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Measurement of the $\Lambda$ hyperon lifetime

The ALICE collaboration
Acharya, Shreyasi , Adamova, Dagmar , Adler, Alexander , Aglieri Rinella, Gianluca , Agnello, Michelangelo , Agrawal, Neelima , Ahammed, Zubayer , Ahmad, Shakeel , Ahn, Sang Un , Ahuja, Ishaan
Phys.Rev.D 108 (2023) 032009, 2023.
https://doi.org/10.17182/hepdata.141278

Abstract
A new, more precise measurement of the $\Lambda$ hyperon lifetime is performed using a large data sample of Pb$-$Pb collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV with ALICE. The $\Lambda$ and $\overline{\Lambda}$ hyperons are reconstructed at midrapidity using their two-body weak decay channel $\Lambda \rightarrow \mathrm{p} + \pi^{-}$ and $\overline{\Lambda} \rightarrow \overline{\mathrm{p}} + \pi^{+}$. The measured value of the $\Lambda$ lifetime is $\tau_{\Lambda} = [261.07 \pm 0.37 \ ( \rm stat.) \pm 0.72 \ (\rm syst.) ]\ \rm ps$. The relative difference between the lifetime of $\Lambda$ and $\overline{\Lambda}$, which represents an important test of CPT invariance in the strangeness sector, is also measured. The obtained value $(\tau_{\Lambda}-\tau_{\overline{\Lambda}})/\tau_{\Lambda} = 0.0013 \pm 0.0028 \ (\mathrm{stat.}) \pm 0.0021 \ (\mathrm{syst.})$ is consistent with zero within the uncertainties. Both measurements of the $\Lambda$ hyperon lifetime and of the relative difference between $\tau_{\Lambda}$ and $\tau_{\overline{\Lambda}}$ are in agreement with the corresponding world averages of the Particle Data Group and about a factor of three more precise.

  • Table 1

    Figure 3

    10.17182/hepdata.141278.v1/t1

    Lproper spectrum of Lambda and exponential fit for the lifetime extraction. Only statistical uncertainties are shown for each data point...

  • Table 2

    Figure 3

    10.17182/hepdata.141278.v1/t2

    Lproper spectrum of Antilambda and exponential fit for the lifetime extraction. Only statistical uncertainties are shown for each data point...

  • Table 3

    Figure 3

    10.17182/hepdata.141278.v1/t3

    Lproper spectrum of Lambda and Antilambda and exponential fit for the lifetime extraction. Only statistical uncertainties are shown for each...

  • Table 4

    Figure 4

    10.17182/hepdata.141278.v1/t4

    Lambda lifetime measured in different centrality intervals. Only statistical uncertainties are shown.

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