The onset of pion condensation in heavy-ion collisions at the LHC energies

20 May 2014, 16:30
spectrum (darmstadtium)



Board: J-01
Poster Thermodynamics and Hadron Chemistry Poster session


Dr Viktor Begun (UJK)


Statistical models of hadron production have become one of the cornerstones of our understanding of ultra-relativistic heavy-ion collisions [1]. However, the measured proton abundances in Pb+Pb collisions at sqrt(sNN) = 2.76 TeV at LHC do not agree with the most common versions of the thermal models. Besides the proton anomaly, the same LHC data exhibits the low-transverse-momentum enhancement of pion spectra by about 25-50% with respect to the predictions of various thermal and hydrodynamic models [2]. In the recent work [3] we connect the proton anomaly with the pion enhancement effect and show that the two problems may be solved naturally within the statistical model which assumes chemical non-equilibrium at the freeze-out and a special combination of freeze-out geometry and flow - the Krakow single-freeze-out model in the Monte-Carlo version implemented in THERMINATOR [4]. We find a remarkable agreement between our model and the measured transverse-momentum spectra of pions and kaons. Although the protons are not included in the fit, our model explains well their spectrum, in addition to their yield. We also find a satisfactory description of hyperons with the same parameters. Correct description of the low-transverse-momentum enhancement of pions within our model suggests that it may be interpreted as a signature of the onset of pion condensation in ultra-relativistic heavy-ion collisions at the LHC energies. This is so, since the freeze-out conditions in the model are very close to the pion condensation point. [1] P. Braun-Munzinger, D. Magestro, K. Redlich, J. Stachel, Phys. Lett. B 518, 41 (2001). [2] B. Abelev et al. [ALICE Collaboration], Phys. Rev. Lett. 109, 252301 (2012); Phys. Rev. C 88, 044910 (2013). [3] V. Begun, W. Florkowski, M. Rybczynski, arXiv:1312.1487 [nucl-th]. [4] M. Chojnacki, A. Kisiel, W. Florkowski and W. Broniowski, Comput. Phys. Commun. 183, 746 (2012).

Primary author

Dr Viktor Begun (UJK)


Maciej Rybczynski (Jan Kochanowski University (PL)) Wojciech Florkowski (Institute of nuclear Physics, Krakow)

Presentation Materials