TY - JOUR
T1 - Precise measurement of the K±→π±e+e− decay
AU - Batley, J.r.
AU - Lazzeroni, C.
AU - Goudzovski, E.
AU - Winhart, A.
AU - Bifani, S.
AU - Culling, A.j.
AU - Kalmus, G.
AU - Munday, D.j.
AU - Slater, M.w.
AU - Wotton, S.a.
AU - Arcidiacono, R.
AU - Bocquet, G.
AU - Cabibbo, N.
AU - Ceccucci, A.
AU - Cundy, D.
AU - Falaleev, V.
AU - Fidecaro, M.
AU - Gatignon, L.
AU - Gonidec, A.
AU - Kubischta, W.
AU - Norton, A.
AU - Maier, A.
AU - Patel, M.
AU - Peters, A.
AU - Balev, S.
AU - Frabetti, P.l.
AU - Hristov, P.
AU - Kekelidze, V.
AU - Kozhuharov, V.
AU - Litov, L.
AU - Madigozhin, D.
AU - Marinova, E.
AU - Molokanova, N.
AU - Polenkevich, I.
AU - Potrebenikov, Yu.
AU - Stoynev, S.
AU - Zinchenko, A.
AU - Monnier, E.
AU - Swallow, E.
AU - Winston, R.
AU - Rubin, P.
AU - Walker, A.
AU - Baldini, W.
AU - Ramusino, A. Cotta
AU - Dalpiaz, P.
AU - Damiani, C.
AU - Fiorini, M.
AU - Gianoli, A.
AU - Martini, M.
AU - Petrucci, F.
AU - NA48/2 collaboration
PY - 2009/6/29
Y1 - 2009/6/29
N2 - A sample of 7253 K±→π±e+e−(γ) decay candidates with 1.0% background contamination has been collected by the NA48/2 experiment at the CERN SPS, which allowed a precise measurement of the decay properties. The branching ratio in the full kinematic range was measured to be BR=(3.11±0.12)×10−7, where the uncertainty includes also the model dependence. The shape of the form factor W(z), where z=2(Mee/MK), was parameterized according to several models, and, in particular, the slope δ of the linear form factor W(z)=W0(1+δz) was determined to be δ=2.32±0.18. A possible CP violating asymmetry of K+ and K− decay widths was investigated, and a conservative upper limit of 2.1×10−2 at 90% CL was established.
AB - A sample of 7253 K±→π±e+e−(γ) decay candidates with 1.0% background contamination has been collected by the NA48/2 experiment at the CERN SPS, which allowed a precise measurement of the decay properties. The branching ratio in the full kinematic range was measured to be BR=(3.11±0.12)×10−7, where the uncertainty includes also the model dependence. The shape of the form factor W(z), where z=2(Mee/MK), was parameterized according to several models, and, in particular, the slope δ of the linear form factor W(z)=W0(1+δz) was determined to be δ=2.32±0.18. A possible CP violating asymmetry of K+ and K− decay widths was investigated, and a conservative upper limit of 2.1×10−2 at 90% CL was established.
U2 - 10.1016/j.physletb.2009.05.040
DO - 10.1016/j.physletb.2009.05.040
M3 - Article
SN - 0370-2693
VL - 677
SP - 246
EP - 254
JO - Physics Letters B
JF - Physics Letters B
IS - 5
ER -