Even physics loves a makeover

" I… see… dead… particles." If you think "spooky stuff" happened only in so-called paranormal events, trying to understand the new findings last month in a recent physics experiment may just be able to steer your sense of wonder less toward entertaining the attack of restive zombies and more toward what 32 institutions in six countries found worthy of expensive and intelligent collaboration to understand some of the most basic building blocks of matter.

Everything decays and nothing does it better than the nucleus of an atom. This decay is what we call "radioactivity" and scientists know that nuclear decay is one of Nature’s most basic processes. They have even long figured out that a nucleus has three ways of doing this: 1) by releasing an "alpha" particle -a term for the release of a nuclei made up two protons and two neutrons, also know as helium-4 nucleus ("alpha" because it is the first kind of radiation observed); 2) by beta radiation, i.e., turning a neutron into a set of proton, electron and some weird, massless particle they call "neutrino"; and 3) by gamma decay which releases very energetic photons or strong electromagnetic radiation.

And as with people and chocolate, even among elements, some are more "decadent" or more "unstable" than others. What makes a nucleus of one element more "decadent" than another nucleus of the same element is the number of neutrons it has. This difference in neutrons is what makes for the different versions or "isotopes" of the same element. This process of decay is also measurable, like counting regular heartbeats echoed from the nucleus, ticking away to its end. This is how scientists figure out how old something is. For example, carbon 14 is an isotope of carbon, which means it has six protons and eight neutrons. Any organic matter whether human, leaf or dinosaur are carbon-based and when they die, it is carbon 14 isotope that is left to tick away to be heard by any persistent CSI officer or archaeologist who digs up the remains to determine how long they have been dead even if those scientists were not even present yet in natural history to sing Auld Lang Syne to departing early humans and pterodactyls. The period it takes for half of the original sample nucleus to decay is called "half-life." Depending on the isotope, this "half-life" ranges from microseconds to billions of years. Carbon 14 has a half-life of 5,700 years. It means that after 5,700 years, organic remains will contain only half as much carbon 14 it started with when it started to decay. But other elements even go for much older stuff! For instance, the decay of uranium 238 to become lead 206 isotope, found locked in ancient crystals, takes a half-life of 4.5 billion years and when scientists found those isotopes, that is how they knew that the Earth is about 4.5 billion years old.

But "listening" to the radioactive heartbeats of past lives is old spooky stuff from science. The very new spooky stuff I want to tell you about now has to do with the second kind of decay I mentioned above involving the "makeover" of a "straightforward" neutron into as set of three "queer" particles – proton, electron and a neutrino. The "neutrino" is often called a "ghost particle" because it can go through anything without being "seen" as it very rarely interacts with anything. To get a better illustration, think of our own Sun. The nuclear processes that fuel our own Sun is supposed to churn out a known number of neutrinos, yet as constantly as we are soaked in sunbeams, very rarely is any neutrino caught on Earth. They most often go through it – like ghosts! If this is too technical for you and you are inclined to understand this better through a political metaphor, just think of how rarely the notion of "service" ever really permeates the working mind of politicians in our country, generation after generation. That is how rarely a neutrino is caught. This is what makes neutrinos like "ghosts" – quite elusive for study. But fortunately in science, the scientific tradition dictates that we do not get caged in our present understanding and figure out more about these "ghosts" in the subatomic world.

Before the experiment called the Main Injector Neutrino Oscillation Search or Minos, which was reported all over the world, including in the BBC last March 31, scientists thought that neutrinos did not have mass, and that they come in three kinds – or "flavors": muon-neutrino, tau-neutrino and electron-neutrino. That the neutrino did not have mass is one rivet in the structure of understanding in the field of particle physics called the Standard Model. The Standard Model is to physics what the Constitution is to a nation except that the assertions that make up the Standard Model is based on evidence that experiments have yielded so far, and not on the whim of politics. 

What the scientists did recently was to create muon-neutrinos in a particle accelerator at the Fermi National Accelerator Laboratory (Fermilab) in Illinois, US. They then fired these muon-neutrinos to a particle detector that was 440 miles away. The spooky thing was the particle detector could not find the same number of muon-neutrinos as that that had been fired. Knowing that these neutrinos very reliably "ignore" anything in between the particle accelerator and the particle detector, nothing could have attracted them during the trip so they could not have just gotten off somewhere along those 440 miles! (As I hope some of you readers are still with me at this point of the column.) In fact, the scientists found that even if the muon-neutrinos had disappeared, other kinds of neutrinos turned up on the other side! This behavior makes a neutrino more like a werewolf that can swing from a person to a wolf from day to night, and back, in an unbroken spell. This means that our neutrinos did not disappear but underwent a "makeover" which scientists call a "neutrino oscillation" which was really spooky and quite piercing to the Standard Model because in order for neutrinos to undergo this "makeover," they have to have mass which they are NOT supposed to have according to the Standard Model!

But thank goodness that when science itself reveals findings that threaten its own long-held theories, it does not go into mass hysteria (no pun intended). Instead, it carefully goes back to the drawing board to see if the basic model in physics has to be redrawn or we just need to reshape some of the rivets that hold the scaffolds of our understanding of the building blocks of matter. Some scientists like Professor Jenny Thomas, a particle physicist at University College London and a member of the Minos team featured in the BBC report, are even saying that this new finding that neutrinos have mass may even provide the missing rivet to home in our understanding on where all that matter that was supposed to be around when the universe started, are now. Where have all that matter gone, "long time passing"? They have been "missing" – no one knows what they look like or what they are. All the scientists know is that if these "missing matter" were not around now, the universe will not be the way it is now. This gap in scientific understanding has made it necessary for scientists to come up with the concept of "dark matter" as a working term for this missing matter. And what do you know, if the Minos scientists were right, these "matter" have not been really "missing" after all – we just had to refine our instruments and understanding in order to put them in focus. We only had to persist in order to understand a little better that the only ghosts there are, are those that we abandon to the mercy of ignorance, to our baseless ear of discovery and distaste for new ideas.

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