Elementary particles Definition and 102 Threads

Hi I've been reading that muons are supposedly leptons (elementary particles), in the past confused for mesons (hadronic particles). They are clearly not mesons, which are composed of a quark and an antiquark. But I've also read that muons decay to an electron and two neutrinos of different...

It is supposed that the smallest posible black hole (BH) has mass of Planck's mass. But obviously one nucleon (or an electron) also acts with gravitational force. If we assume that the smallest possible BH has really Planck's mass, is here any contradiction that a electron acts with...

They say that a photon has two degrees of freedom, its two polarization states. Does that also mean that the electron has only two degrees of freedom, its two spin states? What about the frequency of a photon, is that not a degree of freedom? Or the three space directions that a electron can...

Why are all particles of a particular type of elementary particle all exactly the same? What kind of a process causes a lot of identical elementary particles to appear? How can a infinitely dense, hot, and small piece of space become a system with finite bounds (on energy, number of...

can a gas of neutrons said to behave like ideal gas? neutrons almost satisfy all postulates of kinetic theory.(except maybe about Newtons laws) Also can a gas of protons said to be a ideal gas? protons could be said to be simply hydrogen with electrons removed. the electrons don't have...

I've read everywhere that strings are now taken to be the fundamental particle, but I think that it is taken as one because we cannot go further. After a few years once we can go in we may discover a new elementary particle. I was thinking; isn't energy the fundamental particle? Because even...

The truly elementary mass seems to be the Planck mass which is much larger than the masses of the particles that we see in nature. Maybe what we think of as elementary particles are actually just quasi-particles, excitations of the underlying space-time (like phonons are quantised vibrations...

elementary particles --their place in atom Homework Statement Do elementary particles reside inside the nucleus alone? Homework Equations The Attempt at a Solution

Hello, Maybe a strange question here (I'm not 100% current with the standard model), but does the standard model say anything about a change in the ratios of fermions as the universe expands? (I see Generations I, II & III listed)

What would happen if an electron were accelerated in an attempt to collide with an accelerated proton in a particle accelerator? What would happen in a collision between an electron and a neutron?

Can someone give a list of all the pure numbers that relate to elementary particles (such as the fine-structure constant)? How many such numbers are there? Is it likely that more will be discovered? Thanks

"In particle physics, an elementary particle or fundamental particle is a particle believed not to have substructure; that is, it is believed not to be made up of smaller particles." -Wikipedia How does someone ever possibly (LOGICALLY) conclude that a particle is not made up of smaller...

Please teach me this: I wonder whether there exist only quarks(6 quarks) and leptons being really elementary particles. Or there are many another types of particles? Thank you in advance.

Hi, I had a question about irreducible representations and elementary particles... Namely, I've been told by teachers and read in a few texts that particles ARE irreducible representations, and I have never been able to wrap my mind around what that means. Please keep in mind that I am no...

I have a simple question regarding masses of elementary particles (in string theory). What is the mechanism proposed to explain the tiny but non-zero fermion masses? I know zero masses e.g. due to some symmetry (gauge, conformal) or symmetry breaking (Goldstone bosons). I know the huge...

Hello I am interested if there is yet a theory that states or has relationships that can be interpreted as stating the age of an elemetary particle. For example, if a neutron just sits around (unbounded) passing the time, does it know that it is not allowed to survive a certain age? This...

I don't know if anyone has heard of these even more elementary particles, http://en.wikipedia.org/wiki/Preon There even more fundamental than quarks, i was wondering if they are well excepted into the scientific community or if its a very unlikely that they are real.

Hi, I am B.E. Mechanical Engg. candidate. But i am crazy about particle physics. I want to do research in atomic and particle physics. Can anyone guide me how to get into research since I don't have physics as my graduate degree. I know i have to do msc and phd but can anyone give guidance which...

These are some of the inconsistencies with physics that should be resolved on this forum. Question #1. Relationship Between Mass and Gravity) Gravitational fields exist in elementary particles but cannot be detected in laboratory experiments because they are too weak. However can...

Golden Rule for Decays in Griffiths' "Introduction to Elementary Particles"? Hello, I'm getting a bit bogged down in constant factors while reading Griffiths' "Introduction to Elementary Particles", 1st edition. In particular, I'm having problems with equation 6.15: d\Gamma =...

Has anyone ever considered the outer event horizon of a point particle (classical electron perhaps...)? Does it make sense to consider it Kerr and charged because of spin? Is it comparable with a Planck length? I know we would need a quantum gravity to deal with it, I'm just curious to see what...

Can we see elementary particles using any device? I mean the way we can observe smallest of the viruses by a microscope and the farthest of the objects by a telescope?

Another question that i am not even qualified to ask: So i know that all the quarks have a job creating mesons and baryons. And i know the electron is a lepton with a very important job with the structure of an atom. But what is the importance of the muon, the tao, and all three nutrinoes...

Does anyone know any good book(s) about elementary particles?

Following is a summary from Chapter 20 of Leonard Susskind's 2008 book THE BLACK HOLE WAR: I'd appreciate any further insights, especially on interpreting what Susskind says about String theory as it was vague for me. These are not exact quotes. Elementary particles are usually imagined to be...

What does "collision" mean when dealing with elementary particles? Can someone point me to some online references that will get me started in understanding what is meant by a particle collision? The issues I don't understand- Leptons and quarks are supposed to be point particles. Do they...

Are there elementary, massive particles with zero spin? Thanks in advance.

Hi, could anyone please tell me equations 6.34 and 6.31 from Griffiths elementary particles book ( the new edition)? I need to do problem 6.5, I have the old book, and I can't make any connection. Can't find the new book either right now, and I need to do it by tomorrow.. Please help, i'd...

I was thinking about sitting in a course next quarter that used this textbook, and no prerequisites are listed, so I was wondering what kind of things should I know to get through the text. The thing I am most worried about is my knowledge of QM. I only know the little QM I have studied...

Any ideas here? For that matter, why should the spin of each particle always be the same? Or can we do no better than to say they do, and that its spin is a fundamental property of what defines each particle?

In Souriau's book of symplectic mechanics he describes an elementary dynamical system on which the Poincare group is dynamic and acts transitively. He then describes a massive particle with spin where the spin is some positive number. When we consider this particle in the presence of an external...

how many... till now how many elementary particles are disovered? what are bosons? what happens when fermions interact with bosons?

The Science Channel is running an hour program on the LHC. They make a statement that the pages and pages of equations that describe BBT don't actually work because they don't explain how the elementary particles get their mass. How does this criticism get addressed or is it actually true?

I am confused. I thought that the standard model included 6 quarks and 6 antiquarks, 6 leptons and 6 antileptons and 5 bosons (W+,W-,Z,photon,gluon). However in Griffith's "Introduction to Elementary Particles" (on page 48) he says that there are "12 leptons, 36 quarks, 12 mediators". I am...

Photons(light) follow the fermat's principle of least time...so do all elementary particles also follow fermat's principle of least time?..say electron,proton etc..

My question is stated in the title. I wonder is it that scientists are not able to explain the origin of magnetic moment of elementary particles and say that it's an intrinsic property just like mass.

The formulation of quantum theory does not comply with the notion of objective existence of elementary particles. Objective existence independent of observation implies the distinguishability of elementary particles. In other words: If elementary particles have an objective existence...

Hi! Although nobody can see the shape of elementary particles, we always assume that their shapes are symmetrical, for example, sphere. Why? Is the symmetry a law? Otherwise, are there any other reasons? Patrick

I need to find the electrostatic force & the number of elementary particles between two charged balloons held in the center of their strings (Think of an Isosceles Triangle). Homework Statement Mpurple(balloon) - .00354 kg Mred - .00405 kg Lpurple - .725 m Lred - .68 m θ = 16° T =...

My teacher told me that elementary particles don't have position. Well, I don't understand this; it's like an oxymoron to me. Anyone with a easy-to-understand explanation?

What exactly is electron spin and intrinsic spin of elementary particles.Any link teaching these concepts from scratch would also be appreciated . Thnx

The Background: I'm looking to put together a 40 minute talk on the group structure of elementary particles for a group of undergraduate mathematics students many of whom know little about group theory - sort of a math talk with a physics flavor (no pun intended). So the talk would include...

# It is said that atoms of elements of high atomic mass are unstable. So they emit alpha, beta or gamma rays. Suppose an atom emits alpha rays. The binding energy of alpha particle is about 27 MeV(million electron volt). It is said that as a result of this emission, the binding energy per...

By what means do scientists detect the presence of elementary particles? How do we know what we are looking at through these means of detection? Thanks

Supposing there are some most elementary particles which are not composed of subparticles, would these have any attributes? I mean "attributes of a particle" as something whose value i can determine by looking exclusively at that particle. For example, under this definition, "position" isn't...

He who has read paper Phys Rev. on "Dynamical Model of Elementary Particles" My question concerns the bound (collective) states from paper “Dynamical model of Elementary particles”. So the bound (collective) states are considered in chapter IV. I attach the file (extract from Y. Nambu and G...

Hey, If we use the Friedman Equation form to find time(excpected) for a given particle's Rest Mass energy as our input value, does it mean that the most energetic particles were 'born' first and the lighter particles 'born' later on in time in a linear, sequential order? eg. T quark...

How many elementary particles have been discovered.

Hi there. I'm currently writing an essay on the four fundamental forces of physics for my Advanced Higher course (an SQA qualification) but I got confused on a couple of issues: 1. what quarks make up protons and neutrons? 2. what's a gluon? 3. do neutrinos do anything at all except fly...

String and Tension When reading about string theory, the introductory notion seems to be that the tension in a string is what accounts for its properties, allocating it its mass, charge...However, what is it that causes the actual tension in the string? It is said that the graviton represents...