The tag has no wiki summary.

learn more… | top users | synonyms

4
votes
0answers
208 views

Nature of Microscopic space-time

I am going through the introductory chapter's of Schwinger's Source theory. He writes, It [Source Theory] is a phenomenological theory, designed to describe the observed particles. No speculations ...
-8
votes
2answers
61 views

Which is the heaviest elementary particle? [closed]

Which elementary particle has the greatest rest mass? (For the sake of this question I'll call a photon's rest mass 0, whether it is or isn't (actually, tell me if this is the right thing to do)).
-1
votes
1answer
46 views

Lifespan of particles

After reading a very informative tutorial on elementary particles physics over at http://www.particleadventure.org, I have a question I can't figure out. I understand the need to accelerate a ...
1
vote
0answers
53 views

Fundamental difference between neutron and proton

As I try to understand the elementary particles,I was reading strong interactions and Isospin from a book.Then I came across this: Thus,the strong interactions do not distinguish between a proton ...
0
votes
0answers
58 views

What is the most fundamental peice of matter? What is it that thing which can no more be sub-divided?

I know that there is theory that strings are the most fundamental particles. But if it is a string, then it can be 'cut' into pieces, and if it can be 'cut', then it can be cut at infinitely many ...
1
vote
2answers
63 views

Quarks are now considered to be fundamentals, but so were atoms some time ago. So the way we see is only limited by our technological advances? [duplicate]

After watching this FuseSchool - Global Education episode, I cannot stop thinking how can something not have a substructure, how it cannot be split? http://www.youtube.com/watch?v=nlv06lSAC7c
-1
votes
2answers
70 views

Are particles solid?

My intuitive understanding is that although atoms are mostly empty space, the nucleus is solid. Thus a neutron or a neutrino can collide with it and do things like deflect or cause a nuclear ...
2
votes
1answer
99 views

What is the difference between QFT and elementary particle physics?

I'm a little unclear as to how QFT differs from Elementary particle physics. They both use pictorials of Feynman graphs, is it that Elementary particle physics assumes the point particle perspective, ...
1
vote
1answer
82 views

Elementary particles

That's what Wikipedia says about Elementary Particle: In particle physics, an elementary particle or fundamental particle is a particle whose substructure is unknown, thus it is not known to be ...
1
vote
2answers
88 views

Can we make usable energy from subnuclear particles?

I understand mass and energy are the same, but in this question I will be talking about mass being turned into usable energy (electricity/heat/etc). We can make our energy through chemical reactions ...
14
votes
4answers
3k views

Can you split a photon?

I was wondering if a photon is divisible. If you look at a photon as a particle, then you may be able to split it (in theory). Is it possible and how do you split it?
-1
votes
1answer
53 views

Muons Internal Clocks and Time Dilation? [closed]

I don't get how time dilation affects the half-life of muons? Time is just a tool that is used by humans how does that affect the internal clocks of elementary particles?
6
votes
1answer
273 views

Explaining chirality for spin 1/2 particle

I found the following explanation for chirality for spin 1/2 particles here What happens when you rotate a left- vs right-chiral fermion 360 degree about its direction of motion. Both ...
1
vote
5answers
168 views

Do the particles made in a collider exist outside the collider?

Below is the transcript of a section from Demystifying the Higgs Boson with Leonard Susskind. Around 1:02:23 Susskind says that the heaviest of the fermions is called the top quark. Top quark is ...
3
votes
2answers
199 views

Is there scale by size of all discovered particles?

Atom: Neutron: Elementary particles: Is there scale by size of all discovered particles? From neutron and proton to electron and to boson? Compare to each other, like this I have found ...
5
votes
2answers
245 views

Is ch. 2, sect. 4 of The Feynman Lectures on Physics, Vol. 1 still accurate?

The chapter 2 section 4 of volume 1 is on nuclei and particles. Here are a few things that trouble me. Dr. Feynman says that Another most interesting change in the ideas and philosophy of science ...
-6
votes
1answer
168 views

Has the spin and parity of the Higgs boson been experimentally confirmed? [closed]

I read in a newspaper that the Higgs boson might be the new boson but that this was not confirmed, because we don't know its properties, e.g. its spin or parity. Now I see it confirmed that it is the ...
7
votes
3answers
206 views

Why are all force particles bosons?

All of the force-particles in the standard model are bosons, now my question is pretty short, namely: Why are all force particles bosons? This can't be a coincidence.
2
votes
1answer
376 views

Is it dangerous if one elementary particle with high energy penetrates our brain?

We might be killed if a bullet penetrates our brain. How about an elementary particle moving with high energy penetrates our brain? Assume that we can have exactly a single elementary particle for ...
5
votes
1answer
636 views

Why do quarks have a fractional charge?

I am aware that evidence exists that strongly suggests the existence of quarks and do not doubt it. It is just simply really weird to me that they can have a fractional charge. While other ...
2
votes
1answer
40 views

Asymmetry in muon energies of public CMS dimuon event data

CMS published for educational purposes (caveat) 100.000 dimuon events: https://cms-docdb.cern.ch/cgi-bin/PublicDocDB//ShowDocument?docid=11583 As one easily sees, column 4 shows the first muon's ...
7
votes
2answers
413 views

Is everything made of massless particles?

Photons have no mass. Yet they interact gravitationally, as all energy does, with other energetic and massive particles. This means that if you put multiple photons in a system, you get something that ...
0
votes
2answers
157 views

Elementary (fundamental) properties in electricity

I tend to believe that there are two elementary properties in electricity: Electric charge Coulomb's force I think that I can express any other entity in electricity using just these two (by means ...
6
votes
1answer
154 views

Is color confinement detected?

I'm a graduate student studying QFT. I'm quite interested that is color confinement detected or proved? (both directly and indirectly) Or it is just an assumption?
-3
votes
1answer
148 views

String theory and the SM spectrum [closed]

Long ago, I realized this: (super)string theory can NOT give a well-defined/unique prediction of why the electron (muon, tau) or the neutrino (any flavor) masses have the masses we measure. String ...
0
votes
0answers
93 views

History of the elementary particles

The current model for the elementary particles is the standard model. I understand its basics It is for me however, difficult to wrap my mind around it without having some kind of knowledge of the ...
2
votes
1answer
229 views

Why no fundamental force from the Higgs? [duplicate]

I wish to ask whether I understand the following correctly. This universe seems to have six fundamental elementary bosons namely photon $(\gamma),\ W$-bosons$(W^+,W^-),$ gluon$(g),\ Z$-boson $(Z)$, ...
0
votes
1answer
107 views

Is everything in the physical world composite?

In philosophy there is a principle that anything composite cannot have existed eternally, since it is preceded by its parts and whatever forces assembled it. Is everything in the physical world ...
1
vote
0answers
91 views

Matrix element approximation

In the formula for the decay width of $\Upsilon(4S)$ to B-mesons from $\text{e}^+\text{e}^-$ collisions: $$\Gamma_{\Upsilon(4S)\to B\bar{B}}=\frac{\left|\underline{P}_B \right|}{8\pi ...
2
votes
0answers
94 views

Parton Distribution Functions, average cross section of the nucleon

Say we are given the scattering cross section for neutrinos from $d$ and $\bar{u}$ quarks as $\frac{d\sigma^{d}}{dQ^2}=\frac{G_F^2}{\pi}$, $\frac{d\sigma^{\bar{u}}}{dQ^2}=\frac{G_F^2}{\pi} (1-y)^2$, ...
0
votes
1answer
61 views

Does it happen at high energies (heavier leptons decay)?

A lepton is an elementary particle. The best known of all leptons is the electron which governs nearly all of chemistry as it is found in atoms and is directly tied to all chemical properties. The ...
3
votes
0answers
60 views

Can the mass of a SUSY particle depend on the process it participates in?

I believe that mass is property of every particle,as well as spin etc.Now I'm interested in SUSY particles in cMSSM model.Can it be,that mass of a SUSY particle (at one point in five parameter space) ...
1
vote
1answer
49 views

Can objects, animate or inanimate, be constructed out of basic particles?

If all the elements are made of protons, neutrons and electrons, but some elements are much rarer and more expensive than others, would it be possible to break apart atoms of one element and make ...
1
vote
1answer
432 views

Definition of elementary particle [duplicate]

Possible Duplicate: Why are atoms particles? According to wikipedia an elementary particle or fundamental particle is a particle not known to have substructure. Moreover, I've learned ...
0
votes
3answers
203 views

Is it true that an isolated fundamental particle does not decay?

Is it true that an isolated fundamental/elementary particle does not decay? It seems logical to me.
3
votes
2answers
395 views

Why do physicists think that the electron is an elementary particle?

When we first discovered the proton and neutron, I'm sure scientists didn't think that it was made up of quark arrangements, but then we figured they could be and experiments proved that they were. ...
2
votes
2answers
154 views

Parity, how many dimensions to switch?

Parity is described in Wikipedia as flipping of one dimension, or - in the special case of three dimensional physics - as flipping all of them. Is there any simple rule that generalises both for any ...
1
vote
2answers
342 views

A basic confusion about what is an atom

Wikipedia defines atom as The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. and defines electron as: The ...
5
votes
0answers
415 views

General equation of motion for elementary particles

Elementary particles can be grouped into spin-classes and described by specific equations, see below: Is there a general Lagrangian density from which all these equations can be derived? A ...