A basic model for high energy cosmic ray interactions

Abstract

A Monte Carlo generator of high energy cosmic ray interactions, relying on a very basic and transparent theoretical formalism, in the framework of the Reggeon Field Theory, is presented. The main motivation for our work is to provide a new cosmic ray interaction model characterized by relatively transparent physics, sufficient parameter freedom, and a high computational efficiency, which can be easily managed by external users, including a re-tuning of the model parameters. Such a model can be used for studying potential modifications of the interaction treatment, necessary for describing particular sets of data on extensive air showers initiated by high energy cosmic rays, at a microscopic level, thereby keeping a consistency with general restrictions, like the unitarity, energy-momentum and charge conservation, Lorentz and isospin invariance. Importantly, this should allow one to study a compatibility of such modifications with relevant accelerator data. The model results for particle production and for basic extensive air shower characteristics are presented and discussed.

Figures (23)

• Figure 1: Schematic view of the fragmentation of a fast $ud$ diquark into a proton: both large $x$ and small $x$ limits of the proton LC momentum distribution correspond to a large rapidity $y$ separation between the $u$ and $\bar{u}$ of the vacuum-created $u\bar{u}$ pair. Left: the large $x$ limit ($1-x\propto e^{-y}$) is obtained by slowing down the $\bar{u}$ antiquark. Right: the small $x$ limit ($x\propto e^{-y}$) corresponds to slowing down both the $u$ quark and the original $ud$ diquark.
• Figure 2: Schematic view of the contributions of absorptive (left) and elastic (right) interactions of the virtual pion to $\pi^+p$ scattering. The vertical ellipses correspond to the contributions of uncut Pomeron exchanges. In particular, such exchanges between the incoming pion and the proton, shown by the large ellipses, are responsible for absorptive corrections to the processes.
• Figure 3: Examples of a planar diagram contribution to hadron production in $\pi^+p$ scattering (left) and of an undeveloped cylinder diagram contribution to hadron production in $pp$ scattering (right).
• Figure 4: C.m. energy dependence of total and elastic cross sections for $pp$ and $\bar{p}p$ scattering (left), and of forward elastic $pp$ scattering slope (right), compared to experimental data pdgant19aad23 (points): $pp$ -- red solid lines and filled triangles, $\bar{p}p$ -- blue dashed lines and open squares.
• Figure 5: C.m. energy dependence of total and elastic cross sections for pion-proton (left) and kaon-proton (right) scattering, compared to experimental data pdg (points): $\pi^+p$ and $K^+p$ -- red solid lines and filled triangles; $\pi^-p$ and $K^-p$ -- blue dashed lines and open squares.