Physics – Nuclear Physics – Nuclear Theory
Scientific paper
1997-09-29
Phys.Rev. D58 (1998) 014008
Physics
Nuclear Physics
Nuclear Theory
minor changes to introduction, section 2. In Press Phys. Rev. D
Scientific paper
10.1103/PhysRevD.58.014008
We investigate the problem of the extraction of the isovector and isoscalar spectral functions from data on $e^+e^-\to hadrons$, in the presence of non-zero isospin breaking. It is shown that the conventional approach to extracting the isovector spectral function in the $\rho$ resonance region, in which only the isoscalar contribution associated with $\omega\to \pi\pi$ is subtracted, fails to fully remove the effects of the isoscalar component of the electromagnetic current. The additional subtractions required to extract the pure isovector and isoscalar spectral functions are estimated using results from QCD sum rules. It is shown that the corrections are small ($\sim 2%$) in the isovector case (though relevant to precision tests of CVC), but very large ($\sim 20%$) in the case of the $\omega$ contribution to the isoscalar spectral function. The reason such a large effect is natural in the isoscalar channel is explained, and implications for other applications, such as the extraction of the sixth order chiral low-energy constant, $Q$, are discussed.
No associations
LandOfFree
Isospin Breaking Effects in the Extraction of Isoscalar and Isovector Spectral Functions From $e^+e^-\to hadrons$ does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Isospin Breaking Effects in the Extraction of Isoscalar and Isovector Spectral Functions From $e^+e^-\to hadrons$, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Isospin Breaking Effects in the Extraction of Isoscalar and Isovector Spectral Functions From $e^+e^-\to hadrons$ will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-487139