Azimuthal fluctuations and number of muons at the ground in muon-depleted proton air showers at PeV energies

Muon counting is an effective strategy for discriminating between gamma- and hadron-initiated air showers. However, their detection, which requires shielded detectors, is highly expensive and challenging to implement across large, environmentally sensitive areas. This work allowed us to establish for the first time that at PeV energies the gamma/hadron discriminator based on the new <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>L</a:mi><a:mi>C</a:mi><a:mi>m</a:mi></a:math> variable have proton rejection levels of the order of <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:msup><c:mn>10</c:mn><c:mrow><c:mo>−</c:mo><c:mn>4</c:mn></c:mrow></c:msup></c:math>, outperforming the discrimination power based on the counting of the number of muons. A thorough examination of muon depleted showers at the PeV energies and the simulation strategy devised to achieve the required <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mi mathvariant="script">O</e:mi><e:mo stretchy="false">(</e:mo><e:msup><e:mn>10</e:mn><e:mn>6</e:mn></e:msup><e:mo stretchy="false">)</e:mo></e:math> simulated showers is presented.