Search for neutral charmless B decays at LEP L3 Collaboration

A search for rare charmless decays of Bd 0 and Bs 0 mesons has been performed in the exclusive channels Bd(s) 0��Ǧ�, Bd(s) 0��Ǧ�0 and Bd(s) 0 �� ��0��0. The data sample consisted of three million hadronic Z decays collected by the L3 experiment at LEP from 1991 through 1994. No candidate event has been observed and the following upper limits at 90% confidence level on the branching ratios have been set: Br(Bd 0��Ǧ�) < 4.1 �� 10-4, Br(Bs 0 �� �Ǧ�) < 1.5 �� 10-3, Br(Bd 0��Ǧ�0) < 2.5 �� 10-4, Br(Bg 0��Ǧ�0) < 1.0 �� 10-3, Br(Bd 0���0��0) < 6.0 �� 10-5, Br(Bs 0���0��0) < 2.1 �� 10-4. These are the first experimental limits on Bd 0��Ǧ� and on the Bd 0 neutral charmless modes.