A Large Ion Collider Experiment (ALICE) at CERN \u00a9shutterstock\/D-VISIONS<\/figcaption><\/figure>\nIn contrast, due to the plasma behaving like a liquid, theoretical physicists have utilised multistage relativistic hydrodynamic models to explain the data. However, this has resulted in differences between these models and data with regard to low transverse momentum, in which the conventional and hybrid models fail to explain particle yields in the experiments.<\/p>\n
The research team proposed an innovative method to remedy this deviation.<\/p>\n
Professor Tetsufumi Hirano, the leader of the study and theoretical physicist at Sophia University, explained: \u201cTo find a mechanism that can account for the discrepancy between theoretical modelling and experimental data, we used a dynamical core-corona initialisation (DCCI2) framework in which the particles generated during high-energy nuclear collisions are described using two components: the core, or equilibrated matter, and the corona, or nonequilibrated matter. This picture allows us to examine the contributions of the core and corona components towards hadron production in the low transverse momentum region.\u201d<\/p>\n
Developing the dynamical core-corona initialisation framework<\/h3>\n Using a simulation programme known as PYTHIA, the team performed heavy-ion Pb-Pb collisions at an energy of 2.76 TeV to evaluate the DCCI2 framework. The dynamical initialisation of the quark-gluon plasma fluids enabled the separation of core and corona components, which were caused to undergo hadronisation through switching hypersurface and string fragmentation, respectively. The hardons underwent resonance decays to obtain the transverse momentum (pT<\/sub><\/em>) spectra.<\/p>\nDr Yuuka Kanakubo, a doctoral student at Sophia University, commented: \u201cWe switched off the hadronic scatterings and performed only resonance decays to see a breakdown of the total yield into core and corona components, as hadronic scatterings mix up the two components in the late stage of the reaction.\u201d<\/p>\n
The team analysed the fraction of core and corona components in the\u00a0pT\u00a0<\/sub><\/em>spectra of charged pions, charged kaons, and protons and antiprotons for collisions at 2.76 TeV. Subsequently, these spectra were compared to experimental data from the ALICE detector at LHC<\/a> for Pb-Pb collisions at 2.76 TeV.<\/p>\nThis allowed the researchers to calculate the contributions from corona components. Finally, they examined the effects of contributions from corona components on the flow variables.<\/p>\n
What did the results reveal about quark-gluon plasma?<\/h3>\n The researchers observed a relative increase in corona contributions in the spectral region of approximately 1 GeV for both 0-5% and 40-60% centrality classes. Although this was true for all hadrons, they discovered almost 50% corona contribution to particle production in the spectra of protons and antiprotons in the region of very low\u00a0pT<\/sub><\/em>\u00a0(\u2248 0 GeV).<\/p>\nThe results of complete DCCI2 simulations demonstrated better agreement with the ALICE experimental data compared to when only core components with hadronic scatterings were compared. Moreover, the corona contribution was discovered to be responsible for diluting the four-particle cumulants from core contributions, suggesting more permutations of particles with corona contribution.<\/p>\n
Professor Hirano concluded: \u201cThese findings imply that the nonequilibrium corona components contribute to particle production in the region of very low transverse spectra. This explains the missing yields in hydrodynamic models, which extract only the equilibrated core components from experimental data. This clearly shows that it is necessary to extract the nonequilibrated components as well for a more precise understanding of the properties of QGP.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"
Find out how researchers solved a quark-gluon plasma mystery that has long-evaded scientists and enriches our understanding of the Universe.<\/p>\n","protected":false},"author":15,"featured_media":29869,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[24429],"tags":[814,821],"acf":[],"yoast_head":"\n
Quark-gluon plasma mystery is finally solved<\/title>\n \n \n \n \n \n \n \n \n \n \n \n \n\t \n\t \n\t \n \n \n \n \n \n\t \n\t \n\t \n