Theories depend on finding of particles that can’t be seen

Ken Tapping's weekly astrophysics column from DRAO Herzberg Institute

We can start with a lump of anything; but let’s start with something that is very Canadian – ice. Let’s assume it’s the real late January stuff, solidly frozen to about -20 degrees Celsius.  Being frozen water, ice is a chemical compound with molecules each consisting of two hydrogen atoms and one oxygen atom – H2O.  We put our sample in a closed vessel, and apply heat, and keep applying it.

When we reach 0 degrees Celsius, the ice melts and we have liquid water. Then, around 100 degrees Celsius, depending upon our altitude, the water boils and we have steam, a gas. When we reach around 2,500 degrees, the water molecules themselves start to come apart, and we have a mixture of oxygen and hydrogen.

Atoms consist of two main parts: a nucleus, which is surrounded by a cloud of electrons. As the temperature continues to rise, from tens of thousands of degrees to millions, the atoms start to lose their electrons, and the vessel contains a very hot mixture of naked nuclei and electrons. Then, the nuclei themselves disintegrate, yielding a soup of protons, neutrons and electrons. We keep applying the heat, and when we reach temperatures of billions of degrees and higher, the protons and neutrons start to come apart, yielding a mixture of the fundamental building blocks of matter.  Many years of research into the fundamental nature of matter has culminated in what has become known as the Standard Model, which states that the fundamental building blocks of matter are things called quarks, leptons, gluons, two types of boson, and photons.  However, in 1964, Peter Higgs and several other physicists suggested that the Standard Model as stated would not work, and another fundamental particle is needed, which eventually became known as the Higgs Boson. However, it could not be found.

This was a major problem, because so much of physics depends upon the validity of the Standard Model.  So the searches continued. The big problem is that digging so deeply into the fundamental nature of matter requires extremely high energies.  We have no capability to apply such energies as heat, but we can do it through collisions. The culmination of this line of research is the Large Hadron Collider, located near Geneva, Switzerland. This works by accelerating protons to as close as possible to the speed of light, then colliding them head-on into similarly accelerated protons going in the opposite direction.

The problem is that many important properties of the Higgs Boson could not be calculated beforehand, so the search was done in a rather different way. Experiments were designed so that the results that would be obtained if there were no Higgs could be predicted. Then the results were compared with the predictions and discrepancies noted. The properties of the particle needed to cause the discrepancies were then compared with what is expected from the Higgs Boson. After a string of positive results, we can conclude that the Higgs Boson has been found, the Standard Model still stands, and physics is safe for a little longer.

Mars and Saturn are now getting low in the west after dark.  Venus and Jupiter lie close together in the eastern sky in the early hours before dawn. The Moon will reach first quarter on the 25th.

Ken Tapping is an astronomer with the National Research Council’s Dominion Radio Astro-physical Observatory, Penticton.