The weak interaction studied in traps

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The weak interaction studied in traps

• introduction to the weak interaction
• ?-decay
• from inclusive to exclusive measurements
• the weak charge
• parity non-conserving (PNC) transitions
• the electric dipole moment
• time reversal violation (TRV)
• the importance of traps

Hans Wilschut KVI Groningen (NL)
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Leptons and weak bosonslow energy interactions
The leptons (e-, ?e) (e, ?e) (?-,
??) (?, ??) (?-, ??)
(?, ??)
The bosons W,W-,Z0
Now ! ?e? ??
??
?-
e-
?e
W
Z0
??
??
e-
e-
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Putting in the quarkslow energy interactions
The quarks (u, d) (s, c)
(t, b)
APAC only light quarks
Vud ? Vus
p ? n
q-change
dud
?e
?e
d(-1/3)
n
W
W
e-
u(2/3)
e-
uud
generation change
PNC
?e
s(-1/3)
e-
n
W
Z0
n
e-
u(2/3)
e-
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?-decay charged currents
Initial and final state of nucleus let you steer
the detail of decay Fermi transitions 0? 0
?

N N e,?
?

Gamow-Teller 1? 0
The Nucleus as micro laboratory
Decay probability ? (phase space) (nuclear
structure) (weak interact)
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Structure of the weak interaction
Of all possible interactions only few are allowed
characterization by the Dirac matrices involved
Structure is V - A left handed
interaction beyond right handedness new
bosons more Higgss or.. S, P or T
Scalar Pseudo Scalar Vector (GV) Axial Vector
(GA) Tensor
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Inclusive observable1 decay rate
Decay probability ? (phase space) (nuclear
structure) (weak interact)
super-allowed fermi decay ignore nuclear
structure (almost) integrate phase
space ? Q5

• Vud 0.9740 ? 0.0005
• i Vui2 0.9968 ? 0.0014
• New candidates 62Ga,66As,70Br,74Rb
• need accurate Q..Penning trap!

Z of daugther
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Exclusive measurements
integrate over all spin variables only a and b
remain
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Measurement strategies
exclusive electron-neutrino correlation electron
-recoil correlation inclusive electron
distribution recoil distribution recoil direct
TRAPS indirect recoil messenger
How does it work?
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Inclusive observables2 Recoil distribution
Impact of ?-? on recoil Fermi Gamow-Teller
Recoil
e ?
e
Recoil
?
Vector
Scalar
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Best measurement for aF
Adelberger et al. PRL83(99)1299 32Ar ? 32Cl e
? 32Cl ? 31S p
aF0.9989(52)(39)
107 cts
S
V
exp
line shape
Higher order corrections folded in not
measured Direct measurement for 6He aGT
?0.3343(30) New measurements U. Leuven _at_ ISOLDE
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Correlation experiments
Setup at TRIUMF (Behr et al.) for 38mK (t1/20.93
s 0 ? 0)
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Current value aF0.992(8)(5) improved
statistics? ? (3)(3) current limitation ?
response
other attempts aGT 6He at LPC/GANIL with Paul
trap
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Correlation experiments spin degrees of freedom
? ltJgt vs ? A Wu
experiment Vieira et al. (LANL) 82Rb (t1/275
s 1? 0, (2) ) (SM A ?1) Behr et al. 37K
(t1/21.23 s 3/2? 3/2, (5/2)) (SM A
structure dependent) add recoil measurement TRV
(D)
TRI?P
Na LBL(Freedman) Li Japan
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The weak interaction neutral currents
(N,Z)
(N,Z)
?,Z0
e-
e-
However, Vem ? Qe spin . VPV ? QW
anapole .
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How to measure PNC?
It is too weak to measure directly mix with
normal transition
Make AW large AW?Z?3 and A em small (not too
small) Cs experiments 6S1/2 ?7S1/2 Use Stark
effect for A em
Best result from Boulder experiment QW ?72.1 ?
0.3 ? 0.9 theory ?73.20 ? 0.13
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How to measure PNC?
It is to weak to measure directly mix with
normal transition
F4
F4
F4
7S1/2
7S1/2
7S1/2
F3
F3
F3
6P3/2
6P3/2
6P3/2
F4
F4
F4
6S1/2
6S1/2
6S1/2
F3
F3
F3
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The Bouchiats program for the future

• Other experiments in reliable atoms
• radioactive Fr program at Stony Brook
• and started at Legnaro
• single Ba Paul trap (laser cooled) Seattle
• Spin dependent PNC
• anapole (133Cs done)
• Isotope dependence
• QW ? N there are more radioactive
• isotopes than stable ones
• Other
• molecules enatiomers

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Time reversal violation and EDM
TRV is possible in the SM__ CP or T violation in
K0? K0
Vdx
d u,c,t
s
__ K0
K0
W?
W?
_ _ _ _
_ s u,c,t
d
immeasurably small otherwise extensions SM have
much larger EDM EDM tool for theory selection
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Washington Seattle
de lt 8.7 10-28 e cm
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EDM activities
Any object will do consider method ? guidance by
theory

• point particles e,?,?
• nucleons n
• nuclei Tl, Hg

new ideas Storage rings (APAC99) Ra,Ra
(atomic, nuclear enhancements)
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Summary and outlook
?-decay
condensates
Atomic moments Electric dipole
Nuclear structure ?- and ?-decay
Atomic structure chemistry
Nuclear moments
very rare isotope detection
NIPNET HITRAP BETANET Gascatcher
EXOTRAP EUROTRAP
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Why traps?
Maximal experimental control
TRI?P