On the Spiral Structures in Heavy-Ion Collisions

It is well established that many galaxies, like our Milky Way, exhibit spiral patterns. The entire galactic disc rotates about the galactic centre with different speeds; higher closer to the centre, lower at greater distances - that is, galactic discs do not rotate like a solid compact disc. The spiral arms are the part of the galactic disc where many young stars are being born. Since young stars are also brightest, we can see the spiral structure of other galaxies from afar. Typically spiral galaxies are copiously observed at redshifts z ~ 1. The recently observed grand-design galaxy Q2343-BX442 at z=2.18, however, implies uncertain origin of its spiral structure. Indeed such "old" galaxies usually look rather clumpy because of their dynamically hot discs. In this report, based on self-similarity, we argue that spiral structures may also appear in heavy-ion collisions as messengers of phase transitions. Thus, spiral structures in galactic patterns may be traced back to a few microseconds after the Big Bang.