Speaker
Description
The problem of the excess of muons in extensive air showers (EAS) initiated by very high energy cosmic rays remains an intriguing challenge even for modern upgraded and retuned models of high energy hadron interactions. Collider experiments also demonstrate many indications of some new processes taking place in pp, pA and AA interactions. While some improvements come from the consideration of collective effects originating from high multiplicity of produced partons even in small systems, the standard free string fragmentation model development still has a lot of potential.
In this talk the main features of a new string model of hadronization with the focus on the EAS-related properties are presented. This model is essentially a framework for massive relativistic strings fragmentation. The key features include the proper treatment of strings with non-zero mass, the consideration of the string angular momentum (spin) and its conservation and the new approach to the description and hierarchy of the string-to-hadron transition.
The resulting picture of hadron production features the suppression of scalar mesons production for high-rotation strings. The natural non-symmetrical $\rho^0/\rho^{\pm}$ production that agrees with experimental data is observed. The model also has a natural mechanism for string fragmentation stopping.
