Dijet Measurements in pPb collisions

Results on dijet production in pPb collisions at $5.02$ TeV are discussed with a focus on dijet pseudorapidity, $\eta_{\rm{dijet}}$, and centrality classification biases on it. The normalized $\eta_{\rm{dijet}}$ distributions from data and from calculations with CT10 proton parton distribution function (pPDF) and with EPS09 nuclear parton distribution function (nPDF) are compared. Despite the agreement between data and theoretical calculations for an inclusive centrality selection, as the raw transverse energy deposited in the forward calorimeter (forward activity) increases $\eta_{\rm{dijet}}$ distribution shifts towards lead beam direction an amount that is larger than what would be expected from the impact parameter dependence of nPDFs. To understand the driving mechanism of this shift an additional measurement of $\langle\eta_{\rm{dijet}}\rangle $ as a function of forward activity on lead side is carried out in differential bins of forward activity on proton side. The shift is reduced by keeping proton side activity in a narrow interval.