Introduction

Relativistic Heavy-Ion Nuclear Physics

For a few fleeting moments after the Big Bang the universe was filled with an astonishingly hot and dense soup known as the Quark-Gluon Plasma (QGP), a precursor to the matter we observe today that consisted of elementary particles. Although this Quark-Gluon Plasma also contained leptons and weak gauge bosons, its transport properties were dominated by the strong interaction between quarks and gluons. Utilizing the most powerful particle accelerators, physicists now conduct head-on collisions between heavy ions, such as gold or lead nuclei, to recreate conditions that existed at the birth of the universe [1].

Projects

1. ALICE (A Large Ion Collider Experiments) at CERN LHC 

LHC (The Large Hadron Collider)

ALICE detector

Quantum Chromodynamics (QCD), the theory of strong interaction, deals with the in- teractions between quarks and gluons [2]. QCD has two particular features: the quark confinement inside hadrons (∼ 1 fm) and the asymptotic freedom at large momentum trans- fer scale on short distance [3, 4, 5]. Due to asymptotic freedom, at high temperature, quarks and gluons become weakly coupled, freed from nucleons, forming a new state of matter called the Quark-Gluon Plasma (QGP) [6].

Jets, defined as collimated sprays of high-momentum particles, are experimental signatures of hard-scattered quarks and gluons produced in hadronic interactions. Jet production cross sections are calculable within perturbative Quantum ChromoDynamics (pQCD), and therefore jet measurements provide stringent tests of pQCD predictions. In ultrarelativistic heavy-ion collisions, jets are well calibrated probes of the Quark-Gluon Plasma (QGP) [7].

The centrality is defined as the percentile of the hadronic cross section corresponding to a particle multiplicity, or an energy deposited, measured in ALICE. The impact parameter b, which is defined as the distance between the center of two nuclei, determines the overlap area of the two colliding nuclei. The degree of overlap, called ’centrality’, is defined as a function of the impact parameter b [8].

ALICE is preparing a major upgrade of its detector to be installed during the second long LHC shutdown (LS2). The main objective is to increase the readout capabilities to allow the readout and recording of Pb–Pb minimum bias events at rates in excess of 50 kHz, the expected Pb–Pb interaction rate at the LHC after LS2 [9].

ITS 3

ALICE 3 is a compact, next-generation multipurpose detector at the LHC as a follow-up to the present ALICE experiment. The aim is to build a nearly massless barrel detector consisting of truly cylindrical layers based on curved wafer-scale ultra-thin silicon sensors with MAPS technology, featuring an unprecedented low material budget of 0.05% X0 per layer, with the innermost layers possibly positioned inside the beam pipe [10].

ALICE 3

2. LAMPS (the Large Acceptance Multi-Purpose Spectrometer) at RAON

A new radioactive ion-beam accelerator facility, RAON, is under construction in Korea. Among the seven experimental systems being built, the Large Acceptance Multi-Purpose Spectrometer (LAMPS) in the high-energy experimental hall is the versatile detector system for nuclear physics. Its primary goal is to study the nuclear equation of state (EoS) and the symmetry energy of the compressed nuclear matter, which should be essential to understand the effective nuclear interactions and structure of the astrophysical objects like neutron stars [11].

3. NDPS (Nuclear Data Production System) at RAON

TBD

4. EIC (The Electron-Ion Collider)

The EIC will be a particle accelerator that collides electrons with protons and nuclei to produce snapshots of those particles’ internal structure—like a CT scanner for atoms. The electron beam will reveal the arrangement of the quarks and gluons that make up the protons and neutrons of nuclei. The force that holds quarks together, carried by the gluons, is the strongest force in Nature. The EIC will allow us to study this “strong nuclear force” and the role of gluons in the matter within and all around us. What we learn from the EIC could power the technologies of tomorrow [12].

References

  1. Shen, C.; Heinz, U. The road to precision: Extraction of the specific shear viscosity of the QGP. Nucl. Phys. News 2015, 25, 6–11.
  2. W. Greiner, E. Schramm, Stefan Stein, and D. d’Enteria et al., Quantum Chromodynamics. Springer-Verlag Berlin Heidelberg, 2007. 978-3-540-48534-6. 
  3. K. G. Wilson, “Confinement of Quarks,” Phys. Rev. D10 (1974) 2445–2459.
  4. D. J. Gross and F. Wilczek, “Ultraviolet Behavior of Nonabelian Gauge Theories,” Phys. Rev. Lett. 30 (1973) 1343–1346.
  5. H. D. Politzer, “Reliable Perturbative Results for Strong Interactions?,” Phys. Rev. Lett. 30 (1973) 1346–1349.
  6. Y. Kohsuke, H. Tetsuo, and Y. Miake, Quark-Gluon Plasma: From Big Bang to Little Bang. Cambridge University Press, 2008. 9780521089241.
  7. Jet
  8. Mult
  9. ITS 3
  10. ALICE 3
  11. B. Hong, D.S. Ahn, J.K. Ahn, et al., "Status of LAMPS at RAON", Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, Volume 541, 2023, Pages 260-263, ISSN 0168-583X
  12. https://www.bnl.gov/eic/