Wednesday, April 10, 2013

Understanding the Higgs Boson

Using the Standard Model of quantum mechanics physicists have been able to predict many particles that most people haven't even heard of.  Most people don't know that there is something called a quark, let alone that there are six flavors of quarks (yes, flavors) top, bottom, up, down, strange, and charm.  The up and down quarks make up the protons and neutrons in the nucleus of atoms.  There is another particle that has been quite elusive to these physicists.  This particle called the Higgs Boson is thought to be what gives not only these small particles mass, but also everything else in the universe as well.  The problem with particles like this is that most people don't understand what the Higgs Boson is, how it was found, and most importantly what it means for the future in general.

Graphic Courtesy of The Register, UK.

History of the Higgs Boson.

The Higgs Boson get it's namesake from a Scottish physicist named Peter Higgs.  In 1964 he theorized that there is a particle that does give all others mass.  There are several others that also were theorizing a similar particle, but one group of them published their results a month later than Higgs published his.  In 1995 Fermilab in Chicago found the top quark which they found using their Tevatron particle collider.  This find was at least partially attributed to the Standard Model which incorporates the mechanism that Higgs theorized in 1964.  Prior to 2000 CERN was trying to find the Higgs Boson but was unsuccessful.  In 2000 CERN shut down their particle collider in order to upgrade it to the more powerful one they are currently using.  In 2008 CERN started using their upgraded particle collider to continue the search for the Higgs, but a gas leak forces them to shut down the collider until the following year.  The science community got excited over a possible find from Fermilab in 2010 that was later proved false, but in 2011 some findings were leaked from CERN that there could be a possible Higgs Boson find, but in February of 2012 CERN started accelerating the particles faster in order to increase the probability of finding the Higgs.  The science community had to wait until July 4, 2012 to hear an announcement that CERN had finally found a Higgs like particle (Overbye).  On March 14, 2013 CERN finally declared that they had in fact discovered the Higgs Boson, after almost fifty years of searching

What is a boson?

A boson is one of the two classes of elementary particles in particle physics.  A boson has an integer spin.  That is to say that a spin of 1/2 like that of it's counterpart the fermion isn't possible. A boson is governed by the Bose-Einstein Statistics which gives rise to super-fluidity (similar to what is seen in the liquid helium used to conduct heat away from the magnet in an MRI machine).  Another difference between bosons and the other elementary particle (fermions) is that there isn’t a limit to the number that can occupy the same quantum state.  Which is to say that in a given space, there could be an infinite amount of these bosons or very few, the same number of bosons could be in a teaspoon or in and Olympic size swimming pool.  It is this quality which makes a particle like the Higgs Boson so important.

Higgs Boson Vs. Higgs Field, What’s the difference?

When I started researching this topic more often than not what I heard about was the Higgs Boson, but in almost every source I looked at mentioned a “Higgs Field” I just kept wondering how these two were related at all.  It turns out that in this case the Higgs Boson is the smallest possible particle in a Higgs Field.  Think of it like water.  In a glass of water there are numerous molecules of H2O the smallest particle of water.  Similar to this the Higgs Boson is the particle of water and the water in the glass is the Higgs Field.  So by looking for one single Higgs Boson scientists can prove that the entire Higgs Field exists.  Scientists at CERN (The European Organization for Nuclear Research) used a Large Hadron Collider (LHC) to smash particles together in hopes of seeing a Higgs Boson like particle to prove the existence of this field.

Particle collision from CERN

How does the Higgs Field work?

There are numerous ways to describe how the Higgs Field interacts with particles to give them matter, and some of them are complicated, some don't make sense, and some are great analogies for how the field works.  Keeping in mind that no analogy is perfect, the following analogies are some of the easiest for me to understand.

Water and Sponges

For the sake of this argument imagine that the Higgs Field is a rainstorm.  There is not a way to escape the rain.  No matter how far you try to go, whether it's around the corner or to Pluto, you can't escape from it.  Now, all the particles in the universe are different kinds of sponges.  Some of them are very absorbent and have more mass, while others don't absorb very much water at all and have very little mass.  So, the particles that react with the Higgs Field more are the ones with the most mass, while other sponges don't react that much at all and have very little mass.

Confused yet?  Hopefully the next one helps.


Another way to look at the Higgs Field is to look at it as an infinite field of snow.  As in the last analogy you can't get away from it.  Particles that have very little mass, like a photon (particle of light), are like a person wearing skis.  They move very quickly over the snow because they don't react with it very much at all. Then there are particles that react with the Higgs snowfield a little bit more, like a person wearing snowshoes.  They move slower through the field and this have more mass.  The last image is that of a person sinking into the snow with no snowshoes or skis.  They move very slowly because they are reacting with the snow much more than someone with skis or snowshoes.
Hopefully by now it's starting to make much more sense, but in case it isn't clear just yet there's one more very common explanation that's even used by CERN itself!

The Party

One of the most common analogies used to teach students is an analogy of a celebrity arriving at a party (Organtini).  Since we're discussing particle physics let's say that our celebrity is a very influential physicist.  The physicist represents a particle in this analogy.  As our physicist arrives at the party the crowd is dispersed equally around the room, but when he enters the room people start to flock to him.  He has very little inertia originally (which is a characteristic of having mass) so he has very little mass.  As he moves through more the crowded room more and more people try to get through the crowd to talk to him and he gains inertia and is much harder to stop which is a characteristic of having a lot of mass.  By the time he reaches the opposite end of the room and stops it is much harder for him to get going again since he is reacting with an entire room full of people.

Why is it important to understand the Higgs Boson?

Dark Matter Halo around the Visible Galaxy

So some scientist in Europe found some particle that give every particle in the universe mass, so what?  That doesn't mean anything to most people.  We all just look at mass as something we all have and everything in the universe has it, so why do we care what causes it?  The universe is made up of matter, but eighty percent of it is invisible and is called Dark Matter.  We have almost no grasp of what dark matter is or what it can do, but the discovery of the Higgs Boson is an important first step to understanding Dark Matter (Grossman).  The Higgs Boson is also crucial to proving the Standard Model.  This model was first proposed over fifty years ago, and most of the particles that it theorized have been found.  The only particle that eluded detection was the Higgs Boson.  Now that it has been found it would seem that the Standard Model has been proven correct.  Another theory may have also been proven through the discovery of the Higgs Boson.  The theory of Supersymmetry may have also been proven correct.  This theory states that every particle has a "super partner" with slightly different properties.  Although as of now, scientists have only been able to find the Standard Model Higgs Boson and not it's super-symmetric partner.  Lastly, and possibly most important it validates the building of the LHC at CERN.  The super collider cost a pretty penny to build, with a price tag of $10 Billion.  Finding the Higgs Boson was one of the reasons this collider was built, and in less than five years CERN has already found it.  Just imagine what's to come next after the collider is fully upgraded when it is operational again.

Works Cited

Grossman, Lisa. "What Higgs Result Means For Dark Conspiracy." New Scientist 212.2844/2845 (2011): 8. Academic Search Elite. Web. 14 Apr. 2013.

Organtini, Giovanni. "Unveiling the Higgs Mechanism to Students. " IOP Science. European Journal of Physics, Web.

Overbye, Dennis. "All Signs Point to Higgs, but Scientific Certainty Is a Waiting Game." New York Times 5 Mar. 2013: D6(L). Biography In Context. Web. 14 Apr. 2013.