{"@context":"http://schema.org","@id":"https://doi.org/10.17182/hepdata.77284.v1","@reverse":{"isBasedOn":[{"@type":"ScholarlyArticle","identifier":{"@type":"PropertyValue","propertyID":"URL","value":"https://inspirehep.net/literature/1471838"}},{"@id":"https://doi.org/10.1038/nphys4111","@type":"JournalArticle"}]},"@type":"Dataset","additionalType":"Collection","author":{"@type":"Organization","name":"ALICE Collaboration"},"creator":{"@type":"Organization","name":"ALICE Collaboration"},"datePublished":"2017","description":"CERN-LHC.  The yields of strange (${\\rm K}^{0}_{S}$, $\\Lambda$, $\\bar{\\Lambda}$) and multi-strange ($\\Xi^{-}$, $\\bar{\\Xi}^{+}$, $\\Omega^{-}$, $\\bar{\\Omega}^{+}$) hadrons are measured at midrapidity in proton-proton (pp) collisions at $\\sqrt{s}$ = 7 TeV as a function of the charged-particle multiplicity density (${\\rm d}N_{\\rm ch}/{\\rm d}\\eta$).The production rate of strange particles increases faster than that of non-strange hadrons, leading to an enhancement of strange particles relative to pions, similar to that found in nucleus-nucleus collisions as well as in proton-nucleus collisions at the LHC. This is the first observation of an enhanced production of strange particles in high-multiplicity pp collisions. The magnitude of this strangeness enhancement increases with the event activity, quantified by ${\\rm d}N_{\\rm ch}/{\\rm d}\\eta$, and with hadron strangeness. It reaches almost a factor of two for the $\\Omega$ at the highest multiplicity presented. No enhancement is observed for particles with no strange quark content, demonstrating that the observed effect is strangeness rather than mass related. The results are not reproduced by any of the Monte Carlo models commonly used at the LHC, suggesting that further developments are needed for a complete microscopic understanding of strangeness production and indicating the presence of a phenomenon novel in high-multiplicity pp collisions.","hasPart":[{"@id":"https://doi.org/10.17182/hepdata.77284.v1/t1","@type":"Dataset","description":"$K^{0}_{S}$ transverse momentum spectrum: V0M Class I (pp at $\\sqrt{s}=7$ TeV).","name":"Table 1"},{"@id":"https://doi.org/10.17182/hepdata.77284.v1/t2","@type":"Dataset","description":"$K^{0}_{S}$ transverse momentum spectrum: V0M Class II (pp at $\\sqrt{s}=7$ TeV).","name":"Table 2"},{"@id":"https://doi.org/10.17182/hepdata.77284.v1/t3","@type":"Dataset","description":"$K^{0}_{S}$ transverse momentum spectrum: V0M Class III (pp at $\\sqrt{s}=7$ TeV).","name":"Table 3"},{"@id":"https://doi.org/10.17182/hepdata.77284.v1/t4","@type":"Dataset","description":"$K^{0}_{S}$ transverse momentum spectrum: V0M Class IV (pp at $\\sqrt{s}=7$ TeV).","name":"Table 4"},{"@id":"https://doi.org/10.17182/hepdata.77284.v1/t5","@type":"Dataset","description":"$K^{0}_{S}$ transverse momentum spectrum: V0M Class V (pp at $\\sqrt{s}=7$ TeV).","name":"Table 5"},{"@id":"https://doi.org/10.17182/hepdata.77284.v1/t6","@type":"Dataset","description":"$K^{0}_{S}$ transverse momentum spectrum: V0M Class VI (pp at $\\sqrt{s}=7$ TeV).","name":"Table 6"},{"@id":"https://doi.org/10.17182/hepdata.77284.v1/t7","@type":"Dataset","description":"$K^{0}_{S}$ transverse momentum spectrum: V0M Class VII (pp at $\\sqrt{s}=7$ TeV).","name":"Table 7"},{"@id":"https://doi.org/10.17182/hepdata.77284.v1/t8","@type":"Dataset","description":"$K^{0}_{S}$ transverse momentum spectrum: V0M Class VIII (pp at $\\sqrt{s}=7$ TeV).","name":"Table 8"},{"@id":"https://doi.org/10.17182/hepdata.77284.v1/t9","@type":"Dataset","description":"$K^{0}_{S}$ transverse momentum spectrum: V0M Class IX (pp at $\\sqrt{s}=7$ TeV).","name":"Table 9"},{"@id":"https://doi.org/10.17182/hepdata.77284.v1/t10","@type":"Dataset","description":"$K^{0}_{S}$ transverse momentum spectrum: V0M Class X (pp at $\\sqrt{s}=7$ TeV).","name":"Table 10"},{"@id":"https://doi.org/10.17182/hepdata.77284.v1/t11","@type":"Dataset","description":"$\\Lambda+\\bar{\\Lambda}$ transverse momentum spectrum: V0M Class I (pp at $\\sqrt{s}=7$ TeV).","name":"Table 11"},{"@id":"https://doi.org/10.17182/hepdata.77284.v1/t12","@type":"Dataset","description":"$\\Lambda+\\bar{\\Lambda}$ transverse momentum spectrum: V0M Class II (pp at $\\sqrt{s}=7$ TeV).","name":"Table 12"},{"@id":"https://doi.org/10.17182/hepdata.77284.v1/t13","@type":"Dataset","description":"$\\Lambda+\\bar{\\Lambda}$ transverse momentum spectrum: V0M Class III (pp at $\\sqrt{s}=7$ TeV).","name":"Table 13"},{"@id":"https://doi.org/10.17182/hepdata.77284.v1/t14","@type":"Dataset","description":"$\\Lambda+\\bar{\\Lambda}$ transverse momentum spectrum: V0M Class IV (pp at $\\sqrt{s}=7$ TeV).","name":"Table 14"},{"@id":"https://doi.org/10.17182/hepdata.77284.v1/t15","@type":"Dataset","description":"$\\Lambda+\\bar{\\Lambda}$ transverse momentum spectrum: V0M Class V (pp at $\\sqrt{s}=7$ TeV).","name":"Table 15"},{"@id":"https://doi.org/10.17182/hepdata.77284.v1/t16","@type":"Dataset","description":"$\\Lambda+\\bar{\\Lambda}$ transverse momentum spectrum: V0M Class VI (pp at $\\sqrt{s}=7$ TeV).","name":"Table 16"},{"@id":"https://doi.org/10.17182/hepdata.77284.v1/t17","@type":"Dataset","description":"$\\Lambda+\\bar{\\Lambda}$ transverse momentum spectrum: V0M Class VII (pp at $\\sqrt{s}=7$ TeV).","name":"Table 17"},{"@id":"https://doi.org/10.17182/hepdata.77284.v1/t18","@type":"Dataset","description":"$\\Lambda+\\bar{\\Lambda}$ transverse momentum spectrum: V0M Class VIII (pp at $\\sqrt{s}=7$ TeV).","name":"Table 18"},{"@id":"https://doi.org/10.17182/hepdata.77284.v1/t19","@type":"Dataset","description":"$\\Lambda+\\bar{\\Lambda}$ transverse momentum spectrum: V0M Class IX (pp at $\\sqrt{s}=7$ TeV).","name":"Table 19"},{"@id":"https://doi.org/10.17182/hepdata.77284.v1/t20","@type":"Dataset","description":"$\\Lambda+\\bar{\\Lambda}$ transverse momentum spectrum: V0M Class X (pp at $\\sqrt{s}=7$ TeV).","name":"Table 20"},{"@id":"https://doi.org/10.17182/hepdata.77284.v1/t21","@type":"Dataset","description":"$\\Xi^{-}+\\bar{\\Xi}^{+}$ transverse momentum spectrum: V0M Class I (pp at $\\sqrt{s}=7$ TeV).","name":"Table 21"},{"@id":"https://doi.org/10.17182/hepdata.77284.v1/t22","@type":"Dataset","description":"$\\Xi^{-}+\\bar{\\Xi}^{+}$ transverse momentum spectrum: V0M Class II (pp at $\\sqrt{s}=7$ TeV).","name":"Table 22"},{"@id":"https://doi.org/10.17182/hepdata.77284.v1/t23","@type":"Dataset","description":"$\\Xi^{-}+\\bar{\\Xi}^{+}$ transverse momentum spectrum: V0M Class III (pp at $\\sqrt{s}=7$ TeV).","name":"Table 23"},{"@id":"https://doi.org/10.17182/hepdata.77284.v1/t24","@type":"Dataset","description":"$\\Xi^{-}+\\bar{\\Xi}^{+}$ transverse momentum spectrum: V0M Class IV (pp at $\\sqrt{s}=7$ TeV).","name":"Table 24"},{"@id":"https://doi.org/10.17182/hepdata.77284.v1/t25","@type":"Dataset","description":"$\\Xi^{-}+\\bar{\\Xi}^{+}$ transverse momentum spectrum: V0M Class V (pp at $\\sqrt{s}=7$ TeV).","name":"Table 25"},{"@id":"https://doi.org/10.17182/hepdata.77284.v1/t26","@type":"Dataset","description":"$\\Xi^{-}+\\bar{\\Xi}^{+}$ transverse momentum spectrum: V0M Class VI (pp at $\\sqrt{s}=7$ TeV).","name":"Table 26"},{"@id":"https://doi.org/10.17182/hepdata.77284.v1/t27","@type":"Dataset","description":"$\\Xi^{-}+\\bar{\\Xi}^{+}$ transverse momentum spectrum: V0M Class VII (pp at $\\sqrt{s}=7$ TeV).","name":"Table 27"},{"@id":"https://doi.org/10.17182/hepdata.77284.v1/t28","@type":"Dataset","description":"$\\Xi^{-}+\\bar{\\Xi}^{+}$ transverse momentum spectrum: V0M Class VIII (pp at $\\sqrt{s}=7$ TeV).","name":"Table 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collisions","provider":{"@type":"Organization","name":"HEPData"},"publisher":{"@type":"Organization","name":"HEPData"},"url":"https://www.hepdata.net/record/ins1471838?version=1","version":1}