Speaker
Ms
Yinghui GUAN
(IHEP)
Description
Spontaneous hyperon polarization has been a long standing issue since it was first observed in pp scattering more than 40 years ago. The so called polarizing Fragmentation Function(FF), $D^{\perp}{1T}(z, p^2{\perp}),describestheproductionofatransverselypolarizedhadronfromanunpolarizedquark,wherezdenotesthefractionalenergyofthehadronandp_\perpthetransversemomentumwithrespecttothefragmentingquark.ThepolarizingFFcanbedeterminedbymeasurementofthetransversepolarizationofhyperons.Duetoitschiral−evennature,thesignofthisFFcanbeunambiguouslydeterminedine+e−annihilationandthecomparisonoftheextractedFFtootherprocesses,likeSIDIS,providesauniqueopportunitytotestitsuniversality.TheknowledgeofpolarizingFFwillalsohelptoextendourunderstandingoffactorizationinQCDprocesseswithunintegrateddependencesonintrinsictransversemomenta.Thelargee+e−annihilationdatasamplecollectedbytheBelleexperimentattheKEKBstorageringallowsaprecisionstudyontheproductionoftransverselypolarizedhyperons\Lambda/anti−{\Lambda}transversetoitsproductionplaneine+e−annihilationinclusiveprocess,studiesonbothcasesofwithandwithoutalighthadrontotagtheflavorofthequarkfragmentingtothe\Lambdawillbepresented.Thefeed−downfrom\Sigma^0and\Lambda_c$ decays are also investigated.
Further, this talk will discuss the recent results on the identified di-hadron cross-sections measured at Belle, which are an essential ingredient in the extraction of transversity from a global fit to di-hadron single spin asymmetries.
