ARGUS (1987) measured the ratio of like-sign to opposite-sign dilepton pairs from…

PHYSICS · Multi-part · Fermi University Physics · Particle Physics & Quantum Fields · Flavour, neutrinos and CP violation · Flavour, neutrinos and CP violation

Symmetry and Flavour, Ch B mesons: mixing, time-dependent CP asymmetries and the unitarity triangle

Problem

ARGUS (1987) measured the ratio of like-sign to opposite-sign dilepton pairs from semileptonic B0Bˉ0B^0\bar B^0 pairs produced at the Υ(4S)\Upsilon(4S) to be R=0.21R = 0.21. For a coherent pair this ratio is related to the time-integrated mixing probability χd\chi_d by R=χd/(1−χd)R = \chi_d/(1-\chi_d). ((a)) Find χd\chi_d. ((b)) Find xd=ΔmdτB0x_d = \Delta m_d \tau_{B^0}. ((c)) Using τB0=1.517 ps\tau_{B^0} = 1.517\,\mathrm{ps}, find Δmd\Delta m_d.

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