Magnus Thøgersen

• Zurlo, N.; Zugravel, S. C.; Zingaretti, A.; Zhu, Y.; Zhu, S. & Zhu, J. [Show all 1,054 contributors for this article] (2026). Σ¯± production in pp and p-Pb collisions at √sNN = 5.02 TeV with ALICE. European Physical Journal C. ISSN 1434-6044. 86(2). doi: 10.1140/epjc/s10052-025-15129-2. Full text in Research Archive
• Acharya, S.; Agarwal, A.; Rinella, G. Aglieri; Aglietta, L.; Agnello, M. & Agrawal, N. [Show all 1,069 contributors for this article] (2025). Direct-photon production in inelastic and high-multiplicity proton–proton collisions at √s= 13 TeV. Physics Letters B. ISSN 0370-2693. 868. doi: 10.1016/j.physletb.2025.139645. Full text in Research Archive Show summary

  In this letter, we present the first measurement of direct photons at the transverse momentum of 1 < 𝑝T < 6 GeV/𝑐 at √ midrapidity |𝜂| < 0.8 in inelastic and high-multiplicity proton–proton collisions at a centre-of-mass energy of 𝑠 = 13 TeV. The fraction of virtual direct photons in the inclusive virtual photon spectrum is obtained from a fit to the dielectron invariant mass spectrum. In the limit of zero invariant mass, this fraction is equal to the relative contribution of real direct photons in the inclusive real photon spectrum. Contributions from decays of lightflavour neutral mesons are estimated using independent measurements in proton–proton collisions at the same energy and the same event class. For the first time at the LHC energies, a direct-photon signal is observed at low 𝑝T in both inelastic and high-multiplicity event classes, with a significance of 3.2𝜎 and 1.9𝜎 in terms of standard deviations, correspondingly. The yield of direct photons in inelastic pp collisions is compared to perturbative QCD calculations. The integrated photon yield is studied as a function of charged-particle multiplicity and is compared to the results from other experiments and theoretical calculations. The results show a significant increase of directphoton yield with charged-particle multiplicity.

• Acharya, S.; Agarwal, A.; Rinella, G. Aglieri; Aglietta, L.; Agnello, M. & Agrawal, N. [Show all 1,075 contributors for this article] (2025). First measurement of symmetric cumulants of hexagonal flow harmonics in Pb-Pb collisions at √sNN = 5.02 TeV. Physical Review C. ISSN 2469-9985. 112(2). doi: 10.1103/4ltm-g1qg. Full text in Research Archive Show summary

  Correlations between event-by-event fluctuations of anisotropic flow harmonics are measured in Pb-Pb collisions at a center-of-mass energy per nucleon pair of 5.02 TeV, as recorded by the ALICE detector at the LHC. This study presents correlations up to the hexagonal flow harmonic v6, which was measured for the first time. The magnitudes of these higher-order correlations are found to vary as a function of collision centrality and harmonic order. These measurements are compared to viscous hydrodynamic model calculations with EKRT initial conditions and to the iEBE-VISHNU model with TRENTo initial conditions. The observed discrepancies between the data and the model calculations vary depending on the harmonic combinations. Due to the sensitivity of model parameters estimated with Bayesian analyses to these higher-order observables, the results presented in this work provide new and independent constraints on the initial conditions and transport properties in theoretical models used to describe the system created in heavy-ion collisions

• Acharya, S.; Agarwal, A.; Rinella, G. Aglieri; Aglietta, L.; Agnello, M. & Agrawal, N. [Show all 1,067 contributors for this article] (2025). Multimuons in cosmic-ray events as seen in ALICE at the LHC. Journal of Cosmology and Astroparticle Physics (JCAP). 2025(4), p. 1–30. doi: 10.1088/1475-7516/2025/04/009. Full text in Research Archive Show summary

  ALICE is a large experiment at the CERN Large Hadron Collider. Located 52 meters underground, its detectors are suitable to measure muons produced by cosmic-ray interactions in the atmosphere. In this paper, the studies of the cosmic muons registered by ALICE during Run 2 (2015–2018) are described. The analysis is limited to multimuon events defined as events with more than four detected muons (Nµ > 4) and in the zenith angle range 0 ◦ < θ < 50◦ . The results are compared with Monte Carlo simulations using three of the main hadronic interaction models describing the air shower development in the atmosphere: QGSJET-II-04, EPOS-LHC, and SIBYLL 2.3d. The interval of the primary cosmic-ray energy involved in the measured muon multiplicity distribution is about 4×1015 < Eprim < 6×1016 eV. In this interval none of the three models is able to describe precisely the trend of the composition of cosmic rays as the energy increases. However, QGSJET-II-04 is found to be the only model capable of reproducing reasonably well the muon multiplicity distribution, assuming a heavy composition of the primary cosmic rays over the whole energy range, while SIBYLL 2.3d and EPOS-LHC underpredict the number of muons in a large interval of multiplicity by more than 20% and 30%, respectively. The rate of high muon multiplicity events (Nµ > 100) obtained with QGSJET-II-04 and SIBYLL 2.3d is compatible with the data, while EPOS-LHC produces a significantly lower rate (55% of the measured rate). For both QGSJET-II-04 and SIBYLL 2.3d, the rate is close to the data when the composition is assumed to be dominated by heavy elements, an outcome compatible with the average energy Eprim ∼ 1017 eV of these events. This result places significant constraints on more exotic production mechanisms.

• Zurlo, N.; Zugravel, S. C.; Zhu, Y.; Zhu, S.; Zhu, J. & Zhou, Y. [Show all 1,069 contributors for this article] (2025). Measurements of differential two-particle number and transverse momentum correlation functions in pp collisions at √s = 13 TeV. European Physical Journal C. ISSN 1434-6044. 85(8). doi: 10.1140/epjc/s10052-025-14531-0. Full text in Research Archive Show summary

  Differential two-particle normalized cumulants (R2 ) and transverse momentum correlations (P2 ) are mea- sured as a function of the relative pseudorapidity and azimuthal angle difference (η, ϕ) of charged particle pairs in minimum bias pp collisions at √s = 13 TeV. The mea- surements use charged hadrons in the pseudorapidity region of |η| < 0.8 and the transverse momentum range 0.2 < pT < 2.0 GeV/c in order to focus on soft multiparticle interactions and to complement prior measurements of these correlation functions in p–Pb and Pb–Pb collisions. The correlation func- tions are reported for both unlike-sign and like-sign pairs and their charge-independent and charge-dependent combi- nations. Both the R2 and P2 measured in pp collisions exhibit features qualitatively similar to those observed in p–Pb and Pb–Pb collisions. The η and ϕ root mean square widths of the near-side peak of the correlation functions are evalu- ated and compared with those observed in p–Pb and Pb–Pb collisions and show smooth evolution with the multiplicity of charged particles produced in the collision. The compar- ison of the measured correlation functions with predictions from PYTHIA8 shows that this model qualitatively captures their basic structure and characteristics but feature impor- tant differences. In addition, the RCD 2 is used to determine the charge balance function of hadrons produced within the detector acceptance of the measurements. The integral of the balance function is found to be compatible with those reported by a previous measurement in Pb–Pb collisions.

• Zurlo, N.; Zugravel, S. C.; Zhu, Y.; Zhu, S.; Zhu, J. & Zhou, Zhuo [Show all 1,067 contributors for this article] (2025). System size and energy dependence of the mean transverse momentum fluctuations at the LHC. European Physical Journal C. ISSN 1434-6044. 85(7). doi: 10.1140/epjc/s10052-025-14325-4. Full text in Research Archive Show summary

  Event-by-event fluctuations of the event-wise mean transverse momentum, pT, of charged particles produced in proton–proton (pp) collisions at √ s =5.02TeV, Xe– Xe collisions at √ √ sNN = 5.44TeV, and Pb–Pb collisions at sNN = 5.02TeVare studied using the ALICE detector based on the integral correlator pTpT.The correlator strength is found to decreasemonotonically with increasing produced charged-particle multiplicity measured at midrapidity in all three systems. In Xe–Xe and Pb–Pb collisions, the multiplicity dependence of the correlator deviates significantly from a simple power-law scaling as well as from the predictions of theHIJING andAMPTmodels. The observed deviation from power-law scaling is expected from transverse radial flow in semicentral to central Xe–Xe and Pb–Pb collisions. In pp collisions, the correlation strength is also studied by classifying the events based on the transverse spherocity, S0, of the particle production at midrapidity, used as a proxy for the presence of a pronounced back-to-back jet topology. Lowspherocity (jetty) events feature a larger correlation strength than those with high spherocity (isotropic). The strength and multiplicity dependence of jetty and isotropic events are well reproduced by calculations with the PYTHIA 8 and EPOS LHC models.

• Acharya, S.; Agarwal, A.; Rinella, G. Aglieri; Aglietta, L.; Agnello, M. & Agrawal, N. [Show all 1,072 contributors for this article] (2025). Light neutral-meson production in pp collisions at √s = 13 TeV. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2025(8). doi: 10.1007/JHEP08(2025)035. Full text in Research Archive Show summary

  The momentum-differential invariant cross sections of π0 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 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.

• Acharya, S.; Agarwal, A.; Rinella, G. Aglieri; Aglietta, L.; Agnello, M. & Agrawal, N. [Show all 1,070 contributors for this article] (2025). Studying charm hadronisation into baryons with azimuthal correlations of Λ+ c with charged particles in pp collisions at √𝑠 = 13 TeV. Physics Letters B. ISSN 0370-2693. 868. doi: 10.1016/j.physletb.2025.139681. Full text in Research Archive Show summary

  The distribution of angular correlations between prompt charm hadrons and primary charged particles in pp collisions is sensitive to the charm-quark hadronisation process. In this letter, charm-baryon correlations are measured for the first time by studying the azimuthal-angle difference between charged particles and prompt Λ+ c baryons produced in pp collisions at a centre-of-mass energy of √𝑠 = 13 TeV, with the ALICE detector. Λ+ c baryons are reconstructed at midrapidity (|𝑦| < 0.5) in the transverse-momentum interval 3 < 𝑝T < 16 GeV/𝑐, and correlated with charged particles with 𝑝T > 0.3 GeV/𝑐 and pseudorapidity |𝜂| < 0.8. For 3 < 𝑝Λ+ c ,D T < 5 GeV/𝑐, the comparison with published measurements of D-meson and charged-particle correlations in the same collision system hints at a larger number of low-momentum particles associated with Λ+ c -baryon triggers than with D-meson triggers, both in the collinear and opposite directions with respect to the trigger particle. These differences can be quantified by the comparison of the properties of the near- and away-side correlation peaks, and are not reproduced by predictions of various Monte Carlo event generators, generally underpredicting the associated particle yields at 𝑝assoc T < 1 GeV/𝑐. This tension between Λ+ c -baryon and D-meson associated peak yields could suggest a modified fragmentation of the charm quark, or a different hadronisation process, when a charm baryon is produced in the final state.

• Acharya, S.; Agarwal, A.; Rinella, G. Aglieri; Aglietta, L.; Agnello, M. & Agrawal, N. [Show all 1,070 contributors for this article] (2025). Multiplicity-dependent inclusive J/ψ production at forward rapidity in pp collisions at √s = 13 TeV. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2025(7). doi: 10.1007/JHEP07(2025)238. Full text in Research Archive Show summary

  This paper presents a study of the inclusive forward J/ψ yield as a function of forward charged-particle multiplicity in pp collisions at √s = 13TeV using data collected by the ALICE experiment at the CERN LHC. The results are presented in terms of relative J/ψ yields and relative charged-particle multiplicities with respect to these quantities obtained in inelastic collisions having at least one charged particle in the pseudorapidity range |η| < 1. The J/ψ mesons are reconstructed via their decay into μ+μ− pairs in the forward rapidity region (2.5 < y < 4). The relative multiplicity is estimated in the forward pseudorapidity range which overlaps with the J/ψ rapidity region. The results show a steeper-than-linear increase of the J/ψ yields versus the multiplicity. They are compared with previous measurements and theoretical model calculations.

• Acharya, S.; Agarwal, A.; Rinella, G. Aglieri; Aglietta, L.; Agnello, M. & Agrawal, N. [Show all 1,075 contributors for this article] (2025). Charged-particle multiplicity distributions over a wide pseudorapidity range in p–Pb collisions at √sNN = 5.02 TeV. European Physical Journal C. ISSN 1434-6044. 85(8). doi: 10.1140/epjc/s10052-025-14577-0. Full text in Research Archive Show summary

  This paper presents the primary charged-particle multiplicity distributions in proton–lead collisions at a centre-of-mass energy per nucleon–nucleon collision of √sNN = 5.02 TeV. The distributions are reported for non-single diffractive collisions in different pseudorapidity ranges.The measurements are performed using the combined information from the Silicon Pixel Detector and the Forward Multiplicity Detector of ALICE. The multiplicity distributions are parametrised with a double negative binomial distribution function which provides satisfactory descriptions of the distributions for all the studied pseudorapidity intervals. The data are compared to models and analysed quantitatively, evaluating the first four moments (mean, standard deviation, skewness, and kurtosis). The shape evolution of the measured multiplicity distributions is studied in terms of KNO variables and it is found that none of the considered models reproduces the measurements. This paper also reports on the average charged-particle multiplicity, normalised by the average number of participating nucleon pairs, as a function of the collision energy. The multiplicity results are then compared to measurements made in proton–proton and nucleus–nucleus collisions across a wide range of collision energies.

• Acharya, S.; Agarwal, A.; Rinella, G. Aglieri; Aglietta, L.; Agnello, M. & Agrawal, N. [Show all 1,069 contributors for this article] (2025). First measurement of D*+vector meson spin alignment in Pb–Pb collisions at √sNN = 5.02TeV. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2025(10). doi: 10.1007/JHEP10(2025)094. Full text in Research Archive Show summary

  The first measurement of prompt D∗+-meson spin alignment in ultrarelativistic heavy-ion collisions with respect to the direction orthogonal to the reaction plane is presented. The spin alignment is quantified by measuring the element ρ00 of the diagonal spin-density matrix for prompt D∗+ mesons with 4 < pT < 30 GeV/c in two rapidity intervals, |y| < 0.3 and 0.3 < |y| < 0.8, in central (0–10%) and midcentral (30–50%) Pb–Pb collisions at √sNN = 5.02TeV. Evidence of spin alignment ρ00 > 1/3 has been found for pT > 15 GeV/c and 0.3 < |y| < 0.8 with a significance of 3.1σ. The measured spin alignment of prompt D∗+ mesons is compared with the one of inclusive J/ψ mesons measured at forward rapidity (2.5 < y < 4).

• Acharya, S.; Agarwal, A.; Rinella, G. Aglieri; Aglietta, L.; Agnello, M. & Agrawal, N. [Show all 1,071 contributors for this article] (2025). Measurement of correlations among net-charge, net-proton, and net-kaon multiplicity distributions in Pb-Pb collisions at √sNN = 5.02 TeV. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2025(8). doi: 10.1007/JHEP08(2025)210. Full text in Research Archive Show summary

  Correlations among conserved quantum numbers, such as the net-electric charge, the net-baryon, and the net-strangeness in heavy-ion collisions, are crucial for exploring the QCD phase diagram. In this paper, these correlations are investigated using net-proton number (as a proxy for the net-baryon), net-kaon number (for the net-strangeness), and net-charged particle number in Pb-Pb collisions at √sNN = 5.02TeV with the ALICE detector. The observed correlations deviate from the Poissonian baseline, with a more pronounced deviation at LHC energies than at RHIC. Theoretical calculations of the Thermal-FIST hadron resonance gas model, HIJING, and EPOS LHC event generators are compared with experimental results, where a significant impact of resonance decays is observed. Thermal-FIST calculations under the grand canonical and canonical ensembles highlight significant differences, underscoring the role of local charge conservation in explaining the data. Recent lattice QCD studies have demonstrated that the magnetic field generated by spectator protons in heavy-ion collisions affects susceptibility ratios, in particular those related to the net-electric charge and the net-baryon numbers. The experimental findings are in qualitative agreement with the expectations of lattice QCD.

• Acharya, S.; Rinella, G. Aglieri; Aglietta, L.; Agnello, M.; Agrawal, N. & Ahammed, Z. [Show all 1,076 contributors for this article] (2025). Femtoscopic study of the proton-proton and proton-deuteron systems in heavy-ion collisions at the LHC. Physics Letters B. ISSN 0370-2693. 871. doi: 10.1016/j.physletb.2025.139921. Full text in Research Archive
• Zurlo, N.; Zugravel, S. C.; Zhu, Y.; Zhu, S.; Zhu, J. & Zhou, Y. [Show all 1,084 contributors for this article] (2025). Investigating the p–π± and p–p–π± dynamics with femtoscopy in pp collisions at √s = 13 TeV. European Physical Journal A. ISSN 1434-6001. 61(8). doi: 10.1140/epja/s10050-025-01615-4. Full text in Research Archive
• Abualrob, I. J.; Acharya, S.; Rinella, G. Aglieri; Aglietta, L.; Agnello, M. & Agrawal, N. [Show all 1,068 contributors for this article] (2025). Study of ⟨pT⟩ and its higher moments, and extraction of the speed of sound in Pb-Pb collisions with ALICE. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2025(11). doi: 10.1007/JHEP11(2025)076. Full text in Research Archive Show summary

  Ultrarelativistic heavy-ion collisions produce a state of hot and dense strongly interacting QCD matter called quark-gluon plasma (QGP). On an event-by-event basis, the volume of the QGP in ultracentral collisions is mostly constant, while its total entropy can vary significantly due to quantum fluctuations, leading to variations in the temperature of the system. Exploiting this unique feature of ultracentral collisions allows for the interpretation of the correlation of the mean transverse momentum of produced charged hadrons and the number of charged hadrons as a measure for the speed of sound, cs. This speed is related to the rate at which compression waves travel in the QGP and is determined by fitting the relative increase in with respect to the relative change in the average charged-particle density measured at mid-rapidity. This study reports the event-average of charged particles as well as the variance, skewness, and kurtosis of the event-by-event transverse momentum per charged particle distribution in ultracentral Pb-Pb collisions at a center-of-mass energy of 5.02 TeV per nucleon pair using the ALICE detector. Different centrality estimators based on charged-particle multiplicity or the transverse energy of the event are used to select ultracentral collisions. By ensuring a pseudorapidity gap between the region used to define the centrality and the region used to perform the measurement, the influence of biases and their potential effects on the rise of the mean transverse momentum is tested. The measured is found to strongly depend on the exploited centrality estimator and ranges between 0.1146±0.0028 (stat.)±0.0065 (syst.) and 0.4374±0.0006 (stat.)±0.0184 (syst.) in natural units. The self-normalized variance shows a steep decrease towards ultracentral collisions, while the self-normalized skewness variables show a maximum, followed by a fast decrease. These non-Gaussian features are understood in terms of the vanishing of the impact-parameter fluctuations contributing to the event-to-event [pT] distribution.

• Zurlo, N.; Zugravel, S. C.; Zhu, Y.; Zhu, S.; Zhu, J. & Zhou, Y. [Show all 1,070 contributors for this article] (2025). Observation of deuteron and antideuteron formation from resonance-decay nucleons. Nature. ISSN 0028-0836. 648(8093), p. 306–311. doi: 10.1038/s41586-025-09775-5. Full text in Research Archive
• Acharya, S.; Acharya, S.; Agarwal, A.; Rinella, G. Aglieri; Aglietta, L. & Agnello, M. [Show all 1,082 contributors for this article] (2025). Observation of the Ω⁡(2012) baryon at the LHC. Physical Review D. ISSN 2470-0010. 112(9). doi: 10.1103/v4mh-3r8z. Full text in Research Archive
• Zurlo, N.; Zugravel, S. C.; Zhu, Y.; Zhu, S.; Zhu, J. & Zhou, Y. [Show all 1,075 contributors for this article] (2025). Measurement of isolated prompt photon production in pp and p–Pb collisions at the LHC. European Physical Journal C. ISSN 1434-6044. 85(12). doi: 10.1140/epjc/s10052-025-14802-w. Full text in Research Archive
• Abualrob, I. J.; Acharya, S.; Rinella, G. Aglieri; Aglietta, L.; Agnello, M. & Agrawal, N. [Show all 1,044 contributors for this article] (2025). Multiplicity dependence of Ξ+ c and Ξ0 c production in pp collisions at √s = 13 TeV. Journal of High Energy Physics (JHEP). ISSN 1126-6708. 2025(12). doi: 10.1007/JHEP12(2025)038. Full text in Research Archive
• Acharya, S.; Agarwal, A.; Rinella, G. Aglieri; Aglietta, L.; Agnello, M. & Agrawal, N. [Show all 1,071 contributors for this article] (2025). D0-meson-tagged jet axes difference in proton-proton collisions at √s = 5.02 TeV. Physical Review D. ISSN 2470-0010. 112(9). doi: 10.1103/nt4q-7t77. Full text in Research Archive
• Zurlo, N.; Zugravel, S.C.; Zhu, Y.; Zhu, S.; Zhu, J. & Zhou, Y [Show all 1,067 contributors for this article] (2025). Measurement of the inclusive isolated-photon production cross section in pp and Pb–Pb collisions at sNN=5.02 TeV. European Physical Journal C. ISSN 1434-6044. 85(5). doi: 10.1140/epjc/s10052-025-13971-y. Full text in Research Archive
• Acharya, S.; Agarwal, A.; Rinella, Rinella Aglieri; Aglietta, L.; Agnello, M. & Agrawal, N. [Show all 1,065 contributors for this article] (2025). Medium-induced modification of groomed and ungroomed jet mass and angularities in Pb–Pb collisions at s<inf>NN</inf>=5.02 [Figure presented]. Physics Letters B. ISSN 0370-2693. 864. doi: 10.1016/j.physletb.2025.139409. Full text in Research Archive
• Acharya, S.; Agarwal, A.; Rinella, Rinella Aglieri; Aglietta, L.; Agnello, M. & Agrawal, N. [Show all 1,067 contributors for this article] (2025). Proton emission in ultraperipheral Pb-Pb collisions at sNN =5.02 TeV. Physical Review C. ISSN 2469-9985. 111(5). doi: 10.1103/PhysRevC.111.054906. Full text in Research Archive

View all works in NVA