A fascinating feature of quantum mechanics, in which the B0s, B0 and D0 particles turn into their antimatter partners and back, has been discussed already few times at this page, see 3 March 2013 and 7 November 2012 news. This feature is called oscillations or mixing. The B0s mesons oscillate with by far the highest frequency of about 3 million million times per second (3*1012), on average about 9 times during their lifetime. The B0 mesons oscillate about 37 times slower with a frequency of about 80 thousand million times per second (8*1010). A musical tone is defined by its frequency. LHCb physicists tried to hear this beautiful (involving beauty quarks) matter-antimatter quantum music.
The left video image above shows the last stage of the event filtering process. Two accumulations of events are clearly visible allowing to select the B0 and B0s particles. As the blue box moves through the image we are able to hear the background noise, then the loud tone of B0-B0 oscillations, the background noise again and then the tone of the B0s-B0s oscillations. The higher frequency B0s-B0s oscillations are experimentally more difficult to observe and therefore their tone is weaker. The very high-pitched quantum oscillation frequencies were reduced by millions of times in order to fit into the range that can be heard by humans. Additional explanations can be found in the right hand side video above.