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Size of isospin breaking in charged \(K_{\ell 4}\) decay

  • A. NehmeEmail author
theoretical physics

Abstract.

We evaluate the size of isospin breaking corrections to form factors f and g of the \(K_{\ell 4}\) decay process \(K^ + \rightarrow\pi^ + \pi^-\ell^ + \nu_{\ell}\) which is actually measured by the extended NA48 setup at CERN. We found that, keeping apart the effect of Coulomb interaction, isospin breaking does not affect the moduli. This is due to the cancellation between corrections of electromagnetic origin and those generated by the difference between up and down quark masses. On the other hand, electromagnetism affects considerably the phases if the infrared divergence is dropped out using a minimal subtraction scheme. Consequently, the greatest care must be taken in the extraction of \(\pi\pi\) phase shifts from experiment.

Keywords

Field Theory Elementary Particle Phase Shift Quantum Field Theory Electromagnetism 
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.

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Copyright information

© Springer-Verlag Berlin/Heidelberg 2005

Authors and Affiliations

  1. 1.Faculty of Sciences, Sections II (Fanar) and V (Nabatieh)Lebanese UniversityLebanon

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