Towards resolving the ${}_{\Lambda }^3$H lifetime puzzle

Abstract

Recent ${}_{\Lambda }^3$H lifetime measurements in relativistic heavy ion collision experiments have yielded values shorter by (30$\pm$8)% than the free $\Lambda$ lifetime ${\tau }_{\Lambda }$, thereby questioning the naive expectation that $\tau ({}_{\Lambda }^3\mathrm{H})\approx {\tau }_{\Lambda }$ for a weakly bound $\Lambda$ hyperon. Here we apply the closure approximation introduced by Dalitz and coworkers to evaluate the ${}_{\Lambda }^3$H lifetime, using ${}_{\Lambda }^3$H wavefunctions generated by solving three-body Faddeev equations. Our result, disregarding pion final-state interaction (FSI), is $\tau ({}_{\Lambda }^3\mathrm{H})$=(0.90$\pm$0.01)${\tau }_{\Lambda }$. In contrast to previous works, pion FSI is found attractive, reducing further $\tau ({}_{\Lambda }^3\mathrm{H})$ to $\tau ({}_{\Lambda }^3\mathrm{H})$=(0.81$\pm$0.02)${\tau }_{\Lambda }$. We also evaluate for the first time $\tau ({}_{\Lambda }^3\mathrm{n})$, finding it considerably longer than ${\tau }_{\Lambda }$, contrary to the shorter lifetime values suggested by the GSI HypHI experiment for this controversial hypernucleus.

v2--14 pages, 1 figure, 2 tables, replaced title of v1 and recalculated a shorter ${}_{\Lambda }^3$H lifetime than reported in v1; v3--updated references, matching published version

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Cited by in corpus (23)

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• ${}_{\Lambda }^3\mathrm{H}$ and ${}_{\bar{\Lambda }}^3\bar{\mathrm{H}}$ lifetime measurement in Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=$ 5.02 TeV via two-body decay
• Three-Body Hypernuclei in Pionless Effective Field Theory
• Measurement of the lifetime and $\Lambda$ separation energy of ${}_{\Lambda }^3\mathrm{H}$
• Implications of an increased $\Lambda$-separation energy of the hypertriton
• Revisiting the hypertriton lifetime puzzle
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• Observation of the Antimatter Hypernucleus ${}_{\bar{\Lambda }}^4\overline{H}$
• Nature of the $\Lambda nn$ $(J^{\pi }=1/2^{+},I=1)$ and ${}_{\mathrm{\Lambda }}^3{\mathrm{H}}^{\ast }(J^{\pi }=3/2^{+},I=0)$ states
• Recalibration of the binding energy of hypernuclei measured in emulsion experiments and its implications
• Consequences of increased hypertriton binding for $s$-shell $\Lambda$-hypernuclear systems
• Production of a 4He_Lambda hypernucleus in the 4He(pi, K) reactions reexamined
• Faddeev calculations on lambda hypertriton with potentials from Gel'fand-Levitan-Marchenko theory
• Effective lambda-proton and lambda-neutron potentials from subthreshold inverse scattering
• Hypertriton lifetime
• Recent progress on hypernuclei
• Hypernuclei and Antihypernuclei Production in Heavy-Ion Collisions
• Lifetime of the hypertriton
• Old and New in Strangeness Nuclear Physics
• Production Spectra of ${}^3$He($\pi$, $K$) Reactions with Continuum Discretized Coupled Channels
• Recent progress on few-body hypernuclei