arXiv subjects

Fredrik Borg

Publications and source records attributed to Fredrik Borg.

4 recordsLinked to original sources

arXiv2005

Isospin Breaking in $K\to3π$ Decays III: Bremsstrahlung and Fit to Experiment

We complete here our work on isospin violation in the $K\to3π$ system. We first calculate $K\to2π$ to the same order as we did $K\to3π$ in papers I and II of this series. This adds effects of order $G_{27} p^2 (m_u-m_d)$ and $G_{27} p^2 e^2$ to earlier work. We calculate also the lowest order Bremsstrahlung contributions, $K\to2πγ,3πγ$. With these and our earlier results we perform a full fit to all available CP conserving data in the $K\to2π,3π$ system including isospin violation effects. We perform these fits under various input assumptions as well as test the factorization and the vector dominance model for the weak NLO low energy constants.

hep-ph↗

arXiv2005

Isospin Breaking in $K\to3π$ Decays II: Radiative Corrections

The five different CP conserving amplitudes for the decays $K\to3π$ are calculated using Chiral Perturbation Theory. The calculation is made to next-to-leading order and includes full isospin breaking. The squared amplitudes are compared with the corresponding ones in the isospin limit to estimate the size of the isospin breaking effects. In this paper we add the radiative corrections to the earlier calculated $m_u-m_d$ and local electromagnetic effects. We find corrections of order 5-10 percent.

hep-ph↗

arXiv2004

K -> 3 Pi Decays in Chiral Perturbation Theory

A kaon decaying into three pions is an example of a weak process. However, since the quarks are confined into mesons, the strong interaction also plays an important part. The reaction is a low-energy one, meaning that it takes place in the non-perturbative region of QCD. In that region perturbative QCD doesn't give you any answers and other methods have to be used. The one we use is called Chiral Perturbation Theory.

hep-ph↗

arXiv2004

Isospin Breaking in $K\to3π$ Decays I: Strong Isospin Breaking

The CP conserving amplitudes for the decays $K\to3π$ are calculated in Chiral Perturbation Theory. The calculation is made at the next-to-leading order including strong and local electromagnetic isospin breaking. A comparison is made between the squared amplitudes with and without isospin violation to estimate the size of the effect. We find corrections of order five percent in the amplitudes.

hep-ph↗