Inclusive open charm photoproduction in ultraperipheral collisions at the LHC with in the generalized photon-nucleus fixed-order next-to-leading logarithm framework

We compute the inclusive <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:msup> <a:mi>D</a:mi> <a:mn>0</a:mn> </a:msup> </a:math> production cross section in ultraperipheral Pb-Pb collisions at the LHC as a function of the <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:msup> <c:mi>D</c:mi> <c:mn>0</c:mn> </c:msup> </c:math> transverse momentum and rapidity. These calculations are carried out within the new generalized photon-nucleus FONLL ( <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:mrow> <e:mi mathvariant="normal">G</e:mi> <e:mi>γ</e:mi> <e:mi mathvariant="normal">A</e:mi> <e:mtext>−</e:mtext> <e:mi>FONLL</e:mi> </e:mrow> </e:math> ) framework, which can predict photonuclear cross sections for charm and beauty hadrons in electron-proton, electron-nucleus, and ultraperipheral heavy-ion collisions. The framework relies on fixed-order next-to-leading logarithm (FONLL) to model heavy-quark production in photonuclear collisions and employs a photon-flux reweighting procedure to describe the production cross sections in ultraperipheral heavy-ion collisions. The <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"> <i:mrow> <i:mi mathvariant="normal">G</i:mi> <i:mi>γ</i:mi> <i:mi mathvariant="normal">A</i:mi> </i:mrow> </i:math> calculations are first validated against the photoproduction cross sections of <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" display="inline"> <m:msup> <m:mi>D</m:mi> <m:mo>*</m:mo> </m:msup> </m:math> in electron-proton collisions at HERA. The predictions for the <o:math xmlns:o="http://www.w3.org/1998/Math/MathML" display="inline"> <o:msup> <o:mi>D</o:mi> <o:mn>0</o:mn> </o:msup> </o:math> production cross section in ultraperipheral Pb-Pb collisions at the LHC are then presented and compared to the first experimental results obtained by CMS at <q:math xmlns:q="http://www.w3.org/1998/Math/MathML" display="inline"> <q:mrow> <q:mrow> <q:msqrt> <q:mrow> <q:msub> <q:mrow> <q:mi mathvariant="normal">s</q:mi> </q:mrow> <q:mrow> <q:mi>NN</q:mi> </q:mrow> </q:msub> </q:mrow> </q:msqrt> <q:mo>=</q:mo> <q:mn>5.36</q:mn> <q:mtext> </q:mtext> <q:mtext> </q:mtext> </q:mrow> <q:mi>TeV</q:mi> </q:mrow> </q:math> . The predictions are benchmarked against different choices of nuclear parton distribution functions, fragmentation functions, and renormalization and factorization scales.