Energy and mass dependencies for the characteristics of $p_T$ regions observed at LHC energies

Abstract

The $p_T$ distributions of the $K^0$- and $\phi$ - mesons produced in the $pp$ collisions at $\sqrt{s}=2.76 TeV$ have been analyzed by fitting them using the exponential function. It was observed that the distributions contain several $p_T$ regions similar to the cases with the charged particles, $\pi^0$- and $\eta$- mesons produced in the same events. These regions could be characterized using three variables: the length of the region $L^{c}_K $ and free fitting parameters $a^{c}_K $ and $b^{c}_K $. It was observed that the values of the parameters as a function of energy grouped around certain lines and there are jump-like changes. These observations together with the effect of existing the several $p_T$ regions can say on discrete energy dependencies for the $L^{c}_K $ , $a^{c}_K $ and $b^{c}_K $. The lengths of the regions increase with the mass of the particles. This increase gets stronger with energy. The mass dependencies of the parameters $a^{c}_K $ and $b^{c}_K $ show a regime change at a mass $\simeq 500 MeV/c^2$. According to the phenomenology of string theory, these results could be explained by two processes occurring simultaneously: string hadronization and string breaking. In the experiment we can only measure the spectrum of the hadronized particles, since we cannot access the spectrum of the strings themselves. The string breaking effect could be a signal of string formations and the reason behind the observation of several $p_T$ regions and the jump-like changes for the characteristics of the regions.