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$\pi^0$ and $\eta$ meson production in proton-proton collisions at $\sqrt{s}=8$ TeV

The ALICE collaboration
No Journal Information, 2017

Abstract (data abstract)
CERN-LHC. An invariant differential cross section measurement of inclusive $\pi^0$ and $\eta$ meson production at mid-rapidity in pp collisions at $\sqrt{s}=8$ TeV was carried out by the ALICE experiment at the LHC. The spectra of neutral mesons $\pi^0$ and $\eta$ were measured in transverse momentum ranges of $0.3<p_{\rm T}<35$ GeV/$c$ and $0.5<p_{\rm T}<35$ GeV/$c$, respectively. Next-to-leading order perturbative QCD calculations using fragmentation functions DSS14 for $\pi^0$ and AESSS for $\eta$ overestimate the cross sections of both neutral mesons, but agree with the measured $\eta$/$\pi^0$ ratio within uncertainties. The results are also compared with PYTHIA8.2 predictions for which the Monash2013 tune yields the best agreement with the measured neutral meson spectra. The measurements confirm a universal behavior of the $\eta$/$\pi^0$ ratio observed for NA27, PHENIX and ALICE data for pp collisions from $\sqrt{s}=27.5$ GeV to $\sqrt{s}=8$ TeV within experimental uncertainties. A relation between the $\pi^0$ and $\eta$ production cross sections for pp collisions at $\sqrt{s}=8$ TeV is given by $m_{\rm T}$ scaling for $p_{\rm T}>3.5$ GeV/$c$. However, a deviation from this empirical scaling law is observed for transverse momenta below $p_{\rm T}<3.5$ GeV/$c$ in the $\eta$/$\pi^0$ ratio with a significance of $6.2\sigma$.

  • Table 1

    Data from Fig. 7

    10.17182/hepdata.79044.v1/t1

    Invariant differential cross section of $\pi^0$ produced in inelastic pp collisions at center-of-mass energy 8 TeV, the uncertainty of $\sigma_{MB}$...

  • Table 2

    Data from Fig. 7

    10.17182/hepdata.79044.v1/t2

    Invariant differential cross section of $\eta$ produced in inelastic pp collisions at center-of-mass energy 8 TeV, the uncertainty of $\sigma_{MB}$...

  • Table 3

    Data from Table 6

    10.17182/hepdata.79044.v1/t3

    Integrated yields of $\pi^0$ mesons produced in inelastic pp collisions at center-of-mass energies of 2.76 and 8 TeV. The uncertainties...

  • Table 4

    Data from Table 6

    10.17182/hepdata.79044.v1/t4

    Integrated yields of $\eta$ mesons produced in inelastic pp collisions at center-of-mass energies of 2.76 and 8 TeV. The uncertainties...

  • Table 5

    Data from Table 6

    10.17182/hepdata.79044.v1/t5

    Integrated $\eta$/$\pi^0$ ratio produced in inelastic pp collisions at center-of-mass energies of 2.76 and 8 TeV.

  • Table 6

    Data from Table 6

    10.17182/hepdata.79044.v1/t6

    Mean transverse momenta $\langle p_\text{T}\rangle$ of $\pi^0$ mesons produced in inelastic pp collisions at center-of-mass energies of 2.76 and 8...

  • Table 7

    Data from Table 6

    10.17182/hepdata.79044.v1/t7

    Mean transverse momenta $\langle p_\text{T}\rangle$ of $\eta$ mesons produced in inelastic pp collisions at center-of-mass energies of 2.76 and 8...

  • Table 8

    Data from Fig. 8

    10.17182/hepdata.79044.v1/t8

    The measured ratio of cross sections for inclusive $\eta$ to $\pi^0$ production at a centre-of-mass energy of 8 TeV.

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