# Tagged Questions

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1answer
33 views

### Would an antimatter beam create multiple matter-antimatter explosions?

To expand upon the question - in an atmosphere, would a beam of pure antimatter (disregarding technical difficulties creating such a beam or passing it through a medium) interact with the matter in ...
2answers
87 views

### What if the antimatter in the center of our galaxy could annihilate and cause a chain reaction?

Being said that the antimatter - matter reaction is faster than that of a fission and fusion, what if the antimatter cloud found at the center of our galaxy could really able to react with matter from ...
1answer
43 views

### Could the outer structure of the Universe be made from Antimatter?

Cern recently stated that antimatter may be repelled by matter, much like the opposite effect of Gravity. So is it possible that antimatter is actually repelled to the edges of the Universe to create ...
1answer
110 views

### Strings and QFT: particles moving backward in time?

New question: In string theory and QFT, do particles travel back in time? Not related to antimatter: Do they travel back and forth in time in reality or are these just interpretations of mathematical ...
1answer
72 views

### Antimatter in the universe [duplicate]

Is it possible that some parts of the universe contain antimatter whose atoms have nuclei made of antiprotons and antineutrons, sorrounded by antiprotons? If yes what can be the ways to detect this ...
1answer
124 views

### How to guarantee that a kilogram of antimatter will quickly annihilate another kilogram of matter?

What I mean is, suppose we could somehow get a kilogram of matter and contain it safely. Now lets say we want to make a bomb using this kilogram, now, we have two ways, either store another kilogram ...
2answers
102 views

### How much energy is carried away by neutrinos in matter-antimatter annihilation?

Some people say that neutrinos carry away most of the energy, some others say just a fraction. So what is the truth ? what is the percentage of energy lost due to neutrinos ?
1answer
122 views

### How fast is the matter and antimatter reaction compared to nuclear chain reaction?

What I mean is, the nuclear chain reactions take microseconds for every generation and that is the reason that nuclear weapons exist. Because in nuclear reactors the reaction rate is much slower thus ...
1answer
41 views

### Gravitational potential energy with regards to annihilation

Given particles A, B, C and D, where: A and B have an equivalent mass C and D have an equivalent mass, both larger than A (or B) D is the antiparticle of C. A and B start close to C, but with ...
2answers
82 views

### Effect of mass matter-antimatter annihilation? [duplicate]

Possible Duplicate: What actually happens when an anti-matter projectile collides with matter? If a large amount of antimatter is suddenly released or launched in the open and expands, ...
1answer
53 views

### Could much of the “missing” antimatter make up neutrons?

A neutron can decay into a proton, an electron, and neutrino. Could an antiproton, a positron, and a neutrino combine into a neutron? Could this be where much of the "missing" antimatter is?
3answers
141 views

### Do particle pairs avoid each other? Please end my musings

Can you explain what happens when a particle and its antiparticle are created. Do they whiz away from each other at the speed of light or what? I suppose that they don't because otherwise they would ...
1answer
48 views

### When is the FAIR accelerator supposed to be finished? [closed]

The FAIR accelerator is a planned facility for antiproton and ion research. Ground water wells are being put in, the forest is being cleared... But when is it supposed to be completed? Does anyone ...
2answers
133 views

### how do we know that the base of entire universe is the proton (hydrogen) and not the antiproton?

It may be that the base of a part of the world is anti-proton, We've always been on the planet Earth and the Milky Way. how do we know that the base of entire universe is proton (hydrogen atom)?
2answers
110 views

### matter anti-matter world

let us suppose the gedanken experiment a man isolated into a room he ask if he is made of matter oder of antimatter could he set some experiments to see if he is made of matter or if he is made of ...
2answers
336 views

### Schrödinger's equation, time reversal, negative energy and antimatter

You know how there are no antiparticles for the Schrödinger equation, I've been pushing around the equation and have found a solution that seems to indicate there are - I've probably missed something ...
1answer
818 views

### Anti-matter black hole and time

I have recently read some hard science-fiction story based on an assumption that if time stops (from external observer's perspective) on the event horizon of black hole, then in an anti-matter black ...
0answers
52 views

### Complete annihilation of matter-antimatter [duplicate]

Possible Duplicate: More on matter and anti-matter Everyone knows that when matter and anti-matter come in contact, they result in pure energy. I want to know that if atoms and anti-atoms ...
2answers
313 views

### Creation of particle anti-particle pairs

I was reading some QFT notes and there is one point that I don't understand, they are justifying why we need QFT saying that the number of particles is not preserved once we consider special ...
1answer
100 views

### On non-local physics

Recently I've encountered work by prof. B.V Alekseev, in which he claims that some physical problems can be easily solved if we consider non-local interactions in kinetic theory (interactions of ...
2answers
199 views

### Can a neutron be created from pure energy

Is it possible to create a neutron out of pure energy, i.e. not by bringing a bunch of already-existing quarks together? (A quick calculation using E = mc2 shows the energy required would be about 1.5 ...
1answer
833 views

### Exotic Matter — What is it?

I have a conceptual understanding of some theoretical physics concepts, so without getting into the math, what is exotic matter? I have read some articles that say it is anything not normal, while ...
0answers
62 views

### positronium BEC stability

After reading this article regarding Positronium BEC formation (for lasing purposes), there is a mention in there regarding Ps "up" atoms not annihilating with "down" atoms, the article is pretty ...
0answers
67 views

### scaling laws for density and temperature of high-energy explosions

I'm wondering if there are heuristic ways to derive how the peak density and temperature of nuclear explosions scale with the amount of fissile/fusible material. Does it matter what the explosion ...
2answers
209 views

### Antimatter bomb

I stumbled upon this wikipedia article on antimatter weaponry. Being greatly appalled by the sad fact that large sums of money are being wasted on this, I could not stop myself from thinking for a ...
3answers
175 views

### supressing certain decay paths and enhancing others with interference

In a scattering reaction, there are many possible final states for the products, each with different production rates. Question: Is there a way in which we could in general supress certain rates ...
1answer
102 views

### How many anti-particles hit the ground?

I am curious to know the amount of flux of anti-particles that arrive to the ground in the cosmic rays. The reason is that I thought it should be very improbable that an anti-particle traveling ...
1answer
323 views

### Anti particles: What exactly is inverted?

http://en.wikipedia.org/wiki/Antiparticle says "Corresponding to most kinds of particles, there is an associated antiparticle with the same mass and opposite electric charge." and What is anti-matter? ...
0answers
146 views

### What makes *electric* charge special (wrt. CPT theorem)?

I'm wondering why the 'C' in CPT - charge conjugation - refers specifically to electric charge. Of course you could say that C is just defined as $e^+ \leftrightarrow e^-$... but there has to be ...
1answer
45 views

### Bigger anti-matter particles

I have learned about the existence of positrons as a decay product from uranium fission - if I'm not mistaken. Is there any evidence for higher 'mass' anti-matter, or is that mere speculation or ...
4answers
158 views

### Can cosmic inflation be explained by matter antimatter reactions?

The big bang theory proposes that equal amounts of matter and antimatter were created in the beginning. Shortly afterwards most of it annihilated. Could that have produced enough energy to drive ...
2answers
228 views

### How does Annihilation work?

I'm wondering why matter and antimatter actually annihilates if they come into contact. What exactly happens? Is that a known process? Is it just because of their different charges? Then what about ...
2answers
1k views

### What would happen after the collision matter and the anti-matter [duplicate]

Possible Duplicate: What actually happens when an anti-matter projectile collides with matter? Suppose 1 kg of a stray meteorite anti-matter moves to the earth. What would happen after ...
0answers
54 views

### Energy efficiency of antimatter producion [duplicate]

Possible Duplicate: Matter - Antimatter Reactory Practicality Certain reactions in particle accelerators lead to production of antimatter, which can then be collected in noticeable ...
1answer
191 views

### Anti-Matter for Neutrons

The anti-particle corresponding to a proton or an electron is a particle with an equal mass, but an opposite charge. So what is the anti-particle corresponding to a neutron (which does not possess a ...
2answers
97 views

### Massless particle as a result of annihilation of “heavy” particles

How can a massless particle such a photon be the result of electron-positron annihilation? What about the law of conservation of energy? Is a valid explanation that the pair's energy transforms itself ...
2answers
116 views

### Matter - Antimatter Reactory Practicality

With current technology, would the energy released by a matter-antimatter annihilation be more than the energy needed to created the antimatter in the first place? Would it be worth it? Just curious, ...
3answers
154 views

### mechanism of annihilation

Can the annihilation of matter and antimatter be explained by the electro-weak interaction? Can pair-production be explained in the same way?
2answers
215 views

### Baryon asymmetry

Baryon asymmetry refers to the observation that apparently there is matter in the Universe but not much antimatter. We don't see galaxies made of antimatter or observe gamma rays that would be ...
4answers
610 views

### What is anti-matter?

Matter-- I guess I know what it is ;) somehow, at least intuitively. So, I can feel it in terms of the weight when picking something up. It may be explained by gravity which is itself is defined by ...
3answers
147 views

### What barriers exist to prevent us from turning a baryon into a anti-baryon?

At present the only way we can produce anti-matter is through high powered collisions. New matter is created from the energy produced in these collisions and some of them are anti-matter particles ...
2answers
495 views

### Do particles and anti-particles attract each other?

Do particles and anti-particles attract each other? From the very basic understanding that they are created out of nothing mutually and collide to annihilate each other seems to indicate this happens ...
4answers
861 views

### If an anti-matter singularity and a normal matter singularity, of equal masses, collided would we (outside the event horizon) see an explosion?

If an anti-matter singularity and a normal matter singularity, of equal masses, collided would we (outside the event horizon) see an explosion?
2answers
105 views

### Can the charge of particles spontaneously flip from positive to negative or vice versa?

I'm thinking of matter antimatter annihilation, are there reactions where normal matter converts to antimatter?
2answers
207 views

### Can different species of particles annihilate with other species

Obviously electrons annihilate with positrons, but can a muon annihilate with an positron, or can an anti-taon cancel with a muon? similarly for quarks of different species, e.g. u and anti-strange. ...
3answers
449 views

### What was missing in Dirac's argument to come up with the modern interpretation of the positron?

When Dirac found his equation for the electron $(-i\gamma^\mu\partial_\mu+m)\psi=0$ he famously discovered that it had negative energy solutions. In order to solve the problem of the stability of the ...
2answers
438 views

### What happens if we put together a proton and an antineutron?

A hydrogen nucleus consists of a single proton. A 2-hydrogen (deuterium) nucleus consists of a proton and a neutron. A tritium nucleus consists of a proton and two neutrons. This makes me wonder how ...
2answers
335 views

### the causality and the anti-particles

How can I quantitatively and qualitatively understand the fact that there is a relevence between the existence of anti-particles and the causality?
3answers
635 views

### Why do or don't neutrinos have antiparticles?

This was inspired by this question. According to Wikipedia, a Majorana neutrino must be its own antiparticle, while a Dirac neutrino cannot be its own antiparticle. Why is this true?
1answer
118 views

### Is it possible that portions of the universe are made of antimatter? [duplicate]

Possible Duplicate: Experimental observation of matter/antimatter in the universe I've heard a bit about the antimatter, matter inbalance. But I don't understand how it has been decided ...
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