Recent results on B meson oscillations

This paper presents recent time-dependent measurements of neutral $B$\/ meson oscillations. Similar to the $K^{0}$--$\bar{K}^{0}$\/ system, there are two such systems involving the $b$\/ quark: $B_{d}^{0}$--$\bar{B}_{d}^{0}$ and $B_{\mbox{\scriptsize s}}^{0}$--$\bar{B}_{\mbox{\scriptsize s}}^{0}$\/. Thus the physical states are respectively $K_{S}$\/ and $K_{L}$\/, $(B_{d})_{S}$\/ and $(B_{d})_{L}$\/, and $(B_{\mbox{\scriptsize s}})_{S}$\/ and $(B_{\mbox{\scriptsize s}})_{L}$\/. The oscillation between each pair of states can be used to determine their mass difference. The present world average for the $(B_{d})_{S}$--$(B_{d})_{L}$ mass difference is $\Delta m_{d}$\/~=~0.457$\pm$\/0.019 ps$^{-1}$ (or (3.01$\pm$\/0.13)$\times 10^{-4} \: eV$\/). Using $f_{B_{\mbox{\script size s}}}$\/ = 12\% (the fraction of $B_{\mbox{\scriptsize s}}$ produced in $b$\/ events), the current lower limit on the corresponding $\Delta m_{\mbox{\scriptsize s}}$\/ is 6.1 ps$^{-1}$ (or 4.0$\times 10^{-3} \: eV$\/).