Study of K{sup -}{yields}{pi}{sup 0}e{sup -}{nu}-bar{sub e}{gamma} decay with ISTRA+ setup

Results of study of the K{sup -}{yields}{pi}{sup 0}e{sup -}{nu}-bar{gamma} decay at the ISTRA+ setup are presented. We observed 4476 events of this decay. The branching ratio is found to be R=(Br(K{sup -}{yields}{pi}{sup 0}e{sup -}{nu}-bar{sub e}{gamma}))/(Br(K{sup -}{yields}{pi}{sup 0}e{sup -}{nu}-bar{sub e})) (1.81{+-}0.03(stat.){+-}0.07(syst.)) x 10{sup -2} for E*{sub {gamma}} > 10 MeV and {theta}*{sub e{gamma}} > 10{sup o}. For comparison with the previous experiment the branching ratio with cuts E*{sub {gamma}} > 10 MeV, 0.6 < cos {theta}*{sub e{gamma}} < 0.9 is calculated: R (Br(K{sup -}{yields}{pi}{sup 0}e{sup -}{nu}-bar{sub e}{gamma}))/(Br(K{sup -}{yields}{pi}{sup 0}e{sup -}{nu}-bar{sub e})) (0.47{+-}0.02(stat.) {+-} 0.03(syst.)) x 10{sup -2}. For the cuts E*{sub {gamma}} > 30 MeV and {theta}*{sub e{gamma}} > 20{sup o}, used in most theoretical papers, Br (3.06 {+-} 0.09(stat.) {+-} 0.14(syst.)) x 10{sup -4}. For the asymmetry we get A{sub {xi}} = -0.015 {+-} 0.021. At present it is the best estimate of this asymmetry.