Measurement of the centrality dependence of the dijet yield in $p$+Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 8.16 TeV with the ATLAS detector

ATLAS has measured the dijet per-event yield for anti-$k_t$ $R$ = 0.4 jets at center-of-mass energy $\sqrt{s_{\mathrm{NN}}}$ = 8.16 TeV in $p$+Pb collisions. The measurement was performed using 165 nb$^{-1}$ of $p$+Pb data collected in 2016. This note presents the per-event yield of dijets in terms of kinematic variables that allow for full characterization of the partonic scattering system, i.e. the average $p_{\text{T}}$ of the dijet, $p_{\text{T,Avg}}$ = ($p_{\text{T},1}+p_{\text{T},2}$)$/2$, the boost of the dijet system, $y_{\text{b}}$ = $(y_{1}^{\text{CM}}+y_{2}^{\text{CM}})/2$, and the half rapidity separation between the jets, $y^{*}$ = $|y_{1}^{\text{CM}}-y_{2}^{\text{CM}}|/2$. The central-to-peripheral ratio of the dijet per-event yield in central and peripheral $p$+Pb collisions, $R_\mathrm{CP}$, is constructed.The $R_\mathrm{CP}$ shows a clear dependence on the Bjorken-$x$ of the parton extracted from the proton in the hard-scattering while no clear trend is observed when displaying the results as a function of the $x$ of the parton extracted from the lead nucleus. These results will help the understanding of the effects introduced by the initial state kinematics on dijet production in $p$+Pb collisions.