Measurement of the fine-structure constant casts doubt on dark photon theories

April 13, 2018 by Bob Yirka, Phys.org report
Precision measurements of the fine-structure constant. A comparison of measurements. “0” on the plot is the CODATA 2014 recommended value. The green points are from photon recoil experiments; the red ones are from electron ge − 2 measurements. The inset is a close-up view of the bottom three measurements. Error bars indicate 1s uncertainty. StanfU, Stanford University; UWash, University of Washington; LKB, Laboratoire Kastler Brossel; HarvU, Harvard University. Credit: Science (2018). DOI: 10.1126/science.aap7706

A team of researchers from the University of California and Lawrence Berkeley National Laboratory has conducted an ultra-precise measurement of the fine-structure constant, and in so doing, have found evidence that casts doubts on dark photon theory. In their paper published in the journal Science, the group describes their measurement process and what they found by using it.

The fine-structure constant is a number that characterizes the strength of the force of electromagnetic interactions between charged particles, such as those that are involved in keeping electrons from traveling outside of their atoms. Up until now, it has been derived using the of electrons and calculations that are still considered to be theoretical. As the researchers note, more allow for testing the Standard Model of particle physics. To that end, they sought to measure the constant through more direct means.

To accomplish this feat, they aimed a laser at cesium-133 atoms (matter-wave interferometry) to force them into and then took a close look at what happened between them as they relaxed back to their natural state. The interference that occurred, the team reports, revealed the speed at which the atoms traveled when they were struck by the laser—they used that number to determine the fine-structure constant. They claim their work has allowed for calculating the fine-structure constant to better than one part per billion.

The researchers report that the number they determined has closely matched the theory, which offers some confirmation of theories that suggest electrons are not made up of smaller, unknown particles. But it also casts doubt on theories surrounding the existence of dark photons.

Dark photons, has suggested, are particles nearly identical to photons, but have mass. They may also interact with other particles. If proof could be found of their existence, it would bolster theories regarding dark matter in general, because suggests they would be the force carrier. On the bright side, because the number they extracted was close to that theorized, but not exact, there is still room for other particle theories to explain the discrepancy.

Explore further: NA64 hunts the mysterious dark photon

More information: Richard H. Parker et al. Measurement of the fine-structure constant as a test of the Standard Model, Science (2018). DOI: 10.1126/science.aap7706

Abstract
Measurements of the fine-structure constant α require methods from across subfields and are thus powerful tests of the consistency of theory and experiment in physics. Using the recoil frequency of cesium-133 atoms in a matter-wave interferometer, we recorded the most accurate measurement of the fine-structure constant to date: α = 1/137.035999046(27) at 2.0 × 10−10 accuracy. Using multiphoton interactions (Bragg diffraction and Bloch oscillations), we demonstrate the largest phase (12 million radians) of any Ramsey-Bordé interferometer and control systematic effects at a level of 0.12 part per billion. Comparison with Penning trap measurements of the electron gyromagnetic anomaly ge − 2 via the Standard Model of particle physics is now limited by the uncertainty in ge − 2; a 2.5σ tension rejects dark photons as the reason for the unexplained part of the muon's magnetic moment at a 99% confidence level. Implications for dark-sector candidates and electron substructure may be a sign of physics beyond the Standard Model that warrants further investigation.

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novasp9
3.3 / 5 (3) Apr 13, 2018
Theorists Without Scientific Borders?

Thank goodness for experimentalists!
fthompson495
1 / 5 (7) Apr 13, 2018
Dark photons fill 'empty' space and are displaced by visible matter. What is referred to geometrically as curved space-time physically exists in nature as the state of displacement of the dark photons. The state of displacement of the dark photons is gravity. The state of displacement of the dark photons is the quantization of gravity.
b_man
1 / 5 (5) Apr 13, 2018
Gravity has properties of wave and particle, which has a wavelength of hundreds of billion light years in wavelength. The particle is larger than you can imagine and we, the universe we can see, exists in a gravity particle. The wave action is the dark energy. Infinite Wave Theory... simple as pi:)
grandpa
4.3 / 5 (4) Apr 13, 2018
Good job. on the measurement.
dnatwork
4.5 / 5 (2) Apr 13, 2018
On the bright side, because the number they calculated was close to that theorized, but not exact, there is still room for other particle theories to explain the discrepancy.


That will set off all the folks who rant about theoretical physics experiments just being a scam to employ theoretical physicists.
Alpo1949
5 / 5 (4) Apr 13, 2018
137 is a number I've remembered for a long time. Nice to see precise validation.
thingumbobesquire
5 / 5 (1) Apr 13, 2018
Dark matter isn't force, thus no need of force bosons, i.e. dark photons. All searches for both fifth force both dark photons failed in the same way, like the searches for scalar field, quintessence, scalar and pseudoscalar or phantom, mirror, asymmetric or shadow matter, dark fluid, pseudoHiggs and heavy Higgs, axions, inflatons, dilatons, gravitinos, majorons, tachyons, WIMPs, SIMPs, heavy photons, fat strings, anapoles, unparticles, vector bosons, sterile or right-handed neutrinos, fotino, chargino, gluinos, chameleon particles, technibaryons, dark baryons, fotinos, gravitinos, s-quarks and s-leptons, WIMPs, SIMPs, MACHOs, RAMBOs, DAEMONs, Planck and Bateman's particles, primordial black holes - and I definitely missed some less popular models of dark matter....

Yes. You missed Boltzmann brain particles...
tallenglish
1.8 / 5 (5) Apr 13, 2018
One day, someone is going to ask the obvious question, what if not all matter/light travels at +c and moves forward in time, but can be +/- c and +/- ic (i.e. both real and imaginary, positive and negative).

Think about it, if time is negative relative to us - light and mass would always be moving away from us > c hense dark and none interactive (aka dark matter), if it is +/- ic then energy would appear negative as well and thats dark energy.

What we see (all mass and light) is just the stuff flowing in the same direction as us. Unfortunately this also meens we have no way to see dark matter or dark energy at all and we can prove this idea by the lack of evidence for any of these fancy theories for WIMPS or dark photons, etc, etc.

Keep it simple, figure out what matter/light would be like if they could travel +/- c and +/- ic with one reference frame (us) travelling at +c - the only way they can all interact is via gravity/curvature of spacetime.
tallenglish
1 / 5 (4) Apr 13, 2018
Dark matter isn't force, thus no need of force bosons, i.e. dark photons. All searches for both fifth force both dark photons failed in the same way, like the searches for scalar field, quintessence, scalar and pseudoscalar or phantom, mirror, asymmetric or shadow matter, dark fluid, pseudoHiggs and heavy Higgs, axions, inflatons, dilatons, gravitinos, majorons, tachyons, WIMPs, SIMPs, heavy photons, fat strings, anapoles, unparticles, vector bosons, sterile or right-handed neutrinos, fotino, chargino, gluinos, chameleon particles, technibaryons, dark baryons, fotinos, gravitinos, s-quarks and s-leptons, WIMPs, SIMPs, MACHOs, RAMBOs, DAEMONs, Planck and Bateman's particles, primordial black holes - and I definitely missed some less popular models of dark matter....


Completely agree - the only thing they refuse to test for in any way is time moving any other way but forward, to me it seems obvious, but to most if not all physicists it is aparently impossible.
Hyperfuzzy
1.6 / 5 (7) Apr 13, 2018
Nonsense, there are no photons. OK, neither is there dark matter. i.e. Quantum Electrodynamics is nonsense.
andyf
5 / 5 (7) Apr 13, 2018
Nonsense, there are no photons. OK, neither is there dark matter. i.e. Quantum Electrodynamics is nonsense.


I can't see that for some reason. Maybe it's because of the lack of photons?

Really, HF, you ought to engage your critical faculties (or start taking the meds again) before posting. You aren't doing yourself any favours.

humy
5 / 5 (4) Apr 14, 2018
One day, someone is going to ask the obvious question, what if not all matter/light travels at +c

what matter/light are you referring to that travels over c? As far as I am aware, there is none. So don't understand your question. Currently all known matter/light travels at or less than c, NOT over c.
torbjorn_b_g_larsson
5 / 5 (4) Apr 14, 2018
Interesting series of experiments and their convergence.
On the other side the article oversell the effect on dark matter theories. It is not unherad of that tensions between tehory and/or experiments mount to a fraction around the chosen quality level - here still 0.5 sigma short - just to see later experiments revert the situation. More generic is that the muon magnetic moment resolution is ad hoc, and seems unrelated to the existence of a WIMP dark matter sector as such [ https://en.wikipe...k_photon ]. The muon magnetic moment tension is currently just 0.5 sigma high, so not secure either [ https://en.wikipe...e_moment ].

Theorists Without Scientific Borders?

Thank goodness for experimentalists!


We need both, and theorists are supposed to stride bravely into the unknown just armed with an Occam's Razor and possibly a dark photon BFG [Big Fucking Gun of game fame].
torbjorn_b_g_larsson
5 / 5 (2) Apr 14, 2018
Dark matter isn't force, thus no need of force bosons, i.e. dark photons.


Correct, it is the prediction of the most popular dark matter theory of supersymmetric WIMPs [Weakly Interacting Matter Particles]. Supersymmetry [SS] is a remaining symmetry that is either forbidden or simply broken by WIMPs, and the latter give density and masses that fits cosmologically observed dark matter [ https://en.wikipe...articles ]. If neutrinos suffice to solve the matter/antimatter symmetry breaking as it currently look, SS would fit like a glove and reduce exotic physics to mundane.

Another fact that has made SS WIMP DM popular is that M/string theory trivially (I think) predicts them. So again it is simpler to have a symmetry breaking for reasons of contingency, than new physics thatmakes a fine balance to forbid it.
SamB
not rated yet Apr 14, 2018
That will set off all the folks who rant about theoretical physics experiments just being a scam to employ theoretical physicists.


I see that it has already set off one of the folk who rant about others instead of contributing to the conversation. (And , Yes, that includes me!)
alexander2468
2.6 / 5 (5) Apr 14, 2018
If you believe in faeries and leprechauns is where darkmatters darkphotons play in the woodlands as their shafts of light and their faeries scatter their faerie dust as they dance and play in magic bluebell woods in setting flickering darkphotons.

Well it had to come! after Fritz Zwicky discovered darkmatter, why does every one think they cannot see the darkmatter because it can only be seen with darkphotons which is why Fritz Zwicky could not see the darkmatter, his eyes like ours have not evolved to see darkphotons, the energy of darkphotons is darkenergy.
we have devised an entity darkmatter which we cannot see because it is only visible with darkphotons it does not interact with matter and it has its own darkenergy and we have to believe in darkmatter because it exist, this definition and unquestioning belief required for you to be accepted into the fold has same distinctive religious connotation required for our unquestioning belief and devotion in God!
alexander2468
3.7 / 5 (3) Apr 14, 2018
A hidden sector particles definition is an unobserved hypothetical particle

The darkphoton is a hypothetical hidden sector particle, proposed as an electromagnetic force carrier for darkmatter. Darkphotons would be theoretically detectable by mixing with photons, and their subsequent effect on the interactions of known particles. Darkphotons theorised in 2008 by Lotty Ackerman, Matthew R. Buckley, Sean M. Carroll, and Marc Kamionkowski as the force carrier of the long-range gauge field, "dark electromagnetism" acting on darkmatter. Just like the photons, darkphotons would be massless https://en.wikipe...k_photon
It was already a sector particle before this latest experiment, now it is less than a sector particle.

With darkmatters darkphotons we have achieved the holy grail of zero we've achieved absolute zero!
granville583762
5 / 5 (3) Apr 15, 2018
What a light hearted way to start the day "we've achieved absolute zero!"
alexander2468> A hidden sector particles definition is an unobserved hypothetical particle
With darkmatters darkphotons we have achieved the holy grail of zero we've achieved absolute zero!


granville583762
5 / 5 (3) Apr 15, 2018
We can't see dark photons. Normal matter gravity lensing is normal matter in normal photons we can see. Dark matter gravity lensing is dark matter in the dark photons we can't see. I thought this articles describing not seeing dark photons.
"electrons are not made up of smaller, unknown particles; it also casts doubt on theories surrounding the existence of dark photons."

The experiment "Measurement of the fine-structure constant casts doubt on dark photon theories" also cast doubt on the source of dark photons dark matter, there's always been sufficient matter for lensing, any discrepancy is always accounted for in the end.
alexander2468
3 / 5 (4) Apr 15, 2018
Everyone is pointing out and the article is self is not seeing darkphotons, even if darkmatter existed you still cannot see it, including darkmatter gravitational lensing. Everyone knows there's adequate normalmatter. Concerning "darkphotons would be massless" normalphotons are massless and normalphotons exhibit gravitational lensing. Are you mackita by saying "Massless particles wouldn't exhibit gravitational lensing" also coming to the view darkmatter is not as it is described in its current description!
Just like the photons, darkphotons would be massless
mackita - Massless particles wouldn't exhibit gravitational lensing, which is the most typical sign of dark matter. In addition, they wouldn't stay at place, as dark matter does.

alexander2468
3 / 5 (4) Apr 15, 2018
The Grand Unified Theory obviously cannot take darkmatter, darkenergy and darkphotons into account as the very article indicates, even if the three entities exist they cannot be included in the Grand Unified Theory because their very existence is in doubt, it has as rock solid as the preverbal apple.
mackita - From GUT theory follows,

alexander2468
2.3 / 5 (6) Apr 15, 2018
This the eternal problem of theories, the closer you get to defining the entity in the theory the further away you are to defining the entity. It is a very courageous comment mackita "Currently dark matter is detected just by its gravitational lensing" as Sir Humphrey used to say in Yes Minister.
even if darkmatter existed you still cannot see it, including darkmatter gravitational lensing
mackita - Currently dark matter is detected just by its gravitational lensing.

alexander2468
3.3 / 5 (4) Apr 15, 2018
The hypothesis of dark matter In a talk given in 1884, Lord Kelvin estimated the number of dark bodies in the Milky Way from the observed velocity dispersion of the stars orbiting around the centre of the galaxy. By using these measurements, he estimated the mass of the galaxy, which he determined is different from the mass of visible stars. Lord Kelvin concluded that "many of our stars, perhaps a great majority of them, may be dark bodies" https://en.wikipe...k_matter

There is no real excuse for determining darkmatters existence, since its existence has been known since Lord Kelvin in 1884, 134 years ago, and currently were only able to detect it by gravitational lensing "mackita - dark matter is detected just by its gravitational lensing", which is only visible in darkphotons which we can not see! And now darkphotons existences is in doubt!
rrwillsj
3 / 5 (4) Apr 15, 2018
Anybody seen my Gravity? I know I've left it it lying around here somewhere?

What do you mean you can't see it? Obviously some sort of attractant phenomena is occurring.

Does this mean that since, to date, we haven't seen Gravity? Only it's effect. That you are denying the existence of G?
alexander2468
3 / 5 (4) Apr 15, 2018
This article has not positively disproved darkphotons; we can take it they exist!

The fact darkmatter lensing is visible in normal photons is telling; only normalmatter emits normalphotons where gravitational lensing is visible only in normalphotons!

What you are implying is darkmatter emits normalphotons and darkmatter photons, and when we see gravitational lensing which is always in normalphotons it is darkmatter emitting normalphotons!

There is sufficient mass in the universe proved by matter emitting normalphotons visible in gravitational lensing. we are quibbling over is whether its darkmatter or normalmatter, is now academic the mass is there mackita Psychological tricks do not work in the real world mackita darkmatter does not emit normal photons, only normalmatter emits normalphotons.
mackita - Dark matter lensing is visible in normal photons and it was never observed in other way

baudrunner
4.2 / 5 (5) Apr 15, 2018
I wonder how much money would be saved if all the research that goes into justifying dark matter theory were abandoned, as I think it should be.

To begin with, DM conclusions derive from the study of the millions of years old behavior of galactic clusters that are very far away, the farthest that we can observe. Their interaction seems unpredictable according to conventional wisdom. Conventional wisdom is also very old, over a hundred years ago Einstein said he might be wrong, referring to the speed of light barrier, which he had said could not be broken.

The universe is a lot older than Einstein, and no-one from around here was around when the light from those faraway galaxies left them. For all we know, colossal bodies traveling at superluminal velocities passed between those galaxies, leaving the after effects of their passing by their virtually infinite mass, relative to those galaxies' inertial frames of reference, to be witnessed by us, and cause us much bewilderment.
granville583762
3.4 / 5 (5) Apr 15, 2018
Normal matter in gravity lensing's normal-photons, indisputable a point well put… well done
alexander2468> The fact darkmatter lensing is visible in normal photons is telling; only normalmatter emits normalphotons where gravitational lensing is visible only in normalphotons!

What you are implying is darkmatter emits normalphotons and darkmatter photons, and when we see gravitational lensing which is always in normalphotons it is darkmatter emitting normalphotons!

There is sufficient mass in the universe proved by matter emitting normalphotons visible in gravitational lensing. we are quibbling over is whether its darkmatter or normalmatter, is now academic the mass is there mackita Psychological tricks do not work in the real world mackita darkmatter does not emit normal photons, only normalmatter emits normalphotons.
mackita - Dark matter lensing is visible in normal photons and it was never observed in other way


granville583762
3.4 / 5 (5) Apr 15, 2018
Normal matter and its normal photons creating Einstein's rings

Who would have believed darkmatters turning point, because it cannot be seen, would be in normalmatter emitting normal photons in gravity lensing, so obvious a point that its normal matter emitting normal photons that are creating Einstein's rings.
"Lord Kelvin estimated the number of dark bodies in the Milky Way estimated the mass of the galaxy, which he determined is different from the mass of visible stars"
The number of stars observed in 1884 is not the number observed today and you do not create invisible matter based simply on observed matter because there are black holes stars orbiting around the centre of our galaxy, now how was Lord Kelvin supposed to add these to the observed stars, eventually were reaching the limit to the impenetrable clouds of dust hiding our galaxies centre
alexander2468
4 / 5 (4) Apr 16, 2018
Radial velocity and dispersion pitfalls of creating theories on matter that does not exist
The article on all "galaxies rotating the same", the stars orbital motion equal one orbit of the galaxy, in 1884, Lord Kelvin did not know this, though he should have suspected it due to the unusual orbital rotation of galaxies; so he made a "knights move transgression" devised a theory on matter that did not exist, this matter is based on galactic rotation we know it's simply orbital motion of stars in binary orbit keeping stars apart requires existing matter stars contain countering their gravitational attraction. Lord Kelvin hypothesised what we call dark-matter. Its next "knights move transgression" is when applied to gravitational lensing it's hypothesised to emitting normal-photons, only normal-matter emits normal-photons in an attempt to prove dark-matter exists a state of logic that is difficult to comprehend in isolation with no other proof but the statement its self!
alexander2468
3.7 / 5 (3) Apr 16, 2018
Logicality demands the observed gravitational lensing is normal matter
"mackita - Dark matter lensing is visible in normal photons and it was never observed in other way"

For every one reading this, this statement has nothing to do with mackita. It is the accepted view of darkmatter is only visible in the normal photon normal electromagnetic frequency range in gravitational lensing.
It is the illogicality of the statement its self on who ever devised the theory that when gravitational lensing is observed, it is dark matter because it is observed in the normal photon range - despite the fact only normal matter emits normal photons, logicality demands the observed gravitational lensing is normal matter emitting normal photons!
Hyperfuzzy
1 / 5 (1) Apr 20, 2018
Logicality demands the observed gravitational lensing is normal matter
"mackita - Dark matter lensing is visible in normal photons and it was never observed in other way"

For every one reading this, this statement has nothing to do with mackita. It is the accepted view of darkmatter is only visible in the normal photon normal electromagnetic frequency range in gravitational lensing.
It is the illogicality of the statement its self on who ever devised the theory that when gravitational lensing is observed, it is dark matter because it is observed in the normal photon range - despite the fact only normal matter emits normal photons, logicality demands the observed gravitational lensing is normal matter emitting normal photons!

The Logic not Logicality or the Logic is Flawed Not "illogicality"; since, Fields do not affect fields; therefore, gravitational lensing does not exist!

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