Muonium – Muonium – Physics of a Most Fundamental AtomPhysics of a Most Fundamental Atom

Klaus Jungmann Kernfysisch Versneller Instituut & Rijksuniversiteit Groningen

Simple Atomic SystemSimple Atomic SystemAtomic TheoryAtomic Theory

Fundamental ConstantsFundamental ConstantsFundamental SymmetriesFundamental SymmetriesSearch for New PhysicsSearch for New Physics

Atomic Physics at AcceleratorsAtomic Physics at AcceleratorsPrecision MeasurementsPrecision Measurements

……Condensed Matter PhysicsCondensed Matter Physics

ChemistryChemistryLow energy Muon Beams Low energy Muon Beams

Muonium (M)Muonium (M)

What is it ?What is it ?

What is it good for ?What is it good for ?

• test of electromagnetic bound state theorytest of electromagnetic bound state theory• fundamental constantsfundamental constants• tests of fundamental symmetriestests of fundamental symmetries• search for New Physicssearch for New Physics• tool for condensed matter researchtool for condensed matter research• …… ……

““Muonium is the bound state of a Muonium is the bound state of a positive Muon and an Electron”positive Muon and an Electron”

• ““point-like” particlespoint-like” particles• no (severe) strong interaction effectsno (severe) strong interaction effects• calculable to required accuracycalculable to required accuracy

Muonium (M)Muonium (M)

hydrogen-like atom hydrogen-like atom but no strong but no strong

interactioninteraction

Past of Muonium (Ground State Hyperfine Structure)Past of Muonium (Ground State Hyperfine Structure)

Discovery of Muonium 1960Discovery of Muonium 1960

Hyperfine Structure addressedHyperfine Structure addressedas an Important Quantityas an Important Quantity

From: V. Telegdi, in: “A Festschrift for Vernon W. Hughes”, 1990

There was stimulating There was stimulating competitioncompetition

...

Theorists are confident that muonium HFS

Theorists are confident that muonium HFS

Can be calculated to 10 Hz, if needed

Can be calculated to 10 Hz, if needed (Eides, Pachucki,(Eides, Pachucki,

…)…)

magnetic moment magnetic moment , ,

The worlds most intense quasi continuous muon source - the

LLos AAlamos MMeson PPhysics FFacility

Muonium Hyperfine Structure

Solenoid

ein

S GatedDetector

MW-Resonator/Kr target

Yale - Heidelberg - Los Alamos

pulsedpulsed beambeam essentialessential

old Muoniumold Muonium

freq. scanfreq. scanB scanB scan

Results from LAMPF Muonium HFS ExperimentResults from LAMPF Muonium HFS Experiment

measured:

• 12 = 1 897 539 800(35) Hz ( 18 ppb)• 34 = 2 565 762 965(43) Hz ( 17 ppb)

from Breit-Rabi equation:

12 • exp = 4 463 302 765(53) Hz ( 12 ppb)• theo = 4 463 302 563(520)(34)(<100) Hz (<120 ppb)

12 • p = 3.183 345 24(37) (120 ppb)

alternatively derived:

• mme = 206.768 277(24) (120 ppb)• ppb)

-1= 137.035 999 9 (5)

-1= 137.035 99X X (1)

CODATA 2002

muonium and hydrogen hfs → proton structure

?

1810m

mmr

0

00

K

KK||

K

12102avga

|e

ae

a|3101.2

avgg

|e

ge

g|

er

CPTbreakb,a μμ Invariance LorentzbreakH,d,c,b,a μνμνμνμμ

?

CPT and Lorentz Non-Invariant Models

CPT tests

Are they comparable - Which one is appropriate

Use common ground, e.g. energies

Leptons in External Magnetic Field

Bluhm , Kostelecky, Russell, Phys. Rev. D 57,3932 (1998)

For g-2 Experiments :

Dehmelt, Mittleman,Van Dyck, Schwinberg, hep-ph/9906262

μμ qAiiD

0Dμγ5γμνidνDμγμνicμνσμνH21μγ5γμbμγμamμDμ(iγ

equation DIRAC violating Lorentz and CPT generic

ψ)

2clm

aΔω

lupspinE

|ldownspinEl

upspinE|

lr

l34bl

aωlaωaΔω

avg

ll2

l

cl

a|aa|

cm

ωr

24103.5μr21101.2er :: muonelectron

CPTCPT – ViolationLorentz Invariance Violation

What is best CPT test ?

New Ansatz (Kostelecky)

• K0 10-18 GeV/c2

• n 10-30 GeV/c2

• p 10-24 GeV/c2

• e- 10-27 GeV/c2• Future:

Anti hydrogen 10-18 GeV/c2

often quoted:

• K0- K0 mass difference (10-18)

• e- - e+ g- factors (2* 10-12)

• We need an interaction with a finite strength !

What about Second Generation Leptons?What about Second Generation Leptons?

CPT and Lorentz Invariance from Muon ExperimentsCPT and Lorentz Invariance from Muon Experiments

Muonium:

new interaction below 2* 10-23 GeV

Muon g-2:

new interaction below 4* 10-22 GeV (CERN) 15 times better expected from BNL

V.W. Hughes et al., Phys.Rev. Lett. 87, 111804 (2001)

Present Status of Muonium Ground State Hyperfine Present Status of Muonium Ground State Hyperfine StructureStructure

• No Experimental Activities known at this timeNo Experimental Activities known at this time

• Refinement of Theory going onRefinement of Theory going one.g.e.g. Eides, Grotch, “Three-Loop Radiative-Recoil Corrections to Hyerfine Splitting Eides, Grotch, “Three-Loop Radiative-Recoil Corrections to Hyerfine Splitting in Muonium”, Phys.Rev.D67, 113003 (2003) and hep-ph/0412372 (2005)in Muonium”, Phys.Rev.D67, 113003 (2003) and hep-ph/0412372 (2005) Marciano, “Muonium Lifetime and Heavy Quark Decays”, hep-ph/0403071 Marciano, “Muonium Lifetime and Heavy Quark Decays”, hep-ph/0403071 (2004)(2004) . . .. . .

• Exploitation of the Atom in Condensed Matter ScienceExploitation of the Atom in Condensed Matter Sciencee.g.e.g. Ivanter et al. “On the anomalous muonium hyperfine structure in silicon”Ivanter et al. “On the anomalous muonium hyperfine structure in silicon” J.Phys.: Condens. Matter 15, 7419 (2003) J.Phys.: Condens. Matter 15, 7419 (2003) … …..

NEVISCHICAGO-SRELLAMPFLAMPF latest experiment

Quo

ted

Unc

erta

inty

[kH

z]

Year

History of Muonium Ground StateHyperfine Splitting Measurements

Future Possibilities for Muonium Ground State Future Possibilities for Muonium Ground State Hyperfine StructureHyperfine Structure

LAMPF Experiment limited byLAMPF Experiment limited by STATISTICSSTATISTICS

more more MUONS MUONS needed needed factor > 100 over LAMPF – pulsed > 5*10factor > 100 over LAMPF – pulsed > 5*1088++/s /s below 28 MeV/c below 28 MeV/c

newnew ACCELERATORS ACCELERATORS J-PARC ?J-PARC ? Neutrino Factory ?Neutrino Factory ? Eurisol ?Eurisol ? GSI ?GSI ? FNALFNAL…………....

What other experiments besides the What other experiments besides the Ground State Hyperfine StructureGround State Hyperfine Structure

are possible ?are possible ?

• Gas StopGas Stop

Yields up to 100% foreign gas effectsPolarization up to 50% (B=0) 100% (B>>1T)

++e

+

Kr, Ar

• Beam FoilBeam Foil

Muonium in Vacuo keV energyn=2 state populatedfast muonium

+ 50%

+e 1%

+ee0.01%

+

• SiOSiO22 Powder Powder

thermal Muonium in Vacuo M(2s) /M(1s) < 10-4

Yields up to 12%Polarization 39(9)% velocity 1.5 cm/

+ M

Methods of Muonium ProductionMethods of Muonium Production

Completed Experiments on Muonium 1s-2s IntervalCompleted Experiments on Muonium 1s-2s Interval

Pioneering effort at Pioneering effort at KEKKEK ((Chu,Mills,Nagamine et al.)Chu,Mills,Nagamine et al.)

Precision measurement at Precision measurement at RALRAL ((HHeidelberg – eidelberg – OOxford – xford – RRutherford – utherford – SStrathclyde – trathclyde – SSiberia –iberia –YYaleale Collaboration)Collaboration)

Muonium 1S-2S Experiment

-.25 R

1S

2S

244 nm

244 nm

Ene

rgy

-R

0

ekin

Laser

Diagnostics

Detection

in

e

Target

Mirror

Heidelberg - Oxford - Rutherford - Sussex - Siberia - Yale

The most intense pulsed muon source – ISIS at the

RRutherford AAppleton LLaboratory

Muonium 1S-2S Experiment

-.25 R

1S

2S

244 nm

244 nm

Ene

rgy

-R

0

ekin

Laser

Diagnostics

Detection

in

e

Target

Mirror

Heidelberg - Oxford - Rutherford - Sussex - Siberia - Yale

MuoniumMuonium1s-2s 1s-2s

At RALAt RAL1987 -20001987 -2000

Results:Results:

1s-2s = 2455 528 941.0(9.1)(3.7) MHz

1s-2s = 2455 528 935.4(1.4) MHz

mm= 206.768 38 (17) m= 206.768 38 (17) me e (0.8ppm)(0.8ppm)

qq= [ -1 -1.1 (2.1) 10= [ -1 -1.1 (2.1) 10-9 -9 ] q] qe-e-

(2.2 ppb)(2.2 ppb)

exp

theo

Future Possibilities for Muonium 1s-2s IntervalFuture Possibilities for Muonium 1s-2s Interval

• No Precision Experiment Activities known at No Precision Experiment Activities known at this timethis time

• Exploitation of Laser Spectroscopy to obtainExploitation of Laser Spectroscopy to obtain

““Slow Muons” Condensed Matter ScienceSlow Muons” Condensed Matter Science(K. Nagamine et al. @RAL)(K. Nagamine et al. @RAL)

Y Matsuda Y Matsuda et alet al J. Phys. G: Nucl. Part. Phys.J. Phys. G: Nucl. Part. Phys. 29,29, 2039 (2003) 2039 (2003)

Future Possibilities for Muonium 1s-2s IntervalFuture Possibilities for Muonium 1s-2s Interval

RAL Experiment limited byRAL Experiment limited by STATISTICSSTATISTICS

more more MUONS MUONS needed needed factor > 1000 over RAL – pulsed > 5*10factor > 1000 over RAL – pulsed > 5*1088++/s/s below 28 MeV/c below 28 MeV/c would enable cw laser spectroscopy ! (precision !)would enable cw laser spectroscopy ! (precision !)

newnew ACCELERATORS ACCELERATORS J-PARC ?J-PARC ? Neutrino Factory ?Neutrino Factory ? Eurisol ?Eurisol ? GSI ?GSI ? . . . . .. . . . .

QEDm

QEDm

QED

, ,

g

+e-

HFS, n=1QED correctionsweak contribution

+e-

1S-2S

m

QED corrections

ge h

m c2

g-2

hadronic contributionweak contributionNew Physics

a = a m c

e B=

a p

a p

p-

Experiment:

Fundamental Constants of Interest to g-2

Theory: weakhadronicAAAa

...483624

21

* need for muon ! * hadronic and weak corrections* various experimental sources ofbetter 100ppb>need constants at very moderate * no concern for (g-2) even with recent corrections accuracy

* a and B (p) measured in (g-2) experiment <better 0.35 and 0.1 ppm>* c is a defined quantity <“infinite” accuracy>* m () is measured in muonium spectroscopy (hfs) <better 120 ppb> NEW 2000* eis measured in muonium spectroscopy (1s -2s) <better 1.2 ppb> NEW 1999* p in water known >> probe shape dependence << <better 26 ppb>* 3He to p in water >> gas has no shape effect << <better 4.5 ppb> being improved

Any New Effort to improve significantly onAny New Effort to improve significantly onthe the Muon Magnetic AnomalyMuon Magnetic Anomaly will need better will need better

constants !constants !

Where should they come from, if not fromWhere should they come from, if not fromMuonium Spectroscopy Muonium Spectroscopy ??

Muonium – Antimuonium Conversion Muonium – Antimuonium Conversion up to Nowup to Now

Did first Searchfor ConversionAmato et al.Phys.Rev.Lett. 21,1709 (1968)

PredictedM-M

Conversion1957-

NamedSystem

“Muonium” ?

The most intense continuos sourceof muons – the

Cyclotron Facilityat the

PPaul SScherrer IInstitut

Present Activities concerning Muonium – Present Activities concerning Muonium – Antimuonium ConversionAntimuonium Conversion

• No Experimental Activities known at this timeNo Experimental Activities known at this time

• Theory is proposing lots of modelsTheory is proposing lots of modelse.g.e.g. Clark, Love “Muonium-Antimuonium Oscillations and Massive Majorana Neutrinos”, Clark, Love “Muonium-Antimuonium Oscillations and Massive Majorana Neutrinos”, hep-ph/0307264 (2003)hep-ph/0307264 (2003) Gusso, Pires, Pires, Rodrigues da Silva “Minimal 3-3-1 Model, lepton Mixing and Gusso, Pires, Pires, Rodrigues da Silva “Minimal 3-3-1 Model, lepton Mixing and Muonium- Antimuonium Conversion”, hep-ph/0208062 (2002)Muonium- Antimuonium Conversion”, hep-ph/0208062 (2002) Cvetic,Dib, Kim, Kim, “Muonium-Antimuonium Conversion in models with heavy neutrinos”,Cvetic,Dib, Kim, Kim, “Muonium-Antimuonium Conversion in models with heavy neutrinos”, hep-ph/0504126 (2005)hep-ph/0504126 (2005) Applequist, Christensen, Piai, Schrock “ Flavour-Changing Processes in Extended Technicolor”,Applequist, Christensen, Piai, Schrock “ Flavour-Changing Processes in Extended Technicolor”, Phys. Rev.D70, 093919 (2004)Phys. Rev.D70, 093919 (2004)……..

Future Possibilities for Muonium – Antimuonium Future Possibilities for Muonium – Antimuonium SearchesSearches

PSI Experiment limited byPSI Experiment limited by STATISTICSSTATISTICS

more more MUONS MUONS needed needed factor > 1000 over PSI – pulsed > 1*10factor > 1000 over PSI – pulsed > 1*1099++/s /s below 28 MeV/c below 28 MeV/c

newnew ACCELERATORS ACCELERATORS J-PARC ?J-PARC ? Neutrino Factory ?Neutrino Factory ? Eurisol ?Eurisol ? GSI ?GSI ? FNAL FNAL . . . . .. . . . .

Old Muonium for Muonium-Antimuonium Conversion ?Old Muonium for Muonium-Antimuonium Conversion ?

• P(M) sin2 [const * (GMM/GF)*t]*exp[-*t]

• Background exp(- n *t) ; n-fold coincidence detection

• For GMM << GF M gains over Background• P(M) / Background t2 * exp[+(n-1)* *t]

Pulsed ACCELERATORPulsed ACCELERATOR

There is not only Muonium SpectroscopyThere is not only Muonium Spectroscopywaiting for a push by Intense Muon Beamswaiting for a push by Intense Muon Beams

Muon Experiments Possible at a CERN Neutrino Factory -Expected Improvements

Muon Physics Possibilities at Muon Physics Possibilities at Any High Power Proton DriverAny High Power Proton Driver i.e. i.e. 4 MW 4 MW

<<<<

Muon Physics Possibilities at Muon Physics Possibilities at Any High Power Proton DriverAny High Power Proton Driver i.e. i.e. 4 MW 4 MW

K Jungmann 18-Apr-2001

J-PARCJ-PARCis one is one

PossibilityPossibility

There are othersThere are others as well:as well:• Neutrino Factory ?Neutrino Factory ?• Muon Collider ?Muon Collider ?• GSI ?GSI ?• … …..

Thank You Vernon for providing us theThank You Vernon for providing us the perhaps most perhaps most

Ideal AtomIdeal Atom

Muonium (M)Muonium (M)