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-1
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0answers
40 views

Can a quark be changed to a different flavour?

For example, is it possible to change an up quark into a down quark or vice versa? If so, what is the practical process for doing such a thing? What is the theory behind it? For an example, lets say ...
-2
votes
1answer
54 views

How can alpha or beta emission maintain equal numbers of protons and electrons? [duplicate]

In radioactivity we know that a parent nucleus can disintegrate into daughter nuclei by emitting alpha or beta particles. If this is true then how can the daughter nucleus have as many electrons as ...
11
votes
2answers
967 views

What is the color of a group of trillions of electrons, protons, and neutrons

Since an electron is smaller than visible light, then what what color would a group of electrons (trillions of electrons) be if there were enough of them to be seen by the eye? What color would a ...
0
votes
0answers
20 views

Could artificial atoms not based on quantum dots be created at a similiar size to natural atoms

I'm aware of current pace of quantum dot technology so I am aware they are not close to the smaller size of natural atoms of known elements so I wondered if it's theoretically possible to achieve this ...
0
votes
1answer
26 views

Binding energy per nucleon in radioisotopes of hydrogen

I understand that greater binding energy per nucleon implies a more stable atom and atoms undergo nuclear fusion and fission to attain higher binding energy per nucleon. The binding energy per nucleon ...
3
votes
1answer
94 views

Interpreting the Cross Section Ratio R

Below is experimental data for the ratio $$R=\frac{\sigma(e^+e^-\rightarrow hadrons)}{\sigma(e^+e^-\rightarrow\mu^+\mu^-)}$$ as a function of the centre of mass energy $\sqrt s$. I am interested in ...
2
votes
0answers
37 views

Identical Particle Wavefunctions

Consider the process $$\rho^0\rightarrow\pi^0+\pi^0$$ The $\rho^0$ has $J=1$ whilst the two pions have $S_{tot}=0$ and thus require $L_{tot}=1$ by conservation of angular momentum. Consequently this ...
1
vote
1answer
90 views

Tree Level Feynman Diagrams of Electron Positron Interaction

Consider the interaction $$e^-+e^- \rightarrow e^-+e^-$$ The following is a tree level Feynman diagram for this: We can also make the paths of the two electrons on the right hand side cross over and ...
0
votes
1answer
66 views

How do photons interact with nucleons [closed]

Is question can be considered as an extension of the interaction between photon and atomic electron, where the energy level of atomic electron is elevated when absorbing photons and the process is ...
0
votes
1answer
102 views

What is a Parton Level Feynman Diagram?

I am studying elementary particle physics and I am wondering what a parton level Feynman diagram is? My understanding is that partons are representations of the quark and gluon substructure of hadrons,...
1
vote
1answer
57 views

The Space Between Atoms And Sub-Atomic Particles And More [closed]

I was wondering what the space between atoms or electrons is called. Is it Vacuum ? And what is in there ? Is it really free or empty space ? And if so, how can nothing exist ? It is a bit of an odd ...
2
votes
2answers
80 views

Why did James Chadwick use berryllium to discover neutrons?

In Rutherford's alpha particle scattering experiment he used gold foil because it's malleable and can be drawn into very thin sheet. Why did James Chadwick use Berryllium while discovering neutrons ...
1
vote
0answers
28 views

How does a Collider work? [closed]

How does a collider work, explained using various Physics theories (or if there is a main one) . How does the acceleration play a part in the individual sub-atomic kinetic levels. What happens when ...
3
votes
1answer
198 views

Where else than Atoms do Photons Disappear and Reappear from? [closed]

Where does photons come from and disappear to? Can photons be destroyed and created? Without atoms would photons exist? What other ways then from atoms can photons be made?
-1
votes
1answer
115 views

How Do Low Kinetic Energy and High Kinetic Energy Atoms Attraction differ?

Will atoms of 2 difrent energy levels electron and/or Kinetic attract more than 2 Atoms at he same energy level? Do 2 high energy level atoms attract more than 2 low energy atoms?
1
vote
1answer
27 views

Doesn't the subsequent change in effective nuclear charge and atomic radii disrupt the standing wave in which electron moves?

Electrons move in standing waves around the nucleus. However, as the Atomic No. along a period increases, the effective nuclear charge on the valence electrons increases and the atomic radii decrease. ...
3
votes
2answers
59 views

Beta decay of radiocarbon

I read some weird equation on wikipedia about the beta decay of radiocarbon: ${^{14}_{6}C} \rightarrow {^{14}_{7}N} + e^{-} + \overline{\nu_{e}}$ The problem with this equation that it does not ...
1
vote
2answers
257 views

Red Photon Blue Photon

Why in space red light travels farther and is more observed in dying stars before a star becomes a black hole? while on Earth in water and air the blue light travels the farthest. For example: a T....
1
vote
2answers
88 views

How do you determine if the spin is up or down?

Fundamental particles such as quarks and leptons can have a spin either up or down. These spins are (obviously) opposite of each other. But what differentiates them? Let's say you examine a pair of ...
0
votes
1answer
67 views

Atoms Inside a Lightning Bolt

What happens to atoms trapped in lightning? Why do electrons not split an atom but can change them inside the bolt? Can atoms travel on a bolt?
0
votes
0answers
30 views

Bonding Two Cationic Hydrogen Isotopes (protium) yields H2 or He?

If you have two hydrogen atoms. And they are the isotope form "Protium" (1 neutron removed) and they are also cationized +1 (1 electron removed) then you have (in a sense) a single proton (two of them ...
0
votes
2answers
23 views

Probability of splitting nucleus

I'm sorry if this is a dumb question, but I was just wondering. Say we have a 20 x 20 cm sheet of sulphur, and we have a knife made of iron. If I take the knife, and repeatedly cut the sulphur for an ...
0
votes
1answer
124 views

Does the neutrino have charge? Obviously not!

I was recently reading "Particle Physics: A Very Short Introduction" by Oxford University Press, and in it (I haven't finished it yet though) he says, "The weak force changes one variety of ...
-4
votes
1answer
68 views

what make orbitals and can they be destroyed? [closed]

What is making an orbital to be an orbital? I mean how are the orbital formed. If big bang theory is true that there was nothing before the big bang then definitely these orbitals in the atom would ...
1
vote
1answer
57 views

How might we measure the size of a proton? (Without high energy collisions) [closed]

What methods could we use to measure the diameter of sub-atomic particles. Please think of something inventive, like an indirect technique. Or name some of the lesser known techniques that have been ...
5
votes
2answers
305 views

If mesons were stable could they form atoms?

if there were stable enough mesons similar to protons and neutrons could they capture electrons to form exotic elements. if not why is this not possible?
1
vote
2answers
130 views

Are there unobservable, undiscovered atoms?

Is it possible that there is a network of atomic activity that our current scientific instrumentation cannot detect? In other words, could it be possible that there are unobservable, undiscovered ...
1
vote
1answer
203 views

Do subatomic particles have finite size?

We know atoms are mostly "made" out of empty space, so the nucleus and all the subatomic particle are very small in compared to the magnitude of the atoms. We also know that atoms are incredibly small,...
1
vote
1answer
97 views

Is there a repulsive force between neutrons at all distances or just real close?

With particles of the same charge there is a repulsive force at all distances and physicists talk about neutrons repelling each other. Does this repulsion occur at all distances like with charges ...
2
votes
3answers
256 views

Why do neutrons decay after 6 minutes?

If I understand correctly, Beta decay only occurs when an atom (or in this case subatomic particle) is unstable. Are neutrons consider unstable? If so why? And if they are not unstable is there is ...
0
votes
1answer
128 views

Is there any evidence that subatomic particles are affected by gravity?

If so what experiment has been done to show this?
0
votes
3answers
348 views

What evidence is there for quantum leaps?

I find this very strange that an electron can 'teleport' from one energy level to another. So what evidence suggests this?
1
vote
1answer
113 views

Where does the mass of a nucleon originate in an atom?

The mass of the three quarks in the nucleons make up only about one to two percent of the mass of the nucleons. What makes up the other 98 percent?
0
votes
0answers
326 views

Is there a limit to what we zoom into if it is in fact infinite

I read that recently we were able to view the first atom (hydrogen) under a microscope. This got me thinking about the idea of measurements and zoom lenses. Say hypothetically we were able to build a ...
1
vote
3answers
597 views

New subatomic particles

In reference to the findings talked about here http://online.wsj.com/articles/two-new-subatomic-particles-found-using-large-hadron-collider-scientists-say-1416409980 and other similar articles ...
0
votes
0answers
51 views

Why does not electron cloud collapse over Nucleus? [duplicate]

Gravitational Force & Electrostatic Force should have attracted electron cloud & collapse it over positively charged nucleus.But it doesnot happen One rationale I find behind the phenomenon ...
7
votes
2answers
789 views

Miniature Neutron Stars?

Is the nucleus of a carbon atom, for example, as dense as a neutron star? I read that neuton stars also contain protons. Thinking more broadly, are we surrounded by quadrillion of quadrillions of ...
5
votes
2answers
1k views

How many subatomic particles can absorb/emit photons?

Is the electron the only subatomic particle that can absorb and emit a photon?
0
votes
2answers
343 views

What does temperature look like at the subatomic level?

I am trying to get a better understanding of the definition of temperature at the subatomic level. I have a background in molecular biology with some college physics, but no deep quantum mechanics ...
1
vote
1answer
276 views

Atomic physics question - exciting of electrons during bonding

As I have learnt, when bonding takes place in an atom, such as carbon, the electron in its $s$-subshell gets excited and jumps to the open spot in the $p$-subshell. This is why carbon is able to form ...
2
votes
4answers
501 views

Has a photon or electron ever been observed in a state of superposition?

Has subatomic particles ever been seen in a state of superposition or do we just detect information like qubits about the state of the particle? So is actual matter in superposition or is it just ...
2
votes
1answer
240 views

Why is water blue (on a quantum level)

OK, lets formulate it differently and say water works as a blue passing / red restricting filter. It is actually observable. Just do a dive in a swimming pool with white light (maybe even at night) ...
1
vote
1answer
101 views

Nuclear fission mechanism: neutron capture

Consider this nuclear fission reaction: $\mathrm{^{235}U+{}^1n\to{}^{236}U \text{ (excited)}\to{} ^{92}Kr+{}^{141}Ba+3{}^1n}$ I have not understand why a thermal neutron ($^1$n with $E\simeq 0.025$ ...
0
votes
1answer
84 views

quarks annihilation process

I am appreciating particle physics and I read about mesons. In quark's model, mesons are pairs of quark-antiquark. Now I think that in general matter-antimatter annihilate and so I don't understand ...
1
vote
0answers
46 views

Subnuclear physics vs wave function

This question is more a philosophical question than a physics one. When we appreciate particle physics we study that in order to explain some experimental results we have to introduce a new particle (...
4
votes
2answers
493 views

Are nodes and orbitals in atoms simply probability distribution clouds or are they of any physical relevance?

I fail to understand what the electron clouds actually signify. Such as the $p$ orbitals, which have a dumbbell like shape. Now I am aware that they aren't actual trajectories of electrons, but what ...
0
votes
0answers
40 views

Definition of momentum-entangled particles

When we can say that two particle are momentum entangled ? I just read an article where it's said that two momentum entangled particles share the same momentum value in opposite directions no matter ...
1
vote
1answer
70 views

How we can manipulate the momentum of a particle?

Is there any way to affect a particle's momentum value?
5
votes
1answer
158 views

What does energy represent in $E= mc^2$?

Due to energy-mass equivalence, any object with mass can be said to have a corresponding amount of energy. So in a 5kg object there are 450,000,000,000 joules. A joule as I understand it is the ...
1
vote
0answers
147 views

What does it mean for a subatomic particle to “have” energy?

From my limited classical interpretation of the universe, i've always found it convenient to think of energy as what happens when an object isnt in its equilibrium position in the universe, and thus ...