Global polarization of hyperons and spin alignment of vector mesons in quark matters

<sec>Relativistic heavy ion collider (RHIC) as a dedicated nuclear facility has made few major discoveries in physics. This year marks the 30th STAR Collaboration formation and 23th of detector operation data collection at RHIC. In last two decades, collected many datasets, exhibiting scientific versatility flexibility RHIC facility. The total dataset first is less than 1 million good events, currently there are about billion events per dataset.</sec><sec>The Global Hyperon Polarization was proposed 2004. immediately prompted to search for this phenomenon from early datasets. null results were presented Quark Matter Conference Shanghai 2006 subsequently published. Although peripheral continuous efforts following decade, no positive result been observed experimentally. situation changed decade with upgrade high rate time-of-flight (TOF) progress Beam Energy Scan Phase I (BES-I). experimental global polarization hyperons 2017 spin alignment vector mesons 2023 RHIC-STAR confirm theory which established nearly twenty years ago. these measurements open way studying properties hot dense matter created high-energy collisions new degree freedom, spin.</sec><sec>We briefly review proposals measurements, summarize related existing facilities theoretical explanations original proposal. basic understanding proposal still valid fundamental, that is, angular momentum system can transform into effect observable experiment. However, it appears each case model needed explain observation. We need more help us unify all phenomena.</sec><sec>Over past five years, successfully installed 3 detectors we have begun see physical analysis datasets those functions. What makes viable after 20 its evolution through successful upgrades, programs added by year. next big thing forward tracking (3 layers silicon strips 4 sTGC chambers) calorimetry (electromagnetic hadronic calorimeters). addition structure protons using polarized proton beams RHIC, upgrades also provide unique ability investigate origin Λ function rapidity (de-)correlations Au+Au collisions.</sec>