Quarks Definition and 258 Threads

I'm curious about the nature of the evidence for three quarks -- two up and one down -- in the proton. I assume the data is derived from high energy scattering experiments, and looking at the angles and momenta of the scattered particles. But I don't see how, from such experiments, one can say...

Homework Statement What particle(s) does the weak force affect? I think it's electrons but my teacher thought it was quarks since the range of the weak force is <0.003 fm.

How does the exchange of gluons between quarks "bind" them together?

In my A-level Physics course we have been talking about nuclear decay. When an nucleus decays by beta emission the proton number increases. My teacher described a neutron as "an electron and a proton" so that the overall charge is 0. To me this sounds like a simplification. what's really going...

I've been banging my head against the wall for days now trying to figure out how one determines the number of quarks inside the nucleon. I understand it comes from the fact that the Gross-Llewellyn-Smith sum rule is equal to three: \int ^1 _0 F_3 ^N (x) = \int ^1 _0 (u_V (x) + d_V (x)) =...

When you see these particle collider experiments that have confirmed the existence of the various types of quarks, then these experiments are displaying those quarks briefly before they disappear. So what's actually happening to the quarks when they disappear? Are they decaying? If so, then what...

Using electron-neutron scattering I'm trying to find out how the three quarks (udd) behave inside the neutron. S.Kopeky (Phys. Rev. 1995) found that for small Q2 the equation for the neutrons rms-radius goes towards: -6 \hbar \frac{dG_E ^n (Q^2)}{dQ^2} \right|_{Q^2=0} = -0.113 \pm 0.005...

It is clear that the mass of the valence quarks is only a small fraction of the mass of the hadrons (for example, the proton). However, I wonder if it would be possible to get massive protons in QCD if the quarks were truly massless. On one hand, for massless quarks, the pions, as...

hey guys, I am a first year physics student but my physics lecturer invited me to sit in during her third year physics lecture. Of course i didnt fully understand some of it, but i think i at least grasped the concept of confinement (the lecture was on quantum chromodynamics by the way)...

Hi: I have heard that It was found at SLAC that the nucleons are made of 3 quarks, how did they found that if quarks can not be isolated?, and by the way, how do you detect those quarks if they can not be found free in nature? Regards

the colors of the quarks! can anybody tell me if the colors of the quarks does really exist (( green , blue , red)) ((anti green, anti blue, anti red ))) or it is just a way to avoid the exclusion principle?? and they are fermions means they can not exist in the same state and have half...

Can anyone please explain to me how quarks are the fundamental representation of SU(3)? Why is a proton exactly uud and not another combination of quarks? What is a multiplet? Thank you for answers :)

We have seen nuclear power when atoms split. Could it be ..the day we split the proton is the day we end our own world? I just hope E=mc^2 holds. :smile:

According to my notes "any pair of similar quarks must be in identical spin states". What is the reason for this?

How was the charge of up/down quarks determined?

hey i am having a problem problem with understanding the difference between the parton model for the structure of the atom proposed by Richard Feynman and the quark structure... it would be really helpful if someone could give me good links where both of the them are explained in a simple...

Hi I have just started an intro physics course - it has very little maths, explaining as much as possible in words. I am having trouble with understanding the relationship between colour charges and quarks and how they are formed to create hadrons. I understand that the colour charge...

Forgive me if this is a noob question. I know there are no perfectly rigid bodies so that if you had a light-year long rod and pushed it, the other end would not move immediately because if it could, then information could be transmitted FTL. But, what if you pushed on a quark in the same...

Does anyone believe that there are only three generations of leptons and quarks and that higher generations will not be found? I'm curious about people's opinions on this subject. If you believe that higher generations are going to be found why do you believe so, and if you don't believe that...

Quarks are smaller then electrons? I read that when a electron moves from a higher energy level orbit to a lower energy level orbit it emits a "real" quark... So are other quarks virtual?

When one of the quarks was discovered, I was in high school, and I said quarks are not spherical balls of mass. How could nucleons also be spheres if 3 quarks make up a nucleon?! I said atomic and subatomic particles have a poorly defined shape and something of a lack of material substance...

At what point does an atom cross an international border, and can it exist on the cusp, not in either country? I would say that the border, not being a material object as such, is infinitesimally thin. So the atom can't possibly be as thin as the border, therefore there will be a time at...

I've been doing some reading on QCD, and I keep running into the notion of "massless quarks". Are they massless in the sense that if you look at E = \pm \sqrt{p^2 + m^2} the p^2 term dominates and E \sim p or is this something completely different?

I was intrigued by this paper, and apparent implications for Smolin's cosmic natural selection [CNS] conjecture. http://arxiv.org/abs/astro-ph/0609644 Observational constraints on quarks in neutron stars Authors: Pan Nana, Zheng Xiaoping Comments: 16 pages,6 figures We estimate the...

I have been wondering something. Assuming strange quark stars exist (and I know that this is still too early to call), is it possible that a black hole might just be an overgrown quark star that has gone over the required mass (say from feeding on a nearby star or a collision)? Is there any...

Are we even near finding anything smaller than quarks or what quarks are made of?

I am wondering how to calculate how far a neutrino would have to pass through a substance for it to have a probability P of interacting at least once. Water, for instance, has a density of 1 g / cm^3; using Avogadro's number I think this means that there is about 6.02 x 10^29 protons and/or...

Hello, Here I go again :-p I don't understand a few things, let me all questions put in a paragraph so that I don't miss anything What is an energy? (I can't understand the definition provided by the encyclopedia) And, what's up with the vacuum energy? If no particles are there, how can energy...

Hello, I just got into the particle physics and so I met the first problem. Scientists claim that they had discovered higher generation quarks in the colliders but: If quarks are fundamental particles, and all the matter in our universe is only based upon up and down quarks, how 2nd and 3rd...

This appears to be a rather useful overview of the history of high energy/particle physics. I glanced through it quickly, but can someone who is more familiar with this field of study verify that there's nothing obviously erroneous with this? If there isn't, this could be a very good intro to...

I am to find the ratio of the gravitational PE to the Coulomb PE between a t and a \bar{t} quark I don't know what a \bar{t} quark is, but I am guessing that it is a quark that has a charge opposite of that of the t quark? I am given that the charges are +/- \frac{2}{3} e and that the...

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...

example: 2 protons collide and a down-antidown quark pair is created, giving a pi-plus meson, a neutron and a proton. with all those quarks knocking around, are there specific rules saying which particles are formed from them? like, what stops there being a pi-zero meson and 2 protons? or any...

I noticed a peculilarity today. I found a big chart on Wikipedia with a bunch of little particles on it. You can find it here: http://upload.wikimedia.org/wikipedia/en/4/4c/Particle_chart.jpg So anyways. According to the chart, a proton is composed of two up quarks and one down quark. Also...

why is it that the pion with no charge (the one with the 0 in the top corner) actually exists? cos if it's made of an up anti-up or a down anti-down quark, shouldn't they annihilate each other?

hi all. I am new, and am bursting with questions about everything. I've always been interested in quantum physics, however, have never had enough knowledge to do anything about it. But I am in high school! :smile: and after getting bored in our energy and machines physics course, i decided to do...

I'm new to quantium physics but taking an interesting and trying to read more every day. I have a bit of a silly questions - in particle accelerators when collisions with protons or neutrons free quarks, what is the ultimate fate of the free quarks? It's my understanding that a quark isn't...

I'm obviously not going to ask how many strings there are in the universe. :wink: my question. To each quark how many strings are there? Just one unique one? Billions and Billions? Also does Brian Greene's book. "The Elegant Universe: Superstrings, Hidden Dimensions, and the Quest for...

Could someone tell me if the quark has been experimentally proved to exist? I mean in a particle accelerator. Or indirectly inferred.

As far as I've heard, there are 6 "flavors" of quarks, which are divided up into three "colors". There are also antiquarks. So this means thet there's a total of 6*3= 36 quarks. Do all of these quarks have a name? just wondering. :smile: :smile: :mad: :approve: :bugeye: :-p *...

I've been trying to research this area but there doesn't seem to be much out there. Does anyone know of any evidence or theory showing that quarks and leptons are or are not fundamental? I have heard of String Theory but does string theory actually suggest that quarks and leptons are made...

Anyone wants to learn how to calculate with quarks ? Please consult following site ... http://home.hetnet.nl/~inthepicture/quarks/ regards marlon

Neutrons and protons consist of quarks right? my question is ;has anyone theory as to how are they aranged inside of protons/neutrons?. one orbits another or whatever?

the way i understand quarks is that they have mass, yet no physical extensions of any kind. how is this possible?

Under what circumstances could the colour force ( or the strong residual force) become repulsive between quarks? I've heard that changing the spin of a force carrier can in principle make a force repulsive when it was previously attractive.If gluons exchanged between quarks became fermions with...

why do models show pentaquark structures have 4 quarks and an anti-quark, why can't it be just five quarks?

List of reccomended reading for string theory includes- 'A Proposal About the Rest Masses of Quarks' by Jiao Lin Xu Using String Theory the rest mass of quarks is given as- u=930, d=930, s=1110, c=2270, b=5530 The average rest mass of the figures given by the (international) Particle...

If Christoph Schiller is right about the maximum force in nature being 10^ 45 Newtons (c^4 / 4G) then if quarks have a radius and are not point like this would mean (assuming a quark is spherical and made of partial electric charges on the surface of the sphere) that the minimum size a...

If we can learn to accept that Quarks and Leptons are the remnants of the six missing dimensions as described in the M-Theory, our understanding and knowledge of the GUT would increase exponentially. Accepting the concept that Quarks are the missing six dimensions automatically solves several...

If we can learn to accept that Quarks and Leptons are the remnants of the six missing dimensions as described in the M-Theory, our understanding and knowledge of the GUT would increase exponentially. Accepting the concept that Quarks are the missing six dimensions automatically solves several...