# Tag Info

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The anti-particle corresponding to a neutron is an anti neutron! The neutron is made up of one up quark and two down quarks. The anti-neutron is made up of an anti-up quark and two anti-down quarks. Both have zero charge because the charges of the quarks within them balance out. You are correct that elementary particles with no charge are often their own ...

6

That's a great question! Unfortunately, the only honest answer is "that's what we see in nature, with great precision and complete reproducibility." There is no deep theoretical understanding. The more exotic form of your question is phrased in terms the self-energy of an electron, and it's a question that plagued Nobel Laureate Richard Feynman his entire ...

5

This is just a misunderstanding--- "no motion" in quantum mechanics is a different concept than "no motion" in classical mechanics. At zero temperature, nothing stops. Spherical uncharged black holes don't stop particles at the singularity, they absorb particles and time just ends at the singularity for the infalling matter. The wavefunctions are not made to ...

3

You can see a nucleus and the nucleus of a hydrogen atom is a proton which is the same. You can't see below that at least with a source of neutrons that ISIS produce, but you can see down to the level of the proton.

3

Your teacher is referring to the LCAO approximation as a way of calculating molecular orbitals. Suppose you bring two hydrogen atoms together i.e. create a hydrogen molecule. To calculate the electronic structure you need to solve the Schrodinger equation, but even for something as simple as the hydrogen molecule the Schrodinger equation is too complex to ...

2

Short answer: the strong nuclear force. The strong nuclear force binds nucleons (protons and neutrons) together. It is a very short-range force, which is why it only acts over distances on the scale of atomic nuclei. There is repulsion between the protons, which is why, as the number of protons goes up, more and more neutrons are required to stabilize the ...

2

We can image the sub-structure of nucleons by a number of different techniques involving high energy scattering. The results are generally presented in terms of "parton distribution functions" or "structure functions". One such experiment that I had some small relationship with (though not enough to be an author) was NuSea (E866) at Fermilab in the mid ...

2

Oh goodness... that is an immensely complicated topic. Many thousands of people have put in decades of work figuring out exactly what happens when two subatomic particles collide. The calculations are all done using quantum field theory, so I would say if you want to learn about the process involved in describing the outcome of a collision, read up on QFT - ...

2

They are exactly the same, with the different notations arising in different contexts. You could start with a bunch of helium gas and heat it up or shine UV light on it to turn it into a plasma, and then you'd probably say you have $\mathrm{He}^{2+}$ (or $\mathrm{He}\ \mathrm{III}$ if you are an astronomer). The symbol $\alpha$ is more often reserved for ...

2

It's really not clear what hypothetical limits you're imposing. I take your question to mean that in the process of baryogenesis the various baryons like protons and neutrons highly favored up quarks (lots more protons than neutrons). Remember, quarks are subject to confinement so other than a quark-gluon plasma, quarks are confined to baryons. Since ...

2

If you're asking whether we can measure the effect on atomic structure of gravitational forces between the nucleus and the electrons, then the answer is that not only have we never measured such effects but it's unlikely we'll ever be able to measure them as they would be many orders of magnitude below the electrostatic forces that hold the atom together. ...

2

However where did the electron get its energy from in the first place(during the creation of the universe"Big bang"). All energy, and remember energy and mass are related by E=m*c^2, that exists in the universe existed after the first minutes of the Big Bang . For t=0 plus an interval after it where gravitational forces predominate, i.e the realm of ...

1

You have a lot of questions here, and they show you really need to read up on some basic physics, but here goes with some simple answers: Where did the electron get its energy from in the first place? What energy do you mean? Why doesn't everything fall apart when we sit on a chair or grab a pencil,why wont the electrons fall from trajectory and get caught ...

1

Your question is interesting, and gets specifically to the kinds of questions that quantum mechanics was intended to answer in the first place. It helps to understand the motivation behind the original Bohr model of the atom, and how that led to QM in the first place. The problem Bohr was trying to address can be paraphrased as, "If an electron orbits a ...

1

It's a very good question. The electron is described by a wave field which resembles a charge distribution, so it is natural to wonder why it doesn't repel itself and spread out all over. However, the wave is not a classical wave but is quantized, i.e. the energy in a given vibration mode has to come in discrete bundles. One can count how many excitations ...

1

There exists a huge number of experimental evidence that in the subatomic world nature is using quantum mechanics. In quantum mechanics bound states always have the first energy level above 0 energy. Your magnetic field thought experiment creates a bound stated in the collective potential. Free states have to obey the HUP and therefore cannot have 0 fixed ...

1

I will assume you have heard something about proton decay. proton decay is a hypothetical form of radioactive decay in which the proton decays into lighter subatomic particles, such as a neutral pion and a positron.1 There is currently no experimental evidence that proton decay occurs. There are a number of experiments which test whether such decays ...

1

In a sense these "games" exist, need large computing power and are called high energy physics monte carlos. These are very complicated simulations of the reality of the experiment and include all the detector effects. At the first level of the core of these HEP monte carlos there exist tables of "complete" possibilities of scattering products: all ...

1

The electron is stable (from a QFT POV) because there is no particle with less energy (in the Standard Model) that it can decay into while also preserving all known conservation laws. As for the "burst" part that question comes from a classical view of the electron which does not hold since we know from QM that electrons also behave like dual wave-particle ...

1

I don't think there's a good general explanation of this; the best I can do is give a few hand waving arguments. If you look at hydrogen sulphide, which the analogue of water moving one row down in the periodic table, you'll find it does shrink when it freezes, just like most other liquids. So the difference between the H$_2$S and H$_2$O molecules must be ...

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