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High-energy collisions between聽protons听辞谤听heavy ions聽can produce energetic聽photons聽(particles of light) and聽jets, which are sprays of particles created when quarks or gluons are produced in a collision. Studying these聽photon-triggered jetshelps physicists understand how jets lose energy as they travel through the extremely hot, dense state of matter known as the聽quark-gluon plasma, which is created in heavy-ion collisions. In this study, the researchers used computer simulations based on a multistage model of jet evolution to predict several properties of photon-triggered jets and compared the results with measurements from the聽ATLAS,听CMS, and聽STAR聽experiments. The model closely matched experimental results for several key measurements, including how often photon-triggered jets are observed, the relationship between the energies of the jet and the accompanying photon, and the angular separation between them. The researchers also found that including additional sources of photons鈥攕pecifically聽bremsstrahlung photons聽(produced when charged particles are deflected) and photons from particle decays鈥攊mproved agreement with experimental data, particularly in certain energy ranges. These findings demonstrate that the multistage model can accurately describe photon-triggered jet behavior and highlight the importance of accounting for multiple photon sources when studying jet energy loss in heavy-ion collisions.
Fig 1
Nuclear modification factor聽饾憛饾惔鈦潗绰燼s a function of jet-聽 饾憹饾憞聽for photon-triggered jet for central聽0鈥�10%聽(left) and semicentral聽10鈥�30%聽(right) Pb-Pb collisions at聽鈭�饾憼饾憗鈦潙�=5.02聽TeV. The results from聽matter聽 +lbt聽within聽jetscape聽for full events (solid lines) and prompt photon events (dashed lines) are compared with ATLAS data聽[66].