A fresh look at eta2(1645), eta2(1870), eta2(2030) and f2(1910) in pbar-p -> eta + 3pizero

TL;DR

This paper re-analyzes data on eta2 and f2 mesons, resolving discrepancies in their decay branching ratios and confirming resonant behaviors with improved parameter measurements.

Contribution

It provides a revised analysis of meson decay data, clarifying previous inconsistencies and confirming resonance properties with more accurate measurements.

Findings

Confirmed small branching ratio R for eta2(1870)

Identified resonant phase variation in eta2(1870)

Measured eta2(2030) resonance parameters with reduced errors

Abstract

There is a large discrepancy between results of Crystal Barrel and WA102 for the branching ratio R = BR[eta2(1870)->a2(1320)pi]/ BR[eta2(1870)->f2(1270)eta]. An extensive re-analysis of the Crystal Barrel data redetermines branching ratios for decays of eta2(1870), eta2(1645), eta2(2030) and f2(1910). This re-analysis confirms a small value for R of 1.60+-0.39, inconsistent with the value 32.6+-12.6 of WA102. The likely origin of the discrepancy is that the WA102 data contain a strong f2(1910)->a2-pi signal as well as eta2(1870). There is strong evidence that the eta2(1870) has resonant phase variation. A peak in f2(1270)a0(980) confirms closely the parameters of the a2(2255) resonance observed previously. A peak in eta2(2030)-pi is interpreted naturally in terms of pi2(2245) with reduced errors for mass and width M=2285+-20(stat)+-25(syst) MeV, Gamma=250+-20(stat)+-25(syst) MeV.