Science Book Club discussion

This is our book for May. I have created the discussion early because the authors of the book would like to introduce themselves and join us in the discussion.

Hello, everyone!

My name is Stephen Sekula. I am an Associate Professor of Physics at Southern Methodist University (SMU) in Dallas, Texas. I worked with Frank Blitzer and Jim Gates to co-author the book, "Reality in the Shadows (or) What the Heck's the Higgs?" I am tremendously grateful for the chance to be part of this excellent collaboration of thinkers and writers.

Let me tell you a little bit more about myself. I am an experimental physicist. I work on a large, 3000-person collaboration called "ATLAS". We use custom-built, 8-story-tall, 50-yard-long "digital camera" to take millions of pictures each second. These pictures are snapshots of colliding particles. Those particle collisions are designed to recreate the conditions in the early universe. This is to help us learn what were the laws of nature at that time; what were the players in the cosmos at that time; and perhaps reveal new laws or new players we didn't know about. It's a curiosity-driven process, but it touches on deep questions. How did the universe start? What are the rules that govern the universe? What are the building blocks of the universe? Did the universe have to be this way, or could it have been otherwise?

I welcome questions and comments, and look forward to a fruitful discussion of the topics of the book (or anything else related to it about which you might be curious!).

Before I retired, I was an electronics technician in the physics department at the University of Alberta. I occasionally worked on electronics prototypes for the ATLAS project.

Bill wrote: "Before I retired, I was an electronics technician in the physics department at the University of Alberta. I occasionally worked on electronics prototypes for the ATLAS project."

That's amazing! I love how small the world really is. Can you tell me more about the prototypes, and what system in ATLAS they were intended for? At SMU, we work on the "Liquid Argon Calorimeter," which is one of the energy readout systems in the detector. That's not so much my area of expertise; I work on "triggering" on interesting proton-proton collisions, helping to make the final decisions about which collisions to keep and which to skip.

If it's all debris, which are kept?

I had to do a search to jog my memory. In the 90s I wrote some software to display histograms of the data from a test setup for a Readout System for a Liquid Argon Calorimeter. It is described in "Study of a Readout System for a Liquid Argon
Calorimeter at ATLAS" by Norm James Buchanan, for his Master of Science in 1999.

After that I went on to develop the software for a cosmic ray detection system. (not ATLAS related, but many of the people on that project were also working on ATLAS). https://www.sciencedirect.com/science...

I would often walk into the back to see what the machinist were up to: https://cpp-gw.physics.ualberta.ca//c...

Otto wrote: "If it's all debris, which are kept?"

That's a really good question. I like to think about it this way. Our big digital camera is capable of taking 40 million pictures each second, but it's not capable of keeping all 40 million every second. So it's a lot like having a really nice camera in your pocket... like on a mobile phone. Those things can take lots of big photos as fast as you can press the button. You might be using it at a party, and lots of funny things are happening. So you're taking pictures. You're taking LOTS of pictures. But you don't have enough storage to keep them all.

So what do you do? You look at each one quickly and make decisions about which ones to keep, and which to throw out. You have some rules. You don't keep pictures where people have their eyes closed. You don't keep pictures where somebody is caught in an unflattering moment. You don't keep pictures that look too similar to others. So you look through your pictures, and you delete the ones that fail your rules. You keep the "good" ones and you throw out all the others.

We do the same with ATLAS. We have a bunch of rules, based on what kinds of things we expect to be in interesting proton-proton collisions. Some of these are motivated by searches for new kinds of particles, or new kinds of forces, or both. Some are motivated by wanting to improve an old measurement. We keep the interesting ones and delete the rest. That's how we survive so much data from our camera.

Bill wrote: "I had to do a search to jog my memory. In the 90s I wrote some software to display histograms of the data from a test setup for a Readout System for a Liquid Argon Calorimeter. It is described in "..."

Indeed, what a small world. SMU has a responsibility for the design, construction, and maintenance for the optical readout links for the liquid argon calorimeter! I am sure the designs evolved over many years, but the ideas are likely still the same, at their heart. I will check out that report you mentioned. I will also drop your name to my colleagues on the calorimeter to see if there are any memories there!

Thanks, Steve. I should set the record straight here by letting folks know that I'm Otto Barz, the publisher at YBK Publishers who brought out Reality in the Shadow (or) What the Heck's the Higgs? and, along with Bill, will pop into the discussion now and then to ask questions of my own, not being myself a physicist—just a curious publisher [pun intended!].

We're awaiting the arrival of Jim Gates and Frank Blitzer, the co-authors with Steve, who have indicated that they will be joining in as we go along. As questions come along during the reading they will be fielded by whomever picks it up, or you can direct questions to individuals. Similarly, if any of you have questions about the book publishing process, I'll be happy to field those (after all, this is a book group!).

Let's have fun!

Good to know i am apart of such an awsome community. Have started reading the book. Will encourage everybody to read it and post their understanding of the topic here.

Welcome Gitesh. Feel comfortable as you read on to pose questions that you might develop along the way. Jim, Frank, or Steve will be happy to clarify. But, think not just questions. If you come up with sparkling realizations or have an occasional OMG moment, let us hear those too.

Gitesh: Jim Gates, who is traveling, asked that I send along his message:

Hi Gitesh,

Though I have been to Delhi and Roorkee, I have not visited
Bangalore. Thank you acquiring what I like to the call the
"What-The-Heck" physics book.

It was created in a very unusual manner when a "string theorist"
(me), a "rocket scientist" (Frank) and a "Higgs hunter" (Steve)
joined together to give our very different perspectives on this
area of modern physics in an innovative, unique, and (hopefully)
accessible, clear and engaging way.

I am genuinely excited about your delving into "Reality In The
Shadows" and will be awaiting your honest assessment.

Jim

Thanks, Steve, for answering my earlier question about debris so informingly. Got another! Got a lot of them!!

How does the ATLAS digital camera (or anything for that matter) slice up time into such small increments and not fall all over its own feet while doing so?

Is there anything in this book about information theory and error correcting codes in the mathematics of string theory?

I am looking for a book on information theory to add to our June suggestions.

Once again, I'm responding for Jim:

Your query aligns with current and continuing active research. However, there has, to our knowledge, never been created a book that focuses on that direction.

There is available a gratis, popular-level resource that can be found at

https://onbeing.org/programs/s-james-...

As well, there are a number of long-form videos at Youtube
which were also designed as accessible introductions to the mélange of topics you described. These can be found at

https://www.youtube.com/watch?v=b95Kd...

https://www.youtube.com/watch?v=6CLpu...

https://www.brown.edu/about/administr...

Finally, there are similar short-form videos available at

https://www.youtube.com/watch?v=uUrLD...

https://www.youtube.com/watch?v=ZTelS...

We’re a few days into May, and I’m wondering whether anyone beside Gitesh has begun reading “Heck?” We have three of the world’s brightest physics minds ready to talk to you. They’re ready when you are!

I am now on Chapter 5.

[sound of trumpets] one chapter from the excitement of reeling in the Higgs!

At work one day I sat down with a couple of physicists at coffee break. Before long Jonathan Shaffer the Dean of Science came by and joined us. One of the physicist mentioned that there was soon to be an announcement about the Higgs but he couldn't tell us until the next day. The next day they announced finding the Higgs.

Otto wrote: "Thanks, Steve, for answering my earlier question about debris so informingly. Got another! Got a lot of them!!

How does the ATLAS digital camera (or anything for that matter) slice up time into su..."

That is a great question, Otto. The ATLAS digital camera uses extremely fast electronics and software, but by design those pieces have to stay ahead of the structure of proton-proton collisions in the Large Hadron Collider (LHC). Let me comment a little on that first, then quickly summarize how ATLAS gets the data so fast.

The LHC is a circular proton-proton collider. You can think of it as host to a large number (a few thousands) of "buckets" that circulate the ring. Each bucket is really a part of an electromagnetic wave. Protons get caught in the troughs of the waves, and these troughs are what we call "buckets." It's just like surfing: to surf effectively, you want to ride just ahead of the crest of the wave. Protons are made to do the same in a machine like the LHC.

You can learn more about the LHC and how the beams get made from "LHC Animation: The path of the protons" from the CERN Laboratory: https://youtu.be/pQhbhpU9Wrg

Each bucket holds about a hundred-billion protons. We don't smash individual protons together; we smash huge bunches of protons together, in the hopes of getting at least one interesting collision. This happens just about 40 million times each second; two proton-proton bunches, carried around the ring in these electromagnetic buckets, pass through each other that many times per second.

So the ATLAS digital camera has to be fast. It has to catch as many as possible of the particles that might come from a proton-proton collision, and then digitize those signals from the many parts of the camera to pass to electronics for a very fast decision. In fact, our fast decision-making electronics, called the "Level 1 Trigger System," are so fast that they step down from 40 millions collisions per second from the LHC to just 100 thousand interesting collisions per second. Those collisions are then passed to a huge farm of computers known as the "High-Level Trigger," where they will be fully and more slowly processed to decide what's REALLY worth keeping. This process results in just about 1000 collisions per second being saved to long-term storage for future physics analysis. So, in one second 40 million collisions go into the camera; only 1000 interesting collisions come out. This whole process of deciding what to keep and what to reject requires only a few hundred millionths of a second for each collision.

You can see more of this process from this nice CERN movie, "Processing LHC Data": https://videos.cern.ch/record/1541893

We do all of this by taking advantage of a combination of fast, custom-built and off-the-shelf electronics, including custom hardware and custom software designed by the many members of the ATLAS Collaboration over decades. To be a successful experimental physicist these days involves some level of electronics and computer software knowledge, in addition to mathematics and general physics knowledge. It's a lot of fun to be able to take my own personal interest in computers from when I was a kid and turn that into a fruitful aspect of a physics career!

For anyone that missed it, about 45 seconds into the second video there are little red people next to the detectors for size comparison.

Bill wrote: "For anyone that missed it, about 45 seconds into the second video there are little red people next to the detectors for size comparison."

Thanks, Bill. I did miss that first time through. Makes one feel pretty insignificant!!

Stephen wrote: "Otto wrote: "Thanks, Steve, for answering my earlier question about debris so informingly. Got another! Got a lot of them!!

How does the ATLAS digital camera (or anything for that matter) slice up..."

Thanks for the clarity!

Last question—for now!! The second video appears to show the data from all four experiments, Atlas, Alice, LHCb, and CMS, being finally merged as it goes to the CERN data center. They are actually not merged, right? What does each experiment seek to report out? And, does each experiment create separate crashes at their particular site in order to study such crashes in a different manner than is done at the other three sites?

Bill wrote: "At work one day I sat down with a couple of physicists at coffee break. Before long Jonathan Shaffer the Dean of Science came by and joined us. One of the physicist mentioned that there was soon to..."

I was at CERN the day before the announcement. I document in the book my personal observations of that 24 hour period, from the vantage point of a person on ATLAS and in the room for the announcement. Here is one, fun, "day before" story:

As I sat in the CERN cafeteria, whom do I see putting his empty tray on the conveyor to the kitchen? Peter Higgs. I snapped a photo. What could Peter be doing at CERN the day before the two LHC experiments, ATLAS and CMS, present that status of their latest results in the search for the Higgs particle...?

... the rest is history.

Otto wrote: "Bill wrote: "For anyone that missed it, about 45 seconds into the second video there are little red people next to the detectors for size comparison."

Thanks, Bill. I did miss that first time thro..."

Every time I stand in the visitor gallery of the ATLAS detector, I always feel so small. Then I remind myself that the gallery affords a tiny view of just a piece of the experience, maybe 10% of the detector.

And then I feel smaller, and I'm almost in the right frame of mind to be humble before the cosmos. :-)

Hi, I’m Frank Blitzer, co-author with Jim Gates and Steve Sekula of "Reality in the Shadows (or) What the Heck’s the Higgs?" I’m the rocket scientist that Jim Gates mentioned in an earlier post. I’ve worked on such programs as Apollo, the Lacrosse missile, and various satellite systems before retiring some time ago.
The book puts together a good amalgam of the experiences found among a theoretical physicist, an experimental physicist, and myself, an aerospace engineer. Each of us has brought a different perspective and a different process of examination to each of the subjects treated in “Heck.”
I’m pretty confident that you’ll enjoy the read and hope that you will aim some of your questions toward me.

Otto wrote: "Stephen wrote: "Otto wrote: "Thanks, Steve, for answering my earlier question about debris so informingly. Got another! Got a lot of them!!

How does the ATLAS digital camera (or anything for that ..."

That's right, Otto: the data are not merged into one big sample. Each collaboration keeps its own data, analyzes it, and then makes results public based on that data. Some measurements are important enough (for instance, the measured mass of the Higgs particle) that after we each publish we then get together and combine our data to make a singular measurement. ATLAS and CMS have done this on repeated occasions, for example.

The data are all pushed to the world-wide computing grid, but within that larger space (think of it as a big data "cloud") we each have our own little territory (little "cloudlets") where we can see our data but not the data collected by another experiment.

ATLAS and CMS are multi-purpose experiments, so we do a lot of everything and we're very good at some things. Experiments like ALICE and LHCb are more specialized.

ALICE is designed to take high-quality data during special LHC operational periods known as "Heavy Ion Running," when the nuclei of whole atoms - not just protons - are smashed together.

LHCb is designed to study the behavior of a specific class of quark matter, that kind made from bottom quarks (the second-heaviest quark). This is known in the field as "B Physics," since the labels used for particles made from bottom quarks often start with a capital letter "B". I used to be a B-Physicist; I earned my Ph.D. on an older experiment, a predecessor to LHCb, called "BaBar."

Now I am a Higgs physicist, and to do Higgs physics you need to be on one of either ATLAS or CMS. They were designed to find, and then study, the Higgs particle, its cousins the W and Z particles, and quarks like the top quark (the heaviest fundamental particle yet known to humankind).

Thank you, Stephen for this EE answer (excellent and exhaustive)!

Otto wrote: "Thank you, Stephen for this EE answer (excellent and exhaustive)!"

I aim to please. :-)

As I am a "system Engineer", by my focus, I was most intrigued by the kind of tests that could be performed on systems to better our accuracy of the theoretical equations governing a system's behavior. In physics, the collider or accelerator are two such devices that can improve on our understanding of how the physical system works. Running a problem on a collider, for example, gives you particle behavior data on how the particles behave. But applying what you have learned to a model of the physical system, you can help to correct its theoretical behaviors to make the equations more accurate. Thus, from that point forward you can use the equations making your work less expensive, too.

science is a learning algorithm

CANI - constant and never ending improvement

Yes,it is,and addresses many different thing, too.

Along with being this month's selection, Reality in the Shadows (Heck!) has just received this wonderful review from the producer of NOVA. She, like others, is having a GOOD READ.

To say the least, I was fascinated with Reality in the Shadows or What the Heck’s the Higgs? I found myself wishing I had a few days of vacation coming up to take my time and read through it slowly, savoring its encyclopedic yet user-friendly romp through the history of physics right up to the present, to the mysteries that remain unresolved. Jim Gates, Frank Blitzer, and Steve Sekula bring together physics and mathematics, astronomy and astrophysics in a way that tells a compelling story—the quest to understand our universe.

In my many decades of running the PBS science series NOVA, Jim Gates has long been my “go to” guy for episodes about physics, astronomy, and mathematics. No matter how difficult the concept, Jim has a way of explaining it in terms people with no academic background in these fields can understand. And beyond that, the smooth elegance of Jim’s explanations makes you want to “lean in” to grasp their essence, as if he is conveying some deeper, more profound explanation of our world—and usually he is. Blitzer and Sekula add epic story-telling vitality to a real world of ground-truth that complements those abilities of Jim’s that will be recognized by viewers of NOVA.

Anyone who thinks all of the questions of modern physics have been solved and that there’s little left to ponder will be shocked by this book. It presents the history of physics as an important and helpful context to explain the many thorny mysteries that lie ahead, some of which are grounded in or helped by the 2012 discovery of the Higgs Boson. I would not be one bit surprised if in addition to engaging readers, this inspires more than a few young people to recast their future and invest themselves in this ever-enduring effort to understand our world, and by doing so, create the technologies and add to the knowledge that will take us all into the future.

Paula Apsell
Senior Executive Producer, NOVA
Director WGBH Science Unit
WGBH Educational Foundation

Thanks Otto, Stephen, Jim, and Frank for helping out here. Too bad no one had any questions.

This discussion will remain here for anyone that still wants to read the book.

Thank you to you, Bill, for your excellent support. Should there be any questions going forward, we will continue to monitor this thread.

Thank you, Bill for helping us help our readers, too. And thanks for helping to introduce this topic to our lay audience.

Here is another project I worked on. It looks like all the fun happened after I retired.

http://deap3600.ca/image-gallery/

The part I worked on was some of the instrumentation for when they were developing the gluing techniques.

https://www.flickr.com/photos/billbur...