  The ratio of the yields of antiprotons to protons in pp collisions has been
measured by the ALICE experiment at $\sqrt{s} = 0.9$ and $7$ TeV during the
initial running periods of the Large Hadron Collider(LHC). The measurement
covers the transverse momentum interval $0.45 < p_{\rm{t}} < 1.05$ GeV/$c$ and
rapidity $|y| < 0.5$. The ratio is measured to be $R_{|y| < 0.5} = 0.957 \pm
0.006 (stat.) \pm 0.014 (syst.)$ at $0.9$ TeV and $R_{|y| < 0.5} = 0.991 \pm
0.005 (stat.) \pm 0.014 (syst.)$ at $7$ TeV and it is independent of both
rapidity and transverse momentum. The results are consistent with the
conventional model of baryon-number transport and set stringent limits on any
additional contributions to baryon-number transfer over very large rapidity
intervals in pp collisions.
