Measurement of the inelastic cross section in proton–lead collisions at $\sqrt {s_{NN}}=$ 5.02 TeV

The inelastic hadronic cross section in proton–lead collisions at a centre-of-mass energy per nucleon pair of 5.02 TeV is measured with the CMS detector at the LHC. The data sample, corresponding to an integrated luminosity of L=12.6±0.4 nb−1 , has been collected with an unbiased trigger for inclusive particle production. The cross section is obtained from the measured number of proton–lead collisions with hadronic activity produced in the pseudorapidity ranges 3