2.197035(17)x10-6sec (Further factor ~10 improvement expected in 2010) Already Confirms (improves) Previous World Average by error/2.

-1= (+e+e())=G

2m5f(me

2/m2)[1+RC]/1923

RC =/2(25/4-2)(1+/[2/3ln(m/me)-3.7)…] Fermi Th. Other SM and “New Physics” radiative corrections absorbed

into G. Eg. Top Mass, Higgs Mass, Technicolor, Susy,W*…

G=1.166367(5)x10-5GeV-2 precise & important

S Parameter

Use , G, mW, and sin2W(mZ)MSS (Counts ND) & mW*

S/120+(mW/mW*)2=[(G-1.166367x10-5GeV-2)/1.166367x10-5GeV-2

+(-1-137.035999084)/137.035999084 +2(mW-80.351GeV)/80.351GeV

+(sin2W(mZ)MS-0.23132)/0.23132]

-0.085X+0.019X2, X=ln(mH/115GeV)

mW=80.398(25)GeV sin2W(mZ)MS= 0.23125(16) Ave

S=0.10(11) & MW*>2-3TeV No Sign of “New Physics”!

Precision Parameters (status):

Quantity 2006 Value 2009 Value Comment

-1 137.035999710(96) 137.035999084(51) ge-2

G 1.16637(1)x10-5GeV-2 1.166367(5)x10-5GeV-2 PSI mZ 91 .1875(21)GeV 91.1875(21)GeV -

*mt 171.4(2.1)GeV 173.1(1.2)GeV FNAL

mW 80.410(32)GeV 80.398(25)GeV LEP2/FNAL

sin2W(mZ) 0.23125(16) 0.23125(16) Ave.

sin2W(mZ) 0.23070(26) 0.23070(26) ALR

sin2W(mZ) 0.23193(29) 0.23193(29) AFB(bb)

(3 sigma difference?)

sin2W(mZ)MS S S ND

Average 0.23125(16) -0.04(8) +0.10(11) 2(2)

ALR 0.23070(26) -0.32(13) -0.19(15) (SUSY)

AFB(bb) 0.23193(29) +0.32(15) +0.45(17) 9(3)!

If ALR had never been measured: sin2W(mZ)MS=0.23158(20)

That would imply S=+0.28(12)ND~62.4!!) (Heavy Higgs!

4th Generation, mW*1.6TeV…)

We would be waiting for 4th Generation, Technicolor, Extra Dim.

We missed our chance to nail sin2W(mZ)MS at the Z pole!

Future sin2W(mZ)MS Precision: Z Factory?

ii) Hydrogen Muon Capture:

• Muonic Atom (-NN’): <V>=-Z22m, =Z

+(1 + Z22/2 - Capture BR(~Z3/1000))

(capture)=1/-1/ (after time dilation correction)

For N=H, theory clean but high precision lifetimes needed.

nd(1- 5)up=gV(q2)np +igM(q2)/2mNnqp

-gA(q2)n5p-gP(q2)q/mn5p

Chiral Pert. Th. Predicts: gP(-0.88m2)=8.20.2

Exp.(Pre 2007)gP=11-12(1) Off by 3-4 sigma

Muon-H Capture Result (Including recent update with gA=1.275(1))

(capture)=1/-1/ (after time dilation correction) For atomic 1S singlet

(-pn)exp=725(17)sec-1 MuCap

(-pn)SM=717(3)(1-0.0108(gP-8.2))2sec-1

Implies: gP=7.7(1.2)

gpPT8.2(0.2) Good Agreement!

Additional datafurther factor 3 improvement Push as far as possible! Improve Theory

3. Muon Anomalous Magnetic Moment

Final Experimental Result: E821 at BNL

aexp (g-2)/2 =116592080(54)stat(33)sysx10-11

=116592080(63)x10-11

Factor of 14 improvement over CERN results

(Proposing Factor 4 Upgrade at FNAL - Up The Calumet Canal) ) D. Hertzog & B. Lee Roberts

Also, JPAC low energy muon R&D

BNL Muon g-2 Experiment

N(t) = N0 e-t/[1+Acos(at + )]

Standard Model Prediction

aSM = a

QED+aEW+a

Hadronic

QED Contributions:

• aQED=0.5(/)+0.765857410(27)(/)2+

24.05050964(43)(/)3+ 130.8055(80)(/)4+ 663(20)(/)5+… (5 loops)

-1=137.035999084(51) From ae (new)

aQED=116584718.1(2)x10-11 Very Precise!

QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.

Electroweak Loop Effects a

EW(1 loop)=194.8x10-11 goal of E821

2 loop EW corrections are large -21%

aEW(2 loop)=-40.7(1.0)(1.8)x10-11

3 loop EW leading logs very small O(10-12)

• aEW=154(2)x10-11 Non Controversial

• Hadronic Contributions

(some controversey)

e+e-hadrons vs hadrons+(isospin)

Novosibirsk, KLOE vs BaBar (e+e-+-)

KEY REGION

From e+e-hadrons data + dispersion relation a

Had(V.P.)LO=6894(42)(18)x10-11 (Hagiwara et al)

3 loop=aHad(V.P.)NLO+a

Had(LBL)

aHad(V.P.)NLO = -98(1)x10-11

aHad(LBL) = 105(26)x10-11 (Consensus)

a

Had=6901(42)(18)(26)x10-11

aSM=116591773(2)(46)(26)x10-11

a=aexp-a

SM=307(63)(53)x10-11 (3.7!)

• New Physics? Nearly 2xStandard Model!

Most Natural Explanation: SUSY Loops

Generic 1 loop SUSY Conribution: a

SUSY= (sgn)130x10-11(100GeV/msusy)2tan

tan3-40, msusy100-500GeV Natural Explanation

Other Explanations: Hadronic? +isospin data

BaBar e+e-+- rad. return

(a=~150x10-11 (1.9)

Other New Physics ~ 2TeV eg Extra Dimensions

SUSY 1 loop a Corrections

• SUSY Loops are like EW, but depend on:

• 2 spin 1/2 - (charginos)• 4 spin 1/2 0 (neutralinos) including dark matter!• 3 spin 0 sneutrinos and sleptons with mixing

Enhancement tan=2/1~3-40

Implications: sgn0 (dark matter searches easier)

SUSY at LHC very likely

bs, e, edms… Good Bets

“The deviation in a could be to Supersymmetry what the anomalous precession of the perihelion of Mercury was for General Relativity”

J. Marburger Presidential Science Advisor

(Former BNL Director)

• “The g-2 experiment makes me proud to be a physicist”

Bill Foster

Local Congressman

4. Charged Lepton Flavor Violation

• 1947 Muon established as independent elementary lepton: No e+ implies not excited electron

• 1958 Feinberg loop calculation of e+ B(e)<10-4~10-5 implies second neutrino!

1959 Feinberg and Weinberg Study -Ne-N

Coherent Ee105MeV Very Clean-Distinct

Stop - in material (10-10sec)N(1S) atom

i) e Rate0.5x106/sec

ii) NN’ (N=Al)0.7x106/sec

(N=Ti)2.6x106/sec

grows Z4 (very roughly)

• iii) R(N)(NeN)/(NN’)Z (for low Z)

R(Au)<7x10-13 SindrumII at PSI

R(Ti)<7x10-13 Unpublished

Conversion can take very high rate-No Accidentals

Every Muon We Can Produce

mu2e would stop 1011/sec!

Needs Clean Beam & Good Ee Resolution

+e++ Accidentals a problem (for B(e)<10-14)

MEG at PSI (DC Beam)

Ongoing Goal 2x10-13 2x10-14 (upgrade)

2e Fermilab/JPARC R(AleAl)2x10-17!

• Coherent -e Conversion in Nuclei (NeN)

Stop in material, ~10-10sec, N (1S) atom forms

i) (e-) = 0.5x106/sec

ii) (NN’) = 0.7x106/sec (N=Al)

= 2.6x106/sec (N=Ti)

iii) Ne-N R(Tie-Ti)<7x10-13 (Prelim.)

*Signature: m-BE=105 MeV monoenergetic electron

single particleno accidentalshigh rate capability!

It can take every muon we can provide!

Stop 1011/sec!

wait ~0.6x10-6sec (reject prompt background)

Requires ~300keV resolution & Clean beam between pulses

Expected signal

Cosmic raybackground

Prompt background

Experimental signature is105 MeV e- originating in a thin stopping target.

potential sources of fake backgrounds specify much of the design of the beam and experimental apparatus.

Charged Lepton Number Violating ProcessesReaction Bound In Progress Proposed Possible

BR(e) 1.2x10-11 2x10-13SES 2x10-14SES ?

BR(eee) 1x10-12 - 10-15

R(TieTi) 4x10-12 - 2x10-17SES 10-18

(7x10-13)

BR(e) 7.2x10-11 -

BR(KLe) 4.7x10-12 10-13

BR() 5.9x10-8 10-9

BR() <2.0x10-8 10-10

BR(Ze) <1.7x10-6 (10-13 from TieTi!)

(From Marciano, Mori and Roney Annual Reviews)

Straw Tracker

Crystal Calorimeter

Muon Stopping Target

Muon Beam Stop

Superconducting Production Solenoid

(5.0 T – 2.5 T)

Superconducting Detector Solenoid

(2.0 T – 1.0 T)

Superconducting Transport Solenoid

(2.5 T – 2.1 T)

Collimators

Muon Conversion Experiment

Some Theory Considerations: If transition dipole operator (chiral changing) dominates

BR(e)=389R(AleAl)=238R(TieTi) But conversion exp. can be more sensitive by 103-104!

Eg. Popular SUSY Models (may be related to a)

Neutrino Mass & Mixing EffectsLepton Flavor Violation

BR(e)~3/32[m32-m2

2]2/mW4(s13c13s23)2 10-54

R(NeN)~100BR(e)~10-52 still tiny, but enhanced by Chiral conserving amplitudes. (Lesson) Conversion better for Heavy Neutrino Mixing

In General: 1/200BR(e)/R(NeN)200 Physics scale ~3000TeV Probed!

Muon g-2 and LFV

• If SUSY or any other New Physics is responsible for a, it will also induce LFV

via mixing effects. (Chiral Changing)

DL,R=1622ae/GFm2 e<4.5x10-5

Large Slepton Mixing(M2-M1)/M1<4.5x10-5!

Very Near Degeneracy (R Symmetry?)

MEG(e) at 2x10-13 may see an effect

or e<6x10-6! M2-M1O(1MeV)

Sensitivity to Different Muon Conversion Mechanisms

CË = 3000 TeV

Compositeness

Second Higgs doublet

Heavy Z’, Anomalous Z coupling

Predictions at 10-15

Supersymmetry

Heavy Neutrinos

Leptoquarks

5. Muon Collider(+-)/Neutrino Factoryi) Need Copious Source of Protons Fast cycling 8-16GeV Accelerator or Linac Power~4MW >1014 +-/secii) Collect and Cool + & - Beamsiii) Accelerate High Energyiv) Large Storage Ring (~1000 revolutions)v) Luminosity ~ 1034-1035 desirable (at 2TeV)

Energy: 91GeV Z Factory (sin2W, bb,…) 114-150GeV Higgs Pole Resonance(s)

161GeV W+W- (mW) 350GeV tt (mt), HZ… SUSY Pairs 2TeV +-“New Physics”,-- p…

Neutrino Factory SR

Intense Muon Beam: +e+e; -e-e

Leads to clean source of neutrinos

StatisticsE3 Go to 20GeV Very Good 13

e, but osc length ~500km x E(GeV)

Not optimized for CP Violation Long Distances!

Very Good for small 13, New Physics

Currently: All Neutrino Data (including MINOS2009)

sin2213=0.080.04 (relatively large!)

Fogli et al. Hep-ph0905.3549 (2009)

6. Outlook/Vision

PSI Exps. MuLAN, FAST and MuCAP interesting and timely.

Expect Improvement in and gP to continue (2010 results)

No definitive sin2W(mZ)MS in sight (LHC? AFB(Z))

Perhaps aexp improvement (x4) at Fermilab (JPARC?)

BaBar and Belle doing e+e-hadrons + as well as

+hadrons with high statistics. Factor 2 a(V.P.) improvement? (Novosibirsk factor 3)

MEG at PSI: BR(e)~2x10-13 (running!) (future 2x10-14)

2e at Fermilab/JPARC aim for AleAl with 2x10-17 SES!

Sensitive to “New Physics” up to 3000TeV (Robust)

If MEG (e) sees several (5) events

it will be a major discovery. 2e should

then see between 100-10,000 events from AleAl.

If MEG sees nothing, 2e could still see 10,000 events!

2e promises to be a flagship experiment.

With upgrade eg. (project X) it could be extended to

10-18. No better way to push muon technology while doing forefront physics!

2e must do experiment (fast track)

LHC

• Many Discoveries Anticipated:

Higgs, SUSY, Extra Dimensions, Z’, Strong Dynamics etc.

So far, no evidence for New Physics except

perhaps g-2 (Hope Deviation is Correct)

Can Mainland USA get back to Collider HEP?

Project X at Fermilab

• 2MW proton Linac with 8GeV protons

muon, kaon, neutrino physics (motivation)

(Upgradeable to 4MW)

Front end of a muon collider (Real Motivation?)

Z Factory, Higgs,… Neutrino Factory… p,

2 TeV +- Collider at Fermilab

The Future of US Collider HEP is the Muon!