报告题目：Standard Model Physics and Beyond with \eta Meson Decays

报 告 人：David Mack for the JEF/GlueXcollaboration (Thomas Jefferson National Accelerator Facility)

报告时间：2015年4月17日（周五）15:00

报告地点：理科楼三楼报告厅（C302）

报告摘要：Commissioning of the GlueX detector is in progress in Hall D at the upgraded Jefferson Lab in Newport News, Virginia. Although the main mission of GlueX is to use a linearly polarized, 9 GeV photon beam to search for anticipated gluon-quark hybrid mesons, it is also an impressive factory for light mesons. The η(548) is of particular interest as it provides a laboratory to study isospin violation, and to search for laboratory evidence of dark sector particles as well as new, flavor-conserving sources of C and CP violation. Our experimental program will begin with the relatively common η→π+π-π⁰branch (~23%) to better determine the light quark mass ratio. A spin-off of the precise new Dalitz distribution for this branch will be improved direct constraints on C violating, P conserving interactions. Ultimately, we need to upgrade the forward calorimeter from lead glass to lead tungstate to search for lepto-phobic dark matter by the reaction η→γ+B→γ+(π⁰γ). This decay would appear as a bump in the Dalitz plot for the allowed but rare decay η→π⁰2γ. The increased sensitivity of the lead tungstate calorimeter will allow us to extend searches for C violating, P conserving interactions to η→3γ and η→2π⁰γ.