doi:10.1088/1475-7516/2025/07/066engCarmona, J. M.Cortés, J. L.Rescic, F.Reyes, M. A.Terzic, T.Photon absorption in a doubly special relativity model with undeformed free propagation and total momentum conservationART-2025-145264The lack of a dynamical framework within doubly special relativity theories has impeded the development of a corresponding phenomenology of modified interactions. In this work we show that in a model based on the classical basis of κ-Poincaré and total momentum conservation, one has a well-defined cross section of the photon-photon annihilation process, once a prescription for the channel treatment is set. The modification of the interaction can lead to observable effects in the opacity of the Universe to very high-energy gamma rays when the gamma-ray energy approaches the energy scale of the deformation. The magnitude and observability of this deformation are examined as functions of the gamma-ray energy and source distance.2025http://zaguan.unizar.es/record/16275910.1088/1475-7516/2025/07/066http://zaguan.unizar.es/record/162759oai:zaguan.unizar.es:162759info:eu-repo/grantAgreement/ES/AEI/PID2021-126078NB-C21info:eu-repo/grantAgreement/ES/AEI/PRE2019-089024info:eu-repo/grantAgreement/EUR/COST-Action/CA18108info:eu-repo/grantAgreement/ES/DGA/E21-23RJournal of Cosmology and Astroparticle Physics 2025, 07 (2025), 066All rights reservedhttp://www.europeana.eu/rights/rr-f/info:eu-repo/semantics/closedAccess