Measurement of transverse polarization of Lambda at Belle and the K-Long muon (KLM) system of Belle-II

by Dr Yinghui Guan

Monday 12 Mar 2018, 10:00 → 11:00 Asia/Shanghai

B326

Abstract: Spontaneous Lambda polarization has been observed in unpolarized pp collisions years ago while the precise mechanism behind it remains unknown. It is assumed that the so called polarizing Fragmentation Function(FF) plays a important role in this effect. The polarizing FF is of great interest not only because it is strongly connected to the spin structure of hadrons, but also it is chiral-even and the sign is possible to be unambiguously measured so it provides a unique opportunity to test the universality of the FFs. The large e+e- annihilation data sample collected by the Belle experiment at the KEKB storage ring allows a precision study of the production of transversely polarized hyperons and will help us to understand the associated QCD dynamics. The measurement of transverse Lambda polarization in e+e- annihilation in the inclusive production processes at Belle will be presented. The Belle II detector and SuperKEKB, the upgrade of Belle detector and KEKB collider, are being constructed at the KEK laboratory in Tsukuba, Japan. The machine is designed for an instantaneous luminosity of 8x10^35cm^-2s^-1. And the first physical data taking runs at Belle II are anticipated in 2018. The K-Long and muon system of Belle II, which provides the K-Long and muon identification, consists of an alternating sandwich iron plates and active detector elements located outside of the superconducting solenoid. The detector elements includes glass-electrode resistive plate chambers(RPC) layers in barrel and scintillator layers in barrel and endcap. This talk will introduce the Belle-II detector, the commissioning of the KLM system and the status of cosmic ray test on Belle II. About the speaker: Yinghui graduated from University of Chinese Academy of Sciences and obtained her Ph.D with the thesis "Measurement of D0-D0bar mixing parameters y at BESIII". After graduated, Yinghui continued the work at BESIII as a post-doc of IHEP. Then Yinghui moved to Belle and Belle II experiment, as a post-doc of a joint position of PNNL and Indiana University, working for the commissioning of the KLM (K_L and muon) detector at Belle II and also physics analysis at Belle.

Slides CV_guan.pdf IHEP_Seminar_GUAN.pdf