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Il Nuovo Cimento A (1965-1970)

, Volume 57, Issue 4, pp 678–688 | Cite as

Relativistic invariance without angular-momentum conservation

  • F. Selleri
Article

Summary

We show that, contrary to a rather widespread belief, relativistic invariance does not necessarily lead to angular-momentum conservation. Noticing that there is no empirical evidence for such a conservation in weak interactions, we show that a new classification of strange particles is possible in which the K-meson has spin 1/2, the Λ and ∑ have spin 1 and the Ξ has spin 3/2. Our scheme can be proved or disproved with simple experiments.

Keywords

Weak Interaction Relativistic Invariance Usual Scheme Traditional Scheme Strange Particle 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Релятивистская инвариантность без сохранения момента

Резюме

Мы показыбваем, что, в противоложность довольно широко распространенному мнению, релятивистская инвариантность не приводит с неиз-бежностью к сохранению момента. Отмечая, что не сушествует эмпирического подтверждения для такого сохранения в слабых взаимодействиях, мы показываем, что возможна новая классификация странных частиц, в которой К-мезон имеет спин 1/2, Λ и ∑ имеют спин 1 и Ξ имеет спин 3/2. Нашза схема может быть доказана или опровергнута посредством простых экспериментов.

Riassunto

Contrariamente ad una generale opinione la invarianza relativistica non porta necessariamente alla conservazione del momento angolare. Osserviamo che non c'è evidenza empirica per tale legge conservativa nelle interazioni deboli e mostriamo che è possibile dare una nuova elassificazione delle particelle strane in cui il mesone K ha spin 1/2, la Λ e la ∑ hanno spin 1 e la Ξ ha spin 3/2. Il nostro schema può essere controllato con esperimenti assai semplici, almeno concettualmente.

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References

  1. (1).
    Y. Nambu andE. Shrauner:Phys. Rev.,128, 862 (1962).ADSCrossRefGoogle Scholar
  2. (2).
    The Λ and ∑ hyperons are not assumed as spinless because there is conclusive evidence that their magnetic moments are different from zero.Google Scholar
  3. (3).
    No really conclusive evidence for violations of the ΔT=1/2 rule seems in fact to exist. See ref. (8)W. J. Willis:Proceedings of the Heidelberg International Conference on Elementary Particles (Amsterdam, 1968). p. 273. (8) below.Google Scholar
  4. (4).
    We are well aware of the fact that a rotation of the axes leads to a rotatedJ. but to a fixedT. which seems to imply that no sense whatsoever can be attributed to the sumT+J. Nevertheless we think that some sense can be given to such an addition of spin and isotopic spin, for instance by thinking that in every particle there are two associated spins and that the «third component of isospin» is the projection of one spin on the other. In this way both vectors would be rotated while the «third component of isospin» would remain fixed.Google Scholar
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    E. Malamud andP. E. Schlein:Phys. Rev. Lett.,19, 1056 (1967).ADSCrossRefGoogle Scholar
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    S. Bennett, D. Nygren, H. Saal, J. Steinberger andJ. Sunderland:Phys. Rev. Lett.,19, 997 (1967).ADSCrossRefGoogle Scholar
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    N. N. Biswas, N. M. Cason, P. B. Johnson, V. P. Kenney, J. A. Poirier andW. D. Shepared: University of Notre Dame, preprint.Google Scholar
  8. (8).
    E.g. see:W. J. Willis:Proceedings of the Heidelberg International Conference on Elementary Particles (Amsterdam, 1968), p. 273.Google Scholar
  9. (9).
    The K → πγ decay would however be possible in this case.Google Scholar
  10. (10).
    See, for instance,M. Gell-Mann andA. Rosenfeld:Ann. Rev. Nucl. Sci.,7, 407 (1957).ADSCrossRefGoogle Scholar
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    A. M. L. Messiah andO. W. Greenberg:Phys. Rev.,136, B 248 (1964).ADSMathSciNetCrossRefGoogle Scholar

Copyright information

© Società Italiana di Fisica 1968

Authors and Affiliations

  • F. Selleri
    • 1
    • 2
  1. 1.Istituto di Fisica dell' UniversitàBari
  2. 2.Istituto Nazionale di Fisica NucleareSottosezione di BariBariItaly

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