Skip to main content

Questions tagged [antimatter]

Analogous to matter, but with charge of the particles opposite to their ordinary matter counterparts.

Filter by
Sorted by
Tagged with
0 votes
0 answers
33 views

Confusion about time reversion and the Feynman-Stuckelberg interpretation

The Dirac equation $(i\hbar\gamma^{\mu}\partial_{\mu}-mc)\psi(\mathbf{x},t) = 0$ admits solutions with positive and negative energies. In the Feynmann-Stuckelberg interpretation we view negative ...
Jahi02's user avatar
  • 255
0 votes
0 answers
34 views

Action of charge conjugation on bispinors

I'm following an introductory course to particle physics. We have introduced Klein-Gordon's equation for spinless particles and Dirac's equation for spin $1/2$ particles. Klein-Gordon's equation works ...
HomoVafer's user avatar
  • 410
11 votes
3 answers
724 views

How does special relativity lead to anti-particles?

Anti-particles and spinors pop out of the Dirac equation very naturally, yet the Dirac equation is only a modified version of the Schrödinger equation which includes the relativistic energy-momentum ...
eli morhayim's user avatar
1 vote
0 answers
45 views

How to calculate mean energy of fluorine-18 positron?

I know that Fluorine-18 becomes stable when a neutron takes the place of a proton and becomes Oxygen-18 where a positron and nutrino are emitted. Using Einstein formula, I can find the maximum energy (...
Gabriel L.'s user avatar
0 votes
1 answer
70 views

Where is antineutrino in standard model Lagrangian?

I'm somewhat confused by the content I studied in Srednicki's work, where the neutrino is described as a Majorana field. In this framework, there shouldn't technically be antineutrinos, given the ...
Bababeluma's user avatar
0 votes
1 answer
56 views

What if dark matter and anti-matter collided? [closed]

Considering we know both dark matter and antimatter can interact via gravity, just like regular matter, then that means the two can gravitationally interact. However, since dark matter does not ...
Quantum Wonder's user avatar
4 votes
1 answer
132 views

Is the matter-antimatter asymmetry a logical or a statistical problem?

When I read on Wikipedia about Big Bang (Inflation and Baryogenesis), I got the impression that in the beginning of the universe all matter and antimatter had been created exclusively as pairs: ...
a_guest's user avatar
  • 300
12 votes
3 answers
2k views

Do particle & anti-particle pairs belong to the same field?

When trying to understand the idea of virtual particles, the explanations for it seem to imply that, for example, electron-positron pairing happens within the fluctuating electron field, so does this ...
Quantum Wonder's user avatar
-3 votes
1 answer
79 views

Has anyone measured the energy output of matter/antimatter annihilation? [closed]

I've looked everywhere I can think, this side of paywalls, and everyone provides Feynman diagrams or $E=mc^2$ to describe or calculate annihilation. It occurred to me that virtual particles come into ...
Robert Rapplean's user avatar
6 votes
3 answers
2k views

Would normal atoms and antimatter atoms be attracted to each other?

I believe I have been holding a misconception for a long time, surely dating back to some sketchy science fiction. I would like to verify what truth there is in this. Say you had person $A$ floating ...
Paul Cusson's user avatar
3 votes
2 answers
420 views

Average momentum of particle/anti-particle pairs

I'm far from an expert in physics, I've gathered bits from wiki, books and educational videos. So I apologize in advance if my question is not well framed or plain stupid. It's about particle / anti-...
Antoine's user avatar
  • 133
1 vote
0 answers
54 views

Magnetic Monopoles and Its Antimatter and Mirror Particle Counterparts [closed]

I'm trying to understand how magnetic monopoles and how its potential mirror and antiparticle counterparts would behave. So according to the modified lorentz force law $$\vec{F}=q_e\left(\vec{E}+\frac{...
CrazyDolphin's user avatar
1 vote
0 answers
67 views

Relativistic Rocket Equation Derivation

Could somebody help me derive this equation? $$\frac{\mathrm{d}M}{M}=-\frac{\mathrm{d}v(1-v_\mathrm{ex}\frac{v}{c^2})}{(1-\frac{v^2}{c^2})(-v_\mathrm{ex}\frac{v^2}{c^2}+(1-a)v+av_\mathrm{ex})} $$ This ...
spencj95's user avatar
0 votes
0 answers
52 views

Matter vs antimatter asymmetry per particle [duplicate]

What is called matter and what is called antimatter is just a convention, isn't it? For example, suppose we call the bottom, the charm and the down quark antimatter and we call the strange, top, and ...
anoniem's user avatar
  • 147
3 votes
4 answers
191 views

Lagrangian for a free antimatter particle

Context The Lagrangian, $L$, of a free particle is derived many places including in Section 8 of Landau's Theory of Classical Fields. The well-known result for a free material particle of mass $m$ and ...
Michael Levy's user avatar
-1 votes
2 answers
80 views

Can it be disproven that an electron is a wave packet of photons? [closed]

When an electron collides with a positron, both are destroyed and pure energy in the form of photons is released. It seems then that electrons are composed of photons, if photons were released on ...
EngineeringMind's user avatar
1 vote
1 answer
118 views

Do all antiquarks carry and anti-color charge, or can they carry RGB color charges as well?

I know there are antiquarks with anticolor charges. Are there also antiquarks that instead carry color charges? Basically, which of these lists describes the types of quarks that there are: List one: ...
blacktopshaman's user avatar
4 votes
4 answers
1k views

How can the Klein-Gordon equation have negative-energy solution if its Hamiltonian is positive-definite?

In a lesson about the introduction of classical field theory it was mentioned the Klein-Gordon equation $$(\Box + m^2) \phi(x) = 0. \tag{1}$$ But before we got this equation, we studied the ...
Axel Togawa's user avatar
4 votes
3 answers
232 views

If an electron is an elementary particle, where is charge "stored"?

In particular, how can you have both positrons and electrons if there is no "bit" to set or unset? I hope this is not a stupid question, but if a particle has no internal structure, where ...
releseabe's user avatar
  • 2,238
10 votes
1 answer
2k views

Does antimatter have the same half-life as ordinary matter?

Antimatter is just ordinary matter but with opposite electric charge. Scientists have created only a handful of antihelium-4 in the LHC. I am wondering if the half-life of, say, antiRadium-226 is ...
user6760's user avatar
  • 13k
0 votes
0 answers
63 views

Interpreting Feynman diagram of Coulomb scattering of positron

I am trying to understand Coulomb positron scattering. This course explains that: Here the incoming state is in the future and is to be interpreted as a negative-energy electron of four-momentum $-...
Anthill's user avatar
  • 132
0 votes
3 answers
1k views

If matter cannot be created or destroyed, how were scientists able to "create" matter out of light? [duplicate]

It has been proven that scientists are able to "create" (using quotations because I do not understand if it is creating or not) matter from light in a particle collidor. How is this possible ...
Ryan Jadhav's user avatar
0 votes
1 answer
66 views

Does anti-gravitating antimatter break any physical principles?

Other than experimental facts that antimatter gravitates the same as matter does, is there theoretically a reason why antiparticles can't create repulsive gravity?
user74750's user avatar
  • 195
1 vote
1 answer
76 views

If most of an atom's mass comes from binding energy, why did people think that anti-hydrogen could fall up if antimatter had negative mass?

Antimatter isn't bound by anti-energy, so doesn't that mean that even if elementary antimatter particles had negative mass, the total mass of an anti-atom would still be overwhelmingly positive?
Vilim Lendvaj's user avatar
1 vote
2 answers
145 views

Charge conjugated Dirac equation

I would very much like to understand the motivation behind the correlation between: $(i\partial\!\!/-eA\!\!/-m)\psi=0$ and $(i\partial\!\!/+eA\!\!/-m)\psi_c=0$ when dealing with the derivation of the ...
Xhorxho's user avatar
  • 189
0 votes
1 answer
40 views

Does the number of right chiral neutrinos always need to be the same as the number of anti left chiral neutrinos?

Neutrinos are only observed to have a left handed chirality and anti neutrinos are only observed as having a right chirality. In some beyond the standard model hypotheses neutrinos of right chirality ...
The Burger King's user avatar
-1 votes
1 answer
48 views

Mass self-annihilates to violate law of conservation of energy? [closed]

The scenario is this: a large mass $ M $ is made of matter and anti-matter in equal amounts. If given a little energy, it will self-annihilate. Another mass $ m $ is in vicinity. The potential energy ...
Adeel Malik's user avatar
0 votes
1 answer
40 views

Energy Conservation in Pair Annihilation and Feynman-Stuckelberg Interpretation

The textbook "Modern Particle Physics" by Mark Thomson on p. (98) reads: In the left plot, an electron of energy $E$ emit a photon with energy $2E$ and, to conserve energy, produces an ...
Samama Fahim's user avatar
0 votes
0 answers
114 views

Carl Anderson's discovery of positron

The picture below is a photograph taken by Carl Anderson in 1932. It shows for the first time the existence of an anti-electron. https://www.aps.org/publications/apsnews/200408/history.cfm The ...
S Paul's user avatar
  • 109
1 vote
0 answers
38 views

When an electron and a positron annihilate each other are they deleted from existence entirely? Does this follow the conservation of energy?

When an electron and a positron annihilate each other and release gamma rays, is that just changing the energy into something else (following the conservation of energy), or is energy actually being ...
Foutch Levi's user avatar
4 votes
1 answer
104 views

Does CERN produce more matter than antimatter?

CERN's LHC has seen matter-antimatter asymmetry, such as CP symmetry breaking and $B_s^0$ meson decay. The universe produced about 1 part per billion excess of baryons over anti-baryons. My ...
Kevin Kostlan's user avatar
1 vote
0 answers
78 views

Particle Anti-Particle annihilation in Quantum Field Theory

What special distinction does the interaction of a particle with its anti particle have compared to an interaction with some other particle? People often say when a particle and an anti-particle ...
Kaushal Timilsina's user avatar
0 votes
1 answer
62 views

If an equation describes some physical phenomenon is the assumption that it works in all cases? [closed]

I may be misunderstanding the general idea and the following specific example, but I was told that Dirac predicted the existence of the positron based on a formula for the motion of the electron(?) ...
releseabe's user avatar
  • 2,238
0 votes
1 answer
112 views

Are electrons and positrons part of a family of 4 (8? 16?) similar particles?

EDIT: Completely rewritten because of the 'needs clarity' tag and some useful related questions appearing in the side-bar. I hope this is clear now This answer gives a long list of properties of ...
Vincent's user avatar
  • 289
1 vote
2 answers
113 views

Are two oppositely charged black holes, matter & antimatter?

Let's say we have 2 identical black holes, except that their charges are opposite in sign. Can we consider one to be matter, and the other antimatter? After all, I heard that anti-particles are the ...
Juan Perez's user avatar
  • 2,982
7 votes
1 answer
1k views

Observation of the effect of gravity on the motion of antimatter

In a recent paper (https://www.nature.com/articles/s41586-023-06527-1), the authors state that we find that the local gravitational acceleration of antihydrogen is directed towards the Earth and has ...
Jim421616's user avatar
  • 316
1 vote
1 answer
139 views

Drawing appropriate Feynman graphs

I have learned to compute the corresponding mathematical expressions for a Feynman graph, however, I am yet to conceive the idea of drawing them properly for example describes the nucleon-antinucleon ...
Cbb Ttt's user avatar
  • 70
0 votes
1 answer
93 views

Effect of Gravitational Field During Anti-Matter/Matter Collision

This may be a very basic question, please excuse my lack of knowledge but I don't seem to understand the concept of anti-matter gravity. Upon research, many sources align with the conclusion that anti-...
cav3's user avatar
  • 21
1 vote
1 answer
190 views

Why does the Matter Anti-Matter imbalance require breaking CP symmetry? Why can't it occur if time symmetry is broken?

I understand the general argument that, without some breaking of symmetry, all the matter in the universe would annihilate all the anti-matter and we'd be left with nothing but photons and some other ...
The Shepard's user avatar
1 vote
1 answer
150 views

Conservation of momentum with antiparticle annihilation

I'm confused about how momentum can be conserved when a particle and its antiparticle collide. For example, if an electron and positron collide and annihilate to form two photons, then there should be ...
Matthew's user avatar
  • 39
0 votes
1 answer
188 views

What are the differences between electron-positron annihilation and electron-positron scattering?

Reading the wikipedia of Bhabha scattering, I see that the electron-positron annihilation and electron-positron scattering are analyzed seperately. What are the differences between these two processes?...
Michael's user avatar
  • 129
2 votes
1 answer
132 views

Which spinor should be used for an outgoing proton if we treated it like a point particle? $\bar{u}(p)$ (as for electron) or $v(p)$ (as for positron)

Consider the Rutherford scattering $e^-p^+ \rightarrow e^-p^+$ If a proton is a treated as a heavier positron: $i\mathcal{M}=(-ie)\bar{u}(p_3)\gamma^{\mu}u(p_1)i\Pi_{\mu\nu}(-ie)\bar{v}(p_2)\gamma^{\...
Bababeluma's user avatar
0 votes
2 answers
104 views

Matter and Antimatter coexistence [closed]

Isn't it possible that matter and antimatter coexist? Recently, the ALPHA experiment at CERN has been looking into this topic. And I read about it from Fermilab's website, so they are saying how our ...
Curiosity_killing_me's user avatar
-1 votes
2 answers
153 views

True efficiency of an ordinary photovoltaic cell

While learning about antimatter and the conservation of energy, I found that fission reactions convert about 0.1% of mass into energy, fusion reactions convert about 0.7%. I also found a similar ...
manubrio's user avatar
0 votes
1 answer
44 views

What problems might somebody encounter when trying to use the Breit-Wheeler process to produce positron gas?

Let's take a hypothetical an experimental scenario where a stream of high-energy photons from a powerful source is directed via a system of mirrors and lenses in a two coherent rays to a vacuum camera....
Grchinook's user avatar
-2 votes
1 answer
266 views

Are Feynman Diagrams Concealing the True Nature of Particle Scattering? [closed]

I've recently delved back into some alternative interpretations of quantum field theory. While Richard Feynman often emphasized that calculations were sufficient and discouraged fixation on the "...
VVM's user avatar
  • 489
1 vote
1 answer
121 views

Antiparticles of spinors

As far as I know, to couple scalar fields with photons, the fields must be complex, and have two degrees of freedom, which explains why the antiparticles exist. In the spinor cases, spinors themselves ...
Wayne's user avatar
  • 11
0 votes
0 answers
50 views

Left-handed antiphotons in negative-index material?

Do “left-handed” antiphotons propagate in negative-index metamaterials? https://pubs.aip.org/physicstoday/article/57/6/37/914849/Reversing-Light-With-Negative-RefractionMaterials Some quotes from the ...
John Eastmond's user avatar
2 votes
2 answers
732 views

Meaning of annihilate

As a naive person I thought annihilate meant destroy. Matter and antimatter destroy each other, cancel each other, nothing left over. This pure energy idea is a big surprise also it fits no category ...
Nancy Hope's user avatar
1 vote
1 answer
157 views

Are there any black holes made of antimatter? [duplicate]

And what would happen if an antimatter black hole and a matter black hole would collide?
BananaRepublic's user avatar

1
2 3 4 5
20