Selection of Surviving Primary Protons at 4300 m a.s.l. with the ARGO-YBJ experiment

TL;DR

This paper discusses how the ARGO-YBJ experiment at high altitude can identify primary cosmic ray protons below 1 TeV, enabling calibration with direct measurements and improving understanding of cosmic ray composition.

Contribution

It introduces a new method for selecting primary protons using the ARGO-YBJ array at 4300 m altitude, focusing on quasi-unaccompanied events with steep lateral distributions.

Findings

Effective selection of primary protons demonstrated

Calibration potential with satellite and balloon data shown

Enhanced understanding of cosmic ray composition at high energies

Abstract

The primary proton spectrum up to 100 TeV has been investigated by balloon- and satellite-borne instruments. Above this energy range only ground-based air shower arrays can measure the cosmic ray spectrum with a technique moderately sensitive to nuclear composition. An array which exploits the full coverage approach at very high altitude can achieve an energy threshold well below the TeV region, thus allowing, in principle, the inter-calibration of the measured proton content in the primary cosmic ray flux with the existing direct measurements from balloons/satellites. The capability of the ARGO-YBJ experiment, located at the YangBaJing Cosmic Ray Laboratory (4300 m a.s.l., Tibet, P.R. China), in selecting the surviving primary cosmic ray protons is discussed. A procedure looking for quasi-unaccompanied events with a very steep lateral distribution is also presented.