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ALICE Collaboration

Publications and source records attributed to ALICE Collaboration.

At least 55 records · Page 3Linked to original sources

arXiv2026

Exclusive dimuon production and coherent charmonium photoproduction at forward rapidity in ultra-peripheral Pb$-$Pb collisions at $\mathbf{\sqrt{s_{\rm NN}}=5.36}$ TeV

This Paper presents rapidity-differential measurements of coherent J/$ψ$ and $ψ({\rm 2S})$ photoproduction, as well as rapidity- and mass-differential measurements of exclusive dimuon production, in the forward rapidity region $-4 < y < -2.5$ in ultra-peripheral Pb$-$Pb collisions at $\sqrt{s_{\rm NN}}=5.36$ TeV using data recorded by the ALICE detector at the LHC in 2023, corresponding to an integrated luminosity of $\mathcal{L} = 1170 \pm 50~μ{\rm b}^{-1}$. The J/$ψ$ and $ψ({\rm 2S})$ results reveal the significant role of nuclear shadowing effects. The square root of the ratio of the measured quarkonium cross section to the impulse approximation prediction is about 0.76 for J/$ψ$ and 0.71 for $ψ({\rm 2S})$, at $y \approx -3$, corresponding to typical Bjorken-$x$ values of $10^{-2}$. The exclusive dimuon results highlight the sensitivity of such measurements to precise modeling of the photon flux, particularly at impact parameters near the nuclear radius.

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arXiv2026

$\mathbf{\textbf{K}^{0}_{\textbf{S}}}-\mathbf{\textbf{K}^{0}_{\textbf{S}}}$ femtoscopy in Pb$-$Pb collisions at $\mathbf{\sqrt{\textit{s}_{\rm NN}} = 5.02}$ TeV at the LHC

Results from a one-dimensional femtoscopic analysis of ${\rm K}^{0}_{\rm S}-{\rm K}^{0}_{\rm S}$ correlations in Pb$-$Pb collisions at the center-of-mass energy $\sqrt{s_{\mathrm{NN}}}~=~5.02$ TeV using data collected by the ALICE experiment at the LHC are presented. The source radius $R$ and correlation strength $λ$ are studied as a function of centrality and pair-transverse momentum ($k_{\rm T}$) to provide insight into the space-time structure and composition of the particle-emitting source. The observed trends of radii as a function of $k_{\rm T}$ and centrality are consistent with the collective expansion of the system. Comparisons with measurements at $\sqrt{s_{\mathrm{NN}}}~=~2.76$ TeV by the ALICE Collaboration show agreement across multiplicities and $k_{\rm T}$. Hydrokinetic model predictions match the most central collision results but deviate in peripheral events, potentially reflecting limitations in the model's description of peripheral collisions. A comparison with recent measurements at the same energy by the CMS Collaboration shows compatibility in both $R$ and $λ$ within 1.3$σ$. These results extend previous ${\rm K}^{0}_{\rm{S}}-{\rm K}^{0}_{\rm{S}}$ femtoscopy to a higher energy, providing a consistent baseline for future comparisons.

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arXiv2026

Wave-Function Femtometry: Hypertriton - The Ultimate Halo Nucleus

The interaction between nucleons and hyperons - baryons containing a strange quark - is key to understanding the properties of dense nuclear matter, such as that expected in the interior of neutron stars. Direct scattering experiments are hindered by the short lifetime of hyperons, prompting the study of hypernuclei - bound states of nucleons and hyperons - as an alternative approach. The lightest known hypernucleus, the hypertriton ($^3_Λ$H), is a weakly bound state composed of a proton, a neutron and a $Λ$ hyperon, and is believed to exhibit a halo-like structure with the $Λ$ being loosely bound to a deuteron core. Based on the first measurement of hypertriton production in proton-proton collisions at the CERN Large Hadron Collider (LHC), its halo structure is confirmed. A successful description of the hypertriton production yield within the nuclear coalescence framework enables an estimation of the $Λ$ separation from the deuteron core as $9.54^{+2.67}_{-1.11}$ fm.

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arXiv2026

Dijet invariant mass of charged-particle jets in pp and p-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV

The ALICE collaboration presents the first measurement of the dijet invariant mass spectra of charged-particle jets in pp and p-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV. Charged particles in the mid-pseudorapidity region, $|η| < 0.9$, are clustered into jets using the anti-$k_{\rm T}$ algorithm with a resolution parameter $R = 0.4$. The leading and subleading jets are required to have a transverse momentum $p_{\rm T} > 20$ GeV$/c$ and to be contained within $\left|η_{\rm jet}\right| < 0.5$. The dijet invariant mass spectrum and the nuclear modification factor $R_{\rm pA}$ are presented in the low-mass region of 75 to 150 GeV/$c^2$. The nuclear modification factor for charged-particle dijet invariant mass is consistent with unity. This is in line with previous small-system jet studies. Comparisons with Monte Carlo simulations suggest that the low-mass region is sensitive to anti-shadowing effects on parton densities in the nucleus, however, the expected signal is subtle and below the present experimental sensitivity.

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arXiv2026

Measurement of the $\mathbf{B^0}$-meson production cross section in proton--proton collisions at $\mathbf{\sqrt{\textit{s}}=13.6}$ TeV

This article reports the measurement of the transverse-momentum ($p_{\rm T}$) differential production cross section of B$^0$ mesons in proton-proton collisions at a centre-of-mass energy of $\sqrt{s}=13.6$ TeV with the ALICE detector at the CERN LHC. For the first time, the B$^0$ production cross section is measured at midrapidity ($|y|<0.5$) down to $p_{\rm T}=1~\mathrm{GeV}/c$ at LHC energies. The B$^0$ mesons and their charge conjugates were reconstructed via the B$^{0}\to$D$^{-}π^+$ decay channel, followed by the D$^-\to$K$^+π^-π^-$ decay. The measured $p_{\rm T}$-differential production cross section is described within uncertainties by state-of-the-art models based on perturbative quantum-chromodynamics calculations. Its rapidity dependence is also studied by computing the $p_{\rm T}$-differential ratios between the ALICE measurement and the one of B$^+$ mesons performed by the LHCb Collaboration at forward rapidity. The B$^0$ production cross section per unit of rapidity at midrapidity is ${\rm d}σ({\rm B^0})/{\rm d} y|_{|y|<0.5} = 24.2 \pm 1.4~(\text{stat.}) \pm 2.6~(\text{syst.})_{-0.3}^{+0.2}~(\text{extrap.})~μ{\rm b}$.

hep-ex↗

arXiv2026

Evidence of different $Λ_{\rm c}$-baryon and D-meson elliptic flow in Pb$-$Pb collisions at $\mathbf{\sqrt{\textit{s}_{\rm NN}}}$ = 5.36 TeV with ALICE at the LHC

The ALICE collaboration reports the azimuthal-anisotropy coefficient $v_2$ of prompt D$^0$, D$^+$, D$^+_{\rm s}$ mesons and the first measurement of $v_2$ of prompt $Λ_{\rm c}$ baryons in semicentral Pb$-$Pb collisions at a center-of-mass energy per nucleon pair of $\sqrt{s_{\rm NN}} = 5.36$ TeV. The D mesons and $Λ_{\rm c}$ baryons are reconstructed in their hadronic decays at midrapidity ($ |y|<0.8$) in the transverse-momentum interval $0.5< p_{\rm T} < 24$ GeV/$c$. Similar $v_2$ values are measured for D$^0$ and D$^+$, while a hint of a difference ($2.6σ$) emerges between D$^0$ and D$^+_{\rm s}$ mesons in the $1 < p_{\rm T} < 5 $ GeV/$c$ interval. A larger $v_2$ for $Λ_{\rm c}$ baryons with respect to D$^0$ mesons is observed with $3.7σ$ significance for $4 < p_{\rm T} < 12$ GeV/$c$, providing evidence for the partonic origin of charm-hadron $v_2$ and hadron formation via quark coalescence. This interpretation is further supported by comparisons with theoretical calculations of charm-quark transport in a hydrodynamically expanding medium.

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arXiv2026

Production of $Ξ$ and $Ω$ hyperons in high-multiplicity proton-proton collisions at $\sqrt{s}$ = 13 TeV

This paper presents the first measurements of $Ξ$ and $Ω$ hyperon yields at the highest multiplicities reached in pp collisions at $\sqrt{s} = 13$ TeV. This measurement exploits the high-multiplicity pp collisions collected by ALICE with dedicated triggers. The selected collisions are characterised by about 30 charged particles per unit of rapidity, over four times more than in minimum-bias pp collisions at the same centre-of-mass energy, and about twice as many as in minimum-bias p-Pb or very peripheral Pb-Pb collisions at similar energies. The production yields and average transverse momenta of the hyperons agree with trends indicated by previous measurements in pp collisions at lower multiplicities. The difference in average transverse momenta between pp and p-Pb collisions, observed with the new high-multiplicity pp data, provides additional insight into the underlying particle production mechanisms in small systems. The results support a strong correlation between multi-strange hadron production and final-state multiplicity regardless of the collision system at the LHC energies, extending this observation to the highest multiplicity reached in pp collisions. The comparison with several state-of-the-art models (Pythia8.2 with the Monash 2013 tune, Pythia8.2 with Ropes, and EPOS4) suggests that the description of strange-hadron production is improved by recently introduced features such as interactions between overlapping strings in Pythia8.2 with Ropes and the collective expansion of high-density string regions in EPOS4.

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arXiv2026

Measurement of correlations between elliptic flow and mean transverse momentum in pp, p-Pb, and Pb-Pb collisions at the LHC

Measurements of the event-by-event correlation between elliptic flow ($v_2$) and the mean transverse momentum ($[p_{\rm T}]$) using the modified Pearson correlation coefficient $ρ(v_2^2,[p_{\rm T}])$ are reported in pp collisions at $\sqrt{s} = 13$ TeV, and in p-Pb and Pb-Pb collisions at a center-of-mass energy per nucleon pair $\sqrt{s_{\rm NN}} = 5.02$ TeV. This analysis is based on the full LHC Run 2 dataset recorded by ALICE and is performed for the first time in small collision systems with the ALICE detector. In Pb-Pb collisions, the $ρ(v_2^2,[p_{\rm T}])$ measurement shows a non-monotonic dependence on charged particle multiplicity ($N_{\rm ch}$); it first decreases and then increases with an increase in multiplicity. The decreasing trends of $ρ(v_2^2,[p_{\rm T}])$ with increasing multiplicity are also observed in p-Pb and pp collisions for the presented multiplicity range. All three systems show consistent values of $ρ(v_2^2,[p_{\rm T}])$ for $N_{\rm ch} \lesssim 80$. These measurements are also compared with theoretical model calculations, including PYTHIA, where no collectivity is generated, as well as AMPT and IP-Glasma + MUSIC + UrQMD, which produce collective effects in small systems. These comparisons offer unique insights into the origin of collectivity in small systems. They improve the understanding of the initial geometry, size, and their correlations. The comparison also allows an investigation of the role of initial momentum correlations predicted by the Color Glass Condensate framework. The new measurements could not be explained by current state-of-the-art models, offering insights into the initial stage of collisions in small systems and also imposing strong constraints on the existing theoretical models. This will significantly advance our understanding of the collective phenomena observed in small systems at the LHC.

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arXiv2026

First measurement of the strong interaction scattering parameters for the $\mathbf{K^-d}$ and $\mathbf{K^+d}$ systems

Charged kaon--deuteron interactions offer a sensitive probe of the strangeness sector of QCD at low energy, particularly through their scattering parameters. Despite available theoretical predictions, experimental constraints remain absent, particularly for the $\rm K^{-}d$ system. The first measurement of femtoscopic correlation functions for $\rm K^{-}d \oplus K^{+}\overline{d}$ and $\rm K^{+}d \oplus K^{-}\overline{d}$ particle pairs in Pb--Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV recorded by ALICE at the LHC is presented. Correlation functions for both systems are analyzed in three centrality classes and fitted using the Lednický--Lyuboshitz model to extract the source size and strong interaction scattering lengths. The $\rm K^{-}d$ scattering length is found to be $\Re f_0 = -1.44 \pm 0.15\text{ (stat.)}^{+0.10}_{-0.10}$ (syst.) fm and $\Im f_0 = 1.34 \pm 0.33$ (stat.)$^{+0.21}_{-0.15}$ (syst.) fm, while for $\rm K^{+}d$ the value $\Re f_0 = -0.68 \pm 0.16$ (stat.)$^{+0.09}_{-0.09}$ (syst.) fm is obtained. These results provide the first constraints on the $\rm K^{\pm} d$ interaction modeling at low energy, delivering a long-awaited experimental benchmark for testing chiral QCD dynamics.

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arXiv2026

Inclusive $ψ(2S)$ production at midrapidity in pp collisions at $\sqrt{s} = 13$ TeV

Inclusive production of $ψ(2S)$ mesons is measured for the first time at midrapidity ($|y| < 0.9$) in pp collisions at $\sqrt{s} = 13$ TeV using the ALICE detector at the LHC. The measurement is performed in the transverse-momentum ($p_{\rm T}$) range of 4 to 16 GeV/$c$ and is based on events triggered by the Transition Radiation Detector, corresponding to an integrated luminosity of $1.7 \pm 1.8\%$ (syst.) pb$^{-1}$. The $p_{\rm T}$-differential production cross section of the $ψ(2S)$ and its ratio to the J/$ψ$ production cross section are presented. The results extend the accessible $p_{\rm T}$ range down to 4 GeV/$c$, and a mild rise of the $ψ(2S)$-to-J/$ψ$ cross section ratio with increasing $p_{\rm T}$ is observed. The measurements are compared with theoretical predictions based on NRQCD and the ICEM model.

hep-ex↗

arXiv2026

Measurement of $π^0$-hadron correlations relative to the event plane in semicentral Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV

Per-trigger yields of $π^0$-hadron correlations were measured in semicentral Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV in ALICE at the LHC. The reconstructed $π^0 \rightarrow γγ$, with a transverse momentum of $11 < p_{\rm T}(π^0) < 14$ GeV/$c$, is used as the trigger particle to calculate yields of associated charged particles on the near- and away-side. The photons are reconstructed using the ALICE Electromagnetic Calorimeter, and the charged particles are measured in the ALICE central barrel within a pseudorapidity range of $|η|<0.8$. The yields are reported relative to the orientation of the $π^0$ with the $2^{\rm nd}$-order event plane, and are background subtracted using the reaction plane fit method. The data give an indication of a suppression of the associated charged-particle yields near $p_{\rm T} \approx 2$ GeV/$c$ when comparing out-of-plane to in-plane trigger particles. At associated charged-particle $p_{\rm T} > 3$ GeV/$c$, no significant event-plane dependence is observed within uncertainties. The results are compared with predictions from the JEWEL model, which implements jet energy loss in an expanding medium. JEWEL predicts no significant modification of either the near- or away-side associated yields, independent of whether medium recoils are included. The observed behavior may indicate the presence of additional energy-loss mechanisms beyond those governed by path-length dependence.

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arXiv2026

Deuteron coalescence probability in jets in p-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV

This article presents the first measurement of the (anti)deuteron and antiproton transverse-momentum distributions, the deuteron coalescence parameter, and the ratio between the yields of deuteron and proton in and out of jets in p-Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV. Three regions are used to study the jet-correlated production: Toward, Away, and Transverse to the jet axis, which direction is approximated by the leading particle in the event with $p_{\rm T}^{\rm lead} > 5$ GeV/$c$. The jet contribution is obtained from the Toward region by subtracting the underlying event, which dominates the Transverse region. In p-Pb collisions, an enhancement of the coalescence parameter $B_{\rm 2}$ is observed in jets compared to the underlying event. The enhancement is larger than the one observed in a similar analysis already in pp collisions. The results are compared with predictions from PYTHIA 8.314 using the Angantyr model with a deuteron production model based on ordinary nuclear reactions. The model is able to qualitatively reproduce the large enhancement of the coalescence parameter in jets with respect to the out-of-jets one. The results are further compared in detail with similar ones from previous studies for pp collisions at $\sqrt{s} = 13$ TeV.

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arXiv2026

Measurement of the charged-particle-jet transverse-momentum fraction carried by prompt and non-prompt J/$ψ$ mesons in pp collisions at $\sqrt{s}=13$ TeV

The measurement of the transverse-momentum fraction ($z^{\rm ch}$) carried by prompt and non-prompt J/$ψ$ in charged-particle jets in proton--proton collisions with a center-of-mass energy $\sqrt{s}= 13$ TeV is reported by the ALICE Collaboration at the CERN Large Hadron Collider. The measurement is based on a Transition Radiation Detector triggered data sample corresponding to an integrated luminosity of $\mathcal{L} = 1.63\pm0.03$ pb$^{-1}$. Inclusive J/$ψ$ mesons with transverse momentum ($p_{\rm T}$) above 1 GeV/$c$ are reconstructed at midrapidity through the electron--positron decay channel. The prompt and non-prompt J/$ψ$ contributions are separated using the secondary vertices from beauty-hadron decays. Jets are reconstructed from J/$ψ$-meson candidates and charged particles using the anti-$k_{\rm T}$ algorithm with jet resolution parameter $R = 0.4$ in the pseudorapidity range $|η_{\text{jet}}| < 0.5$. The distribution of the charged-particle jet $p_{\rm T}$ fraction carried by the prompt and non-prompt J/$ψ$ mesons, $z^{\rm ch}$, is measured in the range $0.3 < z^{\rm ch} \leq 1.0$ for the jet-$ p_{\rm T}$ range $7 < p_{\rm T}^{\rm jet} < 15$ GeV/$c$. The measured $z^{\rm ch}$ distributions for prompt and non-prompt J/$ψ$ are compared to pQCD calculations and PYTHIA 8 simulations. Prompt and non-prompt J/$ψ$ production within charged-particle jets are found to be qualitatively well reproduced by PYTHIA 8 for $z^{\rm ch}<0.9$, however, as $z^{\rm ch}$ approaches one, the simulations overshoot the measured data, indicating an overestimation of the fraction of isolated J/$ψ$. This observed tension between data and simulations in the highest $z^{\rm ch}$ bins reflects the challenge of simulating hadronization of low-momentum jets.

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arXiv2026

Long-range transverse momentum correlations and radial flow in Pb$-$Pb collisions at the LHC with ALICE

This Letter presents measurements of long-range transverse-momentum correlations using a new observable, $v_{0}(p_\mathrm{T})$, serving as a probe of event-by-event radial-flow fluctuations, the underlying radial expansion, and the medium properties in heavy-ion collisions. Results are reported for inclusive charged particles, pions, kaons, and protons across various centrality intervals in Pb$-$Pb collisions at $\sqrt{s_\mathrm{NN}} = 5.02$ TeV, recorded by the ALICE detector. A pseudorapidity-gap technique, similar to that used in anisotropic-flow studies, is employed to suppress short-range correlations. At low $p_\mathrm{T}$, a characteristic mass ordering consistent with hydrodynamic collective flow is observed. At higher $p_\mathrm{T}$ ($> 3$ GeV/$c$), protons exhibit larger $v_{0}(p_\mathrm{T})$ than pions and kaons, in agreement with expectations from quark-recombination models. Comparisons to viscous hydrodynamic calculations with varying bulk viscosity and equation of state demonstrate the sensitivity of the $v_{0}(p_\mathrm{T})$ observable to these key medium properties. The findings establish $v_{0}(p_\mathrm{T})$ as a valuable addition to the set of observables used in Bayesian analyses for extracting the transport properties and constraining the equation of state of strongly interacting matter, while also helping to systematically explore its sensitivity and impact within such global studies.

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arXiv2026

Common femtoscopic hadron-emission source in pp collisions at the LHC

The femtoscopic study of pairs of identical pions is particularly suited to investigate the effective source function of particle emission, due to the resulting Bose-Einstein correlation signal. In small collision systems at the LHC, pp in particular, the majority of the pions are produced in resonance decays, which significantly affect the profile and size of the source. In this work, we explicitly model this effect in order to extract the primordial source in pp collisions at $\sqrt{s}=13$ TeV from charged $π- π$ correlations measured by ALICE. We demonstrate that the assumption of a Gaussian primordial source is compatible with the data and that the effective source, resulting from modifications due to resonances, is approximately exponential, as found in previous measurements at the LHC. The universality of hadron emission in pp collisions is further investigated by applying the same methodology to characterize the primordial source of K$-$p pairs. The size of the primordial source is evaluated as a function of the transverse mass ($m_{\rm T}$) of the pairs, leading to the observation of a common scaling for both $π- π$ and K$-$p, suggesting a collective effect. Further, the present results are compatible with the $m_{\rm T}$ scaling of the p$-$p and p$-Λ$ primordial source measured by ALICE in high multiplicity pp collisions, providing additional evidence for the presence of a common emission source for all hadrons in small collision systems at the LHC. This will allow the determination of the source function for any hadron-hadron pairs with high precision, granting access to the properties of the possible final-state interaction among pairs of less abundantly produced hadrons, such as strange or charmed particles.

hep-ph↗

arXiv2026

Measurement of isolated prompt photon production in pp and p-Pb collisions at the LHC

This paper presents the measurement of the isolated prompt photon inclusive production cross section in pp and p-Pb collisions by the ALICE Collaboration at the LHC. The measurement is performed in p-Pb collisions at centre-of-mass energies per nucleon pair of $\sqrt{s_{\rm{NN}}} = 5.02$ TeV and $8.16$ TeV, as well as in pp collisions at $\sqrt{s} = 5.02$ TeV and $8$ TeV. The cross section is obtained at midrapidity $(|y|<0.7)$ using a charged-track based isolation momentum $p_{\rm T}^{\rm{iso, ch}} < 1.5$ GeV/$c$ in a cone with radius $R=0.4$. The data for both collision systems are well reproduced by perturbative QCD (pQCD) calculations at next-to-leading order (NLO) using recent parton distribution functions for free (PDF) and bound (nPDF) nucleons. Furthermore, the nuclear modification factor $R_{\text{pA}}$ for both collision energies is consistent with unity for $p_{\rm T} > 20$ GeV/$c$. However, deviations from unity ($R_{\rm pA}<1$) of up to 20% are observed for $p_{\rm T} < 20$ GeV/$c$ with limited significance, indicating the possible presence of nuclear effects in the initial state of the collision. The suppression increases with decreasing \pt with a significance of $2.3σ$ for a non-zero slope and yields $R_{\rm pA}<1$ with a significance of $1.8σ$ at $\sqrt{s_{\rm NN}} = 8.16$ TeV for $p_{\rm T} < 20$ GeV/$c$. In addition, a significance of $1.1σ$ is observed for $R_{\rm pA}<1$ at the lower collision energy $\sqrt{s_{\rm NN}} = 5.02$ TeV for $p_{\rm T} < 14$ GeV/$c$. The magnitude and shape of the suppression are consistent with pQCD predictions at NLO using nPDFs that incorporate nuclear shadowing effects in the Pb nucleus.

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arXiv2026

Observation of deuteron and antideuteron formation from resonance-decay nucleons

High-energy hadronic collisions generate environments characterized by temperatures above 100 MeV [1,2], about 100,000 times hotter than the center of the Sun. It is therefore currently unclear how light (anti)nuclei with mass number A of a few units, such as the deuteron, $^3$He, or $^4$He, each bound by only a few MeV, can emerge from these collisions [3,4]. The ALICE collaboration reports that deuteron-pion momentum correlations in proton-proton (pp) collisions provide model-independent evidence that about 90% of the observed (anti)deuterons are produced in nuclear reactions [5] following the decay of short-lived resonances, such as the $Δ(1232)$. These findings, obtained by the ALICE experiment at the Large Hadron Collider (LHC) resolve a gap in our understanding of nucleosynthesis in ultra-relativistic hadronic collisions. Beyond offering insights on how (anti)nuclei are formed in hadronic collisions, the results can be employed in the modeling of the production of light and heavy nuclei in cosmic rays [6] and dark matter decays [7,8].

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arXiv2026

$\overlineΣ^{\pm}$ production in pp and p-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV with ALICE

The transverse momentum spectra and integrated yields of anti-$Σ$ hyperons ($\overlineΣ^{\pm}$) have been measured in pp and p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV with the ALICE experiment. Measurements are performed via the newly accessed decay channel $\overlineΣ^{\pm} \rightarrow {\rm\overline{n}}π^{\pm}$. A new method of antineutron reconstruction with the PHOS electromagnetic spectrometer is developed and applied to this analysis. The $p_{\rm T}$ spectra of $\overlineΣ^{\pm}$ are measured in the range $0.5 < p_{\rm T} < 3$ GeV/$c$ and compared to predictions of the PYTHIA 8, DPMJET, PHOJET, EPOS LHC and EPOS4 models. The EPOS LHC and EPOS4 models provide the best descriptions of the measured spectra both in pp and p-Pb collisions, while models which do not account for multiparton interactions provide a considerably worse description at high $p_{\rm T}$. The total yields of $\overlineΣ^{\pm}$ in both pp and p-Pb collisions are compared to predictions of the Thermal-FIST model and dynamical models PYTHIA 8, DPMJET, PHOJET, EPOS LHC and EPOS4. All models reproduce the total yields in both colliding systems within uncertainties. The nuclear modification factors $R_\mathrm{pPb}$ for both $\overlineΣ^{+}$ and $\overlineΣ^{-}$ are evaluated and compared to those of protons, $Λ$ and $Ξ$ hyperons, and predictions of EPOS LHC and EPOS4 models. No deviations of $R_\mathrm{pPb}$ for $\overlineΣ^{\pm}$ from the model predictions or measurements for other hadrons are found within uncertainties.

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