E. Widmann, Antihydrogen GS-HFS, p. 1 LEAP03, Yokohama, March 4, 2003 Measurement of the Hyperfine Structure of Antihydrogen E. Widmann, R.S. Hayano, M. Hori, T. Yamazaki ASACUSA collaboration LEAP03, Yokohama, March 4, 2003 CPT Symmetry and other fundamental symmetries Ground-state hyperfine structure Measurement using atomic beams LOI submitted to AD: SPSC-I-226
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E. Widmann, Antihydrogen GS-HFS, p. 1 LEAP03, Yokohama, March 4, 2003 Measurement of the Hyperfine Structure of Antihydrogen E. Widmann, R.S. Hayano, M.
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E. Widmann, Antihydrogen GS-HFS, p. 1 LEAP03, Yokohama, March 4, 2003
Measurement of the Hyperfine Structure of AntihydrogenE. Widmann, R.S. Hayano, M. Hori, T. Yamazaki
ASACUSA collaboration
LEAP03, Yokohama, March 4, 2003
CPT Symmetry and other fundamental symmetriesGround-state hyperfine structureMeasurement using atomic beams
LOI submitted to AD: SPSC-I-226
E. Widmann, Antihydrogen GS-HFS, p. 2 LEAP03, Yokohama, March 4, 2003
History of Violations of Fundamental Symmetries
Historically it was believed that nature would conserve symmetries of space
Observed symmetry violations in weak interaction
Size and pattern of CPT violation?
Size of effect
Parity violation
1956 Theory: Lee & Young1957 ß-decay Wu et al. π -> µ -> e decay
100 %
CP violation 1964 K0 decays: Kronin and Fitch
2001 B decays: BELLE, BaBar
ε ~2.3 x 10–3
T violation 1998 K0 decays: CPLEAR A ~ 7 x 10–3
E. Widmann, Antihydrogen GS-HFS, p. 3 LEAP03, Yokohama, March 4, 2003
Verifications of CPT Symmetry: Comparison of particle – antiparticle
properties
simple comparison of dimensionless numbers misleading pattern of CPT violation unknown (P: weak interaction, CP: K, B mesons)
E. Widmann, Antihydrogen GS-HFS, p. 4 LEAP03, Yokohama, March 4, 2003
Precision Spectroscopy of Hydrogen and CPT
Sensitivities1S-2S
Electron mass Proton mass proton charge
radius Rp2S-2P
RpGS-HFS
Proton magnetic moment µp
µe Proton magnetic
radius RMTheory
Rp and RM
E. Widmann, Antihydrogen GS-HFS, p. 5 LEAP03, Yokohama, March 4, 2003
Ground-State Hyperfine Structure of (Anti)Hydrogen
One of the most accurately measured quantities in physics hydrogen maser, Ramsey νHF = 1.420405751766(9) GHz
spin-spin interaction positron - antiproton
Leading: Fermi contact term
magnetic moment of pbar only known to 0.3%
Fermi contact term differs from experiment by about 32 ppm
Zeemach corrections magnetic and electric form
factors of (anti)proton
Evaluation for Hydrogen: 3 ppm deviation theory-exp. remains
GS-HFS also contains information on form factors (structure) of (anti)proton!
Zemach
d
LNM
OQPz2
11
2
3
4
2 2Z m p
p
G p G pe E M( ) ( )
E. Widmann, Antihydrogen GS-HFS, p. 6 LEAP03, Yokohama, March 4, 2003
History of Hydrogen HFS Measurements
1936Simple atomic beams ~ 5 %
1947Atomic beams plus 4 x 10–6 discovery of anomalous
microwave resonance magnetic moment of e–
1950 4 x 10–8
1960-70Hydrogen maser 6 x 10–13 not possible for antimatter
N.B. HFS spectroscopy of trapped antihydrogen does not lead to high precision due to the inhomogeneous magnetic field inside the trap
E. Widmann, Antihydrogen GS-HFS, p. 7 LEAP03, Yokohama, March 4, 2003
Layout to measure HFS using atomic beams
Production from trapped antiprotons and positions
atoms “evaporate” from formation region No neutral-atom trap needed !!
use atomic beam method focusing and spin selection by
sextupole magnets spin-flip by microwave
radiation low-background high-efficiency
detection of antihydrogen through annihilation
E. Widmann, Antihydrogen GS-HFS, p. 8 LEAP03, Yokohama, March 4, 2003