17 Yassine, R. Abou Adamczewski-Musch, J. Asal, C. Becker, M. Belounnas, A. Blanco, A. Blume, C. Chlad, L. Chudoba, P. Ciepał, I. Dreyer, J. Esmail, Waleed Ahmed Mohammed Fabbietti, L. Floersheimer, H. Förtsch, J. Fonte, P. Friese, J. Fröhlich, I. Galatyuk, T. Greifenhagen, R. Grunwald, M. Gumberidze, M. Harabasz, S. Heinz, T. Höhne, C. Hojeij, F. Holzmann, Romain Huck, H. Idzik, M. Kämpfer, B. Kampert, K-H. Kardan, B. Kedych, V. Kim, S. Koenig, I. Koenig, W. Kohls, M. Kolas, J. Kornakov, G. Kotte, R. Kres, I. Krueger, W. Kugler, A. Lalik, R. Lebedev, S. Linev, S. Linz, F. Lopes, L. Lorenz, M. Malige, A. Markert, J. Matulewicz, T. Maurus, S. Metag, V. Michel, J. Molenda, A. Müntz, C. Nabroth, M. Naumann, L. Nowakowski, K. Opíchal, A. Orliński, J. Otto, J. -H. Parschau, M. Pauly, C. Pawlowska-Szymanska, D. Pechenov, V. Pechenova, Olga Pfeifer, D. Piasecki, K. Pietraszko, J. Povar, T. Prościński, K. Prozorov, A. Przygoda, W. Pysz, K. Ramstein, B. Rathod, N. Ritman, J. Rost, A. Rustamov, A. Salabura, P. Saraiva, J. Scharmann, K. Schild, N. Schwab, E. Scozzi, F. Seck, F. Selyuzhenkov, I. Singh, U. Skorpil, L. Smyrski, J. Spies, S. Sreejith, A. Ströbele, H. Stroth, J. Sumara, K. Svoboda, O. Szala, M. Tlusty, P. Traxler, M. Treliński, S. Udrea, I. C. Ulrich-Pur, F. Ungethum, C. Wagner, V. Weber, A. A. Wendisch, C. Wirth, J. Władyszewska, A. Zbroszczyk, H. P. Zherebtsova, E. Zieliński, M. Zumbruch, P. HADES Collaboration HAD FHF HADES@FAIR arXiv 10.48550/ARXIV.2512.12454 9 We present the first observation of $\mathrm{^{3}_ΛH}$ and $\mathrm{^{4}_ΛH}$ in Ag+Ag collisions at $\mathrm{\sqrt{s_{NN}}}$ = 2.55 GeV, emitted around mid-rapidity. The hypernuclei are reconstructed via their two-body decay channels and identified through their weak-decay topology, employing an artificial neural network for enhanced discrimination. The analysis methodology is validated using $Λ$ hyperons. The resulting rapidity distributions, dN/dy, exhibit a bell shape centered at mid-rapidity. The yield of $\mathrm{^{4}_ΛH}$ is equal to or exceeds that of $\mathrm{^{3}_ΛH}$, which contrasts the measurement from the STAR collaboration at $\mathrm{\sqrt{s_{NN}}}$ = 3 GeV and is consistent with a scenario in which hypernuclei receive feed-down from excited states. The data enable a high-precision measurement of the hypernuclei lifetimes. For the $\mathrm{^{3}_ΛH}$, a lifetime of $\mathrm{τ_{^{3}_ΛH}}$ = $(239 \pm 23{\mathrm{(stat)}} \pm 18{\mathrm{(sys)}})\,\mathrm{ps}$, is extracted, consistent on the 1$σ$ level with that of the free $Λ$. In contrast, the $\mathrm{^{4}_ΛH}$ lifetime of $\mathrm{τ_{^{4}_ΛH}}$ = $(209 \pm 7{\mathrm{(stat)}} \pm 10{\mathrm{(sys)}})\,\mathrm{ps}$, shows a 4.5 $σ$ deviation from the free $Λ$ lifetime. The results consolidate the available world data. PUB:(DE-HGF)25, ; 28, ; Nuclear Experiment (nucl-ex) High Energy Physics - Experiment (hep-ex) FOS: Physical sciences Preprint 2025 GSI-2026-00377 2025 https://repository.gsi.de/record/365286 https://doi.org/10.48550/ARXIV.2512.12454