Proposed Particle Help Explains Odd Galactic Photons

July 25, 2008 By Laura Mgrdichian feature

In 2002, a satellite called INTEGRAL was launched by the European Space Agency with an instrument on board to detect and measure gamma rays from space. Four years later, it yielded some intriguing data: An unusually high number of gamma-ray photons from the galactic center carried the same energy—a particular, significant energy—and nobody could figure out why.

The energy is 511 keV (kilo electron volts), and it happens to be the exact rest-mass energy of the positron, the electron anti-particle, which emits a 511 keV photon when it annihilates with an electron. The gamma rays, then, are a telltale sign of positrons in the galactic center. Where those positrons come from, however, is not so clear.

At one point, scientists thought the positrons might originate as electron-positron pairs often referred to as positronium, an "element" that exists for a very short time before the electron and positron annihilate. For positronium to be the source of the gamma rays, there would have to be lots of it, but the usual positron sources, such as black holes and supernovae, don't emit enough of them.

"Theorists have thought that the 511 keV line might be from dark matter annihilation located at the center of our galaxy, but all the well known standard dark-matter candidates, such as the lightest super-particle, could not fit the data," said astrophysicist Seong Chan Park to PhysOrg.com.

Park and colleagues Ji-Haeng Huh, Jihn E. Kim, and Jong-Chul Park are researchers at Seoul National University in Korea, and the group recently proposed an explanation that involves a new particle.

The group suggests that the positrons come from a "millicharged fermion," a very lightweight particle with a tiny electric charge. The suggestion isn't groundbreaking, as many physicists think that there may be some new physics—a new particle, specifically—underlying the gamma-ray production.

"Most preferred interpretations of the 511 keV gamma rays involve the introduction of new particles, and a millicharged fermion has been proposed before, as far back as 20 years ago, as a dark-matter candidate." said Park. "But in this work we have handled the urgent problem of interpreting the 511 keV anomaly using millicharge fermions, within certain physical constraints."

The proposed particle can produce positrons, which would emit 511 keV gamma-ray photons by decaying into positrons and electrons, which would annihilate and emit the photons. Alternatively, it could annihilate with its own antiparticle to yield an electron and positron that would then annihilate.

The millicharged fermion, if it exists, would have escaped detection at collider experiments because its electric charge is so minute, say Park and his colleagues. They also suggest the particle as a dark-matter candidate, possibly making up 10 percent of the dark matter in the universe.

"In the beginning, we worried if the idea of 'millicharged' dark matter might be inconsistent with any existing experimental data," says Park. "As it turns out, that it is not the case and there is room to fit all of them, which is interesting."

This research is described in the June 3, 2008, online edition of Physical Review D.

Citation: Phys. Rev. D 77, 123503 (2008)

Copyright 2008 PhysOrg.com.
All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com.

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deatopmg
2.8 / 5 (19) Jul 25, 2008
OMG!! - another new particle to bolster the paradigm (the standard model). A paradigm that needs ever increasing complexity and invocation of "don't ask!" to do only a poor job of explaining the gathered evidence.

And just how do the positron and electron "annihilate" each other??? Positronium always forms before the "annihilation" where the 2 basic particles circle each other in an orbit that is known to be about the diameter of the proton. After rotating about 50,000 times they vanish and emit 2; 511 kev photons. They never get near enough to each other to "annihilate" and they never emit the rotational energy which is about 16 x 2 x 511 kev. So, there is NO conservation of angular momentum if they "annihilate". Something else happens that is BASIC to particle physics and cannot be explained away by sweeping it under the rug or invoking "don't ask" to preserve the paradigm. This is NOT science it's faith.

Look, if nature uses only 3 particles (electron, proton, and neutron) to make all the known elements and their isotopes and it uses 4 bases (A, C, G, & T) to build the most complex (known) molecules, DNA, leading to complex life then something is CLEARLY WRONG with the proliferation of particles and forces (close to 100 and climbing) needed to support the standard model. The implication is that the standard model is an exception to Ockham's razor. I simply don't believe that.

Something was and still is fishy in the state of Denmark.
MonsieurX
2.5 / 5 (11) Jul 25, 2008
511 = 111111111 in base 2. Maybe a message?
nilbud
2.8 / 5 (10) Jul 25, 2008
511=10 in base 511.
El_Nexus
3.8 / 5 (10) Jul 25, 2008
MonsieurX,
it's just coincidence. One electron-volt is the energy gained by an electron when accelerated through a potential difference of one volt. Now, a volt in is defined in terms of amperes and watts. And the value of the ampere depends on our standard units of length and time, the metre and the second. So if our units of length and time were, say, cubits and fortnights the value of the ampere would be different and all the values that depened on the ampere would also be different, including the 511eV.
Hunabku
2.4 / 5 (14) Jul 26, 2008
I'm with deatopmg. Einstein is rolling in his grave while quantum physicists make a yet another theory or try another attempt to tie in a new particle into the hodgepodge reality that exists mostly in their heads. Understandably their reality is becoming more convoluted and precarious - further from and less clear in describing observed phenomena.

Rather than start over and try new, more cohesive and elegant approaches, they continue to stack more cards on their house. For example, do you know what "Nasty Infinities" are? They infinitely large numbers that reoccur in their math - they are nasty because physicists don't like em so they "renormalize" into large numbers - that completely undermines their math and subsequent theories- also see the "ultraviolet catastrophe" in quantum physics.

The problem with all these physicists is they are too vested in their theories and approval of their peers to veer from the status woe. Also, as mentioned, they are too abstracted from the reality of observation. The best approach would be to observe the phenomena and then use a little imagination to view it in a new way - kind of like Einstein did.

The universe is not probabilistic - you just don't understand how it all works - get over yourself. It is ALL interconnected and consciousness is a product of spacetime less we forget. For me, something like a "holographic universe" with nested infinities seems closer to what's really going on - and yes finite numbers and infinities can peacefully coexist!
Trippy
4.1 / 5 (9) Jul 26, 2008
The ultraviolet catastrophe was a consequence of classical mechanics, not quantum mechanics.

Quantum Mechanics actually resolved the ultraviolet catastrophe.

Here's an idea, why don't you explain why the gamma ray photons have the distribution that's observed of them, and why they happen to have the same energy as the gamma rays observed when positrons and electrons annihalate.

What's your proposed source for the positrons?
yyz
4.7 / 5 (6) Jul 26, 2008
Interested readers may want to check out this (mercifully) short paper "Galactic 511 keV line from MeV milli-charged dark matter" @ arXiv:0711.3528v3 [astro-ph] from 12-1-07. The devil may be in the details, but to quote Trippy 'What's your proposed source for the positrons?'
Ragtime
Jul 26, 2008
This comment has been removed by a moderator.
superhuman
4.6 / 5 (8) Jul 26, 2008
...Look, if nature uses only 3 particles (electron, proton, and neutron) to make all the known elements and their isotopes and it uses 4 bases (A, C, G, & T) to build the most complex (known) molecules, DNA, leading to complex life ...


Life is not that simple, most complex are proteins which are formed from combinations of 20 amino acids, which are then often modified by enzymatic reactions and decorated with a various small molecules which also include quite complex branched glycan chains.
Enthalpy
5 / 5 (7) Jul 26, 2008
To explain unexpected observations, you may check the observation, or improve a model, or improve a complete theory.

Example: as Arno&Penzias observed 3K excess noise in their receiver, they first checked the receiver, then people imagined new noise sources, and only eventually it was taken for a cosmological clue.

Here some people want to take the opposite way, and my feeling is really bad about it.

Hearing "511keV" lets me think "positron" - not some kind of particle unknown even to an unproved theory, that would additionally emit exactly the same gamma as a positron does. My bet is that we simply need a model of some source of positrons there. It shouldn't be difficult at the galactic centre, where energies are huge and objects widely unknown.
superhuman
4.3 / 5 (8) Jul 26, 2008
Id much rather settle on the source of positrons as being currently unknown then on some new particle designed specifically to "solve" the problem.

That said if they can come up with an accelerator experiment which will detect or rule out this particle then its still worth pursuing.
Enthalpy
3.5 / 5 (4) Jul 26, 2008
The 2008 news is that the v4 of this paper is published:
0711.3528v4
http://arxiv.org/...1.3528v4 (click under Download)

They answer one of my concerns: their exotic particle would produce positrons, which then create the well known gamma energy.

Hopefully the LHC gives us clarity about new particles or their absence, and about strings branes and all that jazz.
deatopmg
3.8 / 5 (4) Jul 27, 2008
...Look, if nature uses only 3 particles (electron, proton, and neutron) to make all the known elements and their isotopes and it uses 4 bases (A, C, G, & T) to build the most complex (known) molecules, DNA, leading to complex life ...


Life is not that simple, most complex are proteins which are formed from combinations of 20 amino acids, which are then often modified by enzymatic reactions and decorated with a various small molecules which also include quite complex branched glycan chains.


and what defines how the proteins, sugars, Fe/S complexes, etc, etc, etc, etc are assembled? - simply the 4 bases (and an odd 5th one here and there as needed)
Trippy
4 / 5 (1) Jul 28, 2008
The 2008 news is that the v4 of this paper is published:
0711.3528v4
http://arxiv.org/...1.3528v4 (click under Download)

They answer one of my concerns: their exotic particle would produce positrons, which then create the well known gamma energy.

Hopefully the LHC gives us clarity about new particles or their absence, and about strings branes and all that jazz.


That was explicitly stated in the article though - that the milicharged fermions would produce positrons, or positrons and electrons by one of a couple of possible paths, rather then producing the gamma rays directly.

The proposed particle can produce positrons, which would emit 511 keV gamma-ray photons by decaying into positrons and electrons, which would annihilate and emit the photons. Alternatively, it could annihilate with its own antiparticle to yield an electron and positron that would then annihilate.


Anyway, one thing that I noted was missing from this article was another recent article (i'll link to it when and if I find it again) that suggested that a closer, higher resolution look at the gamma rays revealed that they were [i]lopsided[/i], whereas any dark matter related explanation implies that they should be symetrical. The explanation favoured by this paper related to a cluster of high mass stars near the galactic core, and processes related to (IIRC) photo disintegration - essentially, these stars are so big, and so bright, and producing that many photons that weird things start happening (I don't rememder details, I think part of it was photons slamming into nuclii causing nuclii or nucleons to disintegrate) or the photons themselves interacting in a way that some portion of them 'disintegrate' into positron/electron pairs).

I wish I could remember more details, but the explanation was entirely within the realms of known physics - I'll have a look and see if I can find it again.
Trippy
5 / 5 (1) Jul 28, 2008
Here's the article I was referring to:
http://www.esa.in...x_0.html
superhuman
5 / 5 (3) Jul 28, 2008
...Look, if nature uses only 3 particles (electron, proton, and neutron) to make all the known elements and their isotopes and it uses 4 bases (A, C, G, & T) to build the most complex (known) molecules, DNA, leading to complex life ...


Life is not that simple, most complex are proteins which are formed from combinations of 20 amino acids, which are then often modified by enzymatic reactions and decorated with a various small molecules which also include quite complex branched glycan chains.


and what defines how the proteins, sugars, Fe/S complexes, etc, etc, etc, etc are assembled? - simply the 4 bases (and an odd 5th one here and there as needed)


That's also not that simple. DNA itself won't make anything, it needs RNA and proteins and other cellular components to be translated - a working cellular machinery which is always passed to daughter cells with DNA.
Think of it as hardware and software. DNA is the software while cellular machinery is the hardware. One without the other won't work.
So although DNA usually gets all the fame it is in fact only one part of information needed to make life, the rest is encoded in cells structure.
DNA portion is actually relatively simple and already well understood while the structure is extremely complex and we are nowhere near understanding it yet.
Yes
1 / 5 (2) Jul 28, 2008
Maybe Mr MonsieurX was not so confused by physics dimensions. The detector converts the measured values first to digital before sending them bits to earth. Maybe a flaw in the digitalization or the transmitter or maybe the receiver or the software.
deatopmg
1 / 5 (2) Jul 28, 2008
...Look, if nature uses only 3 particles (electron, proton, and neutron) to make all the known elements and their isotopes and it uses 4 bases (A, C, G, & T) to build the most complex (known) molecules, DNA, leading to complex life ...


Life is not that simple, most complex are proteins which are formed from combinations of 20 amino acids, which are then often modified by enzymatic reactions and decorated with a various small molecules which also include quite complex branched glycan chains.


and what defines how the proteins, sugars, Fe/S complexes, etc, etc, etc, etc are assembled? - simply the 4 bases (and an odd 5th one here and there as needed)


That's also not that simple. DNA itself won't make anything, it needs RNA and proteins and other cellular components to be translated - a working cellular machinery which is always passed to daughter cells with DNA.
Think of it as hardware and software. DNA is the software while cellular machinery is the hardware. One without the other won't work.
So although DNA usually gets all the fame it is in fact only one part of information needed to make life, the rest is encoded in cells structure.
DNA portion is actually relatively simple and already well understood while the structure is extremely complex and we are nowhere near understanding it yet.


We are WAY off track here! The electron and 2 nucleons define all the elements, a 1 and a zero can/are used to define everything digital today, 4 bases; RNA/DNA, 4 elements; the 20 odd amino acids, 3 elements; the sugars, etc, etc. You can pick around the edges and find a tiny number of exceptions but nature abhors complexity. The Standard Model in no exception.

All these particles, like the new sillicharged fermion, may be necessary to make it "work" but the SM does not describe what really is the BASIS for everything. Something is behind the model and it must be simple.

And that may be what the COMPLETE solution of Dirac's equation (Not the Danish crowds reduction) is telling us. Only electrons and positrons of positive (disruptive) and negative (binding) energy, our 4 real dimensions (X,Y,Z,t) plus 6 more orthogonal dimensions.

K.I.S.S.
holmstar
1 / 5 (2) Jul 29, 2008
deatopmg: while I tend to agree that the "simple" solution tends to be the correct one, there is absolutely nothing in your arguments that proves that physics has a simple solution on any level that we humans will ever be able to observe. It's also perfectly possible that there is no simple solution at all. This will be the case regardless of how many comparisons you make to other processes.

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