No, N-15 absorbs a proton becoming some form of O-16 (normally stable) which has to shed some momentum or energy(?) Because of how it formed and then emits an alpha particle.
I guess I have a lot more to learn about this stuff even on a non technical layman level.
I
Given the speed with which all this occurs, it's just as reasonable to describe these events as
15N is struck by a high energy proton, and splits into an alpha particle and a
12C nucleus.
You can include
16O as an intermediate step if you like. But as barbos says, it has so much energy above it's ground state that it doesn't last long before it spits out an alpha to shed that excess.
The whole process occurs at high temperature (a dozen or more megakelvins) so all the particles have a lot of momentum, and the entire cycle is very strongly exothermic. It's hardly surprising that most of the nuclei involved are in an excited state.