# What is Chromoelectric dipole moment?

Basically, I wonder what Chromoelectric dipole moment is and how it is formed...

It is exactly the same thing as an electric dipole moment, but it's generated from color field. Therefore you must be careful about non-commutativity of the charges

Sehwook Lee
ChrisVer
Gold Member
The Electric Dipole Moment $\vec{d}_f$ of some particle $f$, is defined by its interaction with an electric field $\vec{E}$:

$H_{EDM} = - \vec{d}_f \cdot \vec{E}$

For a spin-1/2 particle, this corresponds to the effective lagrangian density:

$\mathcal{L}_{EDM} = \frac{-i}{2} d_f F_{\mu \nu} \bar{\psi}_f \sigma^{\mu \nu} \gamma^5 \psi_f$

you can have a similar term if you look at quarks $\mathcal{q}_r$, by replacing the electromagnetism with strong ints:

$\mathcal{L}_{CEDM} = \frac{-i}{2} d_r^{CEDM} G_{\mu \nu}^a \bar{\mathcal{q}}_r \sigma^{\mu \nu} \gamma^5 \frac{\lambda^a}{2} \mathcal{q}_r$

and that's how it arises... In general both EDMs and CEDMs generate P and T (so CP) violations.

Sehwook Lee