Reference pp cross-sections for $\Upsilon(1S)$ studies in proton-lead collisions at $\sqrt{s_{NN}} = 5.02$ TeV and comparisons between ALICE and LHCb results

The ALICE and LHCb collaborations have studied $\Upsilon$ (1$S$) production at large rapidities in proton-lead collisions at $\sqrt{s_{NN}} = 5.02$ TeV at the LHC using di-muon fi nal states. The evaluation of cold nuclear matter effects requires the knowledge of the corresponding $\Upsilon$ (1$S$) production cross section in $pp$ collisions at the same centre-of-mass energy and in the same kinematic range. In this note the interpolation procedures used to determine this quantity and the related consistency checks are described. Finally, the results from the two experiments on nuclear modi fication factors are briefly summarized and found to be in good agreement.