${{\mathit D}^{0}}$ $\mathit CP$-EVEN FRACTIONS

The $\mathit CP$-even fraction F$_{+}$, defined for self-conjugate final states, like the coherence factor is useful for measuring the unitary triangle angle $\gamma $ in ${{\mathit B}}$ $\rightarrow$ ${{\mathit D}}{{\mathit K}}$ decays. A purely $\mathit CP$-even state has F$_{+}$ = 1, a $\mathit CP$-odd one has F$_{+}$ = 0. For details, see NAYAK 2015 .

$\mathit CP$-even fraction in ${{\mathit D}^{0}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ decays

INSPIRE   PDGID:
S032EFL
VALUE (%) DOCUMENT ID TECN  COMMENT
$\bf{ 74.6 \pm1.6 }$ OUR AVERAGE  Error includes scale factor of 1.2.
$73.5$ $\pm1.5$ $\pm0.5$ 1
ABLIKIM
2022BF
BES 2.93 fb${}^{-1}$ in ${{\mathit e}^{+}}{{\mathit e}^{-}}$ at 3.773 GeV
$76.9$ $\pm2.1$ $\pm1.0$ 2
HARNEW
2018
Uses CLEO-c data
• • We do not use the following data for averages, fits, limits, etc. • •
$72.9$ $\pm0.9$ $\pm1.8$ 3, 2
DARGENT
2017
from amplitude model
$73.7$ $\pm2.8$
MALDE
2015
CLEO amplitude model independent
1  A combination of three consistent measurements with $\mathit CP$-eigenstate, quasi-$\mathit CP$-eigenstate and $\mathit CP$-mixed tags.
2  Obtained by analyzing CLEO-c data but not authored by the CLEO Collaboration.
3  MALDE 2015 and DARGENT 2017 use different CLEO data sets, so in principle their results could be averaged. However, given the importance that model-independence has in the use of this value, we exclude the amplitude model-derived result from the average.
Conservation Laws:
$\mathit CP$ INVARIANCE
References:
ABLIKIM 2022BF
PR D106 092004 Measurement of the CP-even fraction of D0??+?-?+?-
HARNEW 2018
JHEP 1801 144 Model-independent determination of the strong phase difference between $D^0$ and $\bar{D}^0 \to\pi^+\pi^-\pi^+\pi^-$ amplitudes
DARGENT 2017
JHEP 1705 143 Amplitude Analyses of ${{\mathit D}^{0}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ and ${{\mathit D}^{0}}$ $\rightarrow$ ${{\mathit K}^{+}}{{\mathit K}^{-}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ Decays
MALDE 2015
PL B747 9 First Determination of the $\mathit CP$ Content of ${{\mathit D}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{+}}{{\mathit \pi}^{-}}$ and Updated Determination of the $\mathit CP$ Contents of ${{\mathit D}}$ $\rightarrow$ ${{\mathit \pi}^{+}}{{\mathit \pi}^{-}}{{\mathit \pi}^{0}}$ and ${{\mathit D}}$ $\rightarrow$ ${{\mathit \pi}^{0}}$