Measurement of the lifetime and $\Lambda$ separation energy of $^{3}_{\Lambda}\mathrm H$

TL;DR

This paper reports the most precise measurements to date of the lifetime and Lambda separation energy of hypertriton ($^{3}_{ ext{Lambda}} ext{H}$) using Pb-Pb collision data from ALICE at the LHC, confirming its weakly-bound structure.

Contribution

It provides the most precise experimental values for hypertriton lifetime and separation energy, supporting theoretical predictions and understanding of hypernuclear structure.

Findings

Hypertriton lifetime measured as 253 ± 11 (stat.) ± 6 (syst.) ps.

Lambda separation energy measured as 102 ± 63 (stat.) ± 67 (syst.) keV.

Results are consistent with effective field theory predictions.

Abstract

The most precise measurements to date of the $^{3}_{\Lambda}\mathrm H$ lifetime $\tau$ and $\Lambda$ separation energy ${\rm B}_{\Lambda}$ are obtained using the data sample of Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=$ 5.02 TeV collected by ALICE at the LHC. The $^{3}_{\Lambda}\mathrm H$ is reconstructed via its charged two-body mesonic decay channel ($^{3}_{\Lambda}\mathrm{H} \rightarrow$ $^3$He + $\pi^-$ and the charge-conjugate process). The measured values $\tau = [253 \pm 11 \text{ (stat.)} \pm 6 \text{ (syst.)}]$ ps and ${\rm B}_{\Lambda}= [102 \pm 63 \text{ (stat.)} \pm 67 \text{ (syst.)}]$ keV are compatible with predictions from effective field theories and confirm that the $^{3}_{\Lambda}\mathrm H$ structure is consistent with a weakly-bound system.