LHCb CollaborationAdeva Andany, BernardoBorsato, MartinoChobanova, VeronikaCid Vidal, XabierDosil Suárez, ÁlvaroFernández Albor, Víctor ManuelGallas Torreira, Abraham AntonioGarcía Pardiñas, JuliánHernando Morata, José ÁngelLemos Cid, EdgarLucio Martínez, MiriamMartínez Santos, DiegoPlo Casasus, MáximoPrisciandaro, JessicaRamos Pernas, MiguelRomero Vidal, AntonioSaborido Silva, Juan JoséSanmartín Sedes, BraisSantamarina Ríos, CibránVázquez Regueiro, PabloVieites Díaz, MaríaVázquez Sierra, Carlos2020-05-192020-05-192016LHCb Collaboration et al. (2016). Measurement of the B0s→J/ψη lifetime. Physics Letters B, 762, 484-4920370-2693http://hdl.handle.net/10347/22434Using a data set corresponding to an integrated luminosity of 3fb−1, collected by the LHCb experiment in ppcollisions at centre-of-mass energies of 7 and 8TeV, the effective lifetime in the B0s→J/ψηdecay mode, τeff, is measured to be τeff = 1.479±0.034 (stat)±0.011 (syst)ps. Assuming CPconservation, τeffcorresponds to the lifetime of the light B0smass eigenstate. This is the first measurement of the effective lifetime in this decay mode.eng©2016 The Author. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP3.http://creativecommons.org/licenses/by/4.0/journal article10.1016/j.physletb.2016.10.0061873-2445open access