Analytical dispersive construction of eta -> 3 pi amplitude: First order in isospin breaking

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Analytical dispersive construction of eta -> 3 pi amplitude: First order in isospin breaking. / Kampf, Karol; Knecht, Marc; Novotny, Jiri; Zdrahal, Martin.

I: Physical Review D (Particles, Fields, Gravitation and Cosmology), Vol. 84, Nr. 11, 114015, 2011.

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskrift

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TY - JOUR

T1 - Analytical dispersive construction of eta -> 3 pi amplitude: First order in isospin breaking

AU - Kampf, Karol

AU - Knecht, Marc

AU - Novotny, Jiri

AU - Zdrahal, Martin

PY - 2011

Y1 - 2011

N2 - Because of their small electromagnetic corrections, the isospin-breaking decays n -> 3 pi seem to be good candidates for extracting isospin-breaking parameters similar to(m(d) - m(u)). This task is unfortunately complicated by large chiral corrections and the discrepancy between the experimentally measured values of the Dalitz parameters describing the energy dependence of the amplitudes of these decays and those predicted from chiral perturbation theory. We present two methods based on an analytic dispersive representation that use the information from the NNLO chiral result and the one from the measurement of the charged n -> 3 pi decay by KLOE together in a harmonized way in order to determine the value of the quark mass ratio R. Our final result is R = 37.7 +/- 2.2. This value supplemented by values of m(s)/(m) over cap or even (m) over cap and m(s) from other methods (as sum-rules or lattice) enables us to obtain further quark mass characteristics. For instance the recent lattice value for m(s)/(m) over cap similar to 27: 5 leads to Q = 23.1 +/- 0.7. We also quote the corresponding values of the current masses m(u) and m(d).

AB - Because of their small electromagnetic corrections, the isospin-breaking decays n -> 3 pi seem to be good candidates for extracting isospin-breaking parameters similar to(m(d) - m(u)). This task is unfortunately complicated by large chiral corrections and the discrepancy between the experimentally measured values of the Dalitz parameters describing the energy dependence of the amplitudes of these decays and those predicted from chiral perturbation theory. We present two methods based on an analytic dispersive representation that use the information from the NNLO chiral result and the one from the measurement of the charged n -> 3 pi decay by KLOE together in a harmonized way in order to determine the value of the quark mass ratio R. Our final result is R = 37.7 +/- 2.2. This value supplemented by values of m(s)/(m) over cap or even (m) over cap and m(s) from other methods (as sum-rules or lattice) enables us to obtain further quark mass characteristics. For instance the recent lattice value for m(s)/(m) over cap similar to 27: 5 leads to Q = 23.1 +/- 0.7. We also quote the corresponding values of the current masses m(u) and m(d).

U2 - 10.1103/PhysRevD.84.114015

DO - 10.1103/PhysRevD.84.114015

M3 - Article

VL - 84

JO - Physical Review D - Particles, Fields, Gravitation and Cosmology

JF - Physical Review D - Particles, Fields, Gravitation and Cosmology

SN - 1550-2368

IS - 11

M1 - 114015

ER -