Exploring formation of Quark-Gluon Plasma through two-particle correlations functions in A+A and p+p data

Authors

  • Sihan Chen
  • Yuhe Dai
  • Pinzhen Gong
  • Haoran Hu
  • Zhixuan Luo

DOI:

https://doi.org/10.61173/kd8g9155

Keywords:

PP collision, PbPb collision, quark-gluon plasma, correlation function, QGP Formation

Abstract

This paper is the result of team’s hard work, which delves into the correlation functions in proton-proton and PbPb(Lead-Lead) collisions, scrutinizing their relevance in the formation of quark-gluon plasma. This project first simulated these high-energy collisions and generated a comprehensive dataset of proton-proton and PbPb(Proton-Proton) interactions. The entire analysis is designed around the task of calculating azimuthal and pseudorapidity correlation functions, and wish to compare the differences and similarities between the two collision types. Also delved into these correlation functions in proton-proton collisions as potential evidence for QGP(Quark-gluon plasma), a type of matter typically found in heavy metal collisions such as Pb-Pb. The results reveal unique patterns lurking in the correlation functions that suggest that QGPs may form even in smaller collision systems. Also Quark-Gluon Plasma (QGP) is a state where quarks and gluons move freely at extremely high energy densities. The two-particle correlation function helps identify QGP by measuring how particles are correlated after a collision. Specific patterns in these correlations, like a “ridge” structure, indicate the collective behavior of particles, signaling the formation of QGP. These findings are expected to shed more light on the intricate dynamics in particle collisions and the specific conditions that lead to the formation of QGPs.

References

Δη and Δφ are zero, a visible peak forms. The graphs (2012). Anisotropic flow in event-by-event ideal hydrodynamic also show the differences between pp collision and Pb-Pb simulations of √(s_NN ) = 200 GeV Au + Au collisions. collision. The direction of the ridge-like structures in pp European Physical Journal C, 72, 2128.

collision and Pb-Pb collision are vertical to each other, the [2] Acharya, S., et al. (ALICE Collaboration). (2018). Energy former has such a structure that appears more intensively dependence of jet fragmentation in pp collisions. Physical and concentrated in a certain range of Δη(usually where Review C, 99(5), 054906. |η| < 1), while the latter has such a structure that appears [3] Adam, J., et al. (ALICE Collaboration). (2015). Resonance more pronounced, spanning the central pseudorapidity re- decay dynamics in pp and Pb–Pb collisions at the LHC. Journal gion and a wider azimuthal angle range. of Physics: Conference Series, 668, 012020.

The program also includes some research about [4] Cao, S., Luo, T., Qin, G. Y., & Wang, X. N. (2017). Jet energy QGP (Quark Gluon Plasma). Quark–gluon plas- loss, jet-medium interaction, and jet quenching in high-energy ma (QGP or quark soup) is an interacting localized as- nuclear collisions: A review. European Physical Journal C, 77, sembly of quarks and gluons at thermal (local kinetic) and 552. (close to) chemical (abundance) equilibrium. QGP has [5] Zhou, Y., Xu, H., Li, X., & Song, H. (2017). Investigating close relationship with the distribution of the particles af- elliptic flow and QGP properties with event-by-event viscous ter the collision, which influences the shape of our graphs hydrodynamics in PbPb collisions at √sNN = 2.76 and 5.02 TeV. a lot. Basically, the formation of QGP occurs under high Physical Review C, 96(4), 044904.

density situation, generally in heavy ions’ collision. In [6] Larkoski, A. J., Marzani, S., Soyez, G., & Thaler, J. (2017). the Pb-Pb collision, QGP was going to form two possible Looking inside jets: an introduction to jet substructure and shapes, oval and triangle. The distribution of the particles boosted-object phenomenology. Physics Reports, 658, 1-160.

of these two shapes of QGP can be written into two differ- [7] Chatrchyan, S. (2013). Multiplicity and transverse ent cosine-like functions. By using Fourier transform, two momentum dependence of two- and four-particle correlations in functions can be combined with each other. The shape of pPb and PbPb collisions. Physics Letters B, 724(1), 213-240. this function is highly similar to our graphs, and this ex- https://doi.org/10.1016/j.physletb.2013.06.028

plains why the ridge-like structure occurs in such rhythms. [8] Sahoo, R. (2023). Possible formation of Quark-Gluon Moreover, although proton-proton collisions in modern Plasma in small collision systems at the Large Hadron particle accelerators like the LHC and RHIC can reach Collider: Observations and Challenges. arXiv. https://arxiv.org/ very high energies, the energy density of these collisions abs/2307.14665

remains lower than that achieved in heavy-ion collisions, [9] Zhang, L., Chen, J., Li, W., & Lin, Z.-W. (2022). Implication such as lead-lead collisions. For this reason, QGP can’t of two-baryon azimuthal correlations in pp collisions at LHC form. energies on the QGP. arXiv. https://arxiv.org/abs/2112.14358

In the following days, our team will keep doing research [10] Zhang, L., Chen, J., Li, W., & Lin, Z.-W. (2022). Implication on such a project, and we will try to do our best to use the of two-baryon azimuthal correlations in pp collisions at LHC latest data to draw the most accurate picture. Addition- energies on the QGP. arXiv preprint arXiv:2112.14358. https:// ally, we’ll keep doing research on the formation of QGP arxiv.org/pdf/2112.14358

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Published

2024-10-29