[SEMINARI]: Dr. Fetscher: Transverse polarisation of the positron from polarized muon decay? A new precision measurement and its implications for the Standard Model

[Arcadi Santamaria]

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                              S E M I N A R I

            [Image]    Departament de Física Teòrica     [Image]
                          Universitat de València
                      46100 Burjassot (València) Spain

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       Transverse polarisation of the positron from polarized muon decay? A
      new precision measurement and its implications for the Standard Model

                                Wulf Fetscher

                                (ETH Zurich)

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                     Aula de Seminaris de Física Teòrica
                   Friday 25 of June of 1999 at 11:00 AM
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                                    Resum

  Is the positron from polarized muon decay really transversely polarised?
     Only slightly in the case of the standard model with its lefthanded
 couplings, but maybe sizeably if additional exotic couplings contribute to
  muon decay. A new experiment at PSI is aiming to measure the two possible
  transverse polarization components P_T1 and P_T2 with a precision of 3 x
  10^-3. The energy dependence of P_T1 yields an improved value for the low
 energy parameter eta that is the limiting quantity in the determination of
the Fermi coupling constant G_F. The measurement of P_T2 is the only test of
  time reversal invariance so far in a purely leptonic interaction. I will
    present the experiment, show the results of our test measurements and
discuss the implications of this experiment for our knowledge of the charged
                             weak interaction.

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