D-Star Hexaquark Candidate for Dark Matter

Nuclear physicists at the University of York are putting forward a new candidate for dark matter – a particle they recently discovered called the d-star hexaquark.

Up to 80% of the Universe could be dark matter, but despite many decades of study, its physical origin has remained an enigma. While it cannot be seen directly, scientists know it exists because of its interaction via gravity with visible matter like stars and planets. Dark matter is composed of particles that do not absorb, reflect or emit light.

Journal of Physics G: Nuclear and Particle Physics – A new possibility for light-quark dark matter

Bose-Einstein condensate

The particle is composed of six quarks – the fundamental particles that usually combine in trios to make up protons and neutrons. Importantly, the six quarks in a d-star result in a boson particle, which means that when many d-stars are present they can combine together in very different ways to the protons and neutrons.

The research group at York suggests that in the conditions shortly after the Big Bang, many d-star hexaquarks could have grouped together as the universe cooled and expanded to form the fifth state of matter – Bose-Einstein condensate.

Dr MIkhail Bashkanov and Professor Daniel Watts from the department of physics at the University of York recently published the first assessment of the viability of this new dark matter candidate.


Professor Daniel Watts from the department of physics at the University of York said: “The origin of dark matter in the universe is one of the biggest questions in science and one that, until now, has drawn a blank.

“Our first calculations indicate that condensates of d-stars are a feasible new candidate for dark matter and this new possibility seems worthy of further, more detailed investigation.

Co-author of the paper, Dr Mikhail Bashkanov from the Department of Physics at the University of York said: “The next step to establish this new dark matter candidate will be to obtain a better understanding of how the d-stars interact – when do they attract and when do they repel each other. We are leading new measurements to create d-stars inside an atomic nucleus and see if their properties are different to when they are in free space. ”

The researchers will now collaborate with scientists in Germany and the US to test their theory of dark matter and search for d-star hexaquarks in the cosmos.

Despite many decades of study the physical origin of ‘dark matter’ (DM) in the Universe remains elusive. In this letter we calculate the properties of a completely new DM candidate—Bose–Einstein condensates formed from a recently discovered bosonic particle in the light-quark sector, the hexaquark. In this first study, we show stable Bose–Einstein condensates could form in the primordial early universe, with a production rate sufficiently large that they are a plausible new candidate for DM. Some possible astronomical signatures of such DM are also presented.

SOURCES- University of York, Journal of Physics G: Nuclear and Particle Physics
Written By Brian Wang, Nextbigfuture.com

30 thoughts on “D-Star Hexaquark Candidate for Dark Matter”

  1. I believe that even interacting with a reasonably powerful stellar magnetic field would blow it apart. The mass to charge ratio on a bound electron-D* pair is gigantic. Essentially “exotic” E/M behavior that we don’t see in any other naturally occurring scenario.

    I know they like this Magiconium explanation for dark matter, but the only realistic place I see these particles surviving is in the cold regions between galactic clusters. In which case it does nothing for the galactic angular momentum problem.

  2. I would imagine that if magiconium were to come in contact with ANY other nucleons, once the electrostatic barrier were overcome, the quantum quark swapping would bust the D★s apart, right quick.

    Hence, the quark bomb.

  3. On further thought, due to Gauss’s law of gravity, a given mass inside a given volume should produce exactly the same gravitational field regardless of how it’s distributed inside that volume. Therefore, such a million AMU “atom” should produce the same gravitational lensing as a million AMU of regular matter – at least outside of whatever volume that can enclose both.

    A million AMU atom should have a lot more possible nuclear energy transitions than a million hydrogen atoms. So it should be brighter in gamma.

    If it’s enclosed in an electron cloud, such a cloud should also have many more possible energy transitions than the electron clouds of a million hydrogen atoms. And as you yourself have pointed out, the outer shells should be much more loosely held. That means it would be much more susceptible to ionization, with all the resulting luminescence as the remaining electrons rearrange.

    In total, I’d expect such highly dense matter to be brighter than regular matter.

  4. You can come up with all sorts of wild postulates. But in the end, you have to run the numbers and show that it matches the observations. Dark Matter is so far supported by observations, even if it turns out to be the wrong explanation in the end.

  5. I would imagine that if magiconium were to come in contact with ANY other nucleons, once the electrostatic barrier were overcome, the quantum quark swapping would bust the D★s apart, right quick.

    Continuing from my earlier replies, are you sure that such quark swapping actually occurs?

    As I understand, outside of quark-gluon plasmas, which only occur at extremely high pressure, quarks are very tightly bound inside the individual protons and neutrons – and inside these hexaquarks, in our case.

    Furthermore, if these BECs are indeed highly charged, overcoming the electrostatic barrier would be very very difficult. Consider – how strong must the electric field be near the surface of a million AMU BEC? I wouldn’t be surprised if electrostatic repulsion actually determines the minimum size of such BECs.

    As we know, fusion is plenty hard with charges of only +1.

  6. But you’re not observing a single such “atom”. You’re observing a whole cloud of them.

    AFAIK, observations so far suggest that dark matter clouds are the size of whole galaxies, or even clusters of them. That’s a fairly significant area.

    When you’re observing a galaxy, you’re collecting all of the light that comes from that whole area, regardless of how the sources are distributed inside. At those distances, the whole galaxy is a point source anyway, unless you zoom in enough to resolve the details.

    So similarly, if you observe a galaxy-sized DM cloud, you’d be observing the total of all the light it emits, even if it’s collected into billions of tiny condensates.

    And my point was specifically that DM clouds are galaxy sized. So even if the individual condensates are tiny, the clouds of them aren’t – or mustn’t be, based on current observations of DM.

  7. It might be that physics is just put into a wrong direction, i purpose a anti property on all fields. there is no electron no positron, they’re the same but touched by a different field ‘side’ . It affects all known fields, and during creation of it all it had a single value like the higs field (this field can only be + or – or in special cases both but not be zero, both is a special dimensional directional thing), the field explains why the universe didnt vanish in the bigbang, there was dominance of matter (+). On large scales this anti field is affected by fluctuations in forces and can balance out over the ot, gravity is therefore not a constant force over huge distances, disturbances by the other fields can cause slight swings in this field over large distances, ea making gravity anti gravity.
    The anti field has a connection with empty-space and probability of other field in vacuum, it can create anti particles, or negative space we might detect by particles acting as if they go backwards in time, but its just the field balancing this out. further more it allows to create empty space, pushing apart the other fields, in a sense it could be seen as a memory wall of instructions operating on the other fields, when needed it can create more wall area.
    An analogy as in holographic universe, but with the addition of a field field that this is played upon. (played upon as a program >> lookup yourself quantum correction codes, as to why such a field should exist in nature).

  8. Well, no. Imagine that stars had their current brightness per square meter of surface, but instead of being thousands of miles wide, were an inch wide. They’d be as bright as lightbulbs, and you’d never see them.

    I’m suggesting you could tie up an awful lot of mass in things that are, technically, visible, and still not see them if they were small enough in aggregate.

    Gas you can see, because the individual particles are low mass, so the gas subtends a fairly large angle of the sky.

    Black holes are massive enough individually to cause gravitational lensing events you could detect.

    But a million AMU “atom” wouldn’t cause lensing events, and it would only be as visible as a normal atom, while carrying a million times the mass of hydrogen at a given density. So, on a per mass basis it would be a million times darker.

  9. Unless said condensates are themselves so dense that, even constituting the majority of the mass of the universe, they subtend virtually none of the sky.

    I think that doesn’t match the observations. Dark matter seems to be spread about all over inside and around galaxies etc. So the visual size should be similar to that of galaxies and clusters.

  10. Thanks for the well-considered reply, Brett. 
    I’ve had to move to Chrome, to use this comment system.
    Maybe you too?

    The main ‘problem’ I have with the magiconium-is-the-answer-to-dark-matter is that there is little speculative footing for upper bounds of a million AMU. Why not a billion? 

    That, in context with the point I made about Our Universe’s delightful work-around that allows conglomerates of UUD protons and UDD neutrons to confer probably-infinite stability to otherwise unstable n by way of quantum quark swapping … I would imagine that if magiconium were to come in contact with ANY other nucleons, once the electrostatic barrier were overcome, the quantum quark swapping would bust the D★s apart, right quick.

    Because hexaquarks are demonstrated to have quite-tiny half-lives. Implying that blobonium is pretty touchy stuff from a physical harmony perspective. That swapping quarks would just blow the binding, and thus kaboom… reverting to UUD (p) and UDD (n) matter. 

    Just thinking out loud. 
    ⋅-=≡ GoatGuy ✓ ≡=-⋅

  11. For me it seems to fail more often when following the “Reply…” link from the notification emails. If I load the page without all the extra url parameters, it seems to work better.

  12. I don’t know enough physics to speculate as to what new tech could be developed if we can make and/or detect and gather “nuclei” with atomic masses in the millions.
    I imagine it would give us spectacular new capabilities when dealing with radiation. Ultra thin gamma ray shielding, that sort of thing.
    Given the very interesting chemistry that heavy metals like Uranium can achieve, this stuff would be FILLED with surprises.

  13. Off-on-a-tangent: Yes, I find the reply function just fails to work a fair bit of the time. The more nested the comment I’m replying to, the lower the chances of it working. Sometimes reloading the entire page works.

    Of course failing to reply deletes what I’ve just read, so usually after a long, detailed bit of writing.

  14. Normal matter baryons of the most common type have to be chromatically neutral (with red, green, and blue quarks) but, with two up quarks (each with +2/3 charge) and one down quark (a -1/3 charge).
    But quarks and anti-quarks don’t necessarily destroy each other as mesons consist of a single quark and an antiquark of the same color.
    My own personal theories (that I haul out and play with from time to time) also call for six quarks. Adding an additional two anti-up quarks of the same colors as the up quarks, as well as an anti-down quark of the same color as the down quark, the charge is made neutral and I’ve conjectured that the resultant particle is unable to react with other particles as it now has an integer spin, always returning to its original condition state.
    Other than through gravity, which is more a distortion of space-time than anything else, they can’t even act on each other, except for a relatively short range repulsion. In other words, gravity pulls them closer together over longer distances in space-time, but only so far. It’s imprecise but you could say that, eventually, to force them closer together in space you have to force them further apart in time. Since they can’t actually meet, they can’t clump and form dark matter planets and stars.
    I am not trying to prove anything; I’m just commenting. If there are those of you out there that read about quantum physics and don’t ever play around with it, I don’t know how you do it.

  15. You know, I was about to bash the part where it says:

    scientists know it exists because of its interaction via gravity with visible matter like stars and planets. Dark matter is composed of particles that do not absorb, reflect or emit light

    Which should read more like:

    “many scientists believe it may exist because of observations on what appear to be the effects of gravity on a galactic scale. If dark matter exists then, whatever it is, it does not absorb, reflect, or emit light”

    Its existence is still only conjectured, not proven, and it certainly was not suggested because of its effect on planets.

    But I’m very intrigued about the hexaquarks, all the same.

  16. Goatguy: Still can’t reply directly for some reason.

    If the particles or their condensates are neutralized by electrons, they’re almost certainly NOT dark, those electrons would certainly interact with light. Unless said condensates are themselves so dense that, even constituting the majority of the mass of the universe, they subtend virtually none of the sky. Similar in concept to the idea that the missing mass might have been quantum black holes, only with the individual points of mass being too small for gravitational lensing. Imagine the condensates as isolated atoms with an atomic weight of a million or so; They could be most of the mass of the universe, and still be fairly far apart, countably small numbers per cubic meter.

    But if that much of the universe is composed of them, they should be passing through the Earth, and you and me. And being neutralized by clouds of electrons, should interact with us. They’re proposing condensates with masses ranging from comparable to transuranics at the low end, up to atomic weights (And charges!) of up to millions. The outer shell electrons on these things would be very loosely bound indeed.

    As I note, these things would be subject to stripping passing through matter, and once charged would be very conspicuous and easily detected, and common enough that you’d see frequent events.

    Only if they are for some reason neutral could they be good dark matter candidates. And yet the proposed composition clearly isn’t neutral.

  17. the wave-nature of nucleons allows their quarks to freely intermingle, converting P to N and N to P, thus ‘hiding the instability’.

    Based on the various descriptions in https://en.wikipedia.org/wiki/Atomic_nucleus , my current understanding is that the quarks are fairly tightly bound inside the nucleons. The strong nuclear force that holds them together is just leakage of the color force (?) that binds the quarks inside each nucleon. Something like many thousands (millions? trillions?) of gluon exchanges inside each nucleon, and only a handful between them.

    If you increase the pressure by a lot, the electrons get absorbed by the protons, giving neutronium. But the neutrons are still separate. Increase the pressure much more, and only then you get full mixing – a quark-gluon plasma. But no such mingling at normal pressures.

    That said, that leakage of color force might allow a bound neutron to change into a proton and vice versa. Is that what you meant?

    Looked at another way, the beta decay of a bound neutron must be immediately followed by an electron capture by a neighboring proton, due to their close proximity. But probably a gluon exchange mechanism is more accurate.
    (edit: I may be mixing terms a bit here. Maybe it’s not exactly gluon exchange. I’m still not 100% clear how all of that works.)

  18. ⊕1 of course

    ‘Tis true — so long as modern Physics continues to precess (hey… it is a better analogue than nutate), there’ll first be interesting stuff to argue about, and then perhaps even better stuff that improves our collective lives. 

    One hopes.

    Might give a glance at my top-level post.
    Not sure it adds much, but at least not epically glib.

    ⋅-=≡ GoatGuy ✓ ≡=-⋅

  19. It’s denser than a deuteron, because though it’s composed of the same quarks, instead of them being assembled into two particles bound to each other by nuclear forces, it’s assembled into one particle bound by quark forces. So a density more on the order of a neutron or proton, than a nucleus.

    Yes, I’ve figured that out once I read up on atomic nucleus structure. Thanks.

  20. So, it sounds good.

    10⁻²³ s halflife, for naked D-star hexaquark resonance particles. The stability must be upward of 1,000× present life of universe or 4.32×10²⁰ sec, so that U is not full of high gamma radiation. More like a trillion (10¹²x) times age(U).  Say 10³⁰ sec.  

    The hopeful anomaly-of-Our-Universe is that naked neutrons have a 12 minute halflife, but bound, have halflives potentially infinite.  

    This implies that when SNF (strong nuclear force) bound, the wave-nature of nucleons allows their quarks to freely intermingle, converting P to N and N to P, thus ‘hiding the instability’.  

    A nice effect.  
    God must have had a remarkable sense of humor to invent that one. 
    Lucky for us.

    But imagining that BECs (Bose-Einstein Condensates) would confer infinite time stability to particles having a 10⁻²³ naked-hexaquark HL, is quite far-fetched: It implies that the whole Universe should be totally awash with the things, and that being charged, would bind quite a number of negative charges unto them. As MichaelK and Brett say… perhaps only having gamma-level quantum transitions, but having them, hugely.  Awash, remember?

    Still, can’t dismiss this out of hand.  
    I do wonder about testing the theory.

    Mightn’t the things clump gravitationally?  
    If so, wouldn’t the Universe be … awash … with micro-black-holes?

    The gravitational microlensing observations so far conclude against this.

    ⋅-⋅-⋅ Just saying, ⋅-⋅-⋅
    ⋅-=≡ GoatGuy ✓ ≡=-⋅

  21. Michael: Can’t seem to reply directly to you, some configuration problem on this computer, I think.

    It’s denser than a deuteron, because though it’s composed of the same quarks, instead of them being assembled into two particles bound to each other by nuclear forces, it’s assembled into one particle bound by quark forces. So a density more on the order of a neutron or proton, than a nucleus.

    I honestly don’t see how this thing can be dark enough to qualify as “dark” matter, unless my speculation that it binds to its anti-particle was true. The isolated particles should end up looking much like deuterium, (Indeed, you’d expect some fraction of natural “deuterium” to be these particles, chemically one of these bound to an electron would be almost indistinguishable.)

    The condensates would act like heavy nuclei, VERY heavy nuclii, so you’d expect some hardly bound at all electrons, they shouldn’t be dark at all.

    As far as detection, if one of these condensates passes through condensed matter, you’d expect stripping, and thus something that should be obvious even in a cloud chamber. Nothing esoteric should be needed to detect these things if they’re common enough to solve the missing mass problem.

    So there’s some point the paper must have left unstated, concerning the charge. They really do NOT sound like dark matter candidates to me unless they are electrically neutral for some unstated reason.

  22. For comparison, here are the atomic spectra of hydrogen, uranium, and some others. They’re all in the visible spectrum, despite the differences in mass, number of electrons, and electron binding energies:

    edit re:

    The heavier mass would suggest a lower binding energy

    It turns out that most of the energy of a proton or neutron comes from the relativistic mass of the gluons and quarks moving about inside it. So if the hexaquark has more gluons moving about, that can account for the higher energy, even if the binding energy is stronger (and thus more negative). That would also explain how it is denser than a deuteron.

    On further reading, the quarks of normal matter are tightly bound as triplets inside the protons and neutrons. The forces between the protons and neutrons are much weaker. I was under the mistaken impression that all the quarks would mix up inside a nucleus, which they don’t.

    So in a deuteron, we have an uud triplet (the proton) relatively loosely bound to an udd triplet (the neutron). Whereas in a hexaquark such as d*, all six quarks are tightly bound.

  23. Grey… maybe. I’d expect a condensate of these to act somewhere between neutronium and very heavy nuclei.

    Heavy nuclei are unstable due to a lot of electrostatic repulsion, but this thing seems to have some extra “quantum magic” going on. The single d* isn’t the same as a deuteron, so by extension, its condensate shouldn’t be the same as a heavy nucleus. But there should be similarities.

    If the condensate remains charged, the internal energy shifts should interact with gamma radiation, or maybe hard X-rays. But any surrounding electron cloud should behave much like a normal electron plasma. I think that should be visible all over the spectrum.

    However, a condensate should have enough mass for the quarks to change flavors, so over time it might decay to a less charged form (giving off positrons or something)? But even neutronium can have an EM signature. We know some neutron stars have very strong magnetic fields…

    To partially answer my other question, it seems d* is heavier than a deuteron, so probably a decay from d* to a deuteron is more likely than the other way. https://en.wikipedia.org/wiki/Hexaquark says the free d* only lasted 1e-23 sec in the original observation. Though that may be due to collisions with other stuff.

    The heavier mass would suggest a lower binding energy, which then raises the question – why is denser? Again, some sort of quantum logic beyond my understanding. Probably the same that distinguishes it from a regular deuteron.

  24. Can’t be, no strange quarks in it.

    OK, seriously: Yes, you would expect it to interact with EM radiation, and thus not be dark. OTOH, being charged, you’d expect it to naturally bind with something of the opposing charge. If it were bound to an electron, you’d expect to just get something that behaved like deuterium except when it came to nuclear reactions.

    If it bound to it’s own anti-particle, you’d get something that was electrically neutral, and due to the high mass of both particles, very compact with a first orbital transition of very high energy. But I don’t think that combination would be stable.

    They say that it would form large condensates that are very stable. They’d act like highly charged very massive particles, would attract a cloud of electrons to neutralize it. That combination might not be “dark”, but it could be very grey.

    The paper didn’t seem to discuss the consequences of these particles being charged much, aside from the repulsion necessary to form stable condensates.

  25. Some more info in the introduction section of the paper (2nd link):

    In this letter we present a new possibility for light-quark based DM, motivated by the recent discovery of the d*(2380) hexaquark. The properties of the d*(2380) have been established in recent years following its first experimental observation [5–13]. It has a mass of Md* = 2380 MeV, vacuum width Γ = 70 MeV and quantum numbers I(JP) = 0(3+) and made of six light quarks; 3 u-quarks and 3 d-quarks. The spins of the quarks are aligned and QCD based approaches, such as Chiral quark models, predict a highly compact structure, smaller than a single proton [14]. It therefore offers a completely new bosonic and isoscalar configuration into which light-quark matter can form.

    “Light” here refers to the quark masses. The two light ones, “up” and “down” are the same that compose regular matter. The other quarks, “strange”, “charm”, “bottom”, and “top” are much heavier, so require much more energy to form.

    A proton is up up down (uud), and a neutron is up down down (udd). This hexaquark is 3 up 3 down, so it’s similar to a deuterium nucleus, but denser.

    What’s strange to me is this should have a charge, and therefore should interact with EM radiation. That would make it non-dark. The other thing is – why do we not see transitions from deuterium to d*?

  26. Always nice to see fundamental physics being pushed forward. That way lies the hope of fundamental new technologies.

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