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Main Authors: Griffith, Spencer, Beacom, John F., Li, Jung-Tsung, Peter, Annika H. G.
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2412.08726
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author Griffith, Spencer
Beacom, John F.
Li, Jung-Tsung
Peter, Annika H. G.
author_facet Griffith, Spencer
Beacom, John F.
Li, Jung-Tsung
Peter, Annika H. G.
contents Accurate modeling of how high-energy proton-proton collisions produce gamma rays through the decays of pions and other secondaries is needed to correctly interpret astrophysical observations with the Fermi-LAT telescope. In the existing literature on cosmic-ray collisions with gas, the focus is on the gamma-ray yield spectrum, $d N_γ/dE$. However, in some situations, the joint energy and angular distribution can be observed, so one needs instead $d^2 N_γ/dE \, dΩ$. We provide calculations of this distribution over the energy range from the pion production threshold to $100~{\rm GeV}$, basing our results on FLUKA simulations. We provide the results in tabular form and provide a Python tool on GitHub to aid in utilization. We also provide an approximate analytic formula that illuminates the underlying physics. We discuss simplified examples where this angular dependence can be observed to illustrate the necessity of taking the joint distribution into account.
format Preprint
id arxiv_https___arxiv_org_abs_2412_08726
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Angular Distribution of Gamma Rays Produced in Proton-Proton Collisions
Griffith, Spencer
Beacom, John F.
Li, Jung-Tsung
Peter, Annika H. G.
High Energy Physics - Phenomenology
High Energy Astrophysical Phenomena
Accurate modeling of how high-energy proton-proton collisions produce gamma rays through the decays of pions and other secondaries is needed to correctly interpret astrophysical observations with the Fermi-LAT telescope. In the existing literature on cosmic-ray collisions with gas, the focus is on the gamma-ray yield spectrum, $d N_γ/dE$. However, in some situations, the joint energy and angular distribution can be observed, so one needs instead $d^2 N_γ/dE \, dΩ$. We provide calculations of this distribution over the energy range from the pion production threshold to $100~{\rm GeV}$, basing our results on FLUKA simulations. We provide the results in tabular form and provide a Python tool on GitHub to aid in utilization. We also provide an approximate analytic formula that illuminates the underlying physics. We discuss simplified examples where this angular dependence can be observed to illustrate the necessity of taking the joint distribution into account.
title Angular Distribution of Gamma Rays Produced in Proton-Proton Collisions
topic High Energy Physics - Phenomenology
High Energy Astrophysical Phenomena
url https://arxiv.org/abs/2412.08726