Saturation physics in ultra high energy cosmic rays: heavy quark production

Abstract

In this work we estimate the heavy quark production in the interaction of ultra high energy cosmic rays in the atmosphere, considering that the primary cosmic ray is a proton or a photon. At these energies the saturation momentum Q 2 sat (x) stays above the hard scale µ 2 c = 4m 2 c , implying charm production probing the saturation regime. In particular, we show that the ep HERA data presents a scaling on τ c ≡ (Q 2 + µ 2 c )/Q 2 sat (x). We derive our results considering the dipole picture and the Color Glass Condensate formalism, which one shows to be able to describe the heavy quark production in γp and pp collisions. Nuclear effects are considered for the scattering of primaries with the air nuclei and we provide a parametrization for the charm and bottom differential cross sections, dσ/dx F , which can be used as an input for numerical implementations for lepton flux. Implications on the flux of prompt leptons at the Earth are analyzed and a large suppression is predicted.

Heavy quark production in ultra high energy cosmic ray interactions

“…We have verified that these predictions describe the scarce HERA data for the photoproduction of heavy quarks, as already observed in Ref. [6]. In Fig.…”

“…Our goal is to extend the analysis performed in Ref. [6] some years ago, where the main focus was to estimate the heavy quark cross section in photon-air and proton-air interactions taking into account nuclear effects. In particular, we extend the study for neutrino-proton interactions and explicitly estimate, for the first time, the heavy quark contributions for the total cp; mp and pp cross sections.…”

“…Distinctly from Ref. [6], the cp and pp interactions are analyzed in detail, with the free parameters present in the color dipole predictions being constrained by the experimental data for the total cp cross section and by the recent LHC data for the heavy quark production, which strongly reduces the uncertainty in the predictions for ultra high cosmic ray energies. Moreover, the heavy quark production in a double parton scattering process in cosmic ray pp interactions is estimated for the first time.…”

Cosmic-Ray Studies with Experimental Apparatus at LHC

“…Thus, future models should take into account LHC data to make a significant improvement in the description of EAS. Another phenomena like heavy flavor production [25], creation of strong electromagnetic fields [26] and photo-production of vector mesons [27] can influence the measurements carried out by ground(under) apparatus. Therefore, it is important to perform as much as possible studies of the different components of the EAS to improve our understanding of the forward particle production at very high energies and consequently of the characteristics of the primary cosmic ray flux.…”

Longitudinal profiles of Extensive Air Showers with inclusion of charm and bottom particles

“…Charmed and bottom hadrons are formed from the hadronization of these heavy quarks with sea quarks, in a mechanism called Uncorrelated Fragmentation. More information of the model in [7] and [8].…”