${{\boldsymbol \eta}^{\,'}{(958)}}$ $\rightarrow$ ${{\boldsymbol \eta}}{{\boldsymbol \pi}}{{\boldsymbol \pi}}$ 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 Re(\alpha $) decay parameter
INSPIRE search
• • • We do not use the following data for averages, fits, limits, etc. • • • |
$-0.034$ $\pm0.002$ $\pm0.002$ |
351k |
|
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BES3 |
$-0.054$ $\pm0.004$ $\pm0.001$ |
56k |
|
|
BES3 |
$-0.033$ $\pm0.005$ $\pm0.003$ |
44k |
1 |
|
BES3 |
$-0.072$ $\pm0.012$ $\pm0.006$ |
7k |
2 |
|
VES |
$-0.021$ $\pm0.018$ $\pm0.017$ |
6.7k |
3 |
|
CLEO |
$-0.058$ $\pm0.013$ $\pm0.003$ |
5.4k |
4 |
|
GAM2 |
$-0.08$ $\pm0.03$ |
|
4, 5 |
|
RVUE |
1
See ABLIKIM 2011 for the full correlation matrix.
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2
Superseded by DOROFEEV 2007 , which found this parameterization unacceptable. See below.
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3
Assuming Im($\alpha $) = 0, $\mathit C$ = 0, and $\mathit D$ = 0.
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4
Assuming $\mathit C$ = 0.
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5
From the data of DAUBER 1964 , RITTENBERG 1969 , AGUILAR-BENITEZ 1972B, JACOBS 1973 , and DANBURG 1973 .
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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 ${{\mathit \eta}^{\,'}}$ $\rightarrow$ ${{\mathit \eta}}{{\mathit \pi}^{-}}{{\mathit \pi}^{+}}$ |
| PRL 84 26 |
Rare Decays of the ${{\mathit \eta}^{\,'}}$ |
| PL B177 115 |
Matrix Element of the ${{\mathit \eta}^{\,'}{(958)}}$ $\rightarrow$ ${{\mathit \eta}}{{\mathit \pi}^{0}}{{\mathit \pi}^{0}}$ Decay |
| PR D10 916 |
${{\mathit \eta}^{\,'}{(958)}}$ Branching Ratio, Linear Matrix Element and Dipion Phase Shift |
|