Measurement of B-0 -> pi(+)pi(-)pi(+)pi(-) decays and search for B-0 -> rho(0)rho(0)

Abstract

We report on a search for the decay B-0 -> rho(0)rho(0) and other charmless modes with a pi(+)pi(-)pi(+)pi(-) final state, including B-0 -> rho(0)pi(+)pi(-), nonresonant B-0 -> 4 pi(+/-), B-0 -> rho(0)f(0)(980), B-0 -> f(0)( 980)f(0)(980) and B-0 -> f(0)(980)pi(+)pi(-). These results are obtained from a data sample containing 657 X 10(6) B (B) over bar collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We set an upper limit on B(B-0 -> rho(0)rho(0)) of 1.0 X 10(-6) at the 90% confidence level (C. L.). From our B-0 -> rho(0)rho(0) measurement and an isospin analysis, we determine the Cabibbo-Kobayashi-Maskawa phase phi(2) to be 91.7 +/- 14.9 degrees. We find excesses in B-0 -> rho(0)pi(+)pi(-) and nonresonant B-0 -> 4 pi(+/-) with 1.3 sigma and 2.5 sigma significance, respectively. The corresponding branching fractions are less than 12.0 X 10(-6) and 19.3 X 10(-6) at the 90% C.L. In addition, we set 90% C.L. upper limits as follows: B(B-0 -> rho(0)f(0)(980)) < 0.3 X 10(-6), B(B-0 -> f(0)(980)f(0)(980)) < 0.1 X 10(-6), and B(B-0 -> f(0)(980)pi(+)pi(-)) < 3.8 X 10(-6).