Upper limit on the η→π+π− branching ratio with the KLOE detector

We have searched with the KLOE detector for the P and CP violating decay eta --> pi(+)pi(-) in a sample of 1.55 x 10(7) eta's from the decay phi --> etagamma of phi-mesons produced in e(+)e(-) annihilations at DAPhiNE. No signal is found. We obtain the upper limit BR(eta --> pi(+)pi(-)) < 1.3 x 10(-5) at 90% confidence level. (C) 2004 Elsevier B.V. All rights reserved.