Here's why:

* Beta decay involves the emission of a beta particle, which can be either an electron (β-) or a positron (β+).

* Electrons are negatively charged particles that orbit the nucleus of an atom.

* Positrons are the antimatter counterparts of electrons, carrying the same mass but a positive charge.

So, while a beta particle can be a positron, it's more common to think of it as resembling an electron due to its mass and charge.