Wednesday, April 11, 2007

Nuclear strings and cold fusion

The option assuming that strong isospin dependent force acts on the nuclear space-time sheet and binds pn pairs to singlets such that the strong binding energy is very nearly zero in singlet state by the cancellation of scalar and vector contributions, is the most promising variant of nuclear string model. It predicts the existence of exotic di-,tri-, and tetra-neutron like particles and even negatively charged exotics obtained from 2H, 3H,3He, and 4He by adding negatively charged color bond. For instance, 3H extends to a multiplet with em charges 4,3,2,1,0,-1,-2. Heavy nuclei with proton neutron excess could actually be such nuclei.

The exotic states are stable under beta decay for m(π)<me. The simplest neutral exotic nucleus corresponds to exotic deuteron with single negatively charged color bond. Using this as target it would be possible to achieve cold fusion since Coulomb wall would be absent. The empirical evidence for cold fusion thus supports the prediction of exotic charged states.

1. Signatures of cold fusion

In the following the consideration is restricted to cold fusion in which two deuterium nuclei react strongly since this is the basic reaction type studied.

In hot fusion there are three reaction types:

  1. D+D→ 4He+γ ≈(23.8 MeV)

  2. D+D → 3He+ n

  3. D+D → 3H + p.

The rate for the process 1) predicted by standard nuclear physics is more than 10-3 times lower than for the processes 2) and 3). The reason is that the emission of the gamma ray involves the relatively weak electromagnetic interaction whereas the latter two processes are strong.

The most obvious objection against cold fusion is that the Coulomb wall between the nuclei makes the mentioned processes extremely improbable at room temperature. Of course, this alone implies that one should not apply the rules of hot fusion to cold fusion. Cold fusion indeed differs from hot fusion in several other aspects.

  1. No gamma rays are seen.

  2. The flux of energetic neutrons is much lower than expected on basis of the heat production rate an by interpolating hot fusion physics to the recent case.

These signatures can also be (and have been!) used to claim that no real fusion process occurs.

Cold fusion has also other features, which serve as valuable constraints for the model building.

  1. Cold fusion is not a bulk phenomenon. It seems that fusion occurs most effectively in nano-particles of Pd and the development of the required nano-technology has made possible to produce fusion energy in controlled manner. Concerning applications this is a good news since there is no fear that the process could run out of control.

  2. The ratio x of D atoms to Pd atoms in Pd particle must lie the critical range [.85,.90] for the production of 4He to occur. This explains the poor repeatability of the earlier experiments and also the fact that fusion occurred sporadically.

  3. Also the transmutations of Pd nuclei are observed.

Below a list of questions that any theory of cold fusion should be able to answer.

  1. Why cold fusion is not a bulk phenomenon?

  2. Why cold fusion of the light nuclei seems to occur only above the critical value x\simeq .85 of D concentration?

  3. How fusing nuclei are able to effectively circumvent the Coulomb wall?

  4. How the energy is transferred from nuclear degrees of freedom to much longer condensed matter degrees of freedom?

  5. Why gamma rays are not produced, why the flux of high energy neutrons is so low and why the production of 4He dominates (also some tritium is produced)?

  6. How nuclear transmutations are possible?

Could exotic deuterium make cold fusion possible?

One model of cold fusion has been already discussed in TGD framework. The basic idea is that only the neutrons of incoming and target nuclei can interact strongly, that is their space-time sheets can fuse. One might hope that neutral deuterium having single negatively charged color bond could allow to realize this mechanism.

  1. Suppose that part of the target deuterium in Pd catalyst corresponds to exotic deuterium with neutral nuclei so that cold fusion would occur between neutral D in the target and charged incoming D and Coulomb wall in the nuclear scale would be absent. A possible mechanism giving rise to this kind of phase would be a local phase transition in the Pd target possibly involving dark matter hierarchy.

  2. The exotic variant of the ordinary D + D reaction yields final states in which 4He, 3He and 3H are replaced with their exotic counterparts with charge lowered by one unit. In particular, exotic 3H is neutral and there is no Coulomb wall hindering its fusion with Pd nuclei so that nuclear transmutations can occur.
Why the neutron and gamma fluxes are low might be understood if for some reason only exotic 3H is produced, that is the production of charged final state nuclei is suppressed. The explanation relies on Coulomb wall at the nucleon level.

  1. Initial state contains one charged and one neutral color bond and final state A=3 or A=4 color bonds. Additional neutral color bonds must be created in the reaction (one for the production A=3 final states and two for A=4 final state). The process involves the creation of neural fermion pairs. The emission of one exotic gluon per bond decaying to a neutral pair is necessary to achieve this. This requires that nucleon space-time sheets fuse together. Exotic D certainly belongs to the final state nucleus since charged color bond is not expected to be split in the process.

  2. The process necessarily involves a temporary fusion of nucleon space-time sheets. One can understand the selection rules if only neutron space-time sheets can fuse appreciably so that only 3H would be produced. Here Coulomb wall at nucleon level should enter into the game.

  3. Protonic space-time sheets have the same positive sign of charge always so that there is a Coulomb wall between them. This explains why the reactions producing exotic 4He do not occur appreciably. If the quark/antiquark at the neutron end of the color bond of ordinary D has positive charge, there is Coulomb attraction between proton and corresponding negatively charged quark. Thus energy minimization implies that the neutron space-time sheet of ordinary D has positive net charge and Coulomb repulsion prevents it from fusing with the proton space-time sheet of target D. The desired selection rules would thus be due to Coulomb wall at the nucleon level.

For more details see the chapter TGD and Nuclear Physics and the new chapter Nuclear String Hypothesis of of "p-Adic Length Scale Hypothesis and Dark Matter Hierarchy".

No comments: