Not really relevant to the question,but I just got thinking about energy and temperature. Temperature is a measure of the average kinetic energy of a particle in an ensemble, and it occurred to me that the electron volt was a fine way to measure particle energies -- and I had no idea of how hot a gas with average particle energies of 1 eV was. So I looked it up. 1 eV is about 11,600 degrees Kelvin.So the energies that Warren is talking about here are what you'd expect from temperatures of about half a trillion to 1 quadrillion degrees. Returning to the point: perhaps the low-energy processes are simply scooping up ambient charged particles and accelerating them; the preponderance of electrons at those energies can be explained by the fact that electrons vastly outnumber positrons. Then, at higher energies, perhaps we are just looking at the product of pair-creation. Processes at energies above about 1 MeV (rest mass of a positron-electron pair) will produce positrons and electrons in equal numbers. On Wed, Mar 11, 2015 at 5:11 PM, Warren D Smith <warren.wds@gmail.com> wrote:

http://physics.aps.org/articles/v6/40

Some cosmic rays are electrons, some are positrons, and some are other things. Focusing only on the first two, the AMS experiment in the space station finds that the ratio of positrons to electrons depends upon the ray-energy. ENERGY positron fraction 0.5 GeV 0.095 to 0.11 7 GeV 0.02 (min) 100 GeV 0.11 to 0.15 300 GeV 0.15

Why? These energies seem too large to be explained directly by any set of nuclear reactions. There must be cosmic accelerators out there producing these hotties, which makes it mysterious why the positron fraction should depend in this funny way upon energy. Another speculation is that somehow these are coming from hypothetical superheavy "dark matter" particles, in which case this is telling us that their masses ought to be within this energy range.

-- Warren D. Smith http://RangeVoting.org <-- add your endorsement (by clicking "endorse" as 1st step)

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On 3/11/15, Warren D Smith <warren.wds@gmail.com> wrote:

http://physics.aps.org/articles/v6/40

Some cosmic rays are electrons, some are positrons, and some are other things. Focusing only on the first two, the AMS experiment in the space station finds that the ratio of positrons to electrons depends upon the ray-energy. ENERGY positron fraction 0.5 GeV 0.095 to 0.11 7 GeV 0.02 (min) 100 GeV 0.11 to 0.15 300 GeV 0.15

Why? These energies seem too large to be explained directly by any set of nuclear reactions. There must be cosmic accelerators out there producing these hotties, which makes it mysterious why the positron fraction should depend in this funny way upon energy. Another speculation is that somehow these are coming from hypothetical superheavy "dark matter" particles, in which case this is telling us that their masses ought to be within this energy range.

AW: 1 eV is about 11,600 degrees Kelvin.So the energies that Warren is talking about here are what you'd expect from temperatures of about half a trillion to 1 quadrillion degrees. --WDS: an electron has mass 511 KeV. The smallest energy I was talking about is 500 MeV, 1000 times greater, and the largest 500 GeV, i.e. 10^6 times greater. Nuclear reactions generally are below 20 MeV. It is hard to explain the observations without "new physics." Because old physics is symmetric (or anyhow extremely nearly) between matter and antimatter. The observation is showing a large difference in behavior between matter & antimatter. Therefore, this proves there is new physics, QED. (Also, the observation the universe is made of matter, is another such "proof" and I did not need millions of dollars in funding for that one.) However... not so fast. Is it perhaps logically+physically possible to explain the observations without new physics? That's a good question to think about. My thinking: If some pair-creation process created (e+,e-) pairs then some of the (e-)'s got annihilated with nearby electrons, survivors being accelerated... anyhow, survival probability being related to how much they got accelerated... then you could explain a nonconstant PositronFraction(energy) curve. However, it seems to me that one would expect said curve to be monotone decreasing (since higher energies take longer for the acceleration to produce), not (as observed) decreasing then increasing then (maybe) leveling off. To resolve that problem, it seems to me that a second independent cosmic ray producing mechanism is needed too. If those conditions both met then I think it is *logically* possible to produce a curve like what was observed, but this is not necessarily physically realistic. WD: As I recall there was a Scientific American article decades ago about acceleration phenomena in the galaxy producing very energetic cosmic rays. I don't recall what the particles were but somehow I think they were heavy. --WDS: It seems to me that it was almost impossible to tell what particles the cosmic rays were, especially the super high energy ones, until now with space-based detectors. Because all you saw was not the ray itself, but rather a huge air shower of grand^N-daughter particles. You could see particles directly with detectors on balloons and rockets, but only comparatively low energy particles. So, I doubt that "decades ago" one could tell they were "very heavy." And in fact I doubt it, I think they are almost all protons, electrons, positrons, and photons, perhaps with a few alpha particles and antiprotons thrown in. But for the ultra hotties, I would presume nobody knows for sure at present. -- Warren D. Smith http://RangeVoting.org <-- add your endorsement (by clicking "endorse" as 1st step)