Explanation to the article "On the calibration of ultra-high energy EASs at the Yakutsk array and Telescope Array"

TL;DR

This paper defends the accuracy of the energy calibration method used in the Yakutsk array and Telescope Array experiments, clarifying misunderstandings and confirming the validity of their cosmic ray spectrum measurements.

Contribution

It provides a detailed clarification of the energy deposit formula and defends the calibration approach against critiques, supporting the reliability of the cosmic ray spectrum data.

Findings

The energy deposit formula is correctly derived from charged particle interactions.

The calibration method aligns with the physical processes in scintillators.

The cosmic ray spectrum from surface detectors is validated.

Abstract

We provide a detailed commentary on the energy calibration of the TA experiment described in our paper (arXiv:2404.16948 [astro-ph.HE]). That paper concludes that the TA energy estimation, which is tied to optical measurements, might be incorrect. A response from members of the TA Collaboration (arXiv:2407.12892 [astro-ph.HE]) states that this conclusion is wrong and "stems from a misinterpretation and an incorrect application of the TA energy deposit formula". Here we demonstrate that our formula for energy deposit is not in fact a rescaled modification of the TA equation, but follows from description of the processes occurring during the passage of charged particles through 1.2 cm thick scintillator. Our estimation of the TA detector response implies the correctness of the cosmic ray spectrum derived from readings of surface detectors of the array.