Why is the neutron stable inside the nucleus, but the free neutron outside the nucleus is unstable? Or to put it another way, why don’t neutrons in a nucleus decay, and why can’t free neutrons survive on their own? This is one of those problems that is difficult to explain. The decay behaviour of the neutron, which is the β- decay, can be measured and quantified, but the process itself is unknown. Conventional explanations are given in terms of mass-energy of the components and binding energy between them. However that’s a superficial quantification of WHAT happens in the situation. It does not explain HOW and WHY at the deeper level. Our latest paper addresses this topic (http://dx.doi.org/10.5539/apr.v7n1p1).

We started from the assumption that matter particles are not zero-dimensional points, but instead have internal structures and emit discrete fields (Cordus particule structure http://physicsessays.org/doi/abs/10.4006/0836-1398-25.1.132). We then determined how the discrete fields would operate within such a conceptual framework. We created a mathematical formalism of the principles for manipulating discrete forces and transforming one type of particule into another. This was used to determine the structures of the W and Z bosons, and the causes of neutron decay within this framework. It turns out that the stability of the neutron inside the nucleus arises because its pattern of discrete field emissions is complementary to that of the proton. The neutron is stable in this bound state because the assembly with the proton results in a complete, as opposed to incomplete, set of discrete forces. This gives the neutron the ability to resist the disrupting effect of the discrete fields coming at it from its surroundings. Hence the stability of the neutron within the nucleus.

This also means that the neutron is an intermediary between the protons. The discrete fields of the protons are otherwise incompatible with each other. Think of the neutron and proton as rods that join only at their ends. The result is chains of neutron-proton-neutron-proton-…. etc. This we call the ‘nuclear polymer’ and our other work shows how this may be used to explain the stability, instability, and non-existence of nuclides (H to Ne) (http://dx.doi.org/10.5539/apr.v5n6p145).

That addresses the stability question. Regarding the other side of the problem, the instability of the free neutron arises because its own discrete field structures are incomplete. Consequently it is vulnerable to external perturbation by discrete fields arising from other particles in the universe (the ‘fabric’ http://dx.doi.org/10.2174/1874381101306010077). These incoming fields subject the free neuron to discrete forces, and we propose that the neutron spatially re-orientates its own field emissions to evade the incoming disturbances. However there is a high degree of randomness in the discrete fields of the fabric, and eventually the free neutron is caught out and its evasive behaviour is constrained. At this time it decays, via β- decay, into the more stable form of the proton.

The exponential life of the free neutron arises because the decay is determined by the random supply of external discrete fields (the background fabric). Consequently any one neutron has an equal chance of decaying anywhere between zero and infinite time. It’s probability of failing in the next instant is not dependent on how many previous instants have elapsed. In terms of probability this means it has a ‘constant hazard rate’. And a characteristic of such is an exponential lifetime. Thus we can explain why the free neutron has an exponential lifetime, as opposed to any other probability density distribution. We further propose that the magnitude of the neutron’s mean lifetime is determined by the fabric density of the epoch and location of the neutron.

Other implications of this work are that the W bosons are by-products from the weak decay process, and do not cause the decay. The weak decay is shown to be in the same class of phenomenon as annihilation, and is not a fundamental interaction.

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**Originality –** A novel theory has been constructed for the decay process, using a NLHV mechanics that is deeper than quantum theory. This new theory explains the stability-instability of the neutron and is consistent with the new theory for the stability of the nuclides.

**Reference**

Pons, D. J., Pons, A. D., & Pons, A. J. (2015). Weak interaction and the mechanisms for neutron stability and decay *Applied Physics Research, 7*(1), 1-11. doi: http://dx.doi.org/10.5539/apr.v7n1p1