NA64 hunts the mysterious dark photon

November 25, 2016 by Stefania Pandolfi, CERN
An overview of the NA64 experimental set-up at CERN. NA64 hunts down dark photons, hypothetic dark matter particles. Credit: Maximilien Brice/CERN

One of the biggest puzzles in physics is that eighty-five percent of the matter in our universe is "dark": it does not interact with the photons of the conventional electromagnetic force and is therefore invisible to our eyes and telescopes. Although the composition and origin of dark matter are a mystery, we know it exists because astronomers observe its gravitational pull on ordinary visible matter such as stars and galaxies.

Some theories suggest that, in addition to gravity, could interact with visible matter through a new force, which has so far escaped detection. Just as the is carried by the photon, this dark force is thought to be transmitted by a particle called "dark" photon which is predicted to act as a mediator between visible and dark matter.

"To use a metaphor, an otherwise impossible dialogue between two people not speaking the same language (visible and dark matter) can be enabled by a mediator (the ), who understands one language and speaks the other one," explains Sergei Gninenko, spokesperson for the NA64 collaboration.

CERN's NA64 experiment looks for signatures of this visible-dark interaction using a simple but powerful physics concept: the conservation of energy. A beam of electrons, whose initial energy is known very precisely, is aimed at a detector. Interactions between incoming electrons and atomic nuclei in the detector produce visible photons. The energy of these photons is measured and it should be equivalent to that of the electrons. However, if the dark photons exist, they will escape the detector and carry away a large fraction of the initial electron energy.

View of the NA64 experiment set-up. Credit: Christoph Madsen/Noemi Caraban/CERN

Therefore, the signature of the dark photon is an event registered in the detector with a large amount of "missing energy" that cannot be attributed to a process involving only ordinary particles, thus providing a strong hint of the dark photon's existence.

If confirmed, the existence of the dark photon would represent a breakthrough in our understanding the longstanding mystery.

Explore further: 3 knowns and 3 unknowns about dark matter

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liquidspacetime
2 / 5 (4) Nov 25, 2016
We 'detect' the superfluid dark matter every time a double slit experiment is performed, it's what waves.

Superfluid dark matter fills 'empty' space, strongly interacts with and is displaced by baryonic matter.

'The Milky Way's dark matter halo appears to be lopsided'
http://arxiv.org/abs/0903.3802

"the emerging picture of the dark matter halo of the Milky Way is dominantly lopsided in nature."

The Milky Way's halo is not a clump of dark matter traveling along with the Milky Way. The Milky Way's halo is lopsided due to the baryonic matter in the Milky Way moving through and displacing the superfluid dark matter, analogous to a submarine moving through and displacing the water.

What ripples when galaxy clusters collide is what waves in a double slit experiment, the superfluid dark matter which fills 'empty' space.

Superfluid dark matter displaced by baryonic matter relates general relativity and quantum mechanics.
Reg Mundy
2.6 / 5 (5) Nov 25, 2016
we know it exists because astronomers observe its gravitational pull on ordinary visible matter such as stars and galaxies.

Yet again I point out that this is the only evidence for DM.
But if our conception of "gravity" is wrong (which I believe it is), then there is no "evidence" at all.
Whydening Gyre
5 / 5 (2) Nov 25, 2016
I would much prefer "unknown gravitational effect". Maybe even "Dark Gravity"...
arcmetal
3.7 / 5 (3) Nov 25, 2016
Back in 2011 I came across a simple explanation for "dark matter", that seems to go ignored. A commenter named Nanobanano stated this:

I already explained this without Dark Matter, using nothing but
Newton's law of gravity and the concept of an extended, rotating disk.
1) Quit using the entire mass of the galaxy as a point object on
which everything else orbits. That's simply not what is represented
in reality and is freaking absurd.

Overall, Mass is proportional to volume.
If you have a disk, mass of any given concentric ring (or orbital)
is proportional to the square of the RADIUS.

In Newton's law, gravity is inversely proportional to DISTANCE,
which is the same as the RADIUS of an orbital.

So if M = pi*d*r^2, where d is density of matter in the galaxy,
then Newton's law says:

A = G* Pi *d *r^2 / r^2
The r^2 components cancel.

In any stable orbit, "A" will be proportional to velocity.
arcmetal
3.7 / 5 (3) Nov 25, 2016
continuing,

Since d is roughly constant (except in the densest part of the hub,)
this curve, when plotted, gives EXACTLY the same thing as the
observed data, WITHOUT Dark Matter.

-- Nanobanano Dec 05, 2011
Gigel
5 / 5 (2) Nov 26, 2016
this curve, when plotted, gives EXACTLY the same thing as the
observed data, WITHOUT Dark Matter.

-- Nanobanano Dec 05, 2011

That would be interesting to check numerically. I have some doubts on it though, since dark matter is claimed to be in a much larger quantity than normal matter.
Phys1
5 / 5 (1) Nov 26, 2016
Effectively, nanobanano has calculated the rotation about a long cylinder of uniform mass density. In such a case the force varies as 1/r in place of 1/r^2. Obviously, galaxies are not cylinders but pancakes.
hawkingsbrother
Nov 26, 2016
This comment has been removed by a moderator.
hawkingsbrother
Nov 26, 2016
This comment has been removed by a moderator.
hawkingsbrother
Nov 26, 2016
This comment has been removed by a moderator.
hawkingsbrother
Nov 26, 2016
This comment has been removed by a moderator.
billpress11
not rated yet Nov 26, 2016
Arcmetal may have it correct. Look at it like the earth, if you were in the center of the earth what would you weight? It would appear to me, nothing, you would be weightless, the force of gravity would pull at you equally in every direction. . You would actually gain weight as you travel to the surface and weight the most on the surface. You would need an ever increasing velocity to keep from "falling back' into the center of the earth.
Reg Mundy
1 / 5 (3) Nov 26, 2016
Arcmetal may have it correct. Look at it like the earth, if you were in the center of the earth what would you weight? It would appear to me, nothing, you would be weightless, the force of gravity would pull at you equally in every direction. . You would actually gain weight as you travel to the surface and weight the most on the surface. You would need an ever increasing velocity to keep from "falling back' into the center of the earth.

Yes, its called expansion theory. The acceleration at the surface is mistaken for "gravity".
TimLong2001
1 / 5 (3) Nov 26, 2016
Eliminate the expansion interpretation of the background red shift (Doppler shift) and interpret it as a loss of photon energy. The problem will solve itself.
TheGhostofOtto1923
4 / 5 (4) Nov 26, 2016
Hey zephyr
BTW It's possible, that anomalous thrust of EMDrive results just by polarization of microwaves by repeated reflection
A little while ago you thought that EM was weaker than photon drive. Its apparently an order of mag above solar sails and an order below ion drive.

Ever change your mind? (I haven't seen it)

Aren't you more like hawkings evil twisted demonic twin with a hump?

I like dark
https://youtu.be/kdWfuOxSHLw
Captain Stumpy
4.3 / 5 (6) Nov 26, 2016
its called expansion theory.
no, your argument is called expansion "belief"
your expansion belief is not a theory because it's not tested

your expansion BS is not even based in reality and is directly refuted by orbits, tides and the fact that two same sized objects that have different masses and densities are still the same size after periods of time

even a basic knowledge of physics is enough to refute your claims
more to the point - you were proven false here: http://phys.org/n...ong.html

repeating your lie doesn't' make it more true, reg
TheGhostofOtto1923
3.7 / 5 (3) Nov 26, 2016
Aren't you more like hawkings evil twisted demonic twin with a hump?
No no I wasn't making fun of hawkings physical state I was making fun of zephyrs mental state.
hawkingsbrother
Nov 26, 2016
This comment has been removed by a moderator.
Captain Stumpy
3.3 / 5 (7) Nov 26, 2016
WARNING - PHISHING PSEUDOSCIENCE LINK
here I attempted to point the main differences of NASA setup from
@Zeph
links to a known pseudoscience site to validate your claims regarding any science is still pseudoscience

that link you left is to your own personal phishing pseudoscience site

hawkingsbrother
Nov 26, 2016
This comment has been removed by a moderator.
Captain Stumpy
3.3 / 5 (8) Nov 26, 2016
@zephir
Reddit is third party discussion website
1- it is a discussion site, not a science journal

2- your moderated forum of "Physics_AWT" is called pseudoscience
it is called that because you do not adhere to or utilise the scientific method nor do you utilised peer reviewed source material

aether is debunked - falsified
repeating your lie doesn't make it more true

3- you are the moderator and have the ability to phish information to the registered users posting to said forum
arguments to the contrary are easily proven simply by reading the details not only of the site but of the moderation rules

4- i never said you owned reddit, you illiterate moron. i said its your own personal phishing pseudoscience site
that is an accurate descriptor of the reddit page and your ability as MOD

learn to read
learn to science
Reg Mundy
1 / 5 (3) Nov 27, 2016
its called expansion theory.
no, your argument is called expansion "belief"
your expansion belief is not a theory because it's not tested

your expansion BS is not even based in reality and is directly refuted by orbits, tides and the fact that two same sized objects that have different masses and densities are still the same size after periods of time

even a basic knowledge of physics is enough to refute your claims
more to the point - you were proven false here: http://phys.org/n...ong.html

repeating your lie doesn't' make it more true, reg

Hmm, seems I took you off my ignore list too soon.
I took a lot of trouble explaining the "same size" fallacy and how expansion causes orbits without gravity in another thread using terms even a chimpanzee could understand, and you ceased posting on that thread. I assumed (wrongly) that the arrow of logic had at last penetrated your thick skull, but I guess that needs a pickaxe.
Hyperfuzzy
not rated yet Nov 29, 2016
It's only evidence of ignorance!
Phys1
5 / 5 (1) Nov 29, 2016
@Phys.org
I have a question .
Is it ok with the guidelines if Reg attempts to convince his opponent by piercing his skull with a pickaxe?
Ah, it's ok.
Phys1
5 / 5 (2) Nov 29, 2016
@Phys.org
I have a question .
Is it ok in view of the guidelines if Reg attempts to convince his opponent by piercing his skull with a pickaxe?
Ah, it's ok, really ?
Phys1
5 / 5 (2) Nov 29, 2016
Notice that my strategy is now to _shame_ phys.org into moderation.
It won't work but at least I tried :) .
Reg Mundy
not rated yet Nov 29, 2016
@Fizzwun
I see you are doing multiple nearly-identical posts now, is your memory failing so fast? I do not advocate piercing anyones skull with a pickaxe, so I am afraid Strumpy will continue in his state of abysmal stupidity for the foreseeable future.
However, its nice to see his friends stick by him, when your deteriorating intellect reaches his level you will be able to make conversation with him, you know, one grunt for no, two grunts for yes, three grunts for "I've forgotten the question......".

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