The tag has no wiki summary.

learn more… | top users | synonyms

2
votes
2answers
277 views

How the nucleon structure has been identified experimentally?

It is known that nucleons (proton, neutron) are composed of partons (quarks, etc.). How was this identified experimentally? In particular, how it has been identified that nucleons comprise of more ...
1
vote
1answer
199 views

Stability of neutron [duplicate]

Possible Duplicate: How come neutrons in a nucleus don't decay? It is known that free neutron decays in 15 minutes on average. Why is it much more stable when "placed" in nuclei? Edit: ...
8
votes
1answer
530 views

why is there no ninth gluon?

A teacher of mine told me once that there were no ninth gluon because such a one should be white and interact infinitely far, and no one has been observed. Is there also a theoretical reason?
0
votes
2answers
182 views

Speed Distribution of The Particles

I want to know the distribution of the particles's speed. The particles what I mean are nucleons and electrons of element. Consume there is 1kg of iron on room temperature and it's shape is sphere. ...
3
votes
3answers
1k views

What is lepton number?

What exactly is a lepton number of a particle? With the charge (eg proton is just 1, not the exact charge), I can understand because it's a physical property, put a particle with charge + next to ...
1
vote
0answers
32 views

GUT predictions for charm mass?

Most GUT models have some relationship between down-type quarks and leptons, that more or less agree with the observed values after running the renormalization equations. But, what about up-type ...
3
votes
4answers
167 views

is the Z boson one entity or are there as many entities as decay pairs, but they are equivalent and lumped together

just wondering if it is a distinction without a difference - it seeming a bit weird that one thing can decay into different things.
1
vote
2answers
1k views

Why does Davisson-Germer experiment confirm electron's wave-particle duality?

First I apologize if my question is trivial and for my poor English. I was wondering why my teacher states that "electron's wave-particle duality is verified if we observe diffraction of the electron ...
4
votes
1answer
555 views

Does the speed of sand flow in a hourglass depend on a height of a sand column above the hourglass neck?

In a hourglass, does the sand flow through the neck depend on the amount of sand in the upper glass? If we consider a sand flow analogous to fluid flow, then it should depend linearly, but in that ...
8
votes
1answer
2k views

Standard Deviation in Particle Physics

I'm familiar with sigma, and how its usually calculated and used, but would like to know how it's applied to particle physics. I recall reading that the discovery of the Higgs would only be credible ...
4
votes
2answers
515 views

What is the “shape” of atomic/subatomic particles?

I apologize in advance for my ignorance if this is a question with an obvious answer... I am not experienced in this field. But are such particles in the universe points with a charge, or are they ...
1
vote
2answers
120 views

What is a proton-rich atom?

http://wiki.chemprime.chemeddl.org/images/e/e4/Plot_of_Neutron_Number_vs._Proton_Number_.jpg The above graph shows that all elements have more neutrons than protons in this nucleus. So how is there ...
-2
votes
1answer
227 views

Transition of Electric Charge In Collision Between Proton And Antiproton

I know that $$p+\bar{p}\to 4\pi^++4\pi^-+(\gamma)$$ Before the collision, the sum of absolute electric charge value is $2$. $$\left | +1 \right |+\left | -1 \right |=2$$ After the collision, the ...
10
votes
2answers
1k views

How Did Paul Dirac Predict The Existence of Antiproton?

The existence of the antiproton with -1 electric charge, opposite to the +1 electric charge of the proton, was predicted by Paul Dirac in his 1933 Nobel Prize lecture. Quotation by Wikipedia. ...
6
votes
3answers
351 views

Is there Bremsstrahlung radiation for a charged massless particle?

This is a follow up question from: Massless charged particles Since by definition such a particle would interact with photons- resulting in some change in momentum- would the particle emit ...
6
votes
3answers
287 views

References on the non-compositeness of the known elementary particles

What paper(s) or theory(s) describe or prove that the elementary particles that we have determined today cannot be made up of smaller more fundamental particles?
4
votes
1answer
946 views

Why does lambda decay violate parity?

When a lambda particle decays into proton and a pion, I am told it does not conserve parity. Why?
2
votes
2answers
4k views

How do alpha and beta particles ionise surrounding particles?

I've been wondering about this question for a while. If you have alpha and beta particles released from a radioactive core, how do they ionise surrounding particles?
6
votes
1answer
321 views

Unusual particle effects at CERN

In 2010 there were press reports that CERN had identified unusual properties in particle behavour in collisions. One link here. Here is a partial quote: "In some sense, it's like the particles talk ...
3
votes
3answers
1k views

are particles “knots” or “kinks” of excitation in a field?

this is my mental picture for how they travel without a medium, how (like water waves) some can't stay still, why they have wave and particle properties, energy/mass equivalence, conservation, etc. ...