Production of Nuclei, Hyper-Nuclei and Exotics in the ALICE Detector

International Workshop on Discovery Physics at the LHC

Dönigus, Benjamin^1

Institut für Kernphysik, Goethe-Universität Frankfurt, Max-von-Laue-Str. 1, Frankfurt

60438, Germany^1

关键词: Collision systems;    Heavy ion collision;    Measurements of;    Model calculations;    Pb-Pb collisions;    Theoretical calculations;    Thermal model;    Upper limits;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/878/1/012004/pdf
DOI  :  10.1088/1742-6596/878/1/012004

来源: IOP

【 摘 要 】

Measurements of light (anti-)nuclei and (anti-)hypernuclei have been performed in different collision systems, namely pp, p-Pb and Pb-Pb, covering a large range of physics topics at the LHC using the ALICE detector setup. The results of the production of in Pb-Pb collisions is following the expectation of thermal models, whereas the production of nuclei in p-Pb collisions is tending to closer follow the expectations from coalescence models. Both models can give predictions for the production of hypothetical states such as bound states of two Λ hyperons or of a Λ and a neutron, which are expected to decay weakly. The states are searched for and no signal is found, thus upper limits are set which are significantly below the model expectations. Further, the measurement of the lifetime of the hypertriton determined in Pb-Pb collisions at the LHC gives a value significantly below the expectations of the most recent theoretical calculation. Instead this measurement is in agreement with other recent measurements in heavy-ion collisions. The combination of all measurements gives a tension of more than 2σ between the experimental lifetime and the most recent model calculation.