What is Antimatter: Definition and 288 Discussions

In modern physics, antimatter is defined as matter that is composed of the antiparticles (or "partners") of the corresponding particles of "ordinary" matter. Minuscule numbers of antiparticles are generated daily at particle accelerators—total production has been only a few nanograms (ng)—and in natural processes like cosmic ray collisions and some types of radioactive decay, but only a tiny fraction of these have successfully been bound together in experiments to form anti-atoms. No macroscopic amount of antimatter has ever been assembled due to the extreme cost and difficulty of production and handling.
Theoretically, a particle and its anti-particle (for example, a proton and an antiproton) have the same mass, but opposite electric charge, and other differences in quantum numbers. For example, a proton has positive charge while an antiproton has negative charge.
A collision between any particle and its anti-particle partner leads to their mutual annihilation, giving rise to various proportions of intense photons (gamma rays), neutrinos, and sometimes less-massive particle–antiparticle pairs. The majority of the total energy of annihilation emerges in the form of ionizing radiation. If surrounding matter is present, the energy content of this radiation will be absorbed and converted into other forms of energy, such as heat or light. The amount of energy released is usually proportional to the total mass of the collided matter and antimatter, in accordance with the notable mass–energy equivalence equation, E=mc2.Antimatter particles bind with each other to form antimatter, just as ordinary particles bind to form normal matter. For example, a positron (the antiparticle of the electron) and an antiproton (the antiparticle of the proton) can form an antihydrogen atom. The nuclei of antihelium have been artificially produced, albeit with difficulty, and are the most complex anti-nuclei so far observed. Physical principles indicate that complex antimatter atomic nuclei are possible, as well as anti-atoms corresponding to the known chemical elements.
There is strong evidence that the observable universe is composed almost entirely of ordinary matter, as opposed to an equal mixture of matter and antimatter. This asymmetry of matter and antimatter in the visible universe is one of the great unsolved problems in physics. The process by which this inequality between matter and antimatter particles developed is called baryogenesis.

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  1. G

    A Problem evaluating an anticommutator in supersymmetric quantum mechanics

    I am trying to reproduce the results of a certain paper here. In particular, I'm trying to verify their eqn 5.31. The setup is N = 4 gauge quantum mechanics, obtained by the dimensional reduction of N = 1 gauge theory in 4 dimensions. ##\sigma^i## denotes the ith pauli matrix. ##\lambda_{A...
  2. Sasho Andonov

    I Collision of anti-hydrogen with matter

    Fir the time being, the only anti-matter atom which was produced by humans is anti-hydrogen atom. I am wonbdering what will happen if this anti-hydrogen collide with normal atom of (for example) oxygen: What will be anihilated and what will survive?
  3. hyksos

    I Observation of the effect of gravity on the motion of antimatter

    The Alpha Experiment at CERN has finally produced a paper on whether antimatter falls towards the earth under gravity. The research confirms that antimatter acts identically to regular matter in regards to gravity. Observation of the effect of gravity on the motion of antimatter. Anderson...
  4. mfb

    I Antimatter falls down - with (0.75 ± 0.13 ± 0.16)g

    Took longer than expected, but now we have a result. Observation of the effect of gravity on the motion of antimatter Antimatter falls down with (0.75 ± 0.13 (statistical + systematic) ± 0.16 (simulation)) g, compatible with the expected 1 g and ruling out -1 g.
  5. T

    Mass: Uniting Quarks & Antimatter in Unexpected Ways

    Mass behaves opposite that of other quantum numbers when combining matter (quarks) and antimatter. Why?
  6. Q

    B Exploring Antimatter Universes

    Also assuming the two universes were made of the antimatter versions of themselves
  7. S

    B So, a black hole and an antimatter star bump into each other....

    This is a bit hypothetical obviously as I doubt the conditions for this scenario would ever occur in the real universe. Imagine a black hole, about 10 solar masses. It is, amazingly, sitting in an area of space that is a perfect vacuum. Just by chance, a rogue antimatter star of exactly the...
  8. L

    A Interaction between matter and antimatter in Dirac equation

    I'm new to relativistic quantum mechanics and quantum field theory and was trying to learn about the Dirac equation. Unfortunately, I got a little stumped by the interaction between matter and antimatter. It seems like the time derivative of matter is dependent on the spatial derivative of...
  9. Delta2

    B Gravitational force between matter and antimatter

    What is the current scientific consensus on the gravitational force between matter and antimatter. Is it repulsive, attractive or zero?
  10. G

    I Antimatter Susy Sparticles: Exploring Symmetry

    In supersymmetry, are there corresponding antimatter particles to the Susy sparticles similar to the corresponding standard model antimatter particles, e.g., antiselectron, etc.?
  11. DaveC426913

    B Article: "Monster" antimatter particle "slams" into Antarctica

    "A single neutrino has a mass of about 2 billion-billion-billion-billionths of a gram ... A neutrino with 6.3 petaelectronvolts (PeV) of energy ... is equivalent to the energy of a swarm of 6,300 mosquitos [moving at 1mph] ... [or one mosquito accelerated to] Mach-8.2..."...
  12. G

    I Are Supersymmetry Sparticles Paired with Antimatter Counterparts?

    In supersymmetry, are there corresponding antimatter particles to the Susy sparticles similar to the corresponding standard model antimatter particles, e.g., antiselectron, etc.?
  13. J

    I Reason for matter rather than antimatter?

    At the end of the inflation period (if it occurred) the potential energy of the inflaton field decays into particle/antiparticle pairs. When a particle/antiparticle pair is created each component of the total 4-momentum of the pair is zero. This must include the time component as well as the...
  14. Indomitable Dreamer

    My inspirational epic -- Enjoy, correct and criticize to your heart's content

    Greetings, philosophers, scholars, enthusiasts. I'm writing an uplifting sci-fi/fantasy webnovel (240 pages atm), free to all. Only goal – to rekindle fighting spirits. https://www.royalroad.com/fiction/33662/path-of-righteousness https://www.fictionpress.com/s/3340207/1/Path-of-Righteousness...
  15. G

    I Antimatter energy from a small amount of mass

    If an object's energy is proportional to its mass, how can a gram of antimatter produce more energy than 80 kilotons of TNT? Where does all this energy come from such a small amount of mass?Skip to 5:19 of the video where he says this: Please explain this in the most simplest way possible.
  16. P

    B Why do we assume the big bang created matter/antimatter?

    What if pure energy doesn't create matter/antimatter pairs, but entangled matter/matter-wave pairs? Duality is then literally two separate entities. When something becomes observed, the matter-wave becomes one with the particle it "represents". I'd say that would give a galaxy the extra mass...
  17. G

    I Need a layman's explanation for how scientists contain antimatter

    I know how antimatter is created, both naturally and under laboratory conditions. But what boggles me is how we can contain it without it interacting with its surroundings and causing annihilation. Apparently scientists use a "special" magnetic field to contain it. But what's so special about...
  18. M

    Can Antimatter Bombs Cause Explosive Destruction?

    I'm back to writing the sequel to my first novel and for reasons of maximum destruction, an antimatter bomb is in play. But, from various sources an antimatter bomb is not as destructive as the movies - and novels - suggest. Antimatter annihilation results in high-speed neutrinos and a burst of...
  19. B

    B The Physics of a Black Hole Merger: What Happens to Mass?

    What would happen if a black hole made entirely from anti-matter merges with another black hole made from normal matter? Since most of the product left over from the annihilation is in the form of light (gamma rays) would the black hole lose mass?
  20. M

    B Antimatter in relativistic jets

    I have read that relativistic jets emitted by black holes are thought to contain a mixture of matter and antimatter including positrons and electrons. Is there any mechanism known that would lead to matter or electron concentration in one of the two relativistic jets, and antimatter or positron...
  21. Vamsi9955

    I The energy released from antimatter annihilation -- New uses?

    The pure energy released from antimatter annihilation can there be any use of this clean energy for research purposes like the use of light in LIGWO for gravitational waves study can we use it efficiently like light in LIGWO I think we can and it could lead us to reveal mysteries of universe
  22. B

    I Demolecularization using antimatter

    So is it at all possible to artificially generate positrons in extremely large quantities. If so then wouldn't it be possible to shoot them in a constant stream and demolecularize anything they touch?
  23. A

    3 facts that you might not know about antimatter

    Hi! I would like to share with you guys some facts you might not know about antimatter: 1º - Recent studies suggest that an antimatter spacecraft could achieve up to 70% the speed of light, reaching Proxima b in just about 6 years. 2º - The maximum time that antimatter has been stored is...
  24. Abimbola1987

    B Practical Antimatter Production

    Dear All, I read this article Lightning Strikes Produce Antimatter Particles in Earth’s Atmosphere which I find very intriguing and it raises many questions for me, so I will try to contain myself. Here is the accompanying illustration: The first major question is, how did the researchers...
  25. G

    I Antimatter atoms vs atoms with greater mass?

    I was just kinda wondering about this the other day and can't seem to find an answer on Google. Basically I'm wondering what would happen if an atom of anti-hydrogen for example, came in contact with a normal matter atom of greater mass, say a gold atom. I'm figuring that the positron and...
  26. B

    B But WHY do antimatter and matter annihilate on contact?

    Everyone knows that matter and antimatter annihilate upon contact. But exactly WHY this should happen is not at all obvious, at least to me. So what exactly happens when two such particles encounter one another that leads them to disappear in a large release of photons? And for that matter...
  27. A

    B Matter & Antimatter: Attraction & Annihilation Evidence?

    If matter and antimatter are placed next to each other, will they attract each other and annihilate ? Do we have strong evidence regarding the existence of anti-matter ?
  28. Anthony Beckwith

    I An antimatter mirror universe?

    "Our universe could be the mirror image of an antimatter universe extending backwards in time before the Big Bang. So claim physicists in Canada," https://physicsworld.com/a/our-universe-has-antimatter-partner-on-the-other-side-of-the-big-bang-say-physicists/
  29. C

    B Parallel Spacetimes: Matter & Antimatter Separated?

    Is it possible for two plains of parallel spacetime to exist separated by some sort of void? One being antimatter and one being matter with the void bringing neutral territory. Like a piece of paper between two big magnets.
  30. S

    Does electromagnetic radiation react with antimatter?

    And if it does what is the mechanism and can it be used in astronomical spectroscopy?
  31. A

    I Which law/formula proves the existence of antimatter?

    Out of curiosity i was watching some physics documentaries. They threw out quantum theory and relativity and i have taken a modern physics course. I can't say i remember antimatter ever coming up in lecture. I am curious about the math.
  32. Pouya Pourkarim

    I Where Did the Universe's Antimatter Go?

    If the universe was born from nothing then what are the possible reasons that we don’t see the same amount of matter and antimatter now?(if it’s a scientifically correct question)
  33. Gene Naden

    I CP transformation, charge conjugation and antimatter

    Many discussions cite CP transformation as the exchange of particles for anitparticles. But other places it says that charge conjugation alone is sufficient to turn a particle into its antiparticle. So, the question is, when you exchange particles for anitparticles, is it a CP transformation or...
  34. Aarav Sangar

    B Energy density of annihilation

    <Moderator's note: Two threads on the same topic merged in order to have arguments and sources at one place.> Can antimatter-matter be used as a fuel for a rocket? There are various problems for anti-matter to be used as a fuel as it produces a lot of gamma rays. Gamma rays are not healthy to...
  35. ISamson

    Could lightning be creating antimatter in our atmosphere?

    A recent article from phys.org says that a Japanese team of scientists have detected gamma rays coming from lightning strikes, which react with atmospheric Nitrogen and release a positron. Who would have thought that!
  36. A

    A Relativity implies antimatter?

    https://arxiv.org/pdf/hep-ph/0609174.pdf page 8. 2.1.2 Special Relativity Requires Antiparticles This article describes a scenario in which atom A releases an electron which is absorbed by atom B. A=> A+ and B => B- However in a different inertial frame (F) it is possible due to Heisenberg's...
  37. C

    B What caused the asymmetry between matter and antimatter in the early universe?

    What does quantum mechanics have to say about this aspect? Matter usually differs by antimatter having opposite charge. It is said that the Universe in the early stages should have created equal amounts of matter and antimatter. The total charge is conserved no matter the interactions and if...
  38. T

    Max specific energy (energy density by mass) in a capacitor

    Hi folks, here's a thought/conceptual question I've been wondering about. What is the maximum theoretical specific energy (IE Joules/kg or equivalent) for energy stored in the electric field of a capacitor? I know the energy stored in a capacitor is given by U=C V^2/2, and the mass of the system...
  39. T

    A Is Negative Mass Related to Antimatter in Physics?

    In physics we cannot easily imagine “negative” energy for a particle (not a field) in order to have “negative” mass, although the first concept of Dirac for antiparticles was that they were “holes” that were opposite to particle existence and there was a minus in front of mc2.Regardless of...
  40. ISamson

    B Antimatter Creation: Michio Kaku's High School Experiment

    Hello, I have read that Michio Kaku has made antimatter and photographed it when he was only a high schooler. I have read that the used Sodium-22 to produce positrons. How does that happen? I could not find some good sources of answers... Thanks.
  41. Lunct

    B Antimatter and matter canceling out

    Antimatter and matter cancel each other out. What does this mean? Do the particles just cease to exist? Does this go against the law of the conservation of energy? HELP
  42. martin25p2

    I Relationship between negative mass, energy and antimatter

    What is the relationship between negative energy, negative mass and antiparticles? I have read some articles but I am still confused. Does negative mass exist? Does negative energy exist with the exception of the Kasimir effect which I understand. Are antiparticles really only the negatice...
  43. F

    B Do black holes radiate antimatter?

    I'm wondering if black holes radiate antimatter as well as matter? If they radiate antimatter in equal amounts to matter, then would it all cancel out?
  44. P

    I Calculating Antimatter Portion in Protons

    Hi! I am asked to calculete the portion of antimatter present in protons. I am sayed that this portion is given by: r=(3R-1)/(3-R), where R is R=σ(antineutrino)/σ(neutrino). Another definition of r is r=∫x*Q'(x)dx/∫x*Q(x)dx, where Q(x) are partonic densities Q(x)=d(x)+u(x) (d is down quark and...
  45. Quantum Velocity

    B How to change electron and proton charge

    To make antimatter you have to change the charge of proton and electron. So how do you do it
  46. J

    I New Wired article on "where's the antimatter"

    I am a simple layman, but I hope one of you wizards can help me understand something here. I just read the new article in Wired magazine on the problem of the missing antimatter, a topic I have read about before in several popular books on physics and cosmology, and I have a basic understanding...
  47. J

    What would an antimatter engine be like?

    Antimatter thrust engine would be somewhat like a chemical or nuclear thrust engine, but with the difference that the exhaust would be pure light, and the fuel would the lightest possible fuel currently known to theoretically exist. That is known, but what would it really be like, meaning like...
  48. N

    I Longest Antimatter Containment

    Hello, From what I read, the longest antimatter containment ever achieved was >16 minutes by the Alpha project at CERN in 2011. Has this ever been beaten? What is the limiting factor?...the anti-hydrogen will always have a magnetic moment to be held by the magnetic field of the trap, so is it...
  49. Debaa

    B Antimatter Fuel: Will Future Space Travel Rely on It?

    Will we be able to harness antimatter so precisely that we use it as fuel in the future? I mean this would mean a great deal in space travel! Thoughts?
  50. BL4CKB0X97

    I Increased efficiency Antimatter production

    Hi Does anyone know of any papers about Increased efficiency Antimatter production, as I am interested in this area. Apologies if it's in the wrong area. Thanks.