PT Journal AU LHCb Collaboration (Aaij, Rea Jashal, BK Martinez-Vidal, F Oyanguren, A Remon Alepuz, C Ruiz Vidal, J Sanderswood, I TI Nuclear Modification Factor of Neutral Pions in the Forward and Backward Regions in p-Pb Collisions SO Physical Review Letters JI Phys. Rev. Lett. PY 2023 BP 042302 EP 12pp VL 131 IS 4 DI 10.1103/PhysRevLett.131.042302 LA English AB The nuclear modification factor of neutral pions is measured in proton-lead collisions collected at a center-of-mass energy per nucleon of 8.16 TeV with the LHCb detector. The p(0) production cross section is measured differentially in transverse momentum (p(T)) for 1.5 < p(T) < 10.0 GeV and in center-of-mass pseudorapidity (?(c.m.)) regions 2.5 < ?(c.m.) < 3.5 (forward) and -4.0 < ?(c.m.) < -3.0 (backward) defined relative to the proton beam direction. The forward measurement shows a sizable suppression of p(0) production, while the backward measurement shows the first evidence of p(0) enhancement in proton-lead collisions at the LHC. Together, these measurements provide precise constraints on models of nuclear structure and particle production in high-energy nuclear collisions. ER