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Old 10-22-2014, 08:48 PM   #1
Topper
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Default new hints of "dark matter source"???

Hello,

Today I read an interesting article, that they "maybe" found hints of particles called "Axions" which are created in our Sun.
This is a hypothetical particle yet but as I understood correctly, the new part is that this "maybe found the first proof" of this particle.

I don't know if this is really new or not, but here is an English article:

http://www.universetoday.com/115551/...-from-the-sun/

Last edited by Topper; 10-22-2014 at 08:53 PM.
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Old 10-22-2014, 11:26 PM   #2
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so the particle zoo got expanded again?
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Old 10-23-2014, 01:27 AM   #3
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I'm not an expert but it would seem like the X-ray halo surrounding earths em field could be explained by antimatter-matter reactions instead of adding a whole new class of particles.
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Old 10-23-2014, 12:04 PM   #4
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Matter-Antimatter reactions are much higher energy reactions than most particle collisions. I don't know for sure, but I'd expect them to produce light or even gamma photons rather than X-rays. Also I don't know much about the "X-ray halo" but if it had any kind of strength and the reactions did produce X-Rays, then I doubt there would be enough antimatter in the area to produce the required volumes of X-rays. If there was enough antimatter I suspect the constant release of energy would scour the earth clean.
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Old 09-12-2018, 04:09 PM   #5
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physicsworld.com : Physicists target the dark photon

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Physicists in Italy are about to start up a new experiment designed to hunt for hypothetical particles such as the “dark photon” and carriers of a possible fifth force of nature. The Positron Annihilation into Dark Matter Experiment (PADME), located at the National Institute of Nuclear Physics (INFN) laboratories in Frascati outside Rome, will blast a thin diamond target with energetic positrons and record the mass of any exotic new particles produced in the collisions.

Probing the dark side The PADME experiment at the National Institute of Nuclear Physics in Frascati will search for exotic new particles. (Courtesy: C. Di Giulio)
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Old 09-12-2018, 06:18 PM   #6
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Isn't a photon its own anti-particle...what is a dark photon then? Energy without impulse?
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Old 09-12-2018, 09:54 PM   #7
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Yea, my bet's on a null result on this one.

Reminder: When scientists set out to test an idea, it doesn't mean the outcome is certain and just the work of actually finding the result is needed. Experiments are never conducted to find an effect, but to attempt to prove it's not there.
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Old 09-12-2018, 10:10 PM   #8
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Their proposal back in 2014 can be found here.

Also, on the website:
Quote:
The PADME Experiment

The long standing problem of reconciling the cosmological evidence of the existence of dark matter with the lack of any clear experimental observation of it, has recently revived the idea that the new particles are not directly connected with the Standard Model gauge fields, but only through mediator fields or “portals”, connecting our world with new “secluded” or “hidden” sectors. One of the simplest models just adds an additional U(1) symmetry, with its corresponding vector boson A'[1]. All SM particles will be neutral under this symmetry, while the new field will couple to the charged particles of the SM with an effective charge ϵe, so that this new particle is often called “dark photon". Additional interest arises from the observation that A' in the mass range 1 MeV/ c 2 to 1 GeV/ c 2 and coupling ϵ∼10−3, would justify the discrepancy between theory and observation for the muon anomalous magnetic moment, (g − 2)μ. This possibility has been recently disproved in the hypothesis that the A' decays to SM particles only, on the contrary if A' decays to dark sector particles, almost all of the available experimental constraints can be evaded and the dark photon is still a valuable explanation for the muon (g-2) anomaly. Due to the weak experimental signature, the search for invisibly decaying A' requires carefully designed dedicated experiment. At the end of 2015 INFN has formally approved a new experiment, PADME, to search for invisible decays of the A' at the DAFNE Linac in Frascati. The experiment is designed to detect dark photon produced in positron on fixed target annihilation ( e +e −→γ A ′) decaying to dark matter by measuring the final state missing mass. The collaboration aims to complete the design and construction of the experiment by the end of 2017 and to collect ∼10^13 positron on target by the end of 2018, thus allowing to reach the ϵ∼10^−3 sensitivity up to a dark photon mass of ∼26MeV/c^2
Well ... highly technical and beyond my level ...

Last edited by mahdavi3d; 09-12-2018 at 10:35 PM.
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Old 09-13-2018, 06:58 AM   #9
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Aaaargh, the acronyms!
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Old 09-13-2018, 11:58 PM   #10
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Deeply shocked, what next the Fiat 500 and the 2CV?

Luckily the UK has no national car, so we are spared the trauma.

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Volkswagen is ending production of its Beetle in 2019, closing the door on one of the world's most iconic car designs.
The German company said output would end at its plant in Mexico next July after production of celebration models.
https://www.bbc.co.uk/news/business-45516677
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Old 09-14-2018, 12:15 AM   #11
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Quote:
Originally Posted by Notebook View Post
 Deeply shocked, what next the Fiat 500 and the 2CV?

Luckily the UK has no national car, so we are spared the trauma.



https://www.bbc.co.uk/news/business-45516677
Uhm... Wrong thread.
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Old 09-14-2018, 07:28 AM   #12
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Yes, out by one!
Was aiming for the humour thread, but its old now, so if some good moderator could delete please?

N.
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Old 09-14-2018, 07:40 AM   #13
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Quote:
Originally Posted by Notebook View Post
 Deeply shocked, what next the Fiat 500 and the 2CV?

Luckily the UK has no national car, so we are spared the trauma.



https://www.bbc.co.uk/news/business-45516677

Maybe the problem was building this later car for people who prefer to buy a SUV...
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