Updated BBN bounds on hadronic injection in the early universe: The gravitino problem

Late-decaying particles naturally arise in many extensions of the Standard Model, directly impacting key cosmological processes in the early universe, such as Big Bang Nucleosynthesis (BBN). BBN studies often consider only electromagnetic energy injection episodes, but in practice long-lived particles are also amenable to hadronic decays. The latter can greatly alter the predicted abundances of light elements such as D / H , Y p , 3 He / H , and 7 Li / H . Incorporating up-to-date measurements on the abundance of the light elements, we place constraints on the primordial abundance of long-lived particles as a function of their lifetime. Lastly, we apply our results to the gravitino problem and set bounds on the reheating temperature, which controls the gravitino primordial abundance.