The quark model postulates that the hadrons such as protons and neutrons have an inner structure; quarks.

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What is the $t\bar{t}$ production supposed to bring up

The $t\bar{t}$ production, I've read, that will somehow confirm the QCD and might bring up new physics. Why are we studying $t\bar{t}$ production from $p-p$ collisions at the LHC? What are we trying ...
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129 views

Quarks and anti-quarks forming particles [duplicate]

As I know, when particles and anti-particles come close, they anihilate. So somthing caused me a big trouble : how can particle formed by quarks and anti-quarks can exist? I've just found some mesons ...
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159 views

Asymptotic Freedom - Qualitative Explanation

I am doing a (mostly qualitative) course on Particle Physics, and am confused about the concept of asymptotic freedom. The lecture notes basically say that a quark may experience no force/be "unbound" ...
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385 views

Baryon wave function symmetry

If a baryon wavefunction is $\Psi = \psi_{spatial} \psi_{colour} \psi_{flavour} \psi_{spin}$, and we consider the ground state (L=0) only. We know that the whole thing has to be antisymmetric under ...
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153 views

Why is a pion so light compared to a neutron or proton?

A pion is made out of a pair of up and/or down quarks. A neutron or proton is three up or down quarks. So naively I'd expect a pion to be about 2/3 the mass of a nucleon. In fact it's less than 1/6 ...
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271 views

Magnetic monopoles

I am a non-expert in this field, just have a layman's interest in the subject. Has anyone ever considered the possibility of magnetic monopoles (one positive and one negative charge) being confined ...
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358 views

Second baryon octet

Let's temporarily ignore spin. If 3 denotes the standard representation of SU(3), 1 the trivial rep, 8 the adjoint rep and 10 the symmetric cube then it's well-known that 3 x 3 x 3 = 1 + 8 + 8 + 10 ...
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How quark electric charge directly have been measured?

How quarks electric charge directly have been measured when quarks never directly observed in isolation? (Due to a phenomenon known as color confinement.)
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197 views

Facts About Quarks Electric Charge [duplicate]

Quarks have the unusual characteristic of having a fractional electric charge. here there is a new model that suggests maybe an up Quark has no electric charge and infact down Quark has electric ...
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77 views

What would be the effect of an excess of up quarks on stellar formation?

Suppose you had 80% up quarks, and only 20% down quarks. How would this affect stellar formation?
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So there are 6 quarks, what are anti-quarks considered then?

I just recently got into particle physics and the quantum world and I love it. So my first big question is. I watch all these videos and people explain the quarks (up, down, top, bottom, strange, ...
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Are quarks the limits? The end of the fundamental science. For collisions on more higher energies will lead to black holes after all?

Are quarks the limit and the Plank scale is believed to be the limit of distance when the very concept of space and length cease to exist (10^-19) Any attempt to research the existence of shorter ...
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Strong decays of baryons via quark-antiquark pairs

I have the doubly charmed $\Xi_{cc}^{++}$ consisting of ccu quarks. This is meant to decay via strong force, producing a light baryon (cud/uuc/udc etc...) and a quark-antiquark pair along with a ...
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Was the fractional model of quarks electric charge found before discovery of the $\Delta^{++}$?

From Wikipedia: Existence of the $\Delta^{++}$ , with its unusual +2 electric charge, was a crucial clue in the development of the quark model. the fractional model of Quarks electric charge was ...
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179 views

What is mass of free up and down Quark?

Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nuclei. Due to a phenomenon known as color confinement, quarks ...
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533 views

What IS Color Charge?

This question has been asked twice already, with very detailed answers. After reading those answers, I am left with one more question: what is color charge? It has nothing to do with colored light, ...
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What reason(s) exist to suppose that all degeneracy pressures can be overcome in Black-Hole formation?

In models of stellar collapse to a black hole, it is a given that density increases without bound towards a singularity. Electron degeneracy I get. Neutron degeneracy I get. I assume there's some ...
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1answer
147 views

A strange particle, $X$, decays in the following way: $X → π^– + p$. State what interaction is involved in this decay

A strange particle, $X$, decays in the following way: $X → π^– + p$. State what interaction is involved in this decay. I know the answer to be weak interaction, but why is it weak interaction? What ...
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Measuring nucleons using electron beams

sorry if the question is too elementary. From: The Britannica Guide to Particle Physics: The sizes of atoms, nuclei, and nucleons are measured by firing a beam of electrons at an appropriate target. ...
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Origin of lepton/quark generations?

What theoretical explanations exist for the fact that there are three generations of leptons and quarks? I'm not so much asking why there are exactly 3 generations, but rather what makes electron, ...
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About free quarks and confinement

I simply know that a single free quark does not exist. What is the reason that we can not get a free quark? If we can't get a free quark then what is single-top-quark?
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Why isn't Hydrogen's electron pulled into the nucleus? [duplicate]

Possible Duplicate: Why do electrons occupy the space around nuclei, and not collide with them? Why don’t electrons crash into the nuclei they “orbit”? From what I learned in chemistry, ...
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1answer
644 views

How does Delta baryon decay conserve angular momentum?

I'm a chemist so bear with me: I understand the Delta baryons $\Delta^{+}$ and $\Delta^{0}$ to be in some sense spin (and isospin) quartet states of the proton and neutron. These can decay straight ...
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$sss$ decay and violation of strangeness

Why can the hyperon $\Omega^{-}$ not decay by strong interaction? It seems that strangeness must be violated, but why is it the only way?
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451 views

Quark compositions in $\pi^+$ to $\pi^0$ pion decay

Pions can undergo a rare beta-like decay into leptons: Pion beta decay (with probability of about $10^{−8}$) into a neutral pion plus an electron and electron antineutrino (or for positive ...
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Cramer's rule, Origin of Quarks Fractional electric charge? [closed]

In linear algebra, Cramer's rule is an explicit formula for the solution of a system of linear equations with as many equations as unknowns. 2u+1d=1 1u+2d=0 $$a_1d+b_1u=c_1$$ $$a_2d+b_2u=c_2$$ ...
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Pion Decay and Fractional electric Charge disappeared, why?

Since the charged pions decay into two particles, a muon and a muon neutrino Fractional electric Charge disappeared, why? The decay proceeds by the weak interaction $W^{+}$ and can be visualized in ...
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Could the fractional model of Quarks electric charge turn out to be false? [closed]

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, ...
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402 views

What was the first discovery of the delta baryon $\Delta^{++}$?

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, ...
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526 views

What is the relationship between the Higgs field and quarks?

I have some difficulty considering the relative size of each and the meaning behind the shape of Higgs boson. I ask relating to the structures of both the Higgs field and quarks. How is it that the ...
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5answers
436 views

Could Quark model turn out to be false?

Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nuclei. Due to a phenomenon known as color confinement, quarks ...
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1answer
139 views

Relating theta_QCD to neutron EDM

How do I relate the topological $\theta_\text{QCD}$ parameter to the electric dipole moment (EDM) of the neutron? I am very familiar with chiral perturbation theory. I just need to know how to take ...
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Top quark production questions

I am just looking on the TopQuark production via proton antiproton collision and strong interaction. There seem to be three basic possibilities. $q + \bar q \rightarrow Gluon \rightarrow t +\bar t ...
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Quark Radius Upper Bound

If quarks had internal structure (contradicting current beliefs), what is the lowest upper bound on their "radius" based on current experimental results? If possible, I'd prefer to only consider ...
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Could quarks and leptons mix if they carried flavor charges?

If quarks and leptons carried flavor charges that differed across generations (as they do in some theories), then could mixing take place?
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If quarks didn't have mass, could protons (and neutrons) exist?

I read here (mass of a proton) that the mass of a proton is mostly (99%) due to the energy of the strong nuclear force which binds the quarks together, and not the actual mass of the quarks. My ...
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How can a pion have a mass, given it's a “field mediator” and created/destroyed continuously?

Maybe some of my assumptions here are basically wrong, but isn't it true that pion is the "mediator" for the strong force field. the quantum field theory basically says that there are no fields, ...
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Future of colliders and technical limitations

Are there any technical limitations (theoretical or technological) that prevent quark based colliders? ie. Colliding two quarks together.
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Could the Periodic Table have been done using group theory?

These three questions are phrased as alternative-history questions, but my real intent is to understand better how well different modeling approaches fit the phenomena they are used to describe; see 1 ...
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Is there a tb meson?

I was wandering around the particle date group page for meson and couldn't find a meson for top-bottom, which from symmetry you would expect. Q1: Is this because it hasn't been found? Q2: There is ...
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Particle mixing and indistinguishability

Neutral kaons have two flavor combinations: $\mathrm{d}\bar{\mathrm{s}}$ and $\mathrm{s}\bar{\mathrm{d}}$. They can also be weak eigenstates: $\mathrm{\frac{d\bar{s} \pm s\bar{d}}{\sqrt{2}}}$. But ...
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What is the interaction with Higgs field(s) that give the quarks so much different masses?

The masses of quarks are: mu 2∼3 MeV md 4∼6 MeV mc 1.3 GeV ms 80∼130 MeV mt 173 GeV mb 4∼5 GeV
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Neutrino oscillations versus CMK quark mixing

I wish to describe in simple but correct terms the analogy between the Cabibbo–Kobayashi–Maskawa (CMK) and Pontecorvo–Maki–Nakagawa–Sakata (PMNS) matrices. The CMK matrix describes the rotation ...
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Why do electron and proton have the same but opposite electric charge?

What is the explanation between equality of proton and electron charges (up to a sign)? This is connected to the gauge invariance and renormalization of charge is connected to the renormalization of ...
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260 views

What is meant by the rest energy of non-composite particle?

When talking about the rest energy of a composite particle such as a proton, part of the rest energy is accounted for by the internal kinetic energy of its constituent quarks. But what is physically ...
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What forms are theoretically predicted for orbitals or quarks in hadrons and of hadrons in tritium?

We all know very illustrative spatial representations of predicted electron orbitals in atoms which are essentially spatial plots of the solutions of wave equations. In all atoms the electrons occupy ...
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1answer
396 views

Why are the quarks so named?

Quarks have a variety of names (or flavours): Up Down Strange Charm Bottom or Beauty Top or Truth Why do they have such odd names?
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What is new with quark-Gluon Plasma and the bubble formed at RHIC?

RHIC experiment results of forming Quark-Gluon Plasma and a possible bubble was news few months ago. I cannot find any follow up news after that. Does anybody know anything new in this front? I am ...
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What are quarks made of?

So atoms are formed from protons and neutrons, which are formed from quarks. But where do these quarks come from? What makes them?
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Can quark-gluon plasma ever be close to an ideal gas of asymptotically free quarks?

The question inspired by an upcoming colloquim at UCB. A naive interpretation of quark asymptotic freedom seems to imply that at high enough energies they should be weakly interacting. On the other ...