München 2019 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 19: Heavy-Ion Collisions and QCD Phases III
HK 19.5: Talk
Tuesday, March 19, 2019, 15:15–15:30, HS 15
Measurement of the hypertriton lifetime with ALICE at the LHC — •Alberto Caliva for the ALICE collaboration — GSI, Planckstraße 1, 64291 Darmstadt
The hypertriton is the lightest known hypernucleus (nucleus with strangeness). It is composed of a proton and a neutron, constituting the core nucleus of a halo system, and a Λ0 baryon orbiting around it.
The separation energy of the Λ0 baryon from the core nucleus is BΛ = 130 ± 50 keV. According to the existing theoretical calculations, the lifetime of such a loosely bound state is expected to be very close to that of the free Λ0 baryon, while the experimental data indicate that the hypertriton lifetime is significantly smaller compared to that of the free Λ0. This discrepancy is currently not understood and under debate in the scientific community.
In this talk, the ALICE measurement of the lifetime of the hypertriton and the free Λ0 baryon, produced in Pb–Pb collisions at √sNN=5.02 TeV, are presented.
The current status of the hypertriton lifetime puzzle is discussed and the perspectives for high-precision measurements of hyperons and hypernuclei lifetimes after the ALICE upgrade are also presented.