arXiv subjects

Anisa Khatun

Publications and source records attributed to Anisa Khatun.

8 recordsLinked to original sources

arXiv2026

Overview of recent UPC measurements

This contribution presents an overview of recent measurements of photon-induced processes in ultra-peripheral collisions (UPCs) performed with the ALICE experiment at the LHC. Results from Run~2 include detailed studies of exclusive vector meson photoproduction in Pb-Pb collisions. Measurements of incoherent J/$\psi$ photoproduction as a function of energy and the Mandelstam-$|t|$ variable, combined with electromagnetic dissociation (EMD) classification, show a suppression of the energy evolution at large $|t|$, favouring saturation-based descriptions of the gluon structure. Complementary measurements of proton emission in Pb-Pb UPCs constrain nuclear breakup mechanisms and provide a handle on collision geometry through EMD tagging. Coherent $\rho^{0}$ photoproduction exhibits impact-parameter-dependent azimuthal anisotropy consistent with quantum interference effects, while the first polarisation measurement of coherently photoproduced J/$\psi$ confirms $s$-channel helicity conservation. Additional measurements of exclusive multi-hadron photoproduction, including four-pion and charged kaon pair final states, probe resonance contributions and light vector meson couplings to photons and nuclear targets. Run~3 data enable the study of inclusive photonuclear interactions. Measurements of inclusive open charm photoproduction constrain the gluon content of nuclei in the perturbative QCD regime. Studies of identified hadron production and baryon-to-meson ratios in photonuclear collisions provide new information on particle production mechanisms and possible collective effects in photon-induced systems. Photon-photon interactions are also studied through performance and sensitivity analyses for the measurement of the anomalous magnetic moment of the tau lepton, together with projections for future measurements with ALICE~3.

nucl-ex↗

arXiv2026

GAN-based data augmentation for rare and exotic hadron searches in Pb--Pb collisions in ALICE

This work presents a feasibility study aimed at enhancing the reconstruction sensitivity for rare heavy-flavour hadrons in Pb-Pb collisions in the ALICE experiment, using the $\Xi_{c}^{+}$ baryon as a benchmark. The $\Xi_{c}^{+}$ baryon has a low rate of production and some complex decay topologies as for instance the decay $\Xi_{c}^{+} \rightarrow \Xi^{-} + \pi^{+} + \pi^{+}$ considered in this work. Traditional simulation workflows involving event embedding and full detector response are computationally expensive and statistically limited, especially for rare signals. This study represents the first exploration of generative models within the heavy-flavour programme of ALICE. It uses a dataset of reconstructed physics quantities, such as momenta, positions, and decay vertex coordinates of $\Xi_{c}^{+}$ decay products in Pb-Pb collisions as input features, derived from augmented ALICE Monte Carlo simulations. Such features will serve as a training set for Generative Adversarial Networks (GANs) designed to generate statistically significant synthetic signal samples without the need for additional full simulations. While $\Xi_{c}^{+}$ serves as a benchmark, the broader objective is to enable searches for exotic heavy-flavour hadrons or other exotic states with complex decay patterns. By leveraging GAN-based augmentation, this approach supports rare-signal extraction in computationally demanding analyses and opens the way to broader applications of generative models in the ALICE heavy-flavour programme.

hep-ex↗

arXiv2024

Recent ALICE results relevant for PDFs at low and high-$x$, saturation

We present recent results from the ALICE Collaboration on the study of coherent and incoherent J/$\psi$ photoproduction in ultra-peripheral Pb-Pb collisions, including results from exclusive and dissociate J/$\psi$ mesons in ultra-peripheral p-Pb interactions. These measurements provide unique insights into the initial state of protons and ions, with great sensitivity for both gluon saturation and shadowing. Furthermore, we will discuss the prospects for these measurements using the Run 3 and Run 4 data.

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arXiv2024

UPC physics with ALICE in Run 3

The ALICE experiment has undergone a major detector upgrade for Run 3, expanding its detection capabilities for a wide variety of studies. The new continuous readout has significantly enhanced the physics potential for ultra-peripheral collision analyses. In this talk, we discussed some of the physics analyses that can be carried out in ultra-peripheral collisions using the Run 3 data and presented some of the first physics performance plots in both proton-proton and heavy-ion collisions.

hep-ex↗

arXiv2020

$J/ψ$ Production Dynamics: Event shape, Multiplicity and Rapidity dependence in Proton+Proton Collisions at LHC energies using PYTHIA8

High-multiplicity pp collisions at the Large Hadron Collider (LHC) energies have created special importance in view of the Underlying Event (UE) observables. The recent results of LHC, such as long range angular correlation, flow-like patterns, strangeness enhancement etc. in high multiplicity events are not yet completely understood. In the same direction, the understanding of multiplicity dependence of J/$ψ$ production is highly necessary. Transverse spherocity, which is an event shape variable, helps to investigate the particle production by isolating the hard and the soft components. In the present study, we have investigated the multiplicity dependence of J/$ψ$ production at mid-rapidity and forward rapidity through the transverse spherocity analysis and tried to understand the role of jets by separating the isotropic and jetty events from the minimum bias collisions. We have analyzed the J/$ψ$ production at the mid-rapidity and forward rapidities via dielectron and dimuon channels, respectively using 4C tuned PYTHIA8 event generator. The analysis has been performed in two different center-of-mass energies: $\sqrt{s}$ = 5.02 and 13 TeV, to see the energy dependence of jet contribution to the multiplicity dependence study of J/$ψ$ production. Furthermore, we have studied the production dynamics through the dependence of thermodynamic parameters on event multiplicity and transverse spherocity.

hep-ph↗

arXiv2019

J/$ψ$ production as a function of charged-particle multiplicity in pp collisions at $\sqrt{s}$ = 5.02 TeV with ALICE

The relative J/$ψ$ yields as a function of relative charged-particle multiplicity in pp collisions at $\sqrt{s}$ = 5.02 TeV, measured at forward rapidity, are investigated for the first time. A linear increase of the relative J/$ψ$ yield with respect to multiplicity is observed. A comparison of the findings of the present work with the available ALICE measurements obtained in pp collisions at $\sqrt{s}$ = 13 TeV at forward and mid-rapidity indicates that the increase of J/$ψ$ with multiplicity is independent of energy but exhibits a strong dependence on the rapidity gap between the J/$ψ$ and multiplicity measurements. The results are compared with theoretical model calculations.

hep-ex↗

arXiv2017

Measurement of J/$ψ$ production as a function of multiplicity in pp and p-Pb collisions with ALICE

The increase of hard probe production as a function of the charged particle multiplicity in proton-proton and proton-lead collisions is considered to be an interesting observable for the study of multiple parton interactions. In the present work, the correlation between J/$ψ$ production and charged particle multiplicity has been reviewed in pp collisions at $\sqrt{s} = 7$ and 13 TeV and p-Pb collisions at $\sqrt{s_{\rm NN}}$ = 5.02 TeV at mid- and forward rapidities. The J/$ψ$ measurement in pp collisions at $\sqrt{s}$ = 13 TeV using events triggered by the ALICE electromagnetic calorimeter at midrapidity is discussed in this report, too. An increment of the relative J/$ψ$ yields has been observed as a function of the multiplicity. The results have also been compared to theoretical model predictions.

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arXiv2015

Search for Long-Range Correlations in Relativistic Heavy-Ion Collisions at SPS Energies

Long range correlations are searched for by analyzing the experimental data on 16O-AgBr and 32S-AgBr collisions at 200A GeV/c and the results are compared with the predictions of a multi phase transport (AMPT) model. The findings reveal that the observed forward-backward (F-B) multiplicity correlations are mainly of short-range in nature. The range of F-B correlations are observed to extend with increasing projectile mass. The observed extended range of F-B correlations might be due to overall multiplicity fluctuations arising because of nuclear geometry. The findings are not sufficient for making any definite conclusions regarding the presence of long-range correlations.

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