For some time ago the dilemma posed by the contradictory claims of DAMA and Cogent collaborations on one hand and XENON100 collaboration on one hand finds also nice solution in terms of 14 GeV taupion decaying to charged taupions with mass about 7 GeV. See the previous posting.
The decays of electro-pions to gamma pair can explain the observed anomalous gammas from galactic nucleus with energy very nearly to electron rest mass. Could one understand also the anomalous positrons reported by PAMELA as decay products of lepto-pion like states, say tau-pions? Intriguingly, the first figures of the article by Alessandro Strumia discussing the constraints on the possible explanations of the PAMELA anomaly show that the anomalous positron excess starts around 10 GeV, possible it starts already at 7 GeV. It is not possible to say anything certain below 10 GeV since the measurements are affected by the solar actvity below 10 GeV. What is however clear is that the excess cannot be explained by taupion decays with 14 GeV mass since the excess would be localized around energy of about 7 GeV. Higher mass is required.
The article by Alessandro Strumia summarizes various theoretical constraints on the new particle explaining positron and electron excesses. The conclusions are following.
- DM should result in a decay of quite a narrow particle with a mass very near to 2M, which is nearly at rest. What narrow means quantitatively is not clear to me.
- DM should carry a charge mediating long range interaction with the mediating boson which is must lighter than the particle itself: photon is the obvious candidate. Electromagnetically charged dark matter is however in conflict with the standard prejudices about dark matter and actually in dramatic conflict with its basic property of being invisible. Hierarchy of Planck constants is the only solution to the paradox of charged invisible dark matter.
- DM must prefer the decays to leptons since otherwise there would be also antiproton and proton excess which has not been observed.
- The mass of DM should be above 100 GeV.
- If a scaled up variant of ordinary hadron physics characterized by M89 is there as the recent bumps having interpretation as mesons of this physics suggest, there is no deep reason preventing the presence of also the scale variant of leptohadron physics in this scale. Even more, one can argue that colored leptons must appear as both dark and ordinary variants. Dark variants with non-standard value of Planck constant can have masses of ordinary leptons plus possibly their octaves as in the case of tau at least. The decay widths of intermediate gauge bosons require ordinary colored leptons to have mass higher than 45 GeV.
- The mass of scaled up electropion would be obtained by scaling the mass of the dark electropion which for M89 electro-pion physics is in a good approximation 2me=1 MeV by a factor 2(127-89)/2= 219. This gives electropion mass equal to 500 GeV. Ordinary colored electron would therefore have mass of 250 GeV consistent with the lower bound. The conclusion would be rather ironic: we would have seen dark colored electron (in TGD sense) already at seventies and covered it carefelly under the rug and would be seeing now the ordinary colored electron and stubbornly trying to identify it as DM without caring about the fact that if dark matter is invisible in the standard sense it cannot be electromagnetically charged! Nature seems to love vulgar humour and feel no mercy towards pompous theoreticians enjoying monthly salary;-).
- By stretching one's imagination one might play with the thought that superpartners of colored leptons with mass scale of order 100 GeV could form pion like states. The superpartners decay to partner and neutrino since R-parity is not exact invariance in TGD and all depends on how fast this process occurs.
- Skeptic could wonder why the counterparts for colored excitations of quarks are not there and induce the increase of proton and antiproton fluxes.