LAUSR

Abstract A new experimental technique to study the decays of $$ {B}_s^0 $$ B s 0 mesons into final states involving unreconstructable particles is proposed. The method uses a characteristic feature of fast flavour oscillations of $$ {B}_s^0 $$ B s 0 mesons. Analysis of the oscillation-frequency spectrum of partially reconstructed flavour-tagged $$ {B}_s^0 $$ B s 0 decays provides information about the mass spectrum of unreconstructed decay products and suppresses any background that does not come from the decays of $$ {B}_s^0 $$ B s 0 mesons.