Notice bibliographique
Résumé
Under extreme conditions, such as high temperature and density, quarks and gluons can be deconfined. The deconfined matter, quark-gluon plasma (QGP), that existed within the first microsecond after the Big Bang, can be recreated in ultra-relativistic heavy-ion collisions at particle accelerators. One way to investigate the initial conditions and the dynamic evolution of such a collectively expanding medium is by studying the anisotropic flow, quantified by flow coefficients $v_n$. Experimental measurements of the QGP from various flow observables show remarkable agreement with the hydrodynamic calculations, suggesting the QGP behaves like a nearly ideal fluid. The collective behaviour associated with the presence of QGP is also observed in small collision systems at very high multiplicities with significantly more produced particles than in an average small system collision. Based on the existing studies, it is known that the anisotropic flow in small systems is mainly driven by the initial geometry of the system. However, the development of flow from the initial geometry through the dynamic evolution is still under discussion. In this thesis, the anisotropic flow is studied using different observables and across different collision systems. A new generic algorithm is developed to formulate multi-particle cumulants of arbitrary order in Pb--Pb collisions at $\sqrt{s_{\rm{NN}}} = 5.02$ TeV. The measurements of multi-particle cumulants of single and mixed harmonics are reported. \linebreak Mixed harmonic cumulants $MHC(v_m^k,v_n^l)$ have a unique sensitivity to the initial conditions. Thus, the results are compared to the calculations from hydrodynamical models in order to constrain initial conditions and transport properties of the QGP. The flow coefficients $v_2(p_{\rm T})$ are calculated using the two- and four-particle cumulants method. With these observables, it is possible to study the first two moments of the probability density function of elliptic flow, the mean $\langle v_2 \rangle$ and variance $\sigma_{v_{2}}$, and the relative flow fluctuations of identified particles for the first time in heavy-ion collisions. Moreover, the elliptic flow $v_2(p_{\rm T})$ with various identified particle species is studied in Pb--Pb collisions to further probe the initial conditions and properties of QGP, in particular, the particle production mechanisms, e.g., quark coalescence. The flow measurements of identified particles in heavy-ion collisions bring a unique insight into initial conditions and the properties of QGP. Therefore, such a study in small collision systems can contribute to understanding the role of initial conditions and the state of the recreated matter. However, the study of flow coefficients in small systems is more challenging due to significant non-flow contamination. The measurement is performed in p--Pb and pp collisions at $\sqrt{s_{\rm{NN}}} = 5.02$ and 13 TeV, respectively. Thanks to the unique pseudorapidity coverage of ALICE, the flow coefficients with sufficient non-flow suppression are obtained using ultra-long-range two-particle correlations and the template fit method. Many similarities are observed in flow in large and small systems. The measured $v_2(p_{\rm T})$ coefficients exhibit mass ordering in the low transverse momentum region. Such a phenomenon originates from the radial expansion of the system. The baryon-meson grouping at the intermediate transverse momentum, which in Pb--Pb is typically associated with partonic collectivity and quark coalescence, is also reported in p--Pb and pp collisions. These observations are discussed in the context of models with and without the contribution of quark coalescence. The similarities between large and small systems show strong evidence that a droplet of QGP is created in small collision systems at high multiplicities.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,002 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,002 |
| Études des sciences et des technologies | 0,001 | 0,000 |
| Communication savante | 0,001 | 0,000 |
| Science ouverte | 0,000 | 0,001 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,002 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; les deux têtes enseignantes s’accordent sur ce qui est montré ici.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».