The momentum-differential invariant cross sections of π 0 and η mesons are reported for pp collisions at √ s = 13 TeV at midrapidity (|y| < 0.8). The measurement is performed in a broad transverse-momentum range of 0.2 < pT < 200 GeV/c and 0.4 < pT < 60 GeV/c for the π 0 and η, respectively, extending the pT coverage of previous measurements. Transverse-mass-scaling violation of up to 60% at low transverse momentum has been observed, agreeing with measurements at lower collision energies. Transverse Bjorken x (xT) scaling of the π 0 cross sections at LHC energies is fulfilled with a power-law exponent of n = 5.01±0.05, consistent with values obtained for charged pions at similar collision energies. The data are compared to predictions from next-to-leading order perturbative QCD calculations, where the π 0 spectrum is best described using the CT18 parton distribution function and the NNFF1.0 or BDSS fragmentation function. Expectations from PYTHIA8 and EPOS LHC overestimate the spectrum for the π 0 and are not able to describe the shape and magnitude of the η spectrum. The charged-particle multiplicity dependent π 0 and η pT spectra show the expected change of the spectral shape, characterized by a flatter slope with increasing multiplicity. This is demonstrated across a broad transverse-momentum range and up to events with a charged-particle multiplicity exceeding five times the mean value in minimum bias collisions. The η/π0 ratio depends on the charged-particle multiplicity for pT < 4 GeV/c. PYTHIA8 and EPOS LHC qualitatively explain this behavior with an increasing contribution from the feed-down of heavier particles to the π 0 spectrum.

Acharya, S., Agarwal, A., Aglieri Rinella, G., Aglietta, L., Agnello, M., Agrawal, N., et al. (2025). Light neutral-meson production in pp collisions at √s = 13 TeV. JOURNAL OF HIGH ENERGY PHYSICS, 2025(8), 1-47 [10.1007/JHEP08(2025)035].

Light neutral-meson production in pp collisions at √s = 13 TeV

Agrawal N.;Alici A.;Arcelli S.;Bellini F.;Colocci M.;Ercolessi F.;Jacazio N.;Malfattore G.;Romanenko G.;Rubini N.;Sabiu B.;Scioli G.;Strazzi S.;Tomassini S.;
2025

Abstract

The momentum-differential invariant cross sections of π 0 and η mesons are reported for pp collisions at √ s = 13 TeV at midrapidity (|y| < 0.8). The measurement is performed in a broad transverse-momentum range of 0.2 < pT < 200 GeV/c and 0.4 < pT < 60 GeV/c for the π 0 and η, respectively, extending the pT coverage of previous measurements. Transverse-mass-scaling violation of up to 60% at low transverse momentum has been observed, agreeing with measurements at lower collision energies. Transverse Bjorken x (xT) scaling of the π 0 cross sections at LHC energies is fulfilled with a power-law exponent of n = 5.01±0.05, consistent with values obtained for charged pions at similar collision energies. The data are compared to predictions from next-to-leading order perturbative QCD calculations, where the π 0 spectrum is best described using the CT18 parton distribution function and the NNFF1.0 or BDSS fragmentation function. Expectations from PYTHIA8 and EPOS LHC overestimate the spectrum for the π 0 and are not able to describe the shape and magnitude of the η spectrum. The charged-particle multiplicity dependent π 0 and η pT spectra show the expected change of the spectral shape, characterized by a flatter slope with increasing multiplicity. This is demonstrated across a broad transverse-momentum range and up to events with a charged-particle multiplicity exceeding five times the mean value in minimum bias collisions. The η/π0 ratio depends on the charged-particle multiplicity for pT < 4 GeV/c. PYTHIA8 and EPOS LHC qualitatively explain this behavior with an increasing contribution from the feed-down of heavier particles to the π 0 spectrum.
2025
Acharya, S., Agarwal, A., Aglieri Rinella, G., Aglietta, L., Agnello, M., Agrawal, N., et al. (2025). Light neutral-meson production in pp collisions at √s = 13 TeV. JOURNAL OF HIGH ENERGY PHYSICS, 2025(8), 1-47 [10.1007/JHEP08(2025)035].
Acharya, S.; Agarwal, A.; Aglieri Rinella, G.; Aglietta, L.; Agnello, M.; Agrawal, N.; Ahammed, Z.; Ahmad, S.; Ahn, S. U.; Ahuja, I.; Akindinov, A.; A...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/1049858
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