A New Map of All the Particles and Forces (2020)

Inside the free neutron, that's what happens, too. A down quark interacts with a W- to transform itself into an up quark; the neutron is now a proton, with the W- carrying away some of the mass and electric charge.

However, neutrons and protons are more complex than just quarks. They're also big bundles of gluons, exchanging colour charge amongst each other. These gluons have mass and you need energy to create them. They actually account for most of the mass of a neutron/proton. A bound neutron and proton are exchanging these gluons amongst each other, too.

Suppose you had a bound neutron and proton. If the neutron were to decay into a proton, the electric charge of the particles (now both +1) would cause them to repel; you can imagine either of two things might happen: the protons will now move apart _or_ they'll stick together. In the former, you need kinetic energy and in the latter, you're going to need more gluons to hold the whole thing together. Both of those cases requires more energy (==mass) than the neutron would "lose" by converting to a proton.

So, if you can imagine the potential energy landscape, the bound neutron is at a local minimum (lower than a free neutron)

https://arxiv.org/abs/hep-th/9402115

and far far away more of them are being created and inflating, once you far enough way you are in something that looks like our universe, somewhere out there inflation is stopping and the big bang is happening there.

It's easy in my mind looking at the classical black hole picture and wondering what happens around the singularity to wonder if inflation gets re-started inside a black hole and maybe in that old picture where you can go into a rotating black hole and come out in the "asymptotically flat spacetime" it is a universe made by that mechanism.

Of course I think the classical black hole picture might be "not even wrong" and you might run into more than one firewall (such as the inflation zone) on the way there.