Econintersect: Okay, the play on words (boson, boss, bozo) is a rather far stretch, but since it is likely that 99% of the world doesn’t have the foggiest what a boson is we’ll go for it. After all, it did attract your attention and got you to read this far, right?
On 04 July 2012 scientists at the CERN gigantic cyclotron (Large Hadron Collider) research center near Geneva announced that a new physical particle has been detected “with statistical certainty.” The new particle is being hailed as the long-sought Higgs boson, but there remains a possibility that the discovery could rather be a totally new particle which would require an entirely new theory about the fundamental structure of matter. There is also a calculatable probability that nothing was discovered at all and the event was merely a statistical fluctuation.
Caption graphic (Click for larger image): This image made available by CERN shows a typical candidate event including two high-energy photons whose energy (depicted by red towers) is measured in the CMS electromagnetic calorimeter. The yellow lines are the measured tracks of other particles produced in the collision. The pale blue volume shows the CMS crystal calorimeter barrel. CERN/AP
Follow up:This is all a pretty heavy discussion for the non-scientific layman. Heck, it is pretty heavy stuff for those with PhDs in just about any science other than particle physics. However, it has those “in the know” pretty excited. From Reuters:
Joe Incandela, spokesman for one of the two teams hunting for the Higgs particle told an audience at CERN near Geneva: "This is a preliminary result, but we think it's very strong and very solid."
The Higgs particle, although crucial for understanding how the universe was formed, remains theoretical. It explains how particles clumped together to form stars, planets and even life.
What is A Boson?
Because of our estimate of ignorance let’s step back and start with the definition of a boson from Wikipedia:
In particle physics, Boson is a subatomic particle with integer spin (i.e., angular momentum in quantum-mechanical units of 0, 1, etc.) that is governed by Bose-Einstein statistics. The name boson is derived from the surname of the Indian physicist, Satyendra Nath Bose, a contemporary of the German physicist Albert Einstein. Bosons include mesons (e.g., pions and kaons), nuclei of even mass number (e.g., helium-4), and the particles required to embody the fields of quantum field theory (e.g., photons and gluons).
Wow! And that is from a layman’s reference!!
So, our brief summary would be that bosons are one of two classes of subatomic articles that all have integer spins, which distinguishes them from another set of particles (fermions) which all have half integer spins. Particle spin is one of the energy defining parameters that comes out of quantum mechanical theory.
Most bosons are compound particles; there are six elementary bosons divided into three groups. From Wikipedia:
… in the Standard Model, there are six bosons which are elementary:
We will have more about the Higgs boson later.
Note: Satyendra Nath Bose was one of the greatest physicists of the 20th century and should be on anybody’s short list of those who never received a Nobel Prize but should have.
Bosons obey a set of statistical and physical rules which differ from the other set of elementary particles known as fermions. Fermions are such familiar things as electrons, protons and neutrons. The latter two are actually compound particles. One of the key differences between bosons and fermions is that the latter obey what is known as the Pauli Exclusion Principle, a term that should be familiar to anyone who has taken freshman level college chemistry. In essence, Pauli said that two fermion particles cannot simultaneously occupy the same quantum state, which is defined by a physical location in space and a unique set of quantum energy definitions.
Shown is one section of the 17 mile long tunnel housing the Large Hadron Collider that is located in a bif circle buried at a depth varying up to 574 feet. Additional facts and figures available here.
So What Then is The Higgs Boson?
The criticality of the Higgs boson is that it, and it alone, is necessary to account for the existence of mass which is fundamental to the existence of matter. Without the Higgs boson the Standard Model has only energy and no matter. If the new particle detected is indeed the Higgs boson then the Standard Model of particle interaction moves a giant step toward becoming the “Standard Theory” of matter, or as some have called it the “theory of almost everything”. Because the Higgs boson is the last remaining unproven part of the Standard Model, it has been nicknamed the “God particle” because it has the ability to “explain almost everything.”
Many physicists, including Higgs himself, have protested the use of the term “God particle.”
Note: Peter Higgs, who is still alive and attended the 04 July announcement of the detection of what could be “his particle”, could be a leading candidate for the 2012 Nobel Prize in Physics.
What is Being Said in the Media
An article in The Washington Post gave a good summary of what has happened:
The Higgs — famously dubbed “the God particle,” to the chagrin of scientists — is so fundamental to the universe that, in its absence, nothing could exist. The particle is thought to create a sort of force field that permeates the cosmos and imbues other particles with the property known as mass — the resistance to being shoved around.
Actively hunted since the 1970s, the Higgs is the final major piece of the Standard Model, which for physics is the equivalent of chemistry’s periodic table.
However, the new discovery is not an absolute proof of anything. Physicist Victor Stenger discussed potential flaws in the experiment, as well as reasons why we might still have confidence in the result, in the Huffington Post:
Several observers have pointed out a flaw, which is known in the literature as "sampling to a foregone conclusion." That is, the experimenters keep collecting data until the reach the level, in this case 5-sigma, where they then can reject the null hypothesis. The proper method according to the experts is to decide ahead of time what criterion you will use and also how much data you will take before rejecting the null hypothesis. Since that is not generally done, it is technically illegitimate to interpret the result as a probability.
But it's the method we have used in particle physics for half-century and, so far, it has not resulted in any major discovery claim being later proven to be in error. Furthermore, in my experience I saw many 3-sigma bumps go away as more data were accumulated. In any case, physicists no longer leave it just at that. They perform sophisticated Monte Carlo computer simulations of the experiment using their best available models and compare results with (signal plus background) and without (background only) the assumed signal. This was a major activity of mine when I was in research.
Stenger also points out that assumptions made about the normal distribution of fluctuations in the physical world may not be a good one. That is something that has brought others to grief, such as investors and economists. Nicholas Taleb has written a book about the occurrence of things that “couldn’t happen” in his book “The Black Swan.”
Some Perspective on Probability
One of the most difficult concepts is the probabilistic nature of this "discovery." The 5-sigma threshold used in the analysis is not absolute, but has about one chance in 3.5 million of being wrong. That would be equivalent to saying a disease does not exist because only 2,000 people have it currently. That amounts to less than 1 out of 3.5 million.
Maybe the threshold should be 6-sigma, a common quality objective in manufacturing and other processes. That would correspond to 13.8 out of 7 billion, or 1 out of 506.8 million. Extending the disease analogy, in this case if 13 people have have a disease it won't exist with a 6-sigma threshold which would require 14 in a world with more than 7 billion people.
So even 6-sigma is far from absolute.
This "discovery" may correctly be placed on a list that also contains Galileo, Newton, Einstein, measuring the charge of an electron, splitting the atom, definition of the dual nature of light (particle and wave) and the discovery that millions (tens or hundreds of millions?) of planets are in the correct positions in space to be able to support life as we know it.
But the probability can be calculated that the placement there could be removed in the future.
And What If The New Particle Proves to Be a New Unknown Species and Not the Higgs Boson?
If further work on this new discovery finds that it has indeed uncovered a new particle, but it is not the Higgs boson and does not fit in the Standard Model, the entire world of particle physics will be turned upside down. A new model will have to be developed. The world of particle physics will be back in 1960 again.
The announcement of 04 July 2012 would, in the above event, actually have a good chance of moving higher up the list of all-time great scientific events.
From the BBC:
- The Standard Model is the simplest set of ingredients - elementary particles - needed to make up the world we see in the heavens and in the laboratory
- Quarks combine together to make, for example, the proton and neutron - which make up the nuclei of atoms today - though more exotic combinations were around in the Universe's early days
- Leptons come in charged and uncharged versions; electrons - the most familiar charged lepton - together with quarks make up all the matter we can see; the uncharged leptons are neutrinos, which rarely interact with matter
- The "force carriers" are particles whose movements are observed as familiar forces such as those behind electricity and light (electromagnetism) and radioactive decay (the weak nuclear force)
- The Higgs boson came about because although the Standard Model holds together neatly, nothing requires the particles to have mass; for a fuller theory, the Higgs - or something else - must fill in that gap
- The New Yorker: Is the Higgs Not So Big? (GEI News, 07 July 2012)
- CERN Discovery: Scientists Find New Subatomic Particle That Could Be The Elusive Higgs Boson (Reuters, Huffington Post, 04 July 2012)
- Scientists’ search for Higgs boson yields new subatomic particle (Brian Vastag and Joel Achenbach, The Washington Post, 4 July 2012)
- Fermions (Wikipedia)
- Pauli_exclusion_principle (Wikipedia)
- Higgs and Significance (Victor Stenger, Huffington Post, 05 July 2012)
- Higgs boson-like particle discovery claimed at LHC (Paul Rincon, BBC, 4 July 2012)