Measurement of sigma(e+ e- -> pi+ pi-) from threshold to 0.85 GeV^2 using Initial State Radiation with the KLOE detector
Abstract
We have measured the cross section of the radiative process e+e- -> pi+pi-gamma with the KLOE detector at the Frascati phi-factory DAPHNE, from events taken at a CM energy W=1 GeV. Initial state radiation allows us to obtain the cross section for e+e- -> pi+pi-, the pion form factor |F_pi|^2 and the dipion contribution to the muon magnetic moment anomaly, Delta a_mu^{pipi} = (478.5+-2.0_{stat}+-5.0_{syst}+-4.5_{th}) x 10^{-10} in the range 0.1 < M_{pipi}^2 < 0.85 GeV^2, where the theoretical error includes a SU(3) ChPT estimate of the uncertainty on photon radiation from the final pions. The discrepancy between the Standard Model evaluation of a_mu and the value measured by the Muon g-2 collaboration at BNL is confirmed.
Keywords
Cite
@article{arxiv.1006.5313,
title = {Measurement of sigma(e+ e- -> pi+ pi-) from threshold to 0.85 GeV^2 using Initial State Radiation with the KLOE detector},
author = {KLOE Collaboration and F. Ambrosino and F. Archilli and P. Beltrame and G. Bencivenni and C. Bini and C. Bloise and S. Bocchetta and F. Bossi and P. Branchini and G. Capon and T. Capussela and F. Ceradini and P. Ciambrone and E. De Lucia and A. De Santis and P. De Simone and G. De Zorzi and A. Denig and A. Di Domenico and C. Di Donato and B. Di Micco and M. Dreucci and G. Felici and S. Fiore and P. Franzini and C. Gatti and P. Gauzzi and S. Giovannella and E. Graziani and M. Jacewicz and W. Kluge and J. Lee-Franzini and D. Leone and P. Massarotti and S. Meola and S. Miscetti and S. Müller and F. Murtas and M. Napolitano and F. Nguyen and A. Passeri and V. Patera and P. Santangelo and C. Taccini and L. Tortora and G. Venanzoni and R. Versaci},
journal= {arXiv preprint arXiv:1006.5313},
year = {2011}
}
Comments
17 pages, 11 figures, revised treatment of FSR uncertainty, version to appear on Physics Letters B