[He, Y.;Wei, W.;Luo, T.;Wang, X. -N.] Cent China Normal Univ, Key Lab Quark & Lepton Phys MOE, Wuhan 430079, Hubei, Peoples R China.^[He, Y.;Wei, W.;Luo, T.;Wang, X. -N.] Cent China Normal Univ, Inst Particle Phys, Wuhan 430079, Hubei, Peoples R China.^[Cao, S.] Wayne State Univ, Dept Phys & Astron, Detroit, MI 48201 USA.^[Pang, L. -G.;Wang, X. -N.] Univ Calif Berkeley, Phys Dept, Berkeley, CA 94720 USA.^[Pang, L. -G.;Wang, X. -N.] Lawrence Berkeley Natl Lab, Nucl Sci Div, Mailstop 70R0319, Berkeley, CA 94740 USA.