/ hep-ex CERN-EP-2017-019

Production of $\pi^0$ and $\eta$ mesons up to high transverse momentum in pp collisions at 2.76 TeV

Pages: 33

Abstract: The invariant differential cross sections for inclusive $\pi^{0}$ and $\eta$ mesons at midrapidity were measured in pp collisions at $\sqrt{s}=2.76$ TeV for transverse momenta $0.4<p_{\rm T}<40$ GeV/$c$ and $0.6<p_{\rm T}<20$ GeV/$c$, respectively, using the ALICE detector. This large range in $p_{\rm T}$ was achieved by combining various analysis techniques and different triggers involving the electromagnetic calorimeter (EMCal). In particular, a new single-cluster, shower-shape based method was developed for the identification of high-$p_{\rm T}$ neutral pions, which exploits that the showers originating from their decay photons overlap in the EMCal. The measured cross sections are found to exhibit a similar power-law behavior with an exponent of about $6.3$. Next-to-leading order perturbative QCD calculations and generator-level simulations with PYTHIA 8.2 describe the cross sections to about $30$% for the $\pi^{0}$, and between $30$-$50$% for the $\eta$ meson. The new data can therefore be used to further improve the theoretical description of $\pi^{0}$ and $\eta$ meson production.

Note: *Temporary entry*; 33 pages, 11 captioned figures, 7 tables, authors from page 27, figures at http://aliceinfo.cern.ch/ArtSubmission/node/3396

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