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

The ALICE collaboration

doi:10.1007/JHEP08(2025)035

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

The ALICE collaboration

Relativistic Nuclear Physics

Research output: Contribution to journal › Article › peer-review

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Abstract

The momentum-differential invariant cross sections of π⁰ and η mesons are reported for pp collisions at = 13 TeV at midrapidity (|y| < 0.8). The measurement is performed in a broad transverse-momentum range of 0.2 < p_T< 200 GeV/c and 0.4 < p_T< 60 GeV/c for the π⁰ and η, respectively, extending the p_T 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 (x_T) scaling of the π⁰ 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 π⁰ 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 π⁰ and are not able to describe the shape and magnitude of the η spectrum. The charged-particle multiplicity dependent π⁰ and η p_T 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 p_T< 4 GeV/c. PYTHIA8 and EPOS LHC qualitatively explain this behavior with an increasing contribution from the feed-down of heavier particles to the π⁰ spectrum.

Original language	English
Article number	35
Journal	Journal of High Energy Physics
Volume	2025
Issue number	8
DOIs	https://doi.org/10.1007/JHEP08(2025)035
State	Published - Aug 2025

Funding

The ALICE Collaboration would like to thank all its engineers and technicians for their invaluable contributions to the construction of the experiment and the CERN accelerator teams for the outstanding performance of the LHC complex. The ALICE Collaboration gratefully acknowledges the resources and support provided by all Grid centres and the Worldwide LHC Computing Grid (WLCG) collaboration. The ALICE Collaboration acknowledges the following funding agencies for their support in building and running the ALICE detector: A. I. Alikhanyan National Science Laboratory (Yerevan Physics Institute) Foundation (ANSL), State Committee of Science and World Federation of Scientists (WFS), Armenia; Austrian Academy of Sciences, Austrian Science Fund (FWF): [M 2467-N36] and Nationalstiftung für Forschung, Technologie und Entwicklung, Austria; Ministry of Communications and High Technologies, National Nuclear Research Center, Azerbaijan; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Financiadora de Estudos e Projetos (Finep), Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) and Universidade Federal do Rio Grande do Sul (UFRGS), Brazil; Bulgarian Ministry of Education and Science, within the National Roadmap for Research Infrastructures 2020-2027 (object CERN), Bulgaria; Ministry of Education of China (MOEC) , Ministry of Science & Technology of China (MSTC) and National Natural Science Foundation of China (NSFC), China; Ministry of Science and Education and Croatian Science Foundation, Croatia; Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear (CEADEN), Cubaenergía, Cuba; Ministry of Education, Youth and Sports of the Czech Republic, Czech Republic; The Danish Council for Independent Research | Natural Sciences, the VILLUM FONDEN and Danish National Research Foundation (DNRF), Denmark; Helsinki Institute of Physics (HIP), Finland; Commissariat à l’Energie Atomique (CEA) and Institut National de Physique Nucléaire et de Physique des Particules (IN2P3) and Centre National de la Recherche Scientifique (CNRS), France; Bundesministerium für Bildung und Forschung (BMBF) and GSI Helmholtzzentrum für Schwerionenforschung GmbH, Germany; General Secretariat for Research and Technology, Ministry of Education, Research and Religions, Greece; National Research, Development and Innovation Office, Hungary; Department of Atomic Energy Government of India (DAE), Department of Science and Technology, Government of India (DST), University Grants Commission, Government of India (UGC) and Council of Scientific and Industrial Research (CSIR), India; National Research and Innovation Agency - BRIN, Indonesia; Istituto Nazionale di Fisica Nucleare (INFN), Italy; Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT) and Japan Society for the Promotion of Science (JSPS) KAKENHI, Japan; Consejo Nacional de Ciencia (CONACYT) y Tecnología, through Fondo de Cooperación Internacional en Ciencia y Tecnología (FONCICYT) and Dirección General de Asuntos del Personal Academico (DGAPA), Mexico; Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO), Netherlands; The Research Council of Norway, Norway; Pontificia Universidad Católica del Perú, Peru; Ministry of Science and Higher Education, National Science Centre and WUT ID-UB, Poland; Korea Institute of Science and Technology Information and National Research Foundation of Korea (NRF), Republic of Korea; Ministry of Education and Scientific Research, Institute of Atomic Physics, Ministry of Research and Innovation and Institute of Atomic Physics and Universitatea Nationala de Stiinta si Tehnologie Politehnica Bucuresti, Romania; Ministry of Education, Science, Research and Sport of the Slovak Republic, Slovakia; National Research Foundation of South Africa, South Africa; Swedish Research Council (VR) and Knut & Alice Wallenberg Foundation (KAW), Sweden; European Organization for Nuclear Research, Switzerland; Suranaree University of Technology (SUT), National Science and Technology Development Agency (NSTDA) and National Science, Research and Innovation Fund (NSRF via PMU-B B05F650021), Thailand; Turkish Energy, Nuclear and Mineral Research Agency (TENMAK), Turkey; National Academy of Sciences of Ukraine, Ukraine; Science and Technology Facilities Council (STFC), United Kingdom; National Science Foundation of the United States of America (NSF) and United States Department of Energy, Office of Nuclear Physics (DOE NP), United States of America. In addition, individual groups or members have received support from: Czech Science Foundation (grant no. 23-07499S), Czech Republic; FORTE project, reg. no. CZ.02.01.01/00/22_008/0004632, Czech Republic, co-funded by the European Union, Czech Republic; European Research Council (grant no. 950692), European Union; ICSC - Centro Nazionale di Ricerca in High Performance Computing, Big Data and Quantum Computing, European Union - NextGenerationEU; Academy of Finland (Center of Excellence in Quark Matter) (grant nos. 346327, 346328), Finland; Deutsche Forschungs Gemeinschaft (DFG, German Research Foundation) “Neutrinos and Dark Matter in Astro- and Particle Physics” (grant no. SFB 1258), Germany.

Keywords

Hadron-Hadron Scattering
Particle and Resonance Production
QCD

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10.1007/JHEP08(2025)035

Cite this

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title = "Light neutral-meson production in pp collisions at = 13 TeV",

abstract = "The momentum-differential invariant cross sections of π0 and η mesons are reported for pp collisions at = 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 π0 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 π0 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 π0 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 π0 and are not able to describe the shape and magnitude of the η spectrum. The charged-particle multiplicity dependent π0 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 π0 spectrum.",

keywords = "Hadron-Hadron Scattering, Particle and Resonance Production, QCD",

author = "\{The ALICE collaboration\} and S. Acharya and A. Agarwal and \{Aglieri Rinella\}, G. and L. Aglietta and M. Agnello and N. Agrawal and Z. Ahammed and S. Ahmad and Ahn, \{S. U.\} and I. Ahuja and A. Akindinov and V. Akishina and M. Al-Turany and D. Aleksandrov and B. Alessandro and Alfanda, \{H. M.\} and \{Alfaro Molina\}, R. and B. Ali and A. Alici and N. Alizadehvandchali and A. Alkin and J. Alme and G. Alocco and T. Alt and Altamura, \{A. R.\} and I. Altsybeev and Alvarado, \{J. R.\} and Anaam, \{M. N.\} and C. Andrei and N. Andreou and A. Andronic and E. Andronov and V. Anguelov and F. Antinori and P. Antonioli and N. Apadula and L. Aphecetche and H. Appelsh{\"a}user and C. Arata and S. Arcelli and R. Arnaldi and Arneiro, \{J. G.M.C.A.\} and Arsene, \{I. C.\} and M. Arslandok and A. Augustinus and R. Averbeck and F. Bock and Read, \{K. F.\} and J. Schambach and Schmidt, \{N. V.\}",

note = "Publisher Copyright: {\textcopyright} The Author(s) 2025.",

year = "2025",

month = aug,

doi = "10.1007/JHEP08(2025)035",

language = "English",

volume = "2025",

journal = "Journal of High Energy Physics",

issn = "1126-6708",

publisher = "Springer",

number = "8",

}

TY - JOUR

T1 - Light neutral-meson production in pp collisions at = 13 TeV

AU - The ALICE collaboration

AU - Acharya, S.

AU - Agarwal, A.

AU - Aglieri Rinella, G.

AU - Aglietta, L.

AU - Agnello, M.

AU - Agrawal, N.

AU - Ahammed, Z.

AU - Ahmad, S.

AU - Ahn, S. U.

AU - Ahuja, I.

AU - Akindinov, A.

AU - Akishina, V.

AU - Al-Turany, M.

AU - Aleksandrov, D.

AU - Alessandro, B.

AU - Alfanda, H. M.

AU - Alfaro Molina, R.

AU - Ali, B.

AU - Alici, A.

AU - Alizadehvandchali, N.

AU - Alkin, A.

AU - Alme, J.

AU - Alocco, G.

AU - Alt, T.

AU - Altamura, A. R.

AU - Altsybeev, I.

AU - Alvarado, J. R.

AU - Anaam, M. N.

AU - Andrei, C.

AU - Andreou, N.

AU - Andronic, A.

AU - Andronov, E.

AU - Anguelov, V.

AU - Antinori, F.

AU - Antonioli, P.

AU - Apadula, N.

AU - Aphecetche, L.

AU - Appelshäuser, H.

AU - Arata, C.

AU - Arcelli, S.

AU - Arnaldi, R.

AU - Arneiro, J. G.M.C.A.

AU - Arsene, I. C.

AU - Arslandok, M.

AU - Augustinus, A.

AU - Averbeck, R.

AU - Bock, F.

AU - Read, K. F.

AU - Schambach, J.

AU - Schmidt, N. V.

PY - 2025/8

Y1 - 2025/8

N2 - The momentum-differential invariant cross sections of π0 and η mesons are reported for pp collisions at = 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 π0 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 π0 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 π0 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 π0 and are not able to describe the shape and magnitude of the η spectrum. The charged-particle multiplicity dependent π0 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 π0 spectrum.

AB - The momentum-differential invariant cross sections of π0 and η mesons are reported for pp collisions at = 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 π0 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 π0 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 π0 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 π0 and are not able to describe the shape and magnitude of the η spectrum. The charged-particle multiplicity dependent π0 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 π0 spectrum.

KW - Hadron-Hadron Scattering

KW - Particle and Resonance Production

KW - QCD

UR - https://www.scopus.com/pages/publications/105017920249

U2 - 10.1007/JHEP08(2025)035

DO - 10.1007/JHEP08(2025)035

M3 - Article

AN - SCOPUS:105017920249

SN - 1126-6708

VL - 2025

JO - Journal of High Energy Physics

JF - Journal of High Energy Physics

IS - 8

M1 - 35

ER -

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

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Keywords

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