The~$Z\to c\bar c\to\gamma\gamma^*$, $Z\to b\bar b\to\gamma\gamma^*$ triangle diagrams and the~$Z\to\gamma\psi$, $Z\to\gamma\Upsilon$ decays
Teoretičeskaâ i matematičeskaâ fizika, Tome 170 (2012) no. 1, pp. 49-61
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We expounded an approach for studying the $Z\to\gamma\psi$ and $Z\to
\gamma\Upsilon$ decay based on the sum rules for the $Z\to c\bar c\to
\gamma\gamma^*$ and $Z\to b\bar b\to\gamma\gamma^*$ amplitudes and their
derivatives. We calculate the branching ratios of the $Z\to\gamma\psi$ and
$Z\to\gamma\Upsilon$ decays under different suppositions about the saturation of
the sum rules. We find the lower bounds of $\sum_{\psi}BR(Z\to\gamma\psi)=
1.95\cdot10^{-7}$ and $\sum_{\Upsilon}BR(Z\to\gamma\Upsilon)=7.23\cdot10^{-7}$ and
discuss deviations from the lower bounds including the possibility of
$BR[Z\to\gamma J/\psi(1S)]\sim BR[Z\to\gamma\Upsilon(1S)]\sim10^{-6}$, which is
probably measurable at the LHC. Moreover, we calculate the angle
distributions in the $Z\to\gamma\psi$ and $Z\to\gamma\Upsilon$ decays.
Keywords:
$Z$-boson radiative decay, heavy quark, triangle diagram.
@article{TMF_2012_170_1_a3,
author = {N. N. Achasov},
title = {The~$Z\to c\bar c\to\gamma\gamma^*$, $Z\to b\bar b\to\gamma\gamma^*$ triangle diagrams and the~$Z\to\gamma\psi$, $Z\to\gamma\Upsilon$ decays},
journal = {Teoreti\v{c}eska\^a i matemati\v{c}eska\^a fizika},
pages = {49--61},
publisher = {mathdoc},
volume = {170},
number = {1},
year = {2012},
language = {ru},
url = {http://geodesic.mathdoc.fr/item/TMF_2012_170_1_a3/}
}
TY - JOUR AU - N. N. Achasov TI - The~$Z\to c\bar c\to\gamma\gamma^*$, $Z\to b\bar b\to\gamma\gamma^*$ triangle diagrams and the~$Z\to\gamma\psi$, $Z\to\gamma\Upsilon$ decays JO - Teoretičeskaâ i matematičeskaâ fizika PY - 2012 SP - 49 EP - 61 VL - 170 IS - 1 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/TMF_2012_170_1_a3/ LA - ru ID - TMF_2012_170_1_a3 ER -
%0 Journal Article %A N. N. Achasov %T The~$Z\to c\bar c\to\gamma\gamma^*$, $Z\to b\bar b\to\gamma\gamma^*$ triangle diagrams and the~$Z\to\gamma\psi$, $Z\to\gamma\Upsilon$ decays %J Teoretičeskaâ i matematičeskaâ fizika %D 2012 %P 49-61 %V 170 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/item/TMF_2012_170_1_a3/ %G ru %F TMF_2012_170_1_a3
N. N. Achasov. The~$Z\to c\bar c\to\gamma\gamma^*$, $Z\to b\bar b\to\gamma\gamma^*$ triangle diagrams and the~$Z\to\gamma\psi$, $Z\to\gamma\Upsilon$ decays. Teoretičeskaâ i matematičeskaâ fizika, Tome 170 (2012) no. 1, pp. 49-61. http://geodesic.mathdoc.fr/item/TMF_2012_170_1_a3/