Freedom from Symmetry: Six Years of the Higgs Particle

A “cephalopod diagram” of Higgs decay, with vector boson final states in red and fermion final states in blue. Solid lines correspond to final states we’ve definitely seen, and dashed lines represent final states still being hunted. The area of a circle represents its relative rate to that of the bottom-quark final state, which is expected to represent 60% of all Higgs boson decays.

Six years ago on this date, the Higgs boson was (probably) discovered by the ATLAS and CMS Experiments at the Large Hadron Collider in Geneva, Switzerland. I say “probably” because, at the time, all we really knew for sure was that we had discovered a new particle, with a particular mass (about 126 times the proton mass, at the time), that appeared in our experiments in ways consistent with, but not unique to, the predicted Higgs particle.

Well, it’s been 6 years and 1 Nobel Prize in physics since then, and we’re all pretty darn sure it is the Higgs boson predicted in the early 1960s.

But wait. Is it? ATLAS and CMS continue to map out its detailed properties, including one of the biggest sets of prizes in the current data set being collected right now: how much the Higgs boson interacts with the top quark, the heaviest of the 6 known quarks, and the bottom quark, the second-heaviest quark. It’s an unfolding story.

Meanwhile, check out these blog posts from me back in July of 2012, and remind yourself of how glorious it is to see something no one has ever seen before.

Relive the moments before and after the announcement of the “bump” in the data from my friend, Aidan Randle-Conde, who was at the time a post-doctoral researcher at SMU and an avid blogger and science communicator:

“Reality in the Shadows (or) What the Heck’s the Higgs?” is meant to help a new audience come to discover a love of science and especially physics, or to welcome to the frontier those who already discovered that love a long time ago.

And, of course, with further hindsight and many more years of data to inform the discussion, learn more about just what the heck’s the Higgs in our book, “Reality in the Shadows (or) What the Heck’s the Higgs?” by S. James Gates, Jr., Frank Blitzer, and me!

While we know more about this particle since discovering it in 2012-2013, there are many mysteries left. Some prizes are big, but hard to claim in all the noise. For instance, only just a year ago, we spotted the first strong hints of the direct interaction of the Higgs particle and the bottom quark… despite the fact that this should be its favored method of decay! Learn more here:

UPDATE (July 6, 2018): Added the really nice “post-seminar analysis video” from Aidan and some more words about how data in the intervening years has shed light on some questions but left others open.

A View from the Shadows: The Allegory of the Cave

Plato’s “Allegory of the Cave”. This drawing is by Markus Maurer.

Plato’s “Allegory of the Cave” could almost, taken at face value, be the plot of a movie in the “Saw” series [1]. Prisoners in a cave, born into chains and forced forever to face a single wall, know nothing of the reality of what lives behind them. A fire somewhere behind the prisoners cast shadows that play on the walls. Our poor prisoners try to make sense of the reality of the world behind them merely through interpreting these shadows, never able to turn as see the world as it truly is.

It’s has the potential to be a terrible image, but softened a bit it can be a useful metaphor for thinking about what it means to use scientific inquiry to understand the reality of the cosmos. When we discover something using scientific inquiry and describe it mathematically, is that mathematical statement one approximating reality or truly describing reality as it is?

That question aside, Plato himself was not big into what we would now call “science” – in fact, he held many core beliefs that suppressed scientific thinking. In this post, another personal journey into “Reality in the Shadows,” I reflect on the satisfaction of wresting this metaphor our of Plato’s hands and giving it to a new generation. It is my hope that such a generation might only ever know the tools of scientific investigation for use in understanding the natural world. The world is filled with shadows, crying for explanation; I hope a new generation can appreciate how the tools of science can be used to make sense of those shadows in a reliable and reproducible way.

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A View from the Shadows: Reading List

“Reality in the Shadows (or) What the Heck’s the Higgs” is meant to help a new audience come to discover a love of science and especially physics, or to welcome to the frontier those who already discovered that love a long time ago.

Reality in the Shadows” is a book that required years to write. I was the latest addition to the creative team, but it is very much a shared vision between three co-authors each with different perspectives on the subject matter. Jim Gates has a keen mathematical mind and delights in showing an audience that math is not as scary as they have been led to believe (or have wrongly convinced themselves). He sees the deeper connection between mathematics and reality. Frank Blitzer has a deep love of physics as a branch of science that seeks some of the deepest truths about the universe, and brings to bear on this a wealth of experience in computation, engineering, and modeling processes. I’m the experimental physicist and Higgs hunter, who believes that reliably gathered independent lines of evidence are the best way to support, or refute, an idea.

Despite our existing expertise, this book didn’t spring fully formed from the minds of the authors. It was a labor, and that labor benefited from learning. We, too, depended on those who had written things down before us. We drew from many sources to tell the story of the past, present, and possible futures of physics.

Below, find a reading list of material I used to support my writing contributions to the book. I hope some of these will allow you a much deeper and more technical exploration of some subjects in the book. Many are highly technical, but they provided the raw scientific material that I tried to communicate to a general audience.

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