Measurement of the inelastic $pp$ cross section at sqrts = 7 TeV

The proton-proton inelastic cross section at $\sqrt{s}=7$~TeV was measured with the CMS detector at the Large Hadron Collider. The analysis was performed using Zero Bias triggered events on data collected in low luminosity LHC runs. The inelastic events were detected and counted requiring an energy deposit in either of the Hadron Forward Calorimeters. Results for the visible inelastic $pp$ cross section, corresponding to events in which at least one proton loses more than a fraction $\xi\sim5\times10^{-6}$ of its total momentum are presented together with the extrapolated value for the total inelastic $pp$ cross section.