Studies of dijet transverse momentum balance and pseudorapidity distributions in pPb collisions at $$\sqrt{s_{\mathrm{NN}}} = 5.02$$ s NN = 5.02 $$\,\text {TeV}$$ TeV

Abstract

Dijet production has been measured in $$\mathrm {p}\mathrm {Pb}$$ collisions at a nucleon–nucleon centre-of-mass energy of 5.02 $$\,\text {TeV}$$ . A data sample corresponding to an integrated luminosity of 35 $${{\,\text {nb}^{{-1}}}} $$ was collected using the Compact Muon Solenoid detector at the Large Hadron Collider. The dijet transverse momentum balance, azimuthal angle correlations, and pseudorapidity distributions are studied as a function of the transverse energy in the forward calorimeters ( $$E_\mathrm {T}^{4<|\eta |<\mathrm {5.2}} $$ ). For $$\mathrm {p}\mathrm {Pb}$$ collisions, the dijet transverse momentum ratio and the width of the distribution of dijet azimuthal angle difference are comparable to the same quantities obtained from a simulated $$\mathrm {p}\mathrm {p}$$ reference and insensitive to $$E_\mathrm {T}^{4<|\eta |<\mathrm {5.2}} $$ . In contrast, the mean value of the dijet pseudorapidity is found to change monotonically with increasing $$E_\mathrm {T}^{4<|\eta |<\mathrm {5.2}} $$ , indicating a correlation between the energy emitted at large pseudorapidity and the longitudinal motion of the dijet frame. The pseudorapidity distribution of the dijet system in minimum bias $$\mathrm {p}\mathrm {Pb}$$ collisions is compared with next-to-leading-order perturbative QCD predictions obtained from both nucleon and nuclear parton distribution functions, and the data more closely match the latter.