Measurement of theB0Production Cross Section inppCollisions ats=7TeV

Measurements of the differential production cross sections $d\sigma /d{p}_T^B$ and $d\sigma /d{y}^B$ for $B^0$ mesons produced in $pp$ collisions at $\sqrt{s}=7\mathrm{TeV}$ are presented. The data set used was collected by the CMS experiment at the LHC and corresponds to an integrated luminosity of $40{\mathrm{pb}}^{-1}$. The production cross section is measured from $B^0$ meson decays reconstructed in the exclusive final state $J/\psi K_S^0$, with the subsequent decays $J/\psi \to {\mu }^{+}{\mu }^{-}$ and $K_S^0\to {\pi }^{+}{\pi }^{-}$. The total cross section for $p_T^B>5\mathrm{GeV}$ and $|y^B|<2.2$ is measured to be $33.2\pm 2.5\pm 3.5\mu \mathrm{b}$, where the first uncertainty is statistical and the second is systematic.