Download or read book Observation of the Decay B0-]rho+rho- and Measurement of the Branching Fraction and Polarization written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We have observed the rare decay B[sup 0] [yields] [rho][sup +][rho][sup -] in a sample of 89 million B[bar B] pairs recorded with the BABAR detector. We measure the branching fraction [Beta](B[sup 0] [yields] [rho][sup +][rho][sup -]) = (27[sub -6-7][sup +7+5]) x 10[sup -6] and determine the longitudinal polarization fraction [Lambda][sub L]/[Lambda] = 0.99[sub -0.07][sup +0.01] [+-] 0.03. The results are preliminary.