3. Producción

Browse

Search Results

Now showing 1 - 10 of 10

Some of the metrics are blocked by your
consent settings
Long-Range Transverse-Momentum Correlations and Radial Flow in Pb-Pb Collisions at the LHC
(American Physical Society, 2026-01-23)
This Letter presents measurements of long-range transverse-momentum correlations using a new observable, v 0 ( p T ) , serving as a probe of event-by-event radial-flow fluctuations, the underlying radial expansion, and the medium's 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 s 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 T , a characteristic mass ordering consistent with hydrodynamic collective flow is observed. At higher p T ( > 3 GeV / c ), protons exhibit larger v 0 ( p 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 T ) observable to these key medium properties. The findings establish v 0 ( p 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.
22
Some of the metrics are blocked by your
consent settings
System size and energy dependence of the mean transverse momentum fluctuations at the LHC
(Springer Nature, 2025)
Event-by-event fluctuations of the event-wise mean transverse momentum, ⟨Pᴛ⟩, of charged particles produced in proton–proton (pp) collisions at √s = 5.02 TeV, Xe–Xe collisions at √ˢɴɴ = 5.44 TeV, and Pb–Pb collisions at √ˢɴɴ = 5.02 TeV are studied using the ALICE detector based on the integral correlator ⟨⟨ΔPᴛ ΔPᴛ⟩⟩ . The correlator strength is found to decrease monotonically 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 the HIJING and AMPT models. 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. Low-spherocity (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.
4
Some of the metrics are blocked by your
consent settings
Common femtoscopic hadron-emission source in pp collisions at the LHC
(Springer Nature, 2025)
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 √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 ( mₜ ) 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 mT 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.
4
Some of the metrics are blocked by your
consent settings
Observation of the Ωð2012Þ baryon at the LHC
(American Physical Society, 2025)
A signal consistent with the Ω ( 2012 ) baryon has been observed with a significance of 15 σ in pp collisions at s = 13 TeV at the LHC. In this paper, the analysis technique is described and measurements of the mass and width of the Ω ( 2012 ) are reported, along with the first measurement of its transverse-momentum spectrum and yield. This paper corroborates the observation by the Belle Collaboration of this excited Ω state and the observation that the Ω ( 2012 ) has a rather narrow width for a strongly decaying resonance. The yield measurement is combined with a statistical thermal model calculation of strange baryon yield ratios to obtain estimates of the Ω ( 2012 ) − → Ξ K ¯ branching ratios. These results will improve our understanding of the internal structure and mass spectrum of excited baryon states and serve as a baseline for searches regarding modifications of these properties in high-temperature media.
3
Some of the metrics are blocked by your
consent settings
First measurement of Dₛ₁(1⁺)(2536)⁺ and D*ₛ₂(2⁺)(2573)⁺ production in proton-proton collisions at √s = 13 TeV at the LHC
(American Physical Society, 2025)
The production yields of the orbitally excited charm-strange mesons Dₛ₁(1⁺)(2536)⁺ and D*ₛ₂(2⁺)(2573)⁺ were measured for the first time in proton-proton (pp) collisions at a center-of-mass energy of √s = 13 TeV with the ALICE experiment at the LHC. The D⁺ₛ₁ and D*⁺ₛ₂ mesons were measured at midrapidity (|y| < 0.5) in minimum-bias and high-multiplicity pp collisions in the transverse-momentum interval 2 < Pᴛ < 24 GeV/c. Their production yields relative to the D⁺ₛ ground-state yield were found to be compatible between minimum-bias and high-multiplicity collisions, as well as with previous measurements in e±p and e⁺e¯ collisions. The measured D⁺ₛ₁/D⁺ₛ and D*⁺ₛ₂/D⁺ₛ yield ratios are described by statistical hadronization models and can be used to tune the parameters governing the production of excited charm-strange hadrons in Monte Carlo generators, such as PYTHIA 8.
5
Some of the metrics are blocked by your
consent settings
First Measurement of A = 4 Hypernuclei and Antihypernuclei at the LHC
(American Physical Society, 2025)
In this Letter, the first evidence of the 4/Λ H ̅ⅇ antihypernucleus is presented, along with the first measurement at the LHC of the production of (anti)hypernuclei with mass number A = 4, specifically (anti) 4/Λ H and (anti) 4/Λ He. In addition, the antiparticle-to-particle ratios for both hypernuclei (4/Λ H ̅/4/Λ H = and 4/Λ H ̅ⅇ = 4/Λ Hⅇ) are shown, which are sensitive to the baryochemical potential of the strongly interacting matter created in heavy-ion collisions. The results are obtained from a data sample of central Pb-Pb collisions, collected during the 2018 LHC data taking at a center-of-mass energy per nucleon pair of √ˢɴɴ = 5.02 TeV. The yields measured for the average of the charge-conjugated states are found to be [0.78 ± 0.19(stat) ± 0.17(syst)] × 10⁻⁶ for the (anti) 4/Λ H, and [1.08 ± 0.34(stat) ± 0.20(syst)] × 10⁻⁶ for the (anti) 4/Λ He, and the measured antiparticle-to-particle ratios are in agreement with unity. The presence of (anti) 4/Λ H and (anti) 4/Λ He excited states is expected to strongly enhance the production yield of these hypernuclei. The yield values exhibit a combined deviation of 3.3σ from the theoretical ground-state-only expectation, while the inclusion of the excited states in the calculations leads to an agreement within 0.6σ with the present measurements. Additionally, the measured (anti) 4/Λ H and (anti) 4/Λ He masses are compatible with the world-average values within the uncertainties.
3
Some of the metrics are blocked by your
consent settings
Multimuons in cosmic-ray events as seen in ALICE at the LHC
(Institute of Physics, 2025)
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 < Eᵨᵣᵢₘ < 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 Eᵨᵣᵢₘ ∼ 10¹⁷ eV of these events. This result places significant constraints on more exotic production mechanisms.
2
Some of the metrics are blocked by your
consent settings
Exploring nuclear structure with multiparticle azimuthal correlations at the LHC
(Elsevier, 2025)
Details of the nuclear structure of 129Xe, such as the quadrupole deformation and the nuclear diffuseness, are studied by extensive measurements of anisotropic-flow-related observables in Xe–Xe collisions at a centre-of-mass energy per nucleon pair √𝑠 NN = 5.44 TeV with the ALICE detector at the LHC. The results are compared with those from Pb–Pb collisions at √𝑠 NN = 5.02 TeV for a baseline, given that the 208Pb nucleus exhibits a very weak deformation. Furthermore, comprehensive comparisons are performed with a state-of-the-art hybrid model using IP-Glasma+MUSIC+UrQMD. It is found that among various IP-Glasma+MUSIC+UrQMD calculations with different values of nuclear parameters, the one using a nuclear diffuseness parameter of 𝑎0 = 0.492 and a nuclear quadrupole deformation parameter of 𝛽2 = 0.207 provides a better description of the presented flow measurements. These studies represent the first systematic exploration of nuclear structure at TeV energies, utilizing a comprehensive set of anisotropic flow observables. The measurements serve as a critical experimental ben
2
Some of the metrics are blocked by your
consent settings
Femtoscopic study of the proton-proton and proton-deuteron systems in heavy-ion collisions at the LHC
(Elsevier, 2025)
This work reports femtoscopic correlations of p–p (p–p) and p–d (p–d) pairs measured in Pb–Pb collisions at centerof-mass energy per nucleon √ 𝑠NN = 5.02 TeV in the ALICE Collaboration. A fit to the measured proton-proton correlation functions allows one to extract the dependence of the nucleon femtoscopic radius of the particleemitting source on the pair transverse mass (𝑚T ) and on the average charge particle multiplicity ⟨dNch∕d𝜂⟩ 1∕3 for three centrality intervals (0 − 10%, 10 − 30 %, 30 − 50%). In both cases, the expected power-law and linear scalings are observed, respectively. The measured p–d correlations can be described by both two- and threebody calculations, indicating that the femtoscopy observable is not sensitive to the short-distance features of the dynamics of the p-(p-n) system, due to the large inter-particle distances in Pb–Pb collisions at the LHC. Indeed, in this study, the minimum measured femtoscopic source sizes for protons and deuterons have a minimum value at 2.73+0.05 −0.05 and 3.10+1.04 −0.86 fm, respectively, for the 30–50% centrality collisions. Moreover, the 𝑚T -scaling obtained for the p–p and p–d systems is compatible within 1𝜎 of the uncertainties. These findings provide new input for fundamental studies on the production of light (anti)nuclei under extreme conditions.
2
Some of the metrics are blocked by your
consent settings
Multiplicity-dependent jet modification from di-hadron correlations in pp collisions at √s = 13 TeV
(Springer Science and Business Media Deutschland GmbH, 2025)
Short-range correlations between charged particles are studied via two-particle angular correlations in pp collisions at √s = 13 TeV. The correlation functions are measured as a function of the relative azimuthal angle ∆φ and the pseudorapidity separation ∆η for pairs of primary charged particles within the pseudorapidity interval |η| < 0.9 and the transverse-momentum range 1 < Pᴛ < 8 GeV/c. Near-side (|∆φ| < 1.3) peak widths are extracted from a generalised Gaussian fitted over the correlations in full pseudorapidity separation (|∆η| < 1.8), while the per-trigger associated near-side yields are extracted for the short-range correlations (|∆η| < 1.3). Both are evaluated as a function of charged-particle multiplicity obtained by two different event activity estimators. The width of the near-side peak decreases with increasing multiplicity, and this trend is reproduced qualitatively by the Monte Carlo event generators PYTHIA 8, AMPT, and EPOS. However, the models overestimate the width in the low transverse-momentum region (Pᴛ < 3 GeV/c). The per-trigger associated near-side yield increases with increasing multiplicity. Although this trend is also captured qualitatively by the considered event generators, the yield is mostly overestimated by the models in the considered kinematic range. The measurement of the shape and yield of the short-range correlation peak can help us understand the interplay between jet fragmentation and event activity, quantify the narrowing trend of the near-side peak as a function of transverse momentum and multiplicity selections in pp collisions, and search for final-state jet modification in small collision systems.
2

3. Producción

Browse

Filters

Settings

Sort By

Results per page

Search Results