Soudi, Ismail., Zhao, Wenbin., Majumder, Abhijit., Shen, Chun., Putschke, J枚rn Henning., Boudreaux, B., Angerami, Aaron., Arora, R., Bass, Steffen A., Chen, Yuchen., Datta, R., Du, Lipei., Ehlers, Raymond J., Elfner, Hannah., Fries, Rainer J., Gale, Charles., He, Yayun., Jacak, Barbara V., Jacobs, Peter M., Jeon, Sangyoung., Ji, Yi Irene., Kasper, L., Kelsey, Matthew H., Kordell, Michael C., Kumar, Amit., Kunnawalkam-Elayavalli, Raghav., Latessa, J., Lee, Yen Jie., Lemmon, Roy Crawford., Luzum, Matthew., Mak, Simon., Mankolli, Andi., Martin, Christopher B., Mehryar, Haydar., Mengel, Tanner., Nattrass, Christine E., Norman, Jaime., Parker, Cody E., Paquet, Jean Fran莽ois Fran莽ois., Roch, Hendrik., Roland, Gunther., Schenke, Bj枚rn., Schwiebert, Loren., Sengupta, A., Singh, Mayank., Sirimanna, Chathuranga., Soeder, Derek., Soltz, R. A., Tachibana, Yasuki., Velkovska, Julia., Vujanovic, Gojko., Wang, X. N., & Wu, Xiangyu. (2025).听.听Physical Review C,听112(1), 14905.听
We present听x-scape, a new framework to study high-energy collisions between protons (饾憹鈭掟潙�) and between protons and atomic nuclei (饾憹鈭掟潗�). These collisions produce particles that move in different ways: some carry听high momentum听(hard processes), while others move more gently (soft processes). Our model starts by placing small 鈥�hotspots鈥� of energy inside each proton or nucleon. When two hotspots collide, they create high-momentum particles, simulated with the听Pythia generator. The early radiation emitted by these particles is modeled with a new tool called听I-matter, which also accounts for where along the beam these emissions occur.
The energy used to produce these high-momentum particles is subtracted from the surrounding hotspots, which affects the creation of the bulk of the medium in the collision. The resulting showers of particles are simulated with the听matter generator, and we explore cases both with and without energy loss. We then compare our predictions to experimental data on single particles and jets from 饾憹鈭掟潙� and 饾憹鈭扨b collisions. Using data from single particles, we fine-tune the model parameters with a听Bayesian calibration. The comparisons show that x-scape can reproduce key features of the data, highlighting its usefulness. Finally, we study how the momentum of jets (饾憹饾憞) relates to the overall activity in the collision, helping us understand the complex dynamics of high-energy particle interactions.
FIG. 1.
Workflow of the听x-scape-gim听event generator for small collision systems.