{"@context":"http://schema.org","@id":"https://doi.org/10.17182/hepdata.145132.v1","@reverse":{"isBasedOn":[{"@type":"ScholarlyArticle","identifier":{"@type":"PropertyValue","propertyID":"URL","value":"https://inspirehep.net/literature/2712863"}},{"@id":"https://doi.org/10.1038/s41586-024-07823-0","@type":"JournalArticle"}]},"@type":"Dataset","additionalType":"Collection","author":{"@type":"Organization","name":"STAR Collaboration"},"creator":{"@type":"Organization","name":"STAR Collaboration"},"datePublished":"2024","description":"Matter-antimatter asymmetry is a research topic of fundamental interest, as it is the basis for the existence of the matter world, which survived annihilation with antimatter in the early Universe. High energy nuclear collisions create conditions similar to the Universe microseconds after the Big Bang, with comparable amounts of matter and antimatter. Much of the antimatter created escapes the rapidly expanding fireball without annihilation, making such collisions an effective experimental tool to create heavy antimatter nuclear objects and study their properties. In this paper, we report the first observation of the antimatter hypernucleus \\hbox{$^4_{\\bar{\\Lambda}}\\overline{\\hbox{H}}$}, composed of an $\\bar{\\Lambda}$, an antiproton and two antineutrons. The discovery was made through its two-body decay after production in ultrarelativistic heavy ion collisions by the STAR experiment at the Relativistic Heavy Ion Collider. In total, 15.6 candidate \\hbox{$^4_{\\bar{\\Lambda}}\\overline{\\hbox{H}}$} \\ antimatter hypernuclei are obtained with an estimated background count of 6.4. Lifetimes of the antihypernuclei \\hbox{$^3_{\\bar{\\Lambda}}\\overline{\\hbox{H}}$} \\ and \\hbox{$^4_{\\bar{\\Lambda}}\\overline{\\hbox{H}}$} \\ are measured and compared with lifetimes of their corresponding hypernuclei, testing the symmetry between matter and antimatter. Various production yield ratios among (anti)hypernuclei and (anti)nuclei are also measured and compared with theoretical model predictions, shedding light on their production mechanism.","hasPart":[{"@id":"https://doi.org/10.17182/hepdata.145132.v1/t1","@type":"Dataset","description":"Invariant mass distributions of $^3\\hbox{He}+\\pi^-$ (A), $^3\\overline{\\hbox{He}}+\\pi^+$ (B), $^4\\hbox{He}+\\pi^-$ (C) and $^4\\overline{\\hbox{He}}+\\pi^+$ (D). The solid bands mark the signal invariant...","name":"Fig3 (A) $^3_{\\Lambda}H$"},{"@id":"https://doi.org/10.17182/hepdata.145132.v1/t2","@type":"Dataset","description":"Invariant mass distributions of $^3\\hbox{He}+\\pi^-$ (A), $^3\\overline{\\hbox{He}}+\\pi^+$ (B), $^4\\hbox{He}+\\pi^-$ (C) and $^4\\overline{\\hbox{He}}+\\pi^+$ (D). The solid bands mark the signal invariant...","name":"Fig3 (B) $^3_{\\bar{\\Lambda}}\\overline{H}$"},{"@id":"https://doi.org/10.17182/hepdata.145132.v1/t3","@type":"Dataset","description":"Invariant mass distributions of $^3\\hbox{He}+\\pi^-$ (A), $^3\\overline{\\hbox{He}}+\\pi^+$ (B), $^4\\hbox{He}+\\pi^-$ (C) and $^4\\overline{\\hbox{He}}+\\pi^+$ (D). The solid bands mark the signal invariant...","name":"Fig3 (C) $^4_{\\Lambda}H$"},{"@id":"https://doi.org/10.17182/hepdata.145132.v1/t4","@type":"Dataset","description":"Invariant mass distributions of $^3\\hbox{He}+\\pi^-$ (A), $^3\\overline{\\hbox{He}}+\\pi^+$ (B), $^4\\hbox{He}+\\pi^-$ (C) and $^4\\overline{\\hbox{He}}+\\pi^+$ (D). The solid bands mark the signal invariant...","name":"Fig3 (D) $^4_{\\bar{\\Lambda}}\\overline{H}$"},{"@id":"https://doi.org/10.17182/hepdata.145132.v1/t5","@type":"Dataset","description":"(A) (anti)hypernuclei yields versus $L/\\beta\\gamma$. The vertical error bars represent the statistical error only.","name":"Fig4 (A) A=3 particle"},{"@id":"https://doi.org/10.17182/hepdata.145132.v1/t6","@type":"Dataset","description":"(A) (anti)hypernuclei yields versus $L/\\beta\\gamma$. The vertical error bars represent the statistical error only.","name":"Fig4 (A) A=4 particle"},{"@id":"https://doi.org/10.17182/hepdata.145132.v1/t7","@type":"Dataset","description":"Our measured (anti)hypernuclei lifetimes compared with world data and theoretical predictions (solid triangles). Error bars and boxes represent statistical and...","name":"Fig4 (B) Lifetime"},{"@id":"https://doi.org/10.17182/hepdata.145132.v1/t8","@type":"Dataset","description":"Production yield ratios of various particles with the same baryon number. Results combining all collision systems in this work are...","name":"Fig5 This Analysis Au+Au, U+U, Zr+Zr, Ru+Ru"},{"@id":"https://doi.org/10.17182/hepdata.145132.v1/t9","@type":"Dataset","description":"Production yield ratios of various particles with the same baryon number. Results combining all collision systems in this work are...","name":"Fig5  This Analysis Au+Au, U+U"},{"@id":"https://doi.org/10.17182/hepdata.145132.v1/t10","@type":"Dataset","description":"Production yield ratios of various particles with the same baryon number. Results combining all collision systems in this work are...","name":"Fig5  This Analysis Zr+Zr, Ru+Ru"},{"@id":"https://doi.org/10.17182/hepdata.145132.v1/t11","@type":"Dataset","description":"Production yield ratios of various particles with the same baryon number. Results combining all collision systems in this work are...","name":"Fig5  Thermal Model"},{"@id":"https://doi.org/10.17182/hepdata.145132.v1/t12","@type":"Dataset","description":"Reconstruction efficiency as a function of $L/(\\beta\\gamma)$ obtained from the embedding Monte Carlo technique. Hypernuclei have stricter topological cuts than...","name":"Fig2 Tau Bin Efficiency for A=3 Particle"},{"@id":"https://doi.org/10.17182/hepdata.145132.v1/t13","@type":"Dataset","description":"Reconstruction efficiency as a function of $L/(\\beta\\gamma)$ obtained from the embedding Monte Carlo technique. Hypernuclei have stricter topological cuts than...","name":"Fig2 Tau Bin Efficiency for A=4 Particle"},{"@id":"https://doi.org/10.17182/hepdata.145132.v1/t14","@type":"Dataset","description":"H3L, antiH3L, H4L and antiH4L candidate invariant-mass distributions in different $L/\\beta\\gamma$ intervals.","name":"Fig3, invariant-mass distributions for each tau bin of H3L"},{"@id":"https://doi.org/10.17182/hepdata.145132.v1/t15","@type":"Dataset","description":"H3L, antiH3L, H4L and antiH4L candidate invariant-mass distributions in different $L/\\beta\\gamma$ intervals.","name":"Fig3, invariant-mass distributions for each tau bin of antiH3L"},{"@id":"https://doi.org/10.17182/hepdata.145132.v1/t16","@type":"Dataset","description":"H3L, antiH3L, H4L and antiH4L candidate invariant-mass distributions in different $L/\\beta\\gamma$ intervals.","name":"Fig3, invariant-mass distributions for each tau bin of H4L"},{"@id":"https://doi.org/10.17182/hepdata.145132.v1/t17","@type":"Dataset","description":"H3L, antiH3L, H4L and antiH4L candidate invariant-mass distributions in different $L/\\beta\\gamma$ intervals.","name":"Fig3, invariant-mass distributions for each tau bin of antiH4L"},{"@id":"https://doi.org/10.17182/hepdata.145132.v1/t18","@type":"Dataset","description":"$dN/d(L/\\beta\\gamma)$ as a function of $L/\\beta\\gamma$ for $\\Lambda$ and $\\bar{\\Lambda}$, and exponential fits to obtain their lifetimes.","name":"Fig4 Lambda and anti-Lambda"},{"@id":"https://doi.org/10.17182/hepdata.145132.v1/t19","@type":"Dataset","description":"Efficiency corrected $p_{T}$ spectra for $^3\\hbox{He}$, $^3\\overline{\\hbox{He}}$, \\htl, and \\ahtl. The spectra are in the phase space of $|y|<0.7$ with...","name":"Fig5 pT spectra of He3 and anti-He3"},{"@id":"https://doi.org/10.17182/hepdata.145132.v1/t20","@type":"Dataset","description":"Efficiency corrected $p_{T}$ spectra for $^3\\hbox{He}$, $^3\\overline{\\hbox{He}}$, \\htl, and \\ahtl. The spectra are in the phase space of $|y|<0.7$ with...","name":"Fig5 pT spectra of H3L and anti-H3L"}],"identifier":[{"@type":"PropertyValue","propertyID":"HEPDataRecord","value":"https://www.hepdata.net/record/ins2712863?version=1"},{"@type":"PropertyValue","propertyID":"HEPDataRecordAlt","value":"https://www.hepdata.net/record/145132"}],"inLanguage":"en","name":"Observation of the Antimatter Hypernucleus $^4_{\\bar{\\Lambda}}\\overline{\\hbox{H}}$","provider":{"@type":"Organization","name":"HEPData"},"publisher":{"@type":"Organization","name":"HEPData"},"url":"https://www.hepdata.net/record/ins2712863?version=1","version":1}