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Дата изменения: Wed Aug 9 20:40:47 2000
Дата индексирования: Mon Oct 1 22:46:45 2012
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Interaction of ghosts with gluon.

This interaction is described by the non-linear term of (.7), namely

$$S_{\bar{c}cG}= -g \int \bar{c}_{\alpha}(x) \partial^{\mu}(... ...lpha}_{\beta \gamma} G^{\beta}_{\mu}(x) c^{\gamma}(x)) d^4x\;;$$

Fourier transformation and subsequent evaluation of functional derivatives gives us

$$S_{\bar{c}cG}= -g (2\pi)^4 \int \delta(p_1+p_2+p_3) \bar{c}_... ...} G^{\beta}_{\mu_3}(p_3) c^{\gamma}(p_2) d^4p_1 d^4p_2 d^4p_3$$

$$\frac{\delta S_{\bar{c}cG}} {\delta \bar{c}_{\alpha_1}(p_1) ... ...1+p_2+p_3) p_1^{\mu_3}i\, f^{\alpha_1}_{\alpha_2 \alpha_3} \;.$$

The factor $(2\pi)^4 \delta(p_1+p_2+p_3) (-\,i\, f_{ \alpha_1 \alpha_2 \alpha_3})$ is substituted by CompHEP. Thus, this interaction may be implemented as the following record in the Vertex table.

A1	A2	A3	A4	Factor	Lorentz part
G.C	G.c	G		-GG	p1.m3

where $G.C$ and $G.c$ are the CompHEP  notations for the Faddeev-Popov ghosts $\bar{c}$ and $c$ respectively.