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Description
Theory models [1] predict a total of 44 cascade states below 2.5 GeV. Currently, there are only six Ξ states that have at least a three-star rating in the PDG [2], with the production mechanism of these states still remaining mostly elusive. The goal of the “Very Strange” [3] project is to study the quasi-real photoproduction of cascades to search for missing and new states. This work focuses on the analysis of CLAS12 data collected at Jefferson Lab to study the production mechanisms and decays of excited Ξ- states that are not well established, with the possibility of determining their quantum numbers. The new data would make it possible to measure for the first time the beam polarisation transfer and induced polarisation of the Ξ- baryon as a kinematical variable function. Additionally, cascade studies look promising as a tool to differentiate genuine quark states from hadronic molecule states, for which the Ξ(1620) resonance has been proposed as a candidate [4]. Extracting more information about the cascade baryons could also allow us to begin unravelling the composition of the core of neutron stars [5], exploring the hyperon puzzle.
[1] S. Capstick and N. Isgur, “Baryons in a relativized quark model with chromodynamics”, (1986).
[2] J. Beringer et al. (Particle Data Group), “Review of Particle Physics”, (2012).
[3] A. Afanasev et al. (Very Strange Collaboration and CLAS collaboration at JLab), “Photoproduction of the Very Strangest Baryons on a Proton Target in CLAS12”, (2013).
[4] E.Oset, A.Ramos, C. Bernhold, “On the spin, parity and nature of the Ξ(1620) resonance”, (2018).
[5] A. Clevinger et al., “Hybrid equations of state for neutron stars with hyperons and deltas”, (2022).
