Measurement of $$\tau _\text {L}$$ τ L using the $${B} _s^0 \rightarrow J/\psi \eta $$ B s 0 → J / ψ η decay mode

• Published in: The European physical journal. C, Particles and fields Particles and fields, 2023-07, Vol.83 (7), p.1-13
• Main Authors: R. Aaij, A. S. W. Abdelmotteleb, C. Abellan Beteta, F. Abudinén, T. Ackernley, B. Adeva, M. Adinolfi, H. Afsharnia, C. Agapopoulou, C. A. Aidala, S. Aiola, Z. Ajaltouni, S. Akar, K. Akiba, J. Albrecht, F. Alessio, M. Alexander, A. Alfonso Albero, Z. Aliouche, P. Alvarez Cartelle, R. Amalric, S. Amato, J. L. Amey, Y. Amhis, L. An, L. Anderlini, M. Andersson, A. Andreianov, M. Andreotti, D. Andreou, D. Ao, F. Archilli, A. Artamonov, M. Artuso, E. Aslanides, M. Atzeni, B. Audurier, S. Bachmann, M. Bachmayer, J. J. Back, A. Bailly-reyre, P. Baladron Rodriguez, V. Balagura, W. Baldini, J. Baptista de Souza Leite, M. Barbetti, R. J. Barlow, S. Barsuk, W. Barter, M. Bartolini, F. Baryshnikov, J. M. Basels, G. Bassi, B. Batsukh, A. Battig, A. Bay, A. Beck, M. Becker, F. Bedeschi, I. B. Bediaga, A. Beiter, V. Belavin, S. Belin, V. Bellee, K. Belous, I. Belov, I. Belyaev, G. Bencivenni, E. Ben-Haim, A. Berezhnoy, R. Bernet, D. Berninghoff, H. C. Bernstein, C. Bertella, A. Bertolin, C. Betancourt, F. Betti, Ia. Bezshyiko, S. Bhasin, J. Bhom, L. Bian, M. S. Bieker, N. V. Biesuz, S. Bifani, P. Billoir, A. Biolchini, M. Birch, F. C. R. Bishop, A. Bitadze, A. Bizzeti, M. P. Blago, T. Blake, F. Blanc, S. Blusk, D. Bobulska, J. A. Boelhauve, O. Boente Garcia, T. Boettcher, A. Boldyrev, C. S. Bolognani
• Format: Article
• Language: English
• ISSN: 1434-6052
• DOI: 10.1140/epjc/s10052-023-11634-4

Abstract Using a proton–proton collision data sample collected by the LHCb detector and corresponding to an integrated luminosity of $$5.7~\text {fb}^{-1}$$ 5.7 fb - 1 , the lifetime of the light $${{B} ^0_{s}} $$ B s 0 mass eigenstate, $$\tau _{L}$$ τ L , is measured using the $$B^0_s \rightarrow J/\psi \eta $$ B s 0 → J / ψ η decay mode to be $$\begin{aligned} \tau _{\text {L}} = 1.445 \pm 0.016 \text {(stat)} \pm 0.008 \text {(syst)} \,\text {ps}. \end{aligned}$$ τ L = 1.445 ± 0.016 (stat) ± 0.008 (syst) ps . A combination of this result with a previous LHCb analysis using an independent dataset corresponding to 3 fb $$^{-1}$$ - 1 of integrated luminosity gives $$\begin{aligned} \tau _{\text {L}} = 1.452 \pm 0.014 \pm 0.007 \pm 0.002 \,\text {ps}, \end{aligned}$$ τ L = 1.452 ± 0.014 ± 0.007 ± 0.002 ps , where the first uncertainty is statistical, the second due to the uncorrelated part of the systematic uncertainty and the third due to the correlated part of the systematic uncertainty.