Take the 2-minute tour ×
Physics Stack Exchange is a question and answer site for active researchers, academics and students of physics. It's 100% free, no registration required.

The delta baryons (also called delta resonances) are a family of subatomic hadron particles which have the symbols $\Delta^{++}$, $\Delta^{+}$, $\Delta^{0}$, and $\Delta^{−}$ and electric charges +2, +1, 0 and −1 elementary charge respectively.

"existence of the $\Delta^{++}$, with its unusual +2 electric charge, was a crucial clue in the development of the quark model."

  • , three same quarks $\Delta^{++}=uuu$, and two electric charge, isn't it impossible?!.

  • Could the fractional model of Quarks electric charge turn out to be false? (leptons don't have fractional electric charge)

Here are some resources to help you quit smoking:

Quarks do not exist. Everything is made up of positrons and electrons

All real free particles have a charge of -1 , 0, +1 - only quarks have fractional charges which I find unncessary since all particles could be made up of whole charge positrions and electrons. Can anyone cite a particle that could not be made up of positrons/electrons and must be made up of 1/3 charge fraction quarks?"

Fractional Electric Charges were not proposed by QCD, but by the quark model, which came beforehand.

QCD offered a number of inconclusive predictions, such as Color Force and Fractional Electric Charges, Wrong. Fractional Electric Charges were not proposed by QCD, but by the quark model, which came beforehand.

On the breakdown of Quarks fractional electric charge values.

this "thought" that Quarks have a fractional electric charge values may not be true!. according to ahmad reza estakhr research in the field of QCD (Quantum Chromo Dynamics) three times the elementary charge (depending on flavor) Up, Charm and Top Quarks (called Up-Type Quarks) have electric charge of zero! 0 (Which means Up- Type Quarks are uncharged ), while Down, Strange and Bottom Quarks (called Down- Type Quarks) just Could have a electric charge of plus or minus one! (+1, -1) in estakhr's model down-type Quarks are results of electroweak interaction between charged leptons and anti leptons and Up-type Quarks, and this is the reason that Quarks do not have fractional electric charge values. Which means charge of hadron is not the sum of the charge of its constituent quarks, it is just sum of the charge of Down-Type Quarks..."

Nuclear Forces – part 2

In the early 1960’s when a physicist by the name of Murray Gell-Mann put forward the hypothesis for the existence of quarks, he speculated that the charge of an up quark was two thirds of a proton’s, and the down quark was one third of an electron’s charge. In this way a proton consisting of two ups and one down quark would have a charge of +2/3 +2/3 -1/3 = +1. The benefit of such fractional charges is that a neutron could then be said to consist of two downs and one up quark, giving it a net charge of -1/3 -1/3 +2/3 = 0; i.e. a neutral charge. I would suggest that this neutron model must surely be wrong. We know that a neutron decays into a proton and electron. For this model to be correct, it would require that a down quark transform itself into an up quark – changing both its charge type and strength from -1/3 to +2/3 – and that an electron essentially be produced from nowhere! Perhaps this is possible but a simple ‘neutron = proton + electron’ model seems far more likely...."

here is the solution:

If anyone can disprove the existence of three triplets of quarks for $u,u,u \neq \Delta^{++}$ or prove that $\Delta^{++}$ have electric charge of zero then fractional model of Quarks electric charge will breakdown!.

share|improve this question
6  
The up quark has a charge of +2/3 so three up quarks give the $\Delta^{++}$ a charge of +2. I'm not sure I understand your objection to this. The LHC demonstrates the existance of quarks every day. –  John Rennie Sep 22 '12 at 7:53
2  
Assuming my Googling found the correct page for your first reference (franklinhu.com/quarks.html) the author's claims are entirely unsupported by any form of quantitative calculation, unlike QCD calculations. –  John Rennie Sep 22 '12 at 8:01
4  
Shame I don't have 125 rep, otherwise I'd vote the question down. –  user12345 Sep 22 '12 at 10:11
3  
There isn't really a question here, so I'm tempted to delete it, but I'll hold off for now because the answers may contain some useful information. –  David Z Sep 22 '12 at 23:25
1  
I agree with David, this non-question has some astonishingly good answers which are interesting. –  Dilaton Sep 23 '12 at 0:22
show 2 more comments

closed as not a real question by David Z Sep 22 '12 at 23:24

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.If this question can be reworded to fit the rules in the help center, please edit the question.

2 Answers

up vote 6 down vote accepted

The "resources" linked in the post are bad. But there was a time when serious people were interested in the possibility that quarks have integer charges. Han and Nambu introduced the idea, Pati and Salam made a gauge theory of it, Witten suggested how to test it, and this was done at CERN in the 1980s (see page 11). There would be several ways in which the charge of the quarks can show up experimentally (but I don't know a good review), and to maintain the integer-charge theory now, you would need extra new physical effects to explain all the measurements consistent with fractional charge.

Psychological resistance to the idea of fractionally charged quarks probably has two sources: 1) fractions just feel unnatural 2) the quarks always combine into integer-charged hadrons. For 1), the pattern of charges in the standard model can be explained in grand unified theories. For 2), given these charges, the allowed color singlet states in QCD all have integer charge, since they are made of quark-antiquark and/or quark-quark-quark combinations, and those elements only have integer charge. But I feel there ought to be a deeper explanation for 2).

share|improve this answer
add comment

No, quarks couldn't turn out to be non-existent anymore. The evidence that quarks exist involves more than just some playful games in which we add electric charges to construct hadrons.

Quarks show up in many processes. Historically, the important experimental observation was that of the deep inelastic scattering. Much like Rutherford observed the nucleus because particles could get "totally reflect off something hard" rather than just mildly bend their trajectories, deep inelastic scattering showed that protons and neutrons have these "cores" or "nuclei", too.

Because there are 2 or 3 light flavors of quarks, up, down, and slightly heavier strange, one may combine them into many baryons. The lighest ones only contain up and down. It's easy to calculate the charges of up and down from the assumption that up-up-down and up-down-down are proton and neutron, respectively.

But these days, we are testing not just some "binary existence" of quarks. We are testing a whole theory that uses these quarks and predicts everything about their behavior – I mean at the LHC. Whenever quarks are produced, they combine into a shower of strongly interacting particles, the so-called jets, that are moving almost exactly in the same direction. One may literally find out which jets contain some exotic quarks such as the bottom quarks etc. In some sense, we are observing the quarks "really directly" today even though they can't exist in isolation. Quantum Chromodynamics (QCD), a part of the Standard model responsible for quarks and their interactions via gluons, predicts the probability of every process in which particles are processed and transformed or repelled in any way you may think of and all the predictions of QCD have agreed with experiments, usually better that at a 1% accuracy.

You may think that you have arguments to avoid the conclusion that quarks exist but it's only because you're not familiar with a sufficient amount of insights in physics. If you were trying to explain and predict what physicists actually have to explain and predict, you would see that every theory that denies the existence of quarks is born dead.

$uuu$ isn't quite impossible. Indeed, the particle $\Delta^{++}$ exists. It's a part of a decouplet of particles that have a different internal structure than the proton and neutron but they are still possible. They are routinely observed in particle experiments and their mass can be measured, so if your theory predicts that Delta-baryons don't exist, you should immediately abandon your theory, too. Otherwise you're not doing science.

share|improve this answer
2  
The (right) electric charge is an inseparable property of the quarks so everything I say applies to the quarks' electric charge too. –  Luboš Motl Sep 22 '12 at 8:34
2  
Neutron decay is just a down quark decaying into an up quark and a W$^-$ particle. Can you give a reference objecting to this interpretation - NB this would have to be a reference to a peer reviewed article to add any credibility to your arguments. –  John Rennie Sep 22 '12 at 10:04
4  
Dear muster-mark, what's exactly so exciting about the identity $-1/3=-1+2/3$? –  Luboš Motl Sep 22 '12 at 10:54
1  
Thanks for asking, muster-mark, fractional numbers are "decaying" to fractional numbers and integers all the time. What has to hold is the conservation of the charge and it does hold because the identity is true. If you have a problem to calculate with numbers such as $1/3$, I recommend you to enroll into an elementary school or kindergarten again. This server is not an appropriate place to learn how it's possible that $-1/3$ may be rewritten as $-1+2/3$. –  Luboš Motl Sep 22 '12 at 12:50
2  
A difference between our statements is that mine are based on the facts while you are making up yours, based on your misconceptions and emotions. For example, for my claim that fractions are taught at basic schools, see math.berkeley.edu/~wu/fractions2.pdf - Now, do you have a similar reference or evidence showing that in kindergartens, they are falsifying the quark model with fractional charges? ;-) –  Luboš Motl Sep 23 '12 at 7:36
show 7 more comments

Not the answer you're looking for? Browse other questions tagged or ask your own question.