Wednesday Weekly Meeting

Wednesday 27 Aug 2025, 11:00 → 12:00 Asia/Tehran

Ahmad Mashal (ILSF)

General weekly meeting of the school of particles and accelerators (hybrid format)

• Meeting Place: Seminar Room, School of Particles and Accelerators, IPM
• Link to join virtually: https://www.skyroom.online/ch/ipm-particles/weekly-seminar

11:00 → 12:00 Running coupling for holographic QCD with heavy and light quarks: Isotropic case

We consider the running coupling constant in holographic models supported by Einstein-dilaton-Maxwell action for heavy and light quarks. To obtain the dependence of the running coupling constant α on temperature and chemical potential we impose boundary conditions on the dilaton field that depend on the position of the horizon. We use two types of boundary conditions: a simple boundary condition with the dilaton field vanishing at the horizon and a boundary condition that ensures an agreement with lattice calculations of string tension between quarks at zero chemical potential. The location of the first order phase transitions in the (mu,T)-plane does not depend on the dilaton boundary conditions for light and heavy quarks. At these phase transitions, the function α undergoes jumps depending on temperature and chemical potential. We also show that for the second boundary conditions the running coupling decreases with a temperature increase, and the dependence on temperature and chemical potential both for light and heavy quarks is actually specified in quark-gluon plasma (QGP) phase by functions of one variable, demonstrating in this sense automodel behavior.

Speaker: Dr Ali Hajilou (School of Particles and Accelerators - IPM)

Ali-Hajilou-27 Aug 2025-IPM (1).pdf