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Title: Physics and Outlook for Rare, All-neutral Eta Decays

The $$\eta$$ meson provides a laboratory to study isospin violation and search for new flavor-conserving sources of C and CP violation with a sensitivity approaching $$10^{-6}$$ of the isospin-conserving strong amplitude. Some of the most interesting rare $$\eta$$ decays are the neutral modes, yet the effective loss of photons from the relatively common decay $$\eta \rightarrow 3\pi^0 \rightarrow 6\gamma$$ (33$$\%$$) has largely limited the sensitivity for decays producing 3-5$$\gamma$$'s. Particularly important relevant branches include the highly suppressed $$\eta \rightarrow \pi^0 2\gamma \rightarrow 4\gamma$$, which provides a rare window on testing models of $O(p^6)$ contributions in ChPTh, and $$\eta \rightarrow 3\gamma$$ and $$\eta \rightarrow 2\pi^0 \gamma \rightarrow 5\gamma$$ which provide direct constraints on C violation in flavor-conserving processes. The substitution of lead tungstate in the forward calorimeter of the GluEx setup in Jefferson Lab's new Hall D would allow dramatically improved measurements. The main niche of this facility, which we call the JLab Eta Factory (JEF), would be $$\eta$$ decay neutral modes. However, this could likely be expanded to rare $$\eta'(958)$$ decays for low energy QCD studies as well as $$\eta$$ decays involving muons for new physics searches.
Authors:
 [1]
  1. JLAB
Publication Date:
OSTI Identifier:
1133834
Report Number(s):
JLAB-PHY-14-1841; DOE/OR/23177-3052
DOE Contract Number:
AC05-06OR23177
Resource Type:
Conference
Resource Relation:
Journal Name: EPJ Web of Conferences; Journal Volume: 73; Conference: MENU 2013, Rome, Italy, September 30-October 4, 2013
Research Org:
Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS