Relativistic diffusion model for hadron production in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>p</mml:mi></mml:math>-Pb collisions at energies available at the CERN Large Hadron Collider

We investigate charged-hadron production in relativistic heavy-ion collisions of asymmetric systems within a nonequilibrium-statistical framework. Calculated centrality-dependent pseudorapidity distributions for p-Pb collisions at <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:msqrt><a:msub><a:mi>s</a:mi><a:mtext>NN</a:mtext></a:msub></a:msqrt><a:mo>=</a:mo><a:mn>5.02</a:mn></a:mrow></a:math> and 8.16 TeV are compared with data from the Large Hadron Collider. Our approach combines a relativistic diffusion model with formulations based on quantum chromodynamics while utilizing numerical solutions of a Fokker-Planck equation to account for the shift and broadening of the fragmentation sources for particle-production with respect to the stopping (net-baryon) rapidity distributions. To represent the centrality dependence of charged-hadron production in asymmetric systems over a broad region of pseudorapidities, the consideration and precise modeling of the fragmentation sources, along with the central gluon-gluon source, is found to be essential. Specifically, this results in an inversion of the particle-production amplitude from backward to forward dominance when transitioning from central to peripheral collisions, in agreement with recent ATLAS and ALICE p-Pb data at <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:mrow><b:msqrt><b:msub><b:mi>s</b:mi><b:mtext>NN</b:mtext></b:msub></b:msqrt><b:mo>=</b:mo><b:mn>5.02</b:mn><b:mspace width="0.16em"/><b:mi mathvariant="normal">T</b:mi><b:mi mathvariant="normal">e</b:mi><b:mi mathvariant="normal">V</b:mi></b:mrow></b:math>. Published by the American Physical Society 2024