# Tag Info

2

What happens to a particle and antiparticle that collide? The 511keV/c² electron is typically converted into a 511keV photon, and the 511keV/c² positron is converted into another 511keV photon. However it needn't be a 1:1 conversion. Check out positronium where you can read that the triplet state's leading decay is to three gammas. That's three photons, ...

2

"Matter can never be destroyed, so what happens to those particles? Do they just disappear? Where does the mass go?" It's not true that "matter can never be destroyed". According to classical understanding, yes, mass was always conserved and was never destroyed. But that's not entirely correct. The meaning of the well known equation $E=mc^2$ is that energy ...

3

The following diagram and explanation from Cornell University's page A Brief Introduction to Particle Physics may be of help: (Note, as correctly mentioned by @HDE in the comments, the term 'mini Big Bang' is a bit misleading, but the main point remains as @Jon Custer mentioned in the comments: The mass gets converted into energy. And energy can be ...

15

Annihilation conserves everything What might possibly be unintuitive is that during matter-antimatter annihilation nothing disappears - the particles simply get converted to other particles and energy. From the point of gravity, however, energy is mass - so from the point of an outside observer, if no particles escape the system, then it doesn't matter if ...

4

To add just a little to what Chris has said, when the antimatter falls into the black hole - let's say it's a positron - it annihilates with regular matter. In this case, the positron would presumably annihilate an electron, creating two gamma rays (very high energy light) of energy 2*(0.511 MeV). Just as matter cannot escape a black hole, photons (our gamma ...

45

Whether the infalling material is matter or antimatter makes no difference. Fundamentally, the confusion probably comes from thinking of black holes as normal substances (and thus retaining the properties of whatever matter went into making them). Really, a black hole is a region of spacetime with certain properties, notably the one-way surface we call an ...

3

In answer to your question So, what is the anti-particle for proton? The following visual guide from the blog article Why Making Neutral Antimatter is Such A Big Deal! is helpful in this regard:

2

It's called the antiproton. You can literally google "proton antiparticle".

0

Larry Niven dealt with exactly this question in his short story Flatlander and as far as I know his details are quite reasonable. While there is nothing intrinsically different about an antimatter planet from an optical point of view, its interactions with local matter such as solar wind or (for deep space) deep-space gas and dust would leave it rather ...

1

Particle antiparticle potential/hypothetical pairs exist in vacuum as a mathematical description, necessary for calculations of interactions between elementary particles. These mathematically annihilate and reappear within the heisenberg uncertainty principle.In the Hawking radiation case the virtual pairs at the event horizon have a probability one of ...

2

The energy released by the fission of an antimatter bomb would be minuscule compared to the energy released when the antimatter interacts with matter. How much smaller? According to wikipedia's article on nuclear fission, Typical fission events release about two hundred million eV (200 MeV) of energy for each fission event Now the mass (equivalent ...

21

Charged antimatter particles are stored using electric and magnetic fields in near vacuum conditions. (Near-vacuum conditions can be created on Earth) Anti-hydrogen is stored by exploiting its magnetic properties. (While neutral, it still has spin magnetic moment. The storage is done using strong superconducting magnets.) Antiparticles are easier to store ...

0

No. Chemical reactions and some physical properties are determined by the electron structure for normal matter, and symmetrically the same for positron in antimatter. So chemical reactions between antimatter would appear similar in every respect as normal matter behaves. Of course mixing matter with antimatter leads to a much different result, with the ...

3

Particle and anti-particle are described by the same field. Let's look at the Dirac field: $$\psi\left(x\right)=\int\frac{d^{3}p}{\left(2\pi\right)^{3}}\frac{1}{\sqrt{2E_{p}}}\sum_{s}\left(a_{\vec{p}}^{s}u^{s}\left(p\right)e^{-ip\cdot x}+b_{\vec{p}}^{s\dagger}v^{s}\left(p\right)e^{ip\cdot x}\right)$$ where $a_{\vec{p}}^{s}$ ...

7

Both particles and antiparticles arise from the same quantum field. Particles (and antiparticles) are obtained from the Fourier mode expansion of the free quantum field - for a scalar, it is $$\phi(\vec x) = \int \frac{\mathrm{d}^3 p}{(2\pi)^3}\frac{1}{\sqrt{2\omega_p}}\left(a(\vec p)\mathrm{e}^{\mathrm{i}\vec x\cdot\vec p} + b(\vec ... 0 As several answers have stated already: A positron by itself is not known to decay at all. But if you are considering "encounters" in the course of which a given positron ceases to exist, then how about the "absorption" of a positron by a neutron, leaving a proton, accompanied by (emission of) an anti-electron-neutrino:$$\mathbf n + \mathbf e^+ \rightarrow ...

-1

In a dual time universe, black holes are the antimatter induction terminus of the graviton cycle that powers all atomic and galactic motion. So, what we have is a reverse motion antimatter core that strips gravitons from a forward motion wall and in turn the graviton's flip polarity and become antigraviton's that are being broadcasted at frequencies above ...

1

Yes a positron can decay without encountering an electron. But it must encounter another particle because as it is said in another answer, the positron is a stable particle (in the vacuum), so it cannot decay on its own. An example of "decay" not involving an electron: $$e^+ + \mu^- \to \bar{\nu_e} +\nu_{\mu}$$ this decay proceeds via the weak interaction (a ...

-1

I think I figured it out. I was wrong to think that Boltzmann Brain requires to be made out of one kind of matter only - since I was basing it on my own understanding on how brain should be. It does not matter what my understanding of brain is. If I am BB then whole my live is illusion and so are all my past memories that means that actual BB that ...

0

I suppose you would have to imagine a series of particle-antiparticle creation events, all arranged such that the matter particles all end up in the same place and form a "brain", while the antimatter ones all fly out away from them into empty space. This is fantastically unlikely of course, but then we're already talking about a fluctuation that can create ...

1

A small point in addition to Slereah's solution: it is only CP symmetry that is required to have the same half life for particles and antiparticles. A brief story of fundamental symmetries: for a long time it was thought that the laws of physics behave the same in a mirror situation (parity P), and also that antiparticles are exactly indistinguishable from ...

2

Particles and their antiparticles having the same half life is related to the C symmetry (charge symmetry), which roughly states that processes for particles and antiparticles (that is, if you have a system and you apply the C operator on) have identical probabilities. It is not true that all of them do, though, as the weak interaction breaks C symmetry, ...

0

If electric charge is conserved, then electrons and positrons can't decay. We don't know if electric charge is conserved. The most conservative limits for the stability of the electron we seem to have seem to suggest a lifetime of approx. 4.6e26 years from a lab measurement (at BOREXINO, I believe) and >1e39 years from cosmological arguments. Both are far ...

4

No. There are loads of conserved quantities in decay processes like the one you are talking about. Lepton number conservation and charge conservation are the most notable ones for the case of a positron. Also, the sum of the masses of decay products should always be lesser than the mass of the initial particle. (This naturally follows from energy ...

Top 50 recent answers are included