Taken from the Facebook page of The Universe (all credit to the original authors, I am simply sharing it here):
Just under two hours ago, physicists at CERN announced that with near certainty, the Higgs boson particle has been discovered! Specifically, they have observed a new boson with a mass 125.3 GeV +/- 0.6 at 4.9 sigma. (the “golden standard” of science which measures the veracity of the find) But what exactly does that mean? It means the Higgs boson has been confirmed with a 99.99997 percent chance with the mass range of 125 Gev (GigaelectronVolts). The 4.9 sigma indicates a strong signal with the positive probability being an error at 1 in 9 trillion. In other words, it is HIGHLY unlikely that the new found data is a mistake. The “official” announcement is expected to come when more is known about the new particle. There’s still a lot to sort out. Particularly if the new Higgs-like particle behaves like the mass-giving Higgs boson that’s predicted in the standard model. Furthermore, the properties of the new particle still need to be better understood.
Check in with the folks at CERN that were tweeting during the live broadcast:
So. What is the fuss about the Higgs Boson (aka: the “God particle”) and how does it tie into particle physics, the standard model, what does it mean, and what are the implications? I hope to at least answer a few of those questions here for you tonight!
“What is particle physics?”
- Thanks to quantum physics, we now know that space isn’t empty. Besides ordinary matter like protons, electrons and neutrons that compromises the building blocks of all matter, the universe is abound with quantum fields and tiny elementary particles that pop in and out of existence Particle physics is the study of all of the individual subatomic particles and forces that interact to form the universe.
“What is the standard model?”
- In the world of particle physics, subatomic particles are difficult to observe because of their size. They are smaller than an atom and the wavelength of visible light, so the only way we can detect and observe their behavior is by smashing the atomic nucleus of particles together at intense speeds (close to the speed of light), which generates vast amounts of exotic particles that are only created at high energies. These collisions resemble the conditions physicists believe existed during the time of the big bang. Thanks to particle accelerators like the Large Hadron Collider, the Relativistic Heavy Ion Collider and the (now defunct) Tevatron circular particle accelerator, physicists have made a lot of progress in designing a “theory of everything.” This theory postulates how all the subatomic particles in the universe operates and how they interact to comprise the Universe as we know it. One of the most complete models that comes anywhere near producing a “theory of everything,” is the Standard Model of Fundamental Particles and Interactions, which describes how particles and forces interact. The standard model also includes an explanation for 3 of the 4 fundamental forces of nature on a subatomic scale.
The four fundamental forces of nature:
1. The “strong interaction” that’s responsible for holding the nuclei of atoms together.
2. The “weak force” that’s responsible for radioactive decay and neutrino interactions.
3. The electromagnetic force that causes effects such as the interaction of magnetics and electrical charges.
4. The gravitational force that attracts matter to other matter that has mass.
Here’s where the Higgs boson comes into play: We don’t understand why certain particles have mass whereas it’s believed that all force carrying particles should NOT have mass. To the contrary, we’ve learned that particles that carry weak force do have mass, by why do the would-be massless fundamental particles have mass? (I know that was a total mouth full)
The Higgs boson would help explain the means in which these particles in the universe obtain their mass. Peter Higgs (the physicist the elusive particle is named after) developed a theory that explained how particles that carry electromagnetic force or the weak force, can have different masses as the universe gradually cooled. His suggestion was that particles like protons, neutrons and quarks gain mass by interacting with an invisible electromagnetic field that predates the universe, called a “Higgs field.” Some of the particles are able to cut through the Higgs field without picking up mass, while others get bogged down (similar to pulling a beaded necklace through a tub of honey), accumulating mass. If true, this “invisible” field should have an associated particle called the Higgs boson- a particle that supervises interactions with other particles and the electromagnetic “Higgs” field- exchanging virtual Higgs particles with it.
Here’s the best analogy for understanding the Higgs field that I can find:
Since the Higgs boson quickly decays into other more stable particles, it’s far more difficult to observe than other subatomic particles created in particle accelerator collisions. Mimicking the conditions similar to that of the big bang, when it’s created, it’s believe to exist only for a septillionth of a second, making the work of sorting through the data collected from trillions of collisions, a tedious process.
In short (since this is already so long), you should care about the Higgs boson particle because it’s the reason why you exist. In fact, the Higgs boson is basically responsible for all of our physical reality. If particles didn’t have mass, they would zip around the universe at speeds similar to the speed of light, which wouldn’t allow the particles to coalesce into atoms, which in turn, forms matter.
Since i’m officially running short on time, here’s a Q & A that took place that answers a lot of questions you may have that I didn’t address: (some of this can be disregarded now that we know the likely hood of the existence of the particle existing)
“What is the Higgs boson?”
The Higgs so far definitively exists only in the minds of theoretical physicists. There is a nearly complete theory for how the Universe works – all of the particles that make up atoms and molecules and all the matter we see, along with more exotic particles. This is called the Standard Model. However, there is a glaring hole in the theory: it does not explain how it is that all those particles have mass. The Higgs mechanism was proposed in 1964 by six physicists, including the Edinburgh-based theoretician Peter Higgs, as an explanation to fill this hole.
“What is so important about mass?”
Mass is, quite simply, a measure of how much stuff an object – a particle, a molecule, or a Yorkshire terrier – contains. If not for mass, all of the fundamental particles that make up atoms and terriers would whiz around at light speed, and the Universe as we know it could not have clumped up into matter. The Higgs mechanism proposes that there is a field permeating the Universe – the Higgs field – that allows particles to obtain their mass. Interactions with the field – with the Higgs bosons that come from it – are purported to give particles mass. This is not unlike a field of snow, in which trudging through impedes progress; your shoes interacting with snow particles slows you down.
“How do scientists search for the Higgs boson?”
Ironically, the Standard Model does not predict an exact mass for the Higgs itself. Particle accelerators such as the LHC are used to systematically search for the particle over a range of masses where it could plausibly be. The LHC works by smashing together two beams of the sub-atomic particles called protons at close to light speed. This generates a vast shower of particles that are only created at high energies. The Higgs will probably never be observed directly, but scientists at the LHC hope that a Higgs will momentarily exist in this soup of particles. If it behaves as researchers think it will, it should decay further into yet more particles, leaving a trail that could prove its existence.
It is not the first machine to hunt for the particle. The LEP machine, which ran at Cern from 1989-2000, ruled out the Higgs up to a certain mass, and the US Tevatron accelerator searched for the particle above this range before it was switched off this year. These data are still being analysed, and could yet be important in helping confirm or rule out the particle. The LHC, as the most powerful particle accelerator ever built, is just the most high-profile of the experiments that could shed light on the Higgs hunt.
“When will we know if we have found it?”
As with all particle physics, this is a tricky point. The Higgs should show up in a particular range of masses, and signals that indicate it is there in the mess of particles will show up as a kind of “bump” in the data. Making sure that bump is really due to a Higgs is a different matter. If you flip a coin ten times and get eight heads, you might think the coin is somehow “loaded”. But only after hundreds of flips can you say so with the kind of certainty that physics requires for a formal “discovery”. What is clear about the LHC results so far is that the two teams working to find it do not have enough data – enough “flips” – to say that the Higgs has been found or excluded beyond doubt. More experiments will be needed for that.
“How do we know the Higgs exists?”
Strictly speaking, we do not, and that is what is so exciting about the status of the hunt at the LHC – the giant experiment that was built in part to hunt for the Higgs. In its simplest form, the theory predicts a “Standard Model Higgs”, which is the focus of the current hunt. But history has shown that predictions from theory can be wrong, and the absence of the simplest Higgs particle may suggest that it exists at different energies, decays into different particles, or perhaps doesn’t exist at all.
Most professional physicists would say that finding the Higgs in precisely the form that theory predicts would actually be a disappointment. Large-scale projects such as the LHC are built with the aim of expanding knowledge, and confirming the existence of the Higgs right where we expect it – while it would be a triumph for our understanding of physics – would be far less exciting than not finding it. If future studies definitively confirm that the Higgs does not exist, much if not all of the Standard Model would have to be rewritten. That in turn would launch new lines of enquiry that would almost certainly revolutionise our understanding of the Universe, in much the same way as something missing in physics a century ago led to the development of the revolutionary ideas of quantum mechanics.
What is a higgs boson:
Brian Greene talks about the higgs boson particle:
Complete list of elementary particles:
- Jaime and Ney
Again, thanks to the original authors of this article!