The Higgs Field

[little_monkey]

The Standard Model unifies the nuclear, electromagnetic, and weak forces and enumerates the fundamental building blocks of the universe:

6 leptons: electron, electron neutrino, muon, muon neutrino, tau, tau neutrino
6 quarks: d (down), u (up), s (strange), c (charm), b (bottom), t (top)
Each of these has half-integral spin (called fermions) and each has an anti-particle equivalent.

12 Bosons(integral spin): 8 gluons (nuclear force), photon (electromagnetic force), W+, W- and Z bosons (weak force).

The model also has serious flaws--it does not account for gravity, does not explain or predict the masses of the various particles, and requires a number of parameters to be measured and inserted into the theory.

According to the Standard Model, the vacuum in which all particle interactions take place is not actually empty, but is instead filled with a condensate of Higgs particles. The quarks, leptons, and W and Z bosons continuously collide with these Higgs particles as they travel through the "vacuum". The Higgs condensate acts like molasses and slows down anything that interacts with it. The stronger the interactions between the particles and the Higgs condensate are, the heavier the particles become.

Quantum electrodynamics requires the photon to have zero mass, but early attempts to develop an electroweak theory required the bosons to be massless, which is bad because then they would be as abundant as the photons in the universe, which indeed they are not. Peter Higgs and other researchers (who worked independently of Higgs) came across the same idea for settling the puzzle. If there is an otherwise undetectable field filling the universe (now called the Higgs field), it could have associated with it a previously unknown kind of boson, the Higgs particle, which has mass. This would allow any photon-like particle to become massive by swallowing up a Higgs boson. It is thought that all-massive particles get their mass this way.

Some of the questions that the Large Hadron Collider (LHC) will attempt to answer are:
How many kinds (flavors) of Higgs bosons are there? And what are their masses?

Link: strings of ideas: 11/06/2005 - 11/13/2005

[darkendless]

Originally Posted by little_monkey

The Standard Model unifies the nuclear, electromagnetic, and weak forces and enumerates the fundamental building blocks of the universe:

This is a little confusing, i do not understand how you can unify intermolecular and atomic forces. They are different for a reason as they represent actions and reactions between different spectrums of particles?

[little_monkey]

Originally Posted by darkendless

This is a little confusing, i do not understand how you can unify intermolecular and atomic forces. They are different for a reason as they represent actions and reactions between different spectrums of particles?

In quantum field theory, the word "force" is replaced by the word "interaction". It is the nature of that interaction that defines what kind of force is at play. For example, whenever there is an electric field or magnetic field in action, photons are the particles which interact between the two charged bodies. Therefore, any exchange of photons is a display of the electromagnetic force. This is the force that acts between molecules and atoms.

In the nucleus, there are two forces, called the weak nuclear force and the strong nuclear force. Those two played very little at the atomic or molecular level. The weak force involve the W+, W- and Z bosons; and the strong force, the gluons of which there are 8 of them.

The theory that expains the behavior of the electromagnetic force is called quantum electrodynamics, or QED.

The theory that expains the behavior of the strong nuclear force is called quantum chronodynamics, or QCD.

The theory that expains the behavior of the weak nuclear force is called the Weinberg-Salam-Glashow theory of the electro-weak force.

These three theories are lumped together into what is called the Standard Model, the reason being is that these three forces can be represented as interactions mediated by the exchange of a type of particle(s).

Notice that gravity is not part of the Standard Model. And presently, a lot of work is done in research to bring that force under the same mathematical pattern -- that is, as an interaction of particles called gravitons. Those particles have yet to be discovered in labs. And the theory has not been succesful. In fact, there are two competing theories: one called Superstring; and the other, quantum loop gravity.

So for the forces, the particles involved are the photon; the W+, W- and Z bosons; and the 8 gluons. (a total of 12)

For matter, the particles are the 6 quarks -- they make up the protons, the neutrons and other heavier particles; and the 6 leptons -- the electron belonging in that category. (a total of 12)

[Troublemane]

Another possiblity is "Photonics Theory", an obscure concept tossed around in the late 70's. The idea there is that all particles are actually made up of photons that have curved back on themselves, and are locked into circular "standing-wave" type orbits. The photon is actually made up of two mutually dependant waves that collapse and expand synchronously--a magnetic field and an electric field---at right angles to each other. Photonic theory suggests that when a photon of sufficient energy (gamma ray frequency) encounters another photon of the same energy and they pass through each other at a certain angle, they curl back on themselves by electromagnetic induction and get locked into a circular standing wave, which turns out to be the diameter of an electron.---(one becomes an electron and the other photon becomes a positron). This has been done in the lab, and the reverse is also true--when an electron and positron are combined they annihilate each other into photonic energy equal to the original two gamma rays.

There were problems with photonic theory, however, as the proponents tried to argue gravity could be explained through electromagnetic resonance, but the fans of einstein cried foul, so the theory kinda died on the vine. I still think its fascinating though, and kinda goes in line with einsteins famous E=MC^2

[Troublemane]

OH and twistor theory is pretty kewl too. Roger Penrose is awesome.

[little_monkey]

Originally Posted by Troublemane

Another possiblity is "Photonics Theory", an obscure concept tossed around in the late 70's. The idea there is that all particles are actually made up of photons that have curved back on themselves, and are locked into circular "standing-wave" type orbits. The photon is actually made up of two mutually dependant waves that collapse and expand synchronously--a magnetic field and an electric field---at right angles to each other. Photonic theory suggests that when a photon of sufficient energy (gamma ray frequency) encounters another photon of the same energy and they pass through each other at a certain angle, they curl back on themselves by electromagnetic induction and get locked into a circular standing wave, which turns out to be the diameter of an electron.---(one becomes an electron and the other photon becomes a positron). This has been done in the lab, and the reverse is also true--when an electron and positron are combined they annihilate each other into photonic energy equal to the original two gamma rays.

There were problems with photonic theory, however, as the proponents tried to argue gravity could be explained through electromagnetic resonance, but the fans of einstein cried foul, so the theory kinda died on the vine. I still think its fascinating though, and kinda goes in line with einsteins famous E=MC^2

I don't know about this theory, so it would be hard for me to comment on it. But I'm fairly steep into quantum field theory. And QFT is the only theory on the market that I am aware, which can deal consistently with the myriads of nuclear reactions that have been observed in labs.

Here are some examples



n0 → p+ + e− + νe

Ω− → Λ0 + K−

Λ0 → p+ + π−

[little_monkey]

"International scientists working at an underground complex started up a huge particle-smashing machine on Wednesday aiming to recreate the conditions of the "Big Bang" that created the universe.
Experts say it is the largest scientific experiment in human history and the Large Hadron Collider (LHC) is the biggest and most complex machine ever made."

link Scientists send first beam round particle-smasher | U.S. | Reuters

This is a period of great excitement in the physics world as the LHC is about to get functional. Here’s why.

i) One of the theorems of the Standard Model (SM) is that the number of quark families is equal to the number of lepton families, which they are at the moment – each being equal to 3 families, each family containing two particles. So, presently the SM contains 6 leptons and six quarks.

But suppose that another, new lepton is found?!? It would mean a new family of leptons has been discovered. The consequence would then be to find its partner to complete the family AND the two quarks of the corresponding new family. Because of symmetry, these new particles (4 so far) would have their anti-particle partners, thus automatically doubling the number of new particles to 8. So finding one single new lepton would trigger the search of seven more.

ii) Supersymmetry (SUSY) is a theory crucial to String Theory (ST), Grand Unifying Theories (GUT’s) and in cosmology. Now all particles fall into two broad categories: fermions, with half-integral spins, constitute the building blocks of matter; bosons, with integral spins, mediate the force between particles of matter. SUSY postulates that for every boson there is a fermion, and vice-versa. For example, the electron, a fermion with ½ spin, would have a partner dubbed the selectron with spin 0. The photon, a boson with spin 1, would have as its partner, the photino with spin ½.

If any of these are discovered, we wouldn’t know what their use is for, perhaps they might make up Dark matter or Dark energy, but that’s just a guess.

iii) The Higgs boson is crucial to SM. Here’s why. Back in the 1930’s, when people were working on quantum field theory (QFT), they were faced with a theory riddled with infinities. Dirac was the first one to work around by introducing what is called a Lagrange multiplier – a fancy name but technically is very simple, it’s just a constant. The trick is, instead of performing an integration which gives the infinity, one plugs in a constant, does the integration, which now doesn’t go to infinity, then removes the constant. It turns out this made QFT a theory of the real world, but most physicists, including Dirac, were highly unsatisfied with this math trick. Feynman was able to do the same by using graphs and looking at the path integrals by considering all possibilities. When this was applied to the electromagnetic force, quantum electrodynamics (QED) became the most precise theory on this planet.

However, this trick only works because the photon, the particle that mediates the electromagnetic force, is massless. In the weak and strong nuclear forces, the bosons have masses. When that is taken into consideration, the infinities reappear.

Higgs was able to work around this by proposing that these bosons acquire their masses by a process called spontaneous symmetry breaking – a fancy name, but it is just another math trick. The analogy is the particle on a hill. It is at rest and every direction is equal (the symmetry) But once it’s nudged, it will roll down the hill. By choosing a direction, it has broken the symmetry. In the SM, the massless boson acquires mass – that is, breaks the symmetry – by traveling through a Higgs field.

By adopting this scheme, called the Higgs mechanism, Weinberg and Salam were able to get rid of the infinities that plagued SM. So the Higgs particle is a must for SM to be validated.

iv) If no discovery of new particles takes place, then this would be just as intriguing. No SUSY particles means String Theory is in trouble; no Higgs boson, and SM would be on very shaky ground.

And so, the bets are on. Will the LHC confirm SM, SUSY and ST, or throw a monkey wrench into any of these theories???