Measurements of CP-Violating Asymmetries in B0 to a1+-(1260) pi-+ Decays

The authors present measurements of CP-violating asymmetries in the decays B{sup 0} {yields} a{sub 1}{sup {+-}}(1260){pi}{sup {-+}} with a{sub 1}{sup {+-}}(1260) {yields} {pi}{sup {-+}}{pi}{sup {+-}}{pi}{sup {+-}}. The data sample corresponds to 384 x 10{sup 6} B{bar B} pairs collected with the BABAR detector at the PEP-II asymmetric B-factory at SLAC. They measure the time- and flavor-integrated charge asymmetry A{sub CP}{sup 1{sub 1}{+-}} = -0.07 {+-} 0.07 {+-} 0.02, the mixing-induced CP violation parameter S{sub a{sub 1}{pi}} = 0.37 {+-} 0.21 {+-} 0.07, the direct CP violation parameter C{sub a{sub 1}{pi}} = -0.10 {+-} 0.15 {+-} 0.09, and the parameter {Delta}C{sub a{sub 1}{pi}} = 0.26 {+-} 0.15 {+-} 0.07 and {Delta}S{sub a{sub 1}{pi}} = -0.14 {+-} 0.21 {+-} 0.06. From these measured quantities they extract the angle {alpha}{sub eff} = 78.6{sup o} {+-} 7.3{sup o}.