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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 Cet article a éte moissonné depuis la source Math-Net.Ru

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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},
     year = {2012},
     volume = {170},
     number = {1},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/TMF_2012_170_1_a3/}
}
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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/

[1] N. N. Achasov, Pisma v ZhETF, 54:2 (1991), 75–77 | MR

[2] N. N. Achasov, ZhETF, 101:6 (1992), 1713–1723; Исправление, 103:2 (1993), 718

[3] N. N. Achasov, V. K. Besprozvannykh, YaF, 55 (1992), 1934–1941

[4] N. N. Achasov, Phys. Lett. B, 287:1–3 (1992), 213–215 | DOI

[5] N. N. Achasov, ZhETF, 103:1 (1993), 11–17

[6] N. N. Achasov, Pisma v ZhETF, 56:7 (1992), 345 ; Particle World, 4 (1994), 10 | MR

[7] B. Guberina, J. H. Kühn, R. D. Peccei, R. Rückl, Nucl. Phys. B, 174:2–3 (1980), 317–334 ; J. H. Kühn, Acta Phys. Pol. B, 12:4 (1981), 347–398 | DOI

[8] L. Rosenberg, Phys. Rev., 129:6 (1963), 2786–2788 | DOI | Zbl

[9] S. L. Adler, Phys. Rev., 177:5 (1969), 2426–2438 | DOI

[10] N. N. Achasov, Phys. Lett. B, 222:1 (1989), 139–142 | DOI

[11] Particle Data Group, Phys. Lett. B, 667:1–5 (2008), 1–6 | DOI