## Abstract

We study the decays $K\to\pi\pi$ in one-loop

two-flavour Chiral Perturbation Theory.

We provide arguments why the calculation of the coefficient of the

pionic chiral logarithm

$\logm = M^2\log M^2$

is unique and then perform the calculation. As a check we perform the

reduction of the known three-flavour result.

Our result can be used to perform the extrapolation to the physical

pion mass of direct lattice QCD calculations of $K\to\pi\pi$

at fixed $m_s$ or $m_K^2$.

The underlying arguments

are expected to be valid for heavier particles and other processes as well.

two-flavour Chiral Perturbation Theory.

We provide arguments why the calculation of the coefficient of the

pionic chiral logarithm

$\logm = M^2\log M^2$

is unique and then perform the calculation. As a check we perform the

reduction of the known three-flavour result.

Our result can be used to perform the extrapolation to the physical

pion mass of direct lattice QCD calculations of $K\to\pi\pi$

at fixed $m_s$ or $m_K^2$.

The underlying arguments

are expected to be valid for heavier particles and other processes as well.

Original language | English |
---|---|

Pages (from-to) | 466-470 |

Journal | Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics |

Volume | 680 |

Issue number | 5 |

DOIs | |

Publication status | Published - 2009 |

## Subject classification (UKÄ)

- Subatomic Physics

## Keywords

- 11.30.Rd Chiral symmetries
- 12.39.Fe Chiral Lagrangians
- 13.20.Eb Decays of K mesons