Eur. Phys. J. C (2006) 48: 767-780
https://doi.org/10.1140/epjc/s10052-006-0021-9

Experimental Physics

Precise measurement of Γ(K_S→π⁺π^-(γ))/Γ(K_S→π⁰π⁰) with the KLOE detector at DAΦNE

¹ Institute of High Energy Physics, Academica Sinica, Beijing, China
² Laboratori Nazionali di Frascati dell’INFN, Frascati, Italy
³ Institut für Experimentelle Kernphysik, Universität Karlsruhe, Karlsruhe, Germany
⁴ Dipartimento di Fisica, Università e Sezione INFN, Lecce, Italy
⁵ Institute for Theoretical and Experimental Physics, Moscow, Russia
⁶ Dipartimento di Scienze Fisiche, Università “Federico II” e Sezione INFN, Napoli, Italy
⁷ Dipartimento di Fisica, Università e Sezione INFN, Pisa, Italy
⁸ Dipartimento di Energetica, Università “La Sapienza”, Roma, Italy
⁹ Dipartimento di Fisica, Università “La Sapienza” e Sezione INFN, Roma, Italy
¹⁰ Dipartimento di Fisica, Università “Tor Vergata” e Sezione INFN, Roma, Italy
¹¹ Dipartimento di Fisica, Università “Roma Tre” e Sezione INFN, Roma, Italy
¹² Physics Department, State University of New York, Stony Brook, USA
¹³ Physics Department, University of Virginia, Charlottesville, USA

^* e-mail: matteo.palutan@lnf.infn.it

Received: 14 April 2006
Revised: 28 June 2006
Published online: 24 October 2006

Abstract

Using a sample of over 400 million φ→K_SK_L decays produced during the years 2001 and 2002 at the DAΦNE e⁺e^- collider, the ratio R_S ^π=Γ(K_S→π⁺π^-(γ))/Γ(K_S→π⁰π⁰) has been measured with the KLOE detector. The result is R_S ^π=2.2555±0.0012_stat±0.0021_corr-stat±0.0050_syst, which is in good agreement with the previously published result based on the KLOE data sample from the year 2000. The average of the KLOE results is R_S ^π=2.2549±0.0054, reducing the total error by a factor of three, to 0.25%.