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-1
votes
2answers
54 views

Possiblity for particle to be carried by a wave such as a photon or electromagnetic wave/waves in general for means of transportation/travel? [closed]

I am wondering whether it is possible for a photon/EM wave to carry a very small particle like an elementary particle or smaller on it like a highway carries a car traveling on the highway or an ocean ...
-2
votes
1answer
63 views

Why particle needs spin? [closed]

I know the slight difference between rotation about the axis and intrinsic spin of a particle. But, I was puzzle why there is spin other than rotation?
2
votes
1answer
41 views

Solar activity and radioactive decay rates [duplicate]

I recall hearing about this quite some time ago and thought it was very strange. I recently had it pop in my head again and was curious if anyone knew what was going on with this. Variable decay ...
1
vote
1answer
67 views

Is there a problem with our currently known fundamental particles?

Many scientists are searching for particles even more fundamental than leptons, quarks, gluons, etc. and (from what I know) string theory tries to hypothesize one elementary "thing" that everything is ...
2
votes
2answers
128 views

What is the meaning of the size of an elementary particle in QFT? What is the meaning of a point particle? [duplicate]

I have often seen people refer to the size of a particle being at most a given value, or a particle being a point particle, in the context of quantum field theory. Examples are the Wikipedia entry on ...
1
vote
1answer
72 views

Understanding type of force interaction in particle decays

Are there any fundamental rules of thumbs that can be used to identify the type of force interaction (weak, electromagnetic, strong) in a particle decay without drawing the Feynman diagrams at the ...
-1
votes
1answer
48 views

How do comparatively larger particles arise from vibrations of infinitely smaller strings?

In String Theory, how can a string as infinitesimally small as the Planck length, manifest itself as a much larger and massive particle?
3
votes
2answers
77 views

Change of flavour, Weak interaction

I couldn't find a straight and clear answer to this question on the internet: Why is the weak interaction (charged), the only interaction which can change the flavours of the quarks?
0
votes
1answer
43 views

Do Calabi -Yau shapes also influence a strings particle identity?

Since strings reside on the surface of a d-brane, and it' a three dimensional hyperspace, are their manifestations as certain particles also influenced by Calabi Yau Spaces? Could the way strings ...
1
vote
1answer
92 views

What particles are closed strings? [closed]

In String Theory, I understand that gravitons are particles that are closed strings. Are there other particles that are manifested from closed strings?
0
votes
1answer
48 views

Which elementary particles have been seen up to now?

Which elementary particles have been shown up to now? which one except Graviton, haven't seen? I need an update one, I am searching but I couldn't find. If anyone could answer me, I am so thankful.
0
votes
3answers
91 views

How do particles get their charge?

How does an electron get its charge? And how can it maintain that charge for very long (infinite) periods of time? And how come a neutron has no charge since and a proton does? They are both made of ...
10
votes
1answer
1k views

Why do physicists say that elementary particles are point particles?

For example, an electron, it has mass and charge, but is considered to have point mass and point charge, but why? Why are they assumed to have charge and mass in a single infinitely small point in ...
2
votes
0answers
100 views

Shouldn't there be 6 fundamental forces? [closed]

I'm listening to Leonard Susskind's The Black Hole War. In it he states (paraphrased) that a string wrapped around a compact dimension once imparts one unit of charge. Wrapped one way, it's a ...
1
vote
0answers
16 views

Explanation of two slit experiment [duplicate]

Whilst going through 'a brief history of time' ,I faced difficulty in understanding the two slit experiment. How can individual electrons cause fringes?
3
votes
0answers
76 views

Why do we say that elementary particles are pointlike? [duplicate]

When people discuss quantum field theory in a popular context, they say that fundamental particles, such as quarks and electrons, are pointlike, with zero size. However, I don't think this is what ...
0
votes
0answers
19 views

A few positrons collide with a solid body at rest; what can happen?

Suppose we have a macroscopic solid object. Now we have a beam of Positrons that is injected into this solid Body at vacuum. What can happen? There will take place a pair Annihilation of electrons ...
1
vote
0answers
69 views

Do all particles have radiative transitions?

Everybody knows that excited electrons can emit photons upon relaxation. A nucleus too (which is not an elementary particle), can be in an excited state and emit gamma rays upon relaxation: (source) ...
4
votes
4answers
83 views

Is there a theory where there are (recursively) infinitely smaller particles?

So I read that electrons are just points, with no mass, and furthermore, protons look like they have some "size" but that's really 3 "point-like" quarks. We first thought atoms were the smallest ...
3
votes
1answer
42 views

Are there experimental arguments against elementary particles to have wobbling magnetic moment

Elementary particles having angular momentum and magnetic moment are observed or assummed as these are either always parallel or antiparallel. This condition could be satisfied even the instantaneous ...
2
votes
1answer
65 views

Strange Matter and Stars

I am researching some stuff for a WorldBuilding.SE question, which asks if there is a true scientific method (not necessarily at our current technology level) to create a bomb capable of destroying a ...
1
vote
0answers
19 views

Voltage drop along electron beam

A focused electron beam represents a current and unless the charges (electrons) meet no resistance to their movement there should be a voltage drop along the length of the beam. So, assuming the beam ...
-3
votes
1answer
79 views

What do sun spots look like under the surface of the Sun? [closed]

Do sun spots float like oil, float around like a lava lamp, is it more like the tip of an ice burg or what?
3
votes
2answers
555 views

Does the existence (now proved) of gravitational waves imply the existence of Gravitons?

I studied the theoretical part about the Gravitational waves in General Relativity (linearization of gravity and small perturbations of the metric and so on). But I was wondering about: since ...
1
vote
2answers
142 views

Why is an electron considered a point-particle?

Apparently, an electron has mass not greatly smaller than a proton (roughly 1/20, I read, the rest being just binding energy) its volume should, therefore, not be a lot smaller, and its radius between ...
2
votes
1answer
105 views

Which of the properties of particles are intrinsic properties and why? [closed]

For macroscopic objects it's clear that - once observed - the observed property does exist for a while, even if we are no longer observing it. That has to do with the complexity and stability of such ...
2
votes
0answers
107 views

What are elementary particles according to Loop Quantum Gravity? [closed]

Are elementary particles still excitations of quantum fields in LQG?
1
vote
1answer
50 views

Are the leptons in $\beta^-$ decay already present in the nucleus in some form?

In beta minus decay, beta-minus particle and anti-neutrino are ejected, leaving behind daughter nucleus. $\beta^-$ and anti-neutrino both are leptons. Were the leptons already present in the ...
10
votes
2answers
784 views

Why couldn't the decay $\pi^- \to e^- + \bar\nu_e$ occur if electrons were massless?

If we assume that electrons (just like neutrinos) are massless, why can’t the decay $\pi^- \rightarrow e^- + \bar{\nu}_e$ occur under the weak interaction?
2
votes
0answers
78 views

Is muon muon annihilation already realised?

As muon colliders do not yet exist, has muon-muon annihilation already been realized experimentally?
3
votes
1answer
66 views

How do we know that elementary particles possess definite parity?

As I was reading Griffiths' "Introduction to Elementary Particles" Wiley 2008, on chapter 4 "Symmetries", the question stroke me. The same as Parity operator (inversion in 3-dimensional space) we ...
0
votes
1answer
88 views

Does gluons have names?

I was trying to find in some general physics books and using the Internet the answer to my question - does each one of 8 gluons has its own name? For example quarks are named: Up Down Charm Strange ...
1
vote
1answer
109 views

What effects would a finding of Gravitational Repulsion Between Matter and Anti-Matter in the ALPHA Experiment have on Mainstream Theory? [closed]

The actual nature of the gravitational force between matter and anti-matter (attractive or repulsive) remains unsettled: See Are there experiments taking place right now that might show evidence for ...
0
votes
1answer
47 views

Can an atom be formed from a combination of subatomic particles other than electron, proton and neutron (or their antiparticle)?

I have read that there are plenty of elementary particles. Can some of them form some species other than proton and neutron that are able to form a stable atom together with an electron or an electron ...
0
votes
1answer
67 views

Relativistic Scattering

When we work out the relativistic general two-body scattering in the CM frame (like two elementary particles producing two other P1 +P2 -P3 -P4) , the cross section is proportional to absolute final ...
0
votes
1answer
98 views

Strangeness of elementary particles

What is the property, whose violation led to the assumption of strangeness? Prior to the discovery of strangeness was it assumed that particles that are produced by strong interactions can decay only ...
0
votes
1answer
123 views

Why are quarks fundamental particles? [closed]

A neutron decays into a proton by changing one of its down quark into an up quark and releasing energy, positron and neutrino particle. So, a down quark can decay into an up quark. If a quark decays,...
0
votes
1answer
56 views

How many fermions?

Quick question: I just read in a PhD thesis that there are 48 fermions. I count 6 quarks + 3 leptons + 3 neutrinos times 2 for anti-particles = 24 fermions. Am I missing something?
0
votes
2answers
68 views

Are electrons really elementary particles? [duplicate]

I know that physicist do accept that fact as "an assumption", or "as a fact" due to "proofs" (or missing unroof). But are electrons really to be considered as elementary particles?
10
votes
0answers
179 views

In a universe with four spatial dimensions would there be elementary particles with intrinsic isoclinic spin?

Elementary particles have an intrinsic property called spin which is different from classical spin as it does not involve actual rotation and the magnitude of spin cannot be changed but particles with ...
0
votes
1answer
65 views

Particle Physics: Weak Interaction

Consider the following decay equation:- A Kaon(+) decays into a muon(-) and an antineutrino(?) The question is as follows :- State and explain whether the anti-neutrino is an electron, muon or tau ...
0
votes
0answers
41 views

Can an electron in empty space to create electromagnetic radiation?

Is it possible in the empty space to create electromagnetic radiation from oscillations of the charges only of one kind - positive or negative? This question stems from the fact that all man-made ...
32
votes
7answers
3k views

How can the unstable particles of the standard model be considered particles in their own right if they immediately decay into stable particles?

How can the unstable particles of the standard model be considered particles in their own right if they immediately decay into stable particles? It would appear to a layman such as myself that these ...
0
votes
2answers
183 views

Where do electrons come from in thermionic emission?

Let we suppose to have a HV Tube or CRT . The filament is connected to the secondary of the transformer used to supply the filament. At time $t=0$ the wires and cathode are neutrally charged. Then ...
0
votes
4answers
248 views

Why, fundamentally, are particles charged?

This is something that has long bothered me, and I have asked a few physicists and chemists and never gotten a very satisfying answer. Why are particles charged? And I'm not asking (and this is the ...
0
votes
1answer
78 views

Fractional number of particles in the universe?

Is it possible, that the metagalaxy contains a fractional (non whole) number of particles or fractional number of a particular kind of particles (such as electrons)? Sorry, if my question is stupid, ...
4
votes
2answers
226 views

Can quarks be considered real and elementary?

In our current theories all hadrons are made up of quarks and gluons. This view reduces considerably the big family of hadrons by providing a very logical structure in which all quantum properties ...
0
votes
0answers
18 views

Evidence electrons are fundamental particles [duplicate]

Is there any evidence that entities like electrons and quarks are indivisible, i.e. not composed of other, smaller entities? And have I just made a category error by even asking this question?
1
vote
1answer
178 views

How many combination can quarks form?

How many different combinations can quarks produce? E.g. 2 up quarks + 1 down quark = proton. Is this value going to be infinite?
2
votes
0answers
103 views

Are we able to store low energy positrons in a magnetic field for arbitrarily long time?

And if not, what prevents us? Is there a mathematical equation describing the loss rate?