Resumen: Very high-energy astrophysical gamma rays suffer a suppression of their flux along their propagation due to their interaction, through the γγ→e+e− pair-production process, with the soft photon backgrounds present in the Universe. We examine the Universe’s transparency to gamma rays within a Lorentz invariance violation (LIV) framework, focusing on photon subluminal quadratic corrections driven by a high-energy scale. Based on an explicit calculation, we provide a new expression for the cross section that overcomes the limitations of previous approaches and refines existing constraints for the LIV scale, while we introduce a new approximation that may be useful in LIV scenarios beyond effective field theory. These improvements appear essential for setting constraints on LIV effects with future observations at ultrahigh energies, where previous approximations may fall short. Idioma: Inglés DOI: 10.1103/PhysRevD.110.063035 Año: 2024 Publicado en: Physical Review D 110, 6 (2024), 063035 [13 pp.] ISSN: 2470-0010 Financiación: info:eu-repo/grantAgreement/ES/AEI/PRE2019-089024 Financiación: info:eu-repo/grantAgreement/ES/DGA/E21-23R Financiación: info:eu-repo/grantAgreement/ES/MICINN/PGC2022-126078NB-C21 Tipo y forma: Article (Published version) Área (Departamento): Área Física Teórica (Dpto. Física Teórica) Área (Departamento): Área Física Atóm.Molec.y Nucl. (Dpto. Física Teórica)