${{\boldsymbol \eta}^{\,'}{(958)}}$ $\rightarrow$ ${{\boldsymbol \eta}}{{\boldsymbol \pi}}{{\boldsymbol \pi}}$ DECAY PARAMETERS
$\vert $MATRIX ELEMENT$\vert ^2$ = $\vert $1 + $\alpha {}\boldsymbol Y\vert ^2$ + $\boldsymbol C{}\boldsymbol X$ + $\boldsymbol D{}\boldsymbol X{}^{2}$
$\mathit X$ and $\mathit Y$ are Dalitz variables; $\alpha $ is complex and $\mathit C$, and $\mathit D$ are real-valued. Parameters $\mathit C$ and $\mathit D$ are not necessarily equal to $\mathit c$ and $\mathit d$, respectively, in the generalized parameterization following this one. May be different for ${{\mathit \eta}^{\,'}{(958)}}$ $\rightarrow$ ${{\mathit \eta}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ and ${{\mathit \eta}^{\,'}{(958)}}$ $\rightarrow$ ${{\mathit \eta}}{{\mathit \pi}^{0}}{{\mathit \pi}^{0}}$ decays. Because of different initial assumptions and strong correlations of the parameters we do not average the parameters in the section below.
$\boldsymbol C$ decay parameter
INSPIRE search
| • • • We do not use the following data for averages, fits, limits, etc. • • • |
| $0.0027$ $\pm0.0024$ $\pm0.0015$ |
351k |
|
|
BES3 |
| $0.018$ $\pm0.009$ $\pm0.003$ |
44k |
1 |
|
BES3 |
| $0.020$ $\pm0.018$ $\pm0.004$ |
7k |
2 |
|
VES |
|
1
See ABLIKIM 2011 for the full correlation matrix.
|
|
2
Superseded by DOROFEEV 2007 , which found this parameterization unacceptable. See below.
|
|
| References: |
|
| PR D97 012003 |
Measurement of the Matrix Elements for the Decays ${{\mathit \eta}^{\,'}}$ $\rightarrow$ ${{\mathit \eta}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ and ${{\mathit \eta}^{\,'}}$ $\rightarrow$ ${{\mathit \eta}}{{\mathit \pi}^{0}}{{\mathit \pi}^{0}}$ |
|
| PR D83 012003 |
Measurement of the Matrix Element for the Decay ${{\mathit \eta}^{\,'}}$ $\rightarrow$ ${{\mathit \eta}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ |
|
| PAN 68 372 |
Measurement of Form Factors for the Decay ${{\mathit \eta}^{\,'}}$ $\rightarrow$ ${{\mathit \eta}}{{\mathit \pi}^{-}}{{\mathit \pi}^{+}}$ |
|
