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3
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1answer
42 views

Mechanism for inelastic collisions in the particle world

We know that inside particle accelerators we collide ionized particles. But we also know that in the microworld all collisions are elastic (due only to the electrostatic force?) between the particles. ...
2
votes
2answers
93 views

How many of the Standard Model free parameters are mutually independent: (all of them)?

My knowledge of the standard model is very limited so please let me spell out my assumptions first (and please let me know when I have mangled concepts, terminology or I am plainly just out of my ...
0
votes
1answer
68 views

In QFT are fields considered a property/function of spacetime? How do they become “excited”?

I am a total layman in physics, but I've been trying to understand the various existing theories and after reading/watching lectures on QFT for months I still can't find an answer to a few very basic ...
2
votes
0answers
52 views

How do quarks have no spatial extent?

I found an answer to a question I had and that is that quarks have no spatial extent. But how is that possible? Everything has to have some spatial extent; to keep continuing on and on, right?
0
votes
3answers
240 views

Why is every particle a sphere?

I was wondering why is everything in this universe, I mean atoms and well quarks and photons and what not some form of sphere. Is there any exploitation to the sphere being perfect and only thing for ...
33
votes
5answers
3k views

Which is more fundamental, Fields or Particles?

I hope that I am using appropriate terminology. My confusion about quantum theory (beyond my obvious unfamiliarity with its terminology) is basically twofold: I lack an adequate understanding of ...
2
votes
1answer
225 views

Classical models with unbounded particle number

Is there any classical model which deals with the birth, life and death of particles? What application could it have? I am talking about a 'billiard-ball' kind of model, but the kind in which balls ...
0
votes
3answers
162 views

Can two electrons attract each other?

Due to electrostatic repulsion the two electrons will repel each other as they both possess similar charges, lets leave gravitational attractive force out of the picture my question is can there be ...
1
vote
0answers
76 views

Particle annihilation - mathematical description, equations governing it? [duplicate]

I was wondering about this and I would like to know an explanation why do particles and antiparticles annihilate? I would be interested in phenomenological, but most importantly mathematic explanation ...
0
votes
0answers
15 views

Particle aggregation: difference between coagulation and coalescence?

I know there are different processes involved in particle aggregation, and that depending on temperature and other factors one of them may be more significant. I know that particles can aggregate, ...
2
votes
2answers
10k views

Frequency of an Electron

My question is very simple. If frequency is defined as the cylces per unit time, Then what is meant by "Frequency of an Electron" ? If the rotation of electron around a nucleus is considered then, ...
1
vote
1answer
34 views

How to stop particles from clustering on a water surface

For my experiment I have to obtain a water surface (1 m$^2$) seeded with floating particles. I found particles of the right size, density (and very acceptable price): expanded glass granulate. ...
2
votes
1answer
369 views

Lifetimes of stable particles

What are possible lifetimes of up/down quarks, electronic/muonic/tau neutrinos, photon, gluon? I understand they are said to be stable, but, as I saw on wikipedia, the lower bound for the "stable" ...
14
votes
2answers
950 views

What is the physical interpretation of second quantization?

One way that second quantization is motivated in an introductory text (QFT, Schwartz) is: The general solution to a Lorentz-invariant field equation is an integral over plane waves (Fourier ...
0
votes
1answer
46 views

Observer carries beam of light and travels at speed of light

I am more of an "arm-chair" quantum physicists, i.e. I'm interested in books and articles about the subject. In the book "Tao of Physics" (Fritoj Capra) it mentions that when Einstein was 16, he ...
2
votes
3answers
508 views

What is the difference between a charged rho meson and a charged pion?

They both seem to have the same quark content: $$\rho^{+} = u\bar{d} = \pi^{+}$$ and $$\rho^{-} = \bar{u}d = \pi^{-}$$ What is different about the two?
2
votes
2answers
252 views

What is the essential difference between a resonance and a particle?

Let me start by explaining my particle physics background is very patchy, so this question may not be as coherent as I would like it to be. In general terms, what is the difference between a ...
3
votes
0answers
56 views

Large Hadron Collider 2015 upgrade, what can it show us?

I realise that the initial answer to my question that may come to mind is, "we don't know yet, duh!!" But my question is hopefully not opinion based. To be specific, have we now a greater chance of ...
3
votes
4answers
175 views

What really is a particle?

In Classical Mechanics we consider particles as things whose internal structure for the purpose of studying some phenomenon might be neglected. In that setting we associate particles to points and ...
0
votes
2answers
58 views

Is there a word for all the particles in an atom?

That is to say, is there a word that picks out protons, neutrons, AND electrons, rather than just saying "nucleons plus electrons"?
1
vote
1answer
75 views

Alpha particle in vacuum

Does the alpha particle travel in vacuum for ever and ever or can it undergo some transformation eg two protons get separated or the neutron decays etc.?
-1
votes
1answer
30 views

Similarity between particles and antiparticles

I was doing a past exam paper and there was this question: State the similarities between a particle and its antiparticle. The answer given was: Same mass and rest energy. I am not too bothered ...
2
votes
2answers
4k views

Why is lightning considered a plasma?

I was wondering why a lightning bolt is coined as "plasma", or a "spark" from an electrical wire/device is as well, yet flares, molten lava, and burning buildings are not(flares are pyrotechnic, ...
1
vote
0answers
34 views

Deceleration of spherical particle in fluid

If I know the initial velocity of a particle entering a fluid, how can I calculate its deceleration over time ? What parameters would I need to know ? Viscosity of the fluid, weight of the particle ...
0
votes
3answers
113 views

The Higgs field vs the Higgs boson

As I see it the Higgs boson is the mediating particle of the Higgs field and get its own mass from the Higgs field. Isn´t this circular? I mean, for instance, an electron creates a radial electric ...
0
votes
0answers
49 views

Direct interaction theory

I got to know about a kind of theory or formulation of EM which doesn't have the idea of fields in it. In that theory I guess field isn't that which mediates the force between two charged particles. ...
0
votes
0answers
56 views

How many quantum fields are there?

I'm just an aficionado, but my understanding is that in QFT, the photon is an excitation of the electromagnetic field, the electron is an excitation of the electron field, and so on. Is there a ...
3
votes
2answers
46 views

Is the only difference between two particles their location and momentum?

Maybe this would be better suited for philosphy.se, if so, then let me know and i'll move it, but this seemed like a reasonable place to start. Let's start with my motivations for asking such a ...
0
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0answers
22 views

Hot air particles

I have a question- albeit random one!. I recently visited a friends place who used a standard shovel from the shed as a tool for moving hot charcoals around a pizza oven. Unfortunately the shovel was ...
0
votes
1answer
43 views

is electromagnetic phenomena and particle behavior dependent on dark matter?

Dark matter permeates space and coalesce s in its own gravitational attraction. It neither absorbs or emits light or interacts well with baryonic matter. It deflects light on a path and is the sub ...
0
votes
1answer
44 views

How can silicon have a capacity of 8 electrons in the outer shell?

I was reading an article on how solar cells work in this website- http://science.howstuffworks.com/environmental/energy/solar-cell2.htm In that website I have a doubt in the first paragraph i.e.- ...
0
votes
0answers
21 views

Interaction rates from cross sections in a thermalized gas

Consider a target particle embedded in a gas with a thermal distribution of velocities. If we know the cross section $\sigma$ for interactions between the target particle and a gas particle, how do we ...
0
votes
2answers
108 views

Does a photon travel in all directions?

For example i am standing and a beam of light is passing in front of me. I am able to see that beam of light so does it mean that photons are travelling in all directions other than the photons which ...
0
votes
2answers
62 views

Is it possible to make an electromagnetic shield?

Is it possible to make an electromagnetic shield to protect something (or ourselves) against things like bullets, human attacks, metals thrown on us or simple dust particles to protect a spaceship ...
0
votes
0answers
39 views

beta minus decay: expression for maximum electron energy

I'm having some trouble finding an expression for the maximum electron energy in beta minus decay. In the frame where the neutron is initially at rest, conservation of momentum reads: ...
1
vote
1answer
559 views

What was the first discovery of the delta baryon $\Delta^{++}$?

The delta baryons (also called delta resonances) are a family of subatomic hadron particles which have the symbols $\Delta^{++}$, $\Delta^{+}$, $\Delta^{0}$, and $\Delta^{−}$ and electric charges +2, ...
0
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0answers
39 views

Energy transfer (Bohr's stopping formula vs. Bethe's)

I'm currently reading about Bohr and Bethe stopping, and has come across a thing I can't entirely figure out. In my book it states: "Bohr's formula gives a reasonable description of the energy loss ...
1
vote
2answers
66 views

Has energy in 'transit' been incorporated into missing matter calcs.?

Has energy in 'transit' been incorporated into missing matter calcs. ?It would seem that, although very small in mass, the sheer number of particles shhoting about from one end of the universe to the ...
0
votes
1answer
34 views

How does an electron beam condenser work?

For example, a scanning electron microscope has multiple condensers that "focus" the beam into a smaller spot size. How does a condenser actually change the direction of electron flow in a non-uniform ...
1
vote
0answers
50 views

Is there a typology of different fundamental physical objects?

As I understand it (and of course, I may be wrong!).... In classical mechanics, all objects are basically the same in the sense that They are composed of atoms bunched together. These atoms occupy ...
0
votes
3answers
294 views

Center Of Mass Troubles

I understand the concept of Center Of Mass(com), but I am having a difficult time interpreting the equation of the simplified case of one-dimension. The book I am reading defines the position of the ...
4
votes
1answer
65 views

Rejecting background in $B$-meson decay

I want to reconstruct the $B$ mass from the decay $$ B^0 \rightarrow K^{0*} \gamma \quad\text{ where }\quad K^{0*} \rightarrow K^{+} \pi^{-} $$ and the equivalent antiparticle decay. A key element in ...
0
votes
1answer
52 views

two mutually attracted particles in 1D space

I'm wondering - can two particles under attractive force ever come to full stop in 1D space? Or will they oscillate for an infinitely long time?
4
votes
2answers
360 views

The concept of particle in QFT

I never learnt QFT and I apologize for my (probably) elementary question. Somebody told me that in QFT a particle is viewed as an irregularity in the field. On the other hand, in an article in ...
0
votes
0answers
42 views

What does the phrase 'muons are brought to rest' mean?

I have a physics question in a text sheet. I am currently doing work on relativity where calculations of rest frames and laboratory frames are being completed. The formula: $t(\text{laboratory frame}) ...
2
votes
3answers
208 views

Is simulating the entire universe possible?

Is it concievable that we may one day simulate the entire universe with every single particle, field and law of physics factored in? Can n number of particles (say the number of particles that make up ...
0
votes
1answer
60 views

Special Relativity - three body problem

I have a problem with solving three-body problem in special relativity. I know that in general this problem doesn't have good solution, but I have a specific case when it should be good answer. ...
1
vote
1answer
82 views

In Bohmian mechanics, how does the particle's position affect where a particle is detected?

In Bohmian mechanics / pilot wave theory / de Broglie–Bohm theory, my understanding is that a particle's trajectory evolves based on its wave function, and that the position that particle is detected ...
1
vote
2answers
173 views

How do particles interact in Bohmian mechanics / pilot wave theory / de Broglie–Bohm theory?

I've read that in the de Broglie–Bohm interpretation of QM, the particle directed by its wavefunction has a trajectory (meaning both position and velocity) and that these are the only properties ...