The Higgs Boson and the Fundamental Nature of Reality – Sean Carroll

I am an avid viewer of science lectures especially those relating to cosmology, the origins of the universe and quantum mechanics. I found the above lecture by Sean Carroll engrossing and challenging; so much so, I felt compelled to write excerpts in an attempt to internalize the information.

Most of what is written below is verbatim, however some of the lecture is partially redacted to be more reader-friendly:

Trying to find evidence of the Higgs Boson

Not every piece of The Large Hadron Collider (LHC) is overwhelming in its size. This canister is where all the protons come from. The protons come from hydrogen which are shaken up to extract electrons and then fill up the LHC. There are 100’s of trillions of protons in the LHC at any one moment. This canister has enough protons in it to power the LHC for tens of billions of years. Effectively, the protons are smashed together and usually a whole bunch of particles we already know about are detected. The overwhelming majority of data is discarded. A trigger is used to look for interesting events. So there is a lot of effort put into isolating the signal from all the noise.

The Higgs Boson when immediately created instantly decays. The lifetime of a Higgs Boson is a Zeptosecond. You never see the Higgs Boson in the detector. They instantly decay into something else. And because it’s quantum mechanics you don’t know what it’s going to decay into, you can only discuss the probability.  You are looking for an excess number of events of a certain type. Trying to find the Higgs Boson is not like looking for a needle in a haystack, rather it’s analogous to looking for ‘hay’ in a haystack. You are looking for the statistical deviation from the predictable number of produced particles. It’s like trying to verify that there are a few more haystalks of a certain fixed length than you would ordinarily see given the statistics of haystacks.

Quantum Fields

What nature is made up of is fields. Quantum field theory is the central organising principle of modern physics. Quantum field theory is the reconciliation of special relativity with quantum mechanics. It is the best idea we have of understanding the world at a fundamental level. It might not be true. There might be better approximations, but it’s the best understanding we have now. There is absolutely no experiment which has ever been done on earth that even hints that Quantum field theory is not correct. A field doesn’t have a location. It exists everywhere. Particles have a location; and fields fill space.

The Iron filings in the image trace out the lines of the magnetic field. In between the magnet and the metal there is a field stretching out which you don’t see. The field is being affected by the magnet and the metal and they are being drawn to one another.

How does this ‘laser pointer’ know to fall down. It’s because there is a gravitational field. There is a field at every point in space such as the electric field, neutrino field, the up quark field. Quantum field theory tells you that everything is a wave in a field and when we observe vibrating fields we see particles. What ‘we’ see when we look at the world is much less than what there is. What there really is; are waves. But when we look at it we see particles.

Creating the Higg’s Boson anew

By colliding particles together you are not releasing Higgs Bosons. You are creating Higgs Boson’s anew for the very first time. How are we doing that? The quarks and gluons inside your proton are really vibrating waves and when they collide at high energy they start another vibrating wave and that wave becomes the Higgs Boson. A good example of the way this works is if you play a piano sufficiently loudly and there is another piano sitting next to you, the sound waves can reach the strings of the adjoining piano and they will begin to vibrate and resonate. So the fields between the strings are connected to one another. So that is the world as we understand right now. It contains a bunch of fields interacting with one another and transferring their energies back and forth.

The gluons are the particles of the strong nuclear force that hold the quarks together. They merge together to make a top quark which then emits a Higgs Boson and then decays into bottom quarks and bottom anti-quarks. What is really happening here is; these waves in the gluon field set up a wave in the top quark field which converts into a wave in the Higgs Boson field that in turn converts into the waves of the bottom quark field.
So now we have been able to complete the standard model of particle physics.

There are only 2 kinds of fields in nature: Fermions (such as electrons or quarks) and Bosons. They are matter fields and force fields respectively. The matter fields are the Fermions which have the simple property that they only vibrate a ‘fixed’ amount. Converted into ‘particle language’ this means: you can only have one particle in a given place at any one time. The reason this podium is solid and doesn’t collapse in on itself is because the electrons in the atoms that make up the plastic molecules in this podium ‘take up space’ because they are Fermions.
The Bosons fields can oscillate widely. So in particle language you can pile Bosons on top of each other.  Bosonic fields describe forces acting on and between the Fermions such as Gravitons. So these 2 kinds of particles make up everything we have ever observed in any experiment ever done.

So why do we need the Higg’s Boson in the standard model?

Without the Higgs field the standard model would make no sense.  What makes the Higgs field a different field to any other? Consider this scenario: So you go out into empty space in the interstellar vacuum where there is no radiation and no dark matter and you effectively make the minimum amount of energy you can have in a cubic centimeter of that empty space.

All the fields are set to zero. So if you have a magnetic field it has zero energy. If it’s not zero then it has to have some positive amount of energy. You need to put energy in, for the field value to increase. The difference between Higgs and other fields is it wants to be nonzero even in empty space, even at its lower energy configuration. If you were a particle traversing between galaxies you would be moving through the Higgs field. You would not be moving through the other fields because they are close to zero. Essentially, the Higgs field is everywhere and surrounds us all the time. The Higgs Boson particle is a little vibration in the Higgs field and it effects the behaviour of all other particles that are moving through it.

What would a Universe without the Higgs field be like?

There’s a big difference between a universe without a Higgs field and one with it.   Without the Higgs field elementary particles (like electrons and quarks) would be mass-less and move at the speed of light like other mass-less particles: photons and gravitons. Fortunately, electrons don’t move at the speed of light otherwise they would never get stuck to a nucleus and form an atom. The electron encounters the Higgs field as it moves through space which gives it some inertia and mass. Essentially the Higgs field makes particles of nature slow down; join together and form complex structures like you and me.  So without the Higgs there would be no chemistry, no life. An atom forms when an electron joins up with a nucleus and in turn the atoms join together to make molecules. With the Higgs we have a complete theory of the everyday world.

Food for thought

We do know that there are no new parts of nature that we haven’t already found which could exert a substantial influence over our everyday lives. There are no new particles of forces that could be relevant for everyday life that science hasn’t already found.
Could there be new forces of nature? Yes, but they would have to interact with protons, neutrons and electrons. So they would be very weak; weaker than a gravity and short range; like shorter than an atom.