A search for time-integrated $CP$ violation in $D^0 \rightarrow h^{+}h^{-}$ decays and a measurement of the $D^0$ production asymmetry

Preliminary results are presented from time-integrated $D^0 \rightarrow H^{+}h^{-}(h = K, \pi$) studies performed with 37 pb$^{-1}$ of data collected at LHCb in 2010. First, a measurement is made of the difference in time-integrated $CP$ asymmetry, $\Delta A_{CP}$, between $D^0 \rightarrow K^{-} K^{+}$ and $D^0 \rightarrow \pi^{-} \pi^{+}$, yielding $\Delta A_{CP}$ = [-0.28 $\pm$ 0.70 (stat.) $\pm$ 0.25 (sys.)]%. Second, the production asymmetry in $pp$ collisions at $\sqrt{s}$ = 7 TeV of promptly produced $D^0$ mesons, $A_P(D^0)$, is studied as a function of transverse momentum and pseudorapidity. No significant dependence on these variables is observed within the present experimental precision, and a mean value of $A_P(D^0)$ = [-1.08 $\pm$ 0.32 (stat.) $\pm$ 0.12 (sys.)]% is determined within the LHCb acceptance.