- #1
arivero
Gold Member
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Let me describe what I did this week-end since the closing of the previous thread.
I went to look for bibliography; it seems that Brosa did a classification of fission channels that is currently used to systematize the fits of nuclear yields to gaussians.
So I went to the databases for experiments and evaluation doing this kind of fit.
First I found an evaluation for the UK fission data, UKFY3, that makes "five gaussian fit" (actually three, given the central symmetry) and determines the position of "Standard Asymmetric" channels S1 and S2. This was from 1995; then I find in the IAEA another work, from 2008, where a russian team adds a third channel S3 to fit the more extreme "wings" with another gaussian. This work included a fit for two (p,f) experiments,
I took the first table of the most recent work -excitation of fission with protons at 10 MeV- and copied the position of all the peaks. S1 and S2 are told in the literature to be due to shells in the large fragment of fission, and S3 in the small fragment, but I took the small fragment also for S2. For the small fragments I simply subtracted A of the original nucleus minus weight of the large, so some extra systematics up to two neutrons can be argued to be there -not sure without looking at the computer code of the fit-.
Ok so I have S1, A-S2 and A-S3 for a table of ten nuclei, from 233Pa to 245Bk. Then I applied the "rule" 1 AMU = 0.9315 GeV and averaged the columns. Result
S1 peak:
GeV.
A-S2 peak:
A-S3 peak:
Note that the fail of the average is bigger in the low fragment of S2, the dependency being really with atomic numberr A, because the peak is more or less constant in the high fragment (about 130 GeV; you can see all the tables in my blog). Note also that this table was actually new data, not including U nor Pu isotopes. The UKFY3 match did include them and doing the same procedure its S1 peak was
GeV, a thing we already knew from eyeball observation of the fission histogram of traditional nuclear fuel.
So, you see my trouble. Data is very eye-catching, even more that when I first look at it in November of 2003, but the situation is even worse theoretically.
It is not only that we should need some low-momentum exchange to justify the ability of electroweak particles to see all the nucleus. This is almost palatable; there is not only the analogy of atomic levels (where the momentum of the interacting photon is of size of the whole atom) but it is also known in nuclear theory; for instance it happens in neutrino absorption, when the probability of producing a charged lepton goes with the quotient between the lepton mass and the whole nuclear mass. But beyond this, one should need to explain why the decoupling fails and we are able to "see" the masses of W and Z that should be hidden inside Fermi constant. And here is were I left in 2004; now we have another even more unlikely coupling; the Higgs yukawa to proton should be not proton mass, but constituent mass, and this is orders of magnitude small. The only positive thing is that at least it would be higher to neutron (two down quarks) that to proton, consistent with the main role of neutron shells in the traditional model of nuclear scission.
I went to look for bibliography; it seems that Brosa did a classification of fission channels that is currently used to systematize the fits of nuclear yields to gaussians.
So I went to the databases for experiments and evaluation doing this kind of fit.
First I found an evaluation for the UK fission data, UKFY3, that makes "five gaussian fit" (actually three, given the central symmetry) and determines the position of "Standard Asymmetric" channels S1 and S2. This was from 1995; then I find in the IAEA another work, from 2008, where a russian team adds a third channel S3 to fit the more extreme "wings" with another gaussian. This work included a fit for two (p,f) experiments,
I took the first table of the most recent work -excitation of fission with protons at 10 MeV- and copied the position of all the peaks. S1 and S2 are told in the literature to be due to shells in the large fragment of fission, and S3 in the small fragment, but I took the small fragment also for S2. For the small fragments I simply subtracted A of the original nucleus minus weight of the large, so some extra systematics up to two neutrons can be argued to be there -not sure without looking at the computer code of the fit-.
Ok so I have S1, A-S2 and A-S3 for a table of ten nuclei, from 233Pa to 245Bk. Then I applied the "rule" 1 AMU = 0.9315 GeV and averaged the columns. Result
S1 peak:
A-S2 peak:
A-S3 peak:
Note that the fail of the average is bigger in the low fragment of S2, the dependency being really with atomic numberr A, because the peak is more or less constant in the high fragment (about 130 GeV; you can see all the tables in my blog). Note also that this table was actually new data, not including U nor Pu isotopes. The UKFY3 match did include them and doing the same procedure its S1 peak was
So, you see my trouble. Data is very eye-catching, even more that when I first look at it in November of 2003, but the situation is even worse theoretically.
It is not only that we should need some low-momentum exchange to justify the ability of electroweak particles to see all the nucleus. This is almost palatable; there is not only the analogy of atomic levels (where the momentum of the interacting photon is of size of the whole atom) but it is also known in nuclear theory; for instance it happens in neutrino absorption, when the probability of producing a charged lepton goes with the quotient between the lepton mass and the whole nuclear mass. But beyond this, one should need to explain why the decoupling fails and we are able to "see" the masses of W and Z that should be hidden inside Fermi constant. And here is were I left in 2004; now we have another even more unlikely coupling; the Higgs yukawa to proton should be not proton mass, but constituent mass, and this is orders of magnitude small. The only positive thing is that at least it would be higher to neutron (two down quarks) that to proton, consistent with the main role of neutron shells in the traditional model of nuclear scission.
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