Questions tagged [antimatter]

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

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Why do mesons decay?

Why do mesons decay shortly while baryons are more stable? And why do mesons decay, meaning that there are unstable, while they formed because meson is more stable than the two corresponding quarks? ...
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Increase the Inverse Beta Decay Cross Section for Ti-48

Is there a theoretical way to increase the cross section of inverse beta decay for Ti-48? This would be any method for increasing the likelyhood that Ti-48 absorbs an anti neutrino and creates Ca-48 ...
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Why does the charge conjugation of the spinor transform as a spinor?

I have come across (in QFT Nutshell, A. Zee) how the charge conjugation of the spinor, $\psi_c \equiv \gamma^2 \psi^*$, transform (where $\gamma^2=\sigma^2\otimes i\tau^2$ is the component of the ...
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Why does the Higgs boson have electroweak charges $~T_3~$ and $~Y_w~$ but does not have an antiparticle with opposite charges?

(Using $Q=T_3+Y_W$) The Higgs boson has weak isospin $T_3=-\cfrac12$ and weak hypercharge $Y_W=+\cfrac12$. Since every particle has all opposite charges of its antiparticle, why isn't there an anti-...
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High Flux Antineutrino Sources

I was curious if there were any anti neutrino sources with a similar flux to a nuclear reactor. My current purpose does not allow for a nuclear reactor, however, any flux source with a similar flux ...
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Would a flow of current (of positrons) zap us?

I have read this question: Will Positron Cause flow of electricity? To your question, yes, positrons are just as good as electrons for carrying a charge. There is no difference between "...
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What is the intuitive reason why matter and antimatter should be highly reactive?

Common knowledge has it that when an amount of matter and an amount of antimatter come anywhere near each other, they annihilate, leaving nothing but "pure energy". In more technical terms, maybe we ...
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Are the electron and positron doublets in any mathematical sense?

I know left handed electrons and electron neutrinos are isospin doublets. Is there any analogous way in which an electron and a positron are related? My first thought is some sort time-parity doublet.
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Does Hawking radiation violate baryon number conservation? [duplicate]

Throw two baryons into a black hole (baryon number +2), receive Hawking radiation out. Convert the resulting energy into one baryon and one anti-baryon (baryon number 0). Baryon number conservation ...
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Is fission/fusion to iron the most efficient way to convert mass to energy?

Is fission/fusion of any element to iron-56 (or nickel-62?) the best way to convert mass to energy, that doesn't involve black holes? In other words, will we be always limited to convert only about 1%...
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How lepton numbers and baryon numbers of a particle are decided?

Suppose a new particle is discovered how will it be assigned a lepton and baryon number? Moreover, what difference would it make if the electron had +1 lepton number and a positron -1? The same ...
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Why does electron-positron annihilation conserve parity?

I think I'm missing something quite basic here but consider the process: $$ e^- + e^+ \rightarrow 2\gamma$$ Fermions have opposite parity to antifermions so the parity quantum number before the ...
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What it means that there is only one electron in universe? [duplicate]

Could someone explain if this statement is and what could possible mean?
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What is really a negative energy particle (and why is it different from an anti-particle)?

I have read this question: What is negative Energy/Exotic Energy? This does not really give an answer. Why does a particle (charged) change sign passing the event horizon? Black holes and positive/...
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What happens if matter particle and antimatter particle both carry no charge were to collide elastically?

I read that particle carrying charge is able to interact with photon so that when electron and positron collides they may be converted into pure photons, then what about neutron-antineutron collision? ...
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Possible reactions due to antiproton-proton collisions

When an antiproton collides with a proton, then "all" reactions/channels are possible, right? Only constrained by the used energy and sure, some channels are more likely than others but in principle, ...
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Antiparticles travelling backward through time [duplicate]

Could someone please explain to me Feynman and Wheeler's theory of waves acting forward and backward in time? I have read about their idea of an antiparticle behaving as a particle travelling ...
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Wave antiparticle duality

Can an antiparticle such as the antiparticle of an electron - a positron exhbit wave particle duality. We know from de Broglie, and the Davisson-Germer experiment in which we fire electrons from an ...
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Is my analogy on Hawking Radiation correct? [duplicate]

I just want to make sure what I know is correct. Let me explain and if there is anything wrong (any simple detail) with what I said, please, correct me. When the particle crosses the event horizon, ...
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What happens when you dump antimatter onto a naked singularity?

Inspired by this question, what would happen if you dumped antimatter onto a naked singularity? The answers for the previous question suggest that once the antimatter crossed the event horizon, no ...
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In an anti-matter universe, would an anti-matter black hole emit anti-matter gamma radiation? [duplicate]

In an anti-matter universe, when an anti-matter black hole is consuming a large anti-matter star, would it emit anti-matter gamma radiation, or would gamma radiation be the same in either a matter or ...
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What happens if you dump antimatter into a black hole? [duplicate]

Let's say you have a 10 solar mass BH and dump 10 solar masses of antimatter into the BH... What would happen? Would I have a 20 solar mass BH? Would the BH explode Do we even understand what would ...
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Why do people suspect antimatter falls upward? [duplicate]

Antimatter is similar to ordinary matter except they have the opposite charge, i like to know why this difference in their spin would affect their motion in the curvature of our 4-dimensional ...
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Could a solid object made entirely of antimatter safely “touch” ordinary matter without annihilating each other because of EM force?

Most is said about the anti-particles annihilating their ordinary particles counterparts. When antimatter forms anti-atoms, it is said they behave like ordinary matter. Since atoms are more stable ...
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Where does the kinetic energy of an object annihilated in a matter antimatter reaction go?

A bullet is moving at $0.99 c$. Now we annihilate it by having it collide with an equal mass of antimatter. (assume instant and perfect reaction) This will turn both bullet and antimatter into photons....
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Was it ever experimentally verified whether antimatter can form chemical bonds the same way matter does?

It's "common knowledge" that antimatter only differs from matter in its charge, and if left alone, it would behave exactly as matter does. This would infer that atoms of antimatter would form similar ...
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contradiction between total photon energy in the universe and early matter antimatter ratio

When looking at the energy count in the Universe, on one hand we are told dark energy 68%, dark matter 27%, regular matter 5%, neutrinos and photons a very small fraction (trace like). https://en....
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Does an antiparticle leave a different (from the normal particle) mark in a bubble chamber experiment

Experimentalists usually have experiments where they scatter particles superheated transparent liquid, thus checking for the particle's traces. These particles can be for example quarks, and ...
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Are there anti virtual particles (mediator bosons)?

I have read these questions: Can bosons have anti-particles? Is there a possibility for discovery of anti-graviton, i.e. the graviton antiparticle? Antiparticle for Higgs boson? According to ...
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Using Hawking radiation to turn matter into antimatter and vice-versa

I asked this question on the astronomy stack exchange: https://astronomy.stackexchange.com/q/30477 and it was recommended to me that I instead ask it here. My question is related to the following ...
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Why don't electron-positron collisions release infinite energy?

Questions of the form: An electron and a positron collide with E MeV of energy, what is the frequency of the photons released. quite often come up in my A Level course (for often fairly arbitrary ...
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Why does every anyon need to have an antiparticle?

It seems to be a basic requisite to every anyonic model that every type of anyon, say $a$ in the theory comes with an antiparticle $\bar{a}$ (which can be itself) where $a$ and $\bar{a}$ fuse together ...
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Difference between electron, muon and tau neutrinos [duplicate]

What is the difference between the neutrinos of electron, muon and tau leptons.? They all same to be neutral and carry a very small mass. Similarly what is the difference bewteen anti neutrinos of ...
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Could a large amount of antimatter accelerate the universe instead of dark energy? [closed]

It is not known whether antimatter is repulsed by or attracted to matter. For the purpose of this question, I assume that antimatter is repulsive to regular matter (otherwise this question makes no ...
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When is emitting a particle (e.g. neutrino) the same as absorbing an antiparticle?

I've read that Pauli first proposed the neutrino to explain energy and momentum conservation in this equation: $$n \to p^+ + e^- + \overline\nu_e$$ But it is also written differently here: $$\nu_e ...
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Are neutrinos or antineutrinos more prevalent?

As I understand it, neutrinos were first proposed to explain energy and momentum conservation in beta decay, as a hypothetical particle emitted together with the electron and proton. Thus Pauli gave ...
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Do positrons have electric dipole moments?

Is there experimental evidence checking to see if the positron has an electric dipole moment at rest? Or has an experiment measured it’s magnetic dipole moment at rest?
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Graviton particles travelling backwards

I know that time travelling backward particles are anti-matter particles but what about graviton time travelling backward?
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How can one of the particles on a pair of virtual particles created by vacuum fluctuations have negative energy? How does it lower black hole mass?

Assuming Stephen Hawking’s 1975 “Particle Creation by Black Holes” : “One might picture this negative energy flux in the following way. Just outside the event horizon there will be virtual pairs of ...
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Matter antimatter annihilation problems

It can be sai!d that antimatter and matter are opposite excitations in an all permeable quantum field. excitations can be said as waves. so, matter and antimatter can be interpreted as waves or ...
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Did Supernova 2007bi really explode due to antimatter creation?

I was watching a video (https://www.youtube.com/watch?v=IZ59_akUUBs) about massive explosions and came across 2007bi. The video stated that this SN happened due to gamma-ray driven antimatter ...
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Would a penning trap be disrupted if passed through the Earth's magnetic field?

Working on my essay for school and currently talking about using antimatter as a propulsion technique for rockets. At the moment I am talking about potential hazards and was wondering if passing ...
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Why particles annihilate only with their antiparticles? [duplicate]

Why particles annihilate only with their antiparticles? Why can't a particle annihilate with any other antiparticle? Is it because both the particle and the antiparticle have to be excitations of the ...
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How can matter and anti-matter coexist in a meson?

Whilst learning about the nature of subatomic particles, I came along a pion zero meson. What really stumbled me was that the quark configuration of the particles was up and anti-up or down and anti-...
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Quantization of the massless neutrino field

If a massless neutrino or anti-neutrino is considered (in the whole post I consider neutrinos res. anti-neutrinos as mass-less), it is described by the Weyl-equation: $$\overline{\sigma}^{\mu}\...
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What is the minimum distance between an electron and a positron so that they do not annihilate? [duplicate]

What is the minimum distance between an electron and a positron so that they do not annihilate? I want to assume that the location of an electron can be determined with an accuracy of 0.004 Angstroms,...
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Antiproton production threshold

Why is the antiproton threshold on cern 6* m_p and on uspas it is 7 * m_p?
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Is it possible to induce left-handed electromagnetic wave from positrons? [duplicate]

All observations of electromagnetic induction we have, are from the flow of electrons. The accelerated electrons in the antenna rod induce an EM wave with a right handed system of the electric field ...
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When did we first observe annihilation of antimatter?

Firstly, when did we actually observe this process? (I assume we have but I may be wrong about that as well.) Secondly, did we expect it to happen, or not?
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QFT Matter Fields and Anti-Matter Fields

In QFT is it the case that the electron matter field and anti-electron matter field (using the electron as a specific example) are truly distinct physical fields versus different excitation modes of ...