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arXiv · 1212.4524

Precision measurement of $\sigma(e^+e^-\rightarrow\pi^+\pi^-\gamma)/\sigma(e^+e^-\rightarrow \mu^+\mu^-\gamma)$ and determination of the $\pi^+\pi^-$ contribution to the muon anomaly with the KLOE detector

KLOE·KLOE-2 Collaborations·:·D. Babusci·D. Badoni·I. Balwierz-Pytko·G. Bencivenni·C. Bini·C. Bloise·F. Bossi·P. Branchini·A. Budano·L. Caldeira Balkestahl·G. Capon·F. Ceradini·P. Ciambrone·F. Curciarello·E. Czerwinski·E. Dane'·V. De Leo·E. De Lucia·G. De Robertis·A. De Santis·P. De Simone·A. Di Domenico·C. Di Donato·D. Domenici·O. Erriquez·G. Fanizzi·G. Felici·S. Fiore·P. Franzini·P. Gauzzi·G. Giardina·S. Giovannella·F. Gonnella·E. Graziani·F. Happacher·L. Heijkenskjold·B. Hoistad·L. Iafolla·E. Iarocci·M. Jacewicz·T. Johansson·W. Kluge·A. Kupsc·J. Lee-Franzini·F. Loddo·P. Lukin·G. Mandaglio·M. Martemianov·M. Martini·M. Mascolo·R. Messi·S. Miscetti·G. Morello·D. Moricciani·P. Moskal·S. Muller·F. Nguyen·A. Passeri·V. Patera·I. Prado Longhi·A. Ranieri·C. F. Redmer·P. Santangelo·I. Sarra·M. Schioppa·B. Sciascia·M. Silarski·C. Taccini·L. Tortora·G. Venanzoni·R. Versaci·W. Wislicki·M. Wolke·J. Zdebik
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Abstract

We have measured the ratio $\sigma(e^+e^-\rightarrow\pi^+\pi^-\gamma)/\sigma(e^+e^-\rightarrow \mu^+\mu^-\gamma)$, with the KLOE detector at DA$\Phi$NE for a total integrated luminosity of $\sim$ 240 pb$^{-1}$. From this ratio we obtain the cross section $\sigma(e^+e^-\rightarrow\pi^+\pi^-)$. From the cross section we determine the pion form factor $|F_\pi|^2$ and the two-pion contribution to the muon anomaly $a_\mu$ for $0.592<M_{\pi\pi}<0.975$ GeV, $\Delta^{\pi\pi} a_\mu$= $({\rm 385.1\pm1.1_{stat}\pm2.7_{sys+theo}})\times10^{-10}$. This result confirms the current discrepancy between the Standard Model calculation and the experimental measurement of the muon anomaly.

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KLOE, KLOE-2 Collaborations, :, D. Babusci, D. Badoni, I. Balwierz-Pytko, G. Bencivenni, C. Bini, C. Bloise, F. Bossi, P. Branchini, A. Budano, L. Caldeira Balkestahl, G. Capon, F. Ceradini, P. Ciambrone, F. Curciarello, E. Czerwinski, E. Dane', V. De Leo, E. De Lucia, G. De Robertis, A. De Santis, P. De Simone, A. Di Domenico, C. Di Donato, D. Domenici, O. Erriquez, G. Fanizzi, G. Felici, S. Fiore, P. Franzini, P. Gauzzi, G. Giardina, S. Giovannella, F. Gonnella, E. Graziani, F. Happacher, L. Heijkenskjold, B. Hoistad, L. Iafolla, E. Iarocci, M. Jacewicz, T. Johansson, W. Kluge, A. Kupsc, J. Lee-Franzini, F. Loddo, P. Lukin, G. Mandaglio, M. Martemianov, M. Martini, M. Mascolo, R. Messi, S. Miscetti, G. Morello, D. Moricciani, P. Moskal, S. Muller, F. Nguyen, A. Passeri, V. Patera, I. Prado Longhi, A. Ranieri, C. F. Redmer, P. Santangelo, I. Sarra, M. Schioppa, B. Sciascia, M. Silarski, C. Taccini, L. Tortora, G. Venanzoni, R. Versaci, W. Wislicki, M. Wolke, J. Zdebik. 2012-12-18. Precision measurement of $\sigma(e^+e^-\rightarrow\pi^+\pi^-\gamma)/\sigma(e^+e^-\rightarrow \mu^+\mu^-\gamma)$ and determination of the $\pi^+\pi^-$ contribution to the muon anomaly with the KLOE detector. https://doi.org/10.1016/j.physletb.2013.02.029

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