Of Particular Significance

Tag: CosmicRays

The mass of a single proton, often said to be made of three quarks, is almost 1 GeV/c2. To be more precise, a proton’s mass is 0.938 GeV/c2, while that of a neutron is 0.939 GeV/c2.

But the masses of up and down quarks, found in protons and neutrons, are each much less than 0.01 GeV/c2. In short, the mass of each quark is less than one percent of a proton’s or neutron’s mass. If a proton were really made from three quarks, then there would seem to be a huge mismatch.

(Here and below, by “mass” I mean “rest mass” — an object’s intrinsic mass, which does not change with speed. It is sometimes called “invariant mass”. [Particle physicists usually just call it “mass”, though.])

Part of the explanation for the apparent discrepancy is that a proton or neutron is, in fact, made from far more than just three quarks. In its interior, one would find many gluons and a variety of quarks and anti-quarks. However, that doesn’t resolve the issue.

  • Gluons, like photons, have zero rest mass, so they don’t help at all, naively speaking.
  • The typical number of quarks and anti-quarks inside a proton, while more than three, is too small to add up to the proton’s full mass;

And thus one cannot explain the proton or neutron’s large mass as simply the sum of the masses of the objects inside it. The discrepancy remains.

Moreover, as can be verified using either strong theoretical arguments in analogous systems or direct numerical simulations, protons and neutrons would still have a substantial mass even if the quarks and anti-quarks they contain had none at all! Mass — from no mass.

Clearly, then, the solution to the puzzle lies elsewhere.

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON July 22, 2024

You might think I’m about to tell a joke. But no, not me. This is serious physics, folks!

Suppose a particle falls into a hole, and, as in a nightmare (or as in a certain 1970s movie featuring light sabers), the walls of the hole start closing in. The particle will just stay there, awaiting the end. But if the same thing happens to a wavicle, the outcome is very different. Like a magician, the wavicle will escape!

Today I’ll explain why.

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON July 11, 2024

In my role as a teacher and explainer of physics, I have found that the ambiguities and subtleties of language can easily create confusion. This is especially true when well-known English words are reused in scientific contexts, where they may or may not be quite appropriate.

The word “particle”, as used to describe “elementary particles” such as electrons and quarks and photons, is arguably one such word. It risks giving the wrong impression as to what electrons etc. are really like. For this reason, I sometimes replace “particle” with the word “wavicle”, a word from the 1920s that has been getting some traction again in recent years. [I used it in my recent book, where I also emphasized the problems of language in communicating science.]

In today’s post I want to contrast the concepts of particle, wave and wavicle. What characterizes each of these notions? Understanding the answer is crucial for anyone who wants to grasp the workings of our universe.

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON July 9, 2024

After a tiring spring that followed the publication of the book, I’ve taken a little break. But starting tomorrow, I’ll be posting on the blog again, focusing again on the important differences between the conventional notion of “particle” and the concept of “wavicle”. I prefer the latter to the former when referring to electrons, quarks and other elementary objects.

Today, though, some book-related news.

First, a book review of sorts — or at least, a brief but strong informal endorsement — appeared in the New York Times, courtesy of the linguist, author and columnist John McWhorter. Since McWhorter is not a scientist himself, I’m especially delighted that he liked the book and found it largely comprehensible! The review was in a paragraph-long addendum to a longer column about language; here’s an excerpt:

Another positive review recently appeared in Nautilus magazine, written by Ash Jogalekar, a scientist himself — but a chemist rather than a physicist. The full review is available here.

Lastly, the audiobook is in preparation, though I still don’t know the time frame yet.

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON July 8, 2024

For those of you currently in western Massachusetts or eastern upstate New York, some news: I’ll be speaking about my book today, Monday, June 24th, 5:30 pm, in Lenox, MA. At this free event, held at the local institution known simply as “The Bookstore“, I’ll read from the text and discuss its central message. After that, I’ll answer questions from the audience and sign books.

In other news — for those of you waiting (im)patiently for the audiobook, I am glad to report that there is finally some forward movement on that front. I’m still not sure how long it will take for the audio version to become available, but progress should be steady and rapid from here.

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON June 24, 2024

[Update: unfortunately, the link below was taken down before the tour, with no explanation. The tour was instead recorded at https://www.youtube.com/watch?v=67mF5Yx7ZG0.]

Would anyone like a tour of the ATLAS and CMS experiments, the general purpose particle detectors at the Large Hadron Collider that were used to discover the particle known as the Higgs boson? A live, virtual tour is being given today (Tuesday June 11) on YouTube, https://www.youtube.com/watch?v=askq7-9CzrU, at 1700 CERN time — that’s 1600 London time, 11:00 New York time, 8:00 San Francisco time. Find out how these enormous, complex, magnificent devices are constructed, and learn how their various parts work together, 25 million times every second, to allow scientists to track the tiniest objects in the universe. Includes a Q&A at the end for participants.

Picture of POSTED BY Matt Strassler

POSTED BY Matt Strassler

ON June 11, 2024


Buy The Book

Reading My Book?

Got a question? Ask it here.

Media Inquiries

For media inquiries, click here.