Nuclear modification factor of neutral pions in the forward and backward regions in $p$-Pb collisions

Abstract

The nuclear modification factor of neutral pions is measured in proton-lead collisions collected at a center-of-mass energy per nucleon of $8.16\mathrm{TeV}$ with the LHCb detector. The ${\pi }^0$ production cross section is measured differentially in transverse momentum ($p_{\mathrm{T}}$) for $1.5<p_{\mathrm{T}}<10.0\mathrm{GeV}$ and in center-of-mass pseudorapidity (${\eta }_{c.m.}$) regions $2.5<{\eta }_{c.m.}<3.5$ (forward) and $-4.0<{\eta }_{c.m.}<-3.0$ (backward) defined relative to the proton beam direction. The forward measurement shows a sizable suppression of ${\pi }^0$ production, while the backward measurement shows the first evidence of ${\pi }^0$ 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.

All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2021-053.html (LHCb public pages)

References in corpus (8)

• Observation of long-range near-side angular correlations in proton-lead collisions at the LHC
• Parton-to-Pion Fragmentation Reloaded
• Mining for Gluon Saturation at Colliders
• CGC predictions for p+A collisions at the LHC and signature of QCD saturation
• Nuclear effects on the transverse momentum spectra of charged particles in pPb collisions at a nucleon-nucleon center-of-mass energy of 5.02 TeV
• Probing the small-$x$ nuclear gluon distributions with isolated photons at forward rapidities in p+Pb collisions at the LHC
• Measurement of the nuclear modification factor and prompt charged particle production in $p\mathrm{Pb}$ and $pp$ collisions at $\sqrt{s_{\mathrm{NN}}}=5\mathrm{TeV}$
• Proton and pion transverse spectra at RHIC from radial flow and finite size effects

Cited by in corpus (3)

• Complete Next-to-Leading Order Calculation of Single Inclusive ${\pi }^0$ Production in Forward Proton-Nucleus Collisions
• Production of $\eta$ and ${\eta }^{\prime }$ mesons in $pp$ and $p$Pb collisions
• Physics with high-luminosity proton-nucleus collisions at the LHC