Advertisement

Il Nuovo Cimento (1955-1965)

, Volume 27, Issue 6, pp 1352–1358 | Cite as

Measurement ofg/m for muons

  • G. McD Bingham
Article

Summary

A free running «muon stroboscope» was used to measure the ratio of the precession frequencies of muons (f) and protons in water (fp) for the same magnetic field. The stroboscope frequency was 200 MHz. The results obtained were: positive muons stopping in bromo-form (f/fp)+=3.18336±0.00007, negative muons stopping in water (f/fp)\((f/f_p )_{H_2 O}^ - = 3.1808 \pm 0.0004\). The first ratio is assumed to be also that of the free particles and leads to the following values for (g/m+ andm+: (g/m)+=(9.6840±0.0002)·10−3me−1,m+=(206.766±0.005)me whereme is the electron mass. A diamagnetic correction is applied to the second ratio and an equivalent value\((g/m)_{H_2 O}^ - \) is obtained for negative muons stopping in water:\((g/m)_{H_2 O}^ - = (9.6760 \pm 0.0013) \cdot 10^{ - 3} \)me−1. Assuming equal masses for positive and negative muons we obtain: (g(H2O)=g+)/g+==−(8.3±1.4)·10−4. The present experiment is in quite reasonable agreement with the recent Columbia experiment ofHutchinsonet al. From the combined results of both experiments we havem+=(206.765±0.002)me (12 p.p.m.) and (g(H2O)−g+)/g+=−(8.9±0.8)·10−4.

Riassunto

Si è usato uno «stroboscopio di muoni» liberamente rotante per misurare le frequenze di precessione dei muoni (f) e dei protoni (fp) in acqua per campi magnetici uguali. La frequenza dello stroboscopio era di 200 MHz. Si sono ottenuti i seguenti risultati: muoni positivi fermati in bromoformio (f/fp)+=3.18336±0.00007, muoni negative fermati in acqua (f/fp)\((f/f_p )_{H_2 O}^ - = 3.1808 \pm 0.0004\). Si ammette che il primo rapporto sia anche quello delle particelle libere, che porta ai seguenti valori per (g/m)+ em+: (g/m)+=(9.6840±0.0002)·10−3m e −1 ),mτ=(206.766±0.005)me in cuime è la massa dell ’elettrone. Si applica una correzione diamagnetica al secondo rapporto e si ottiene un valore equivalente\((g/m)_{H_2 O}^ - \) per muoni negativi fermati in acqua:\((g/m)_{H_2 O}^ - = (9.6760 \pm 0.0013) \cdot 10^{ - 3} \)m e −1 . Supponendo che i muoni positivi e negativi abbiano masse uguali, si ottiene (g(H2O)−g+)/g+=−(8.3±1.4)·10−4. Questo esperimento si accorda in modo abbastanza ragionevole con il recente esperimento diHutchinsonet al. alla Columbia University. Combinando i risultati di questi due esperimenti si ham+=(206.765±0.002)me (12 p.p.m.) e (g(H2O)−g+)/g+=−(8.9±0.8)·10−4.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. (1).
    R. L. Garwin, D. P. Hutchinson, S. Penman andG. Shapiro:Phys. Rev.,118, 271 (1960).ADSCrossRefGoogle Scholar
  2. (2).
    D. P. Hutchinson, J. Menes, G. Shapiro, A. M. Patlach andS. Penman:Phys. Rev. Lett.,7, 129 (1961);D. P. Hutchinson:A Precise Determination of the Magnetic Moment of the Positive Muon, Nevis-103 (March 1962).ADSCrossRefGoogle Scholar
  3. (3).
    J. A. Pople, W. G. Schneider andH. J. Bernstein:High-Resolution Nuclear Magnetic Resonance (New York, 1959), pp. 279, 443.Google Scholar
  4. (4).
    J. W. M. DuMond:Ann. Phys.,7, 365 (1959).ADSCrossRefGoogle Scholar
  5. (5).
    A. A. Schupp, R. W. Pidd andH. R. Crane:Phys. Rev.,121, 1 (1961).ADSCrossRefGoogle Scholar
  6. (6).
    M. Schiff:Nuovo Cimento,22, 66 (1961).CrossRefMATHGoogle Scholar
  7. (7).
    K. W. Ford, V. W. Hughes andJ. G. Wells:Phys. Rev. Lett.,7, 135 (1961).ADSCrossRefGoogle Scholar
  8. (8).
    G. Charpak, R. J. M. Farley, R. L. Garwin, T. Muller, J. C. Sens andA. Zichichi:Phys. Lett.,1, 16 (1962).ADSCrossRefGoogle Scholar

Copyright information

© Società Italiana di Fisica 1963

Authors and Affiliations

  • G. McD Bingham
    • 1
  1. 1.Lawrence Radiation LaboratoryUniversity of CaliforniaBerkeley

Personalised recommendations