January 5, 2012 -- Part 1
2012 may become the Year of the Higgs.
Over 5000 particle physicists have made a New Year’s resolution to
finally discover this elusive particle or prove it doesn’t exist after
all. For nearly half a century, physicists have searched for the Higgs
boson, consuming over $10 billion and the careers of thousands of
scientists. We may soon have a definitive result — or not.
Why is the Higgs boson such a big deal?
Many physicists believe the Higgs boson
would “explain” why other particles have mass. This isn’t just academic.
Particles without mass travel at the speed of light and are unable to
form atoms, stars, planets, and life. Therefore, understanding the
origin of mass is compelling.
There are 16 known fundamental particles
(plus their antimatter versions). I didn’t include the graviton, the
supposed “carrier” of gravity that remains undetected. Of the known
particles, the photon and gluon have zero mass and the three types of
neutrinos probably have very small masses, but these are not yet
measured. The other 11 particles have non-zero masses that are all
different and that span a huge range — the top quark “weighs” 338,000
times more than the electron. (Antiparticles have exactly the same mass
as their particle partners.) We know precisely what these 11 mass values
are, but don’t really have an explanation for why each has that
particular value. In fact, we don’t know why any particle should have
mass, or even what “mass” is.
To plug this embarrassing void, several
theorists, including British physicist Peter Higgs, proposed the Higgs
boson, a new hypothetical particle that is unlike all known fundamental
particles (it has spin 0). The Higgs is said to be the only particle
that is intrinsically massive; other particles get their mass by
interacting to varying degrees with the Higgs “field” that permeates all
space — it is everywhere, always. Other particles, such as electrons,
interact with the Higgs field and in some sense “clump” with Higgs
bosons, thereby acquiring mass. Some particles interact strongly with
Higgs bosons and thus have large masses, while photons don’t interact
with them at all and thus have zero mass.
But is that really an explanation? We
replaced 16 unexplained masses with 16 unexplained Higgs interaction
strengths (“coupling constants”). This may simply redefine our
ignorance, effectively “kicking the can down the road.” Ultimately, this
may prove to be an important advance of science, but I’d say we’re a
long way from demonstrating that, even if the Higgs boson is discovered.
In his 1994 book, experimental physicist
and Nobel Laureate Leon Lederman nicknamed the Higgs boson “The God
Particle.” Lederman said he really wanted to name it “The Goddamn
Particle” but his publisher vetoed that. This dichotomy highlights a
schism between the two camps of fundamental particle physics.
Long ago, every physicist measured,
calculated, and pondered: Why? Eventually the field grew so complex that
no one could excel at all these tasks, and physicists split into two
camps: experimentalists and theorists. Theorists strive to develop
mathematical models of nature, while experimentalists build instruments
and measure what nature does. The last physicist who was truly great in
both theory and experiment was my father’s mentor Enrico Fermi, who died
in 1954. Today, virtually no one attempts to do both theory and
experiment — the schism is complete.
For theorists who believe the Higgs
boson plugs a major hole in their mathematical models, it may be the
“God Particle.” But for experimentalists who have searched in vain for
decades, the “Goddamn Particle” seems more apt.
Part 2 of this newsletter will talk about the experimental search for Higgs bosons.
Dr. Robert Piccioni
Author of "Everyone's Guide to Atoms, Einstein, and the Universe",
"Can Life Be Merely An Accident?"
& "A World Without Einstein"