Depth Development of Extensive Air Showers from Muon Time Distributions.pdf
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Depth Development of Extensive Air Showers from Muon Time Distributions
L. Cazo?n, R.A. Va?zquez, and E. Zas
Departamento de F??sica de Part??culas, Facultade de F??sica,
Universidade de Santiago de Compostela, 15782 Santiago, SPAIN
We develop an algorithm that has the potential to relate the depth development of ultra high en-
ergy extensive air showers and the time delay for individual muons. The time distributions sampled
at different positions at ground level by a large air shower array are converted into distributions
of production distances using an approximate relation between production distance, transverse dis-
tance and time delay. The method is naturally restricted to inclined showers where muons dominate
the signal at ground level but could be extended to vertical showers provided that the detectors used
can separate the muon signal from electrons and photons. We explore the accuracy and practical
uncertainties involved in the proposed method. For practical purposes only the muons that fall
outside the central region of the shower can be used, and we establish cuts in transverse distance.
The method is tested using simulated showers by comparing the production distance distributions
obtained using the method with the actual distances in the simulated showers. It could be applied
in the search for neutrinos to increase the acceptance to highly penetrating particles, as well as
for unraveling the relative compositions of protons and heavy nuclei. We also illustrate that the
obtained depth distributions have minimum width when both the arrival direction and the core
position are well reconstructed.
PACS numbers: 96.40.Pq; 96.40.Tv
I. INTRODUCTION
When an Ultra High Energy Cosmic Ray (UHECR) particle enters the atmosphere it interacts producing an
extensive air shower that propagates through it and reaches ground level. These showers are routinely detected by
optical systems that collect fl
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