Higgs ahoy!
The Higgs boson particle seems to have been discovered! But what is the Higgs and why was it predicted?
For every field, a boson
The current explanation of matter and space, the Standard Model, developed in the 1960s, is one of the most successful theories of all time (and space!).
It explains all the approximately 200 elementary particles that exist and how they interact with each other. Some of these particles, the Z and W vector bosons, were predicted by the model and subsequently produced in CERN in the 1980s. Their masses were predicted with 99.99% accuracy using the modification developed by Peter Higgs and others in 1964.
A major failing of the early Standard Model was that it could not predict the observed masses of these particles. Indeed, it seemed to predict that they would be massless, as if you and I were as solid as we in fact are but as light as ghosts. It also can’t explain dark energy and dark matter, which seem to make up about 90% of the universe. Their gravitational effect is evident but they can’t be observed.
The Higgs mechanism explained the masses of particles. In the 1960s, Higgs and others proposed that space is permeated by a field, the Higgs field, that clings to particles, giving them the property that we call mass.
Now, it is a truism in physics that for every field there is a particle called a boson, so it was predicted that there would be a Higgs boson. Bosons transmit the field, carrying some of its energy from one place to another. The prime example of this is the photon, and the discovery of its nature shows why physicists are so keen to discover other field bosons.
In the mid 19th century, building on the discoveries of Michael Faraday, James Clerk Maxwell showed that a changing magnetic field could induce an electric field and vice versa. And, crazily, when he multiplied the two constants associated with the electric and magnetic fields*, he got the speed of light!
This means that the electric and magnetic forces are not different but are aspects of each other. Changes in each are mediated by photons of light or, conversely, light is produced by changes in electromagnetic fields. This led to the discovery of many invisible forms of “light”, such as radio waves, microwaves, and X-rays, with an enormous influence on our lives.
This is an example of the unexpected consequences of much scientific research. Physicists are trying to repeat the triumph of Maxwell in uniting two forces and discovering the particles associated with the force field. This has already been done for the electromagnetic and weak forces, the particles transmitting the electroweak force being the W and Z vector bosons. So far, there has not been any influence on our lives from this unification, and there may not be, but we cannot know where a discovery may take us.
Why use a collider to hunt for the Higgs?
The electromagnetic (EM) force is very strong and infinite in extent: its associated particles, photons, are massless.
They are quite easy to produce and are therefore all around us. The weak force, though responsible for a type of radioactivity, is … weak! It’s about 7,000 times weaker than the EM force and only operates over a very short range — less than the diameter of a nucleus. Its bosons, W and Z, have a lot of mass, about 100 times a hydrogen atom, and they are very rare and short-lived. They can only be produced where there is a lot of energy, such as in a particle accelerator.
They were predicted back in 1968 and produced at CERN in 1983 in the Super Proton Synchrotron. Like the Large Hadron Collider, this smashed protons together at high speeds, converting them into pure energy, which then in a few cases “condensed” into W and Z bosons. These decayed into more stable particles in a characteristic way, enabling scientists to deduce their existence.
It wasn’t just luck that W and Z were discovered at CERN. The Higgs mechanism predicted particular masses for W and Z and it was only with the SPS that sufficient energies would be available to produce particles with these masses. CERN’s 1983 experiments were therefore a test for the Standard Model, which it passed.
The Higgs theory predicted a field and a particle, the Higgs boson. Predicting the mass of the Higgs was not straightforward but eventually most estimates settled on a value about 50% higher than the W and Z masses. Sufficient energy was not available from the SPS or from the Large Electron-Positron collider (LEP) that followed it. This had to wait for the construction of the Large Hadron Collider.
If a Higgs is produced, it is predicted to decay immediately into two Z particles, which will then decay into two muons each. These are easily detected because they behave like electrons, but 200 times heavier.
Both of the Higgs boson-hunting experiments at the LHC see a level of certainty in their data that is apparently worth calling a “discovery”. But they are not yet absolutely certain that what they have seen is a Higgs…
* then took the square root and divided the answer into 1. For those who want to try it themselves, c = 1/(?0?0), where ?0 = 4Ι x 10-7 and ?0 = 8.85 x 10-12. You should get c = 3 x 108 m/s approximately.
** Report on possible discovery of Higgs boson.
*** More: here.
Animation of production and decay of Higgs.
The CERN rap! Explains the LHC in verse.
Thatcher and the Higgs boson
Back in 1993, the Conservative Science Minister, William Waldegrave, challenged physicists to come up with an analogy for the Higgs mechanism.
Professor David Miller of UCL produced the following:
“Imagine a room full of Tory party workers. Mrs Thatcher walks in and the workers near her are attracted and cluster round her, giving her a greater ‘mass’ and making it more difficult to get her moving. The party workers are like the Higgs field.
“Now imagine a rumour passing through the room. The party workers cluster round the source and as the rumour passes the cluster also moves.
“Since the clustering gave Thatcher her ‘mass’, the clusters also have mass: they represent the Higgs boson.”
Rafter said,
July 5, 2012 at 10:29 am
There you are, they have agreed, found the glue that we are part of.God help his believers.Or, as they may say, from a particular wall, we did not radiate Yassar.
SteveH said,
July 5, 2012 at 2:56 pm
To Les if he’s listening
I have read that this could open up a whole new field of research but doesn’t this, albeit, important discovery just confirm what they already knew or believed?
Also from this I gather some field exists in the Universe that slows down particles, stops them flying off all over the place. How does this explain the existence of a human being?
Pinkie said,
July 5, 2012 at 8:44 pm
SteveH:
Eh? Isn’t that what science is about? ‘Confirming’ what is already ‘known’ or believed, that is. (Yes, I know it is rather more complicated than that, hence the quotes round ‘confirming’ and ‘known’.)
SteveH said,
July 6, 2012 at 8:46 am
Pinkie,
I saw a documentary about this a few years ago and it asked scientists to predict the likelihood of finding higgs and most said 9 out of 10.
My point is that the standard model already assumes the Higgs so I presume scientific enquiry already includes this in its analysis. This is why I wondered what new fields this confirmation opened, I would have assumed that if they believed the Higgs to be real they would already be working in these new fields.
I am not arguing that they shouldn’t have bothered!
Clive said,
July 6, 2012 at 12:14 pm
“How does this explain the existence of a human being?”
Obviously, beyond the fact that if matter and mass didn’t exist neither could people, it doesn’t.
Modernity's Ghost said,
July 6, 2012 at 3:25 pm
I suppose you can’t be too surprised that thick arse racists, like SteveH, can’t understand science or why it is important.
Surely, it naturally follows from their backward looking conservative outlook on society?
Monsuer Jelly est Formidable said,
July 6, 2012 at 3:36 pm
a taxi driver told me this higgs boson shite is bollox. must be true. isn’t it.
SteveH said,
July 6, 2012 at 4:11 pm
Oh sorry Professor Modernity! My questions were an attempt to understand what this experiment has achieved beyond the confirmation of already assumed theory. I was genuinely intrigued to know as many talking heads had made the point about new fields of research without bothering to explain further. Now I could guess that this confirmation allows scientists to discard avenues of theory that this experiment disprove but I would like to know how the confirmation of already assumed theory can open up new fields. I would expect scientists to be already working in these fields if the theory was already accepted. I won’t wait for an answer from you as I am 99.9999999999999% sure you are totally ignorant of the subject.
Are there no depths to which you will not sink in order to pursue your vendetta’s? What a desperate individual you are.
Clive said,
July 6, 2012 at 6:19 pm
My understanding is that although they think they’ve found the Higgs boson, it’s not quite what they were expecting. So it both confirms the Standard Model and opens up new questions.
I got this from, you know, reading a couple of newspaper reports.