000169449 001__ 169449 000169449 005__ 20260227133540.0 000169449 0247_ $$2doi$$a10.1088/1475-7516/2026/02/039 000169449 0248_ $$2sideral$$a148361 000169449 037__ $$aART-2026-148361 000169449 041__ $$aeng 000169449 100__ $$aBertólez-Martínez, T. 000169449 245__ $$aBBN bounds on neutrinophilic ultralight Dark Matter 000169449 260__ $$c2026 000169449 5060_ $$aAccess copy available to the general public$$fUnrestricted 000169449 5203_ $$aThe high densities in the early Universe provide a unique laboratory to constrain couplings between feebly interacting particles, such as dark matter and neutrinos. In this article, we study how Big Bang Nucleosynthesis can constrain models of Ultra-Light Dark Matter diagonally coupled to neutrinos. We follow an adiabatic formalism which allows to average-out the rapid oscillations of the Dark Matter field and consistently take into account the feedback between the neutrino and the Dark Matter fields. This feedback alters the early Universe dynamics, causing the Dark Matter energy density to scale as radiation, while the neutrino mass scales as a −1 . These two effects modify primordial element abundances by modifying interaction rates and the expansion rate during nucleosynthesis. Then, we use primordial abundances to obtain leading cosmological bounds on the coupling in the range mϕ/eV ∈ (10−22, 10−17), namely g ≲ 0.13(mϕ/eV) for mϕ ≳ 3 × 10−20 eV and g ≲ 1.8 × 10−11q mϕ/eV for mϕ ≲ 3 × 10−20 eV. This consistent cosmological treatment emphasizes that, in the mass interval where its physical assumptions hold, neutrino masses cannot be generated refractively by a direct coupling with an Ultra-Light Dark Matter field. 000169449 536__ $$9info:eu-repo/grantAgreement/ES/DGA-FSE/E21-17R$$9info:eu-repo/grantAgreement/EC/HORIZON EUROPE/101086085/EU/Essential Asymmetries of Nature/ASYMMETRY$$9info:eu-repo/grantAgreement/EC/H2020/860881/EU/Revealing how hidden symmetries shape the universe/HIDDeN$$9This project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No H2020 860881-HIDDeN$$9info:eu-repo/grantAgreement/ES/AEI/MICNN/PID2022-126224NB-C21$$9info:eu-repo/grantAgreement/ES/MICINN/PGC2022-126078NB-C21 000169449 540__ $$9info:eu-repo/semantics/openAccess$$aby$$uhttps://creativecommons.org/licenses/by/4.0/deed.es 000169449 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/publishedVersion 000169449 700__ $$0(orcid)0000-0002-2868-194X$$aLópez-Sarrión, J.$$uUniversidad de Zaragoza 000169449 700__ $$aSalvado, J. 000169449 7102_ $$12004$$2405$$aUniversidad de Zaragoza$$bDpto. Física Teórica$$cÁrea Física Teórica 000169449 773__ $$g2026, 02 (2026), 039 [30 pp.]$$pJ. Cosmol. Astropart. Phys.$$tJournal of Cosmology and Astroparticle Physics$$x1475-7516 000169449 8564_ $$s4210381$$uhttps://zaguan.unizar.es/record/169449/files/texto_completo.pdf$$yVersión publicada 000169449 8564_ $$s585596$$uhttps://zaguan.unizar.es/record/169449/files/texto_completo.jpg?subformat=icon$$xicon$$yVersión publicada 000169449 909CO $$ooai:zaguan.unizar.es:169449$$particulos$$pdriver 000169449 951__ $$a2026-02-27-12:35:54 000169449 980__ $$aARTICLE