Friday, May 12, 2017

Excess of cosmic ray antiprotons as a further support for M89 hadron physics?

I received a link to a quite interesting popular article telling about surplus of antiprotons from cosmic rays interpreted in terms of dark matter particles decays to protons and antiprotons. The article mentions two articles summarizing essentially similar experimental findings.

The first article Novel Dark Matter Constraints from Antiprotons in Light of AMS-02 is published in Phys Rev Letters. The abstract is here.

We evaluate dark matter (DM) limits from cosmic-ray antiproton observations using the recent precise AMS-02 measurements. We properly take into account cosmic-ray propagation uncertainties, fitting DM and propagation parameters at the same time and marginalizing over the latter. We find a significant indication of a DM signal for DM masses near 80 GeV, with a hadronic annihilation cross section close to the thermal value,
< σ v>∼ 2× 10-26 cm3/s. Intriguingly, this signal is compatible with the DM interpretation of the Galactic center gamma-ray excess. Confirmation of the signal will require a more accurate study of the systematic uncertainties, i.e., the antiproton production cross section, and the modeling of the effect of solar modulation. Interpreting the AMS-02 data in terms of upper limits on hadronic DM annihilation, we obtain strong constraints excluding a thermal annihilation cross section for DM masses below about 50 GeV and in the range between approximately 150 and 500 GeV, even for conservative propagation scenarios. Except for the range around ∼ 80 GeV, our limits are a factor of ∼ 4 stronger than the limits from gamma-ray observations of dwarf galaxies.

The second article Possible Dark Matter Annihilation Signal in the AMS-02 Antiproton Data is also published in Phys Rev Letters . The abstract is here.

Using the latest AMS-02 cosmic-ray antiproton flux data, we search for a potential dark matter annihilation signal. The background parameters about the propagation, source injection, and solar modulation are not assumed a priori but based on the results inferred from the recent B/C ratio and proton data measurements instead. The possible dark matter signal is incorporated into the model self-consistently under a Bayesian framework. Compared with the astrophysical background-only hypothesis, we find that a dark matter signal is favored. The rest mass of the dark matter particles is ∼ 20-80 GeV, and the velocity-averaged hadronic annihilation cross section is about (0.2-5) × 10-26 cm3/s, in agreement with that needed to account for the Galactic center GeV excess and/or the weak GeV emission from dwarf spheroidal galaxies Reticulum 2 and Tucana III. Tight constraints on the dark matter annihilation models are also set in a wide mass region.

The proposal is that decay of dark matter particles possibly arriwing from the Galactic center produce proton-antiproton pairs. The mass of the decaying particles would be between 40-80 GeV. I have been talking for years about M89 hadron physics - a scaled up copy of ordinary hadron physics with mass scale 512 times higher than that of ordinary hadron physics. The pion of this physics would have mass about 69 GeV (by scaling from the mass of ordinary pion by factor 512). There are indications for two handfuls of bumps with masses of mesons of ordinary hadron physics scaled up by 512 (see this).

These scaled up pions could be produced abundantly in collisions of cosmic rays in atmosphere (situation would be analogous to that at LHC). It would not be surprising if they would producealso proton and antiproton pairs in their decays? This view about the origin of the dark pions is different from the usual view about dark matter. Dark pions would be created by the cosmic rays arriving from galactic center and colliding with nuclear matter in the Earth's atmosphere rather than arriving from the galactic center.

Can one say that they represent dark matter and in what sense? The TGD based proposal explaining various bumps observed at LHC and having masses 512 times those of ordinary mesons assumes that they are produced at quantum criticality and are dark in TGD sense meaning that the value of effective Planck constant for them is heff=n× h, n=512. Scaled up Compton length would realize long range quantum correlations at criticality. Dark mesons at criticality would be hybrids of ordinary and scaled up mesons: Compton length would same as for ordinary mesons but mass would 512 times higher: Esau's hands and Jacob's voice. This would give a precise meaning to what it means for two phases to be same at quantum criticality: half of both.

See the article M89 Hadron Physics and Quantum Criticality or the chapter New Physics Predicted by TGD: I of "p-Adic length scale hypothesis".

For a summary of earlier postings see Latest progress in TGD.

Articles and other material related to TGD.


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