Academic writing in High Energy Physics

It turns out I was not writing in this blog since last April, which is a bit disappointing.

Since then, I got more and more involved in academic writing; I have a couple draft articles (not within the Collaboration) that I am now polishing, and I got a contract with a prestigious press for a textbook due next year. As a result, I started writing almost every working day, which is something that as a particle physicist you don’t really do.

The life of a particle physicist in a large experimental Collaboration revolves around doing analysis work and service work. The typical service work consists in accessory tasks like working at tuning some calibration of the detector, or reviewing a specific aspect of analyses you did not perform yourself, or other menial tasks that are nevertheless extremely important for the company Collaboration to keep functioning. Not much writing there (except for emails. You will always be writing emails).

The typical analysis work can be roughly schematized in a workflow like this:

  • Design an analysis targeting an interesting physics case, and reading the relevant bibliography (old analyses targeting the same case, related theory papers, etc);
  • Perform the analysis (select an interesting subset of your data sample, estimate some tricky accessory quantities you need, study the systematic uncertainties your analysis is affected by, extract estimates for the parameters you are targeting);
  • Present a few times the analysis in a meeting to get feedback by other members of the collaboration;
  • Write down a detailed internal documentation (the Analysis Note), and get some more feedback;
  • Write down a draft of the public documentation (journal paper or preliminary analysis summary);
  • Get the analysis approved from the point of view of the physics;
  • Get the paper approved from the point of view of the writing (including the best way of relying the desired concepts, and style/grammar considerations).

I don’t claim total generality, I just find that me and most of the colleagues I know have this workflow; you might have a different one, probably a better one, and that’s just fine.

The implication of such a workflow is that you end up writing down the documentation (internal or external) only after having finalized the bulk of all the analysis work; until that moment, the logical organization of the material is deferred to slides presented at meetings. When you write the documentation you are also generally under pressure to respect some deadline—usually a conference in which your result should be presented. Sadly, sometimes there is not even much organization of the material to be done, because most analyses have been performed and optimized in the past, and the modifications you can do are kind of adiabatic (plug in a different estimate for a specific background, or training a classification algorithm, and so on). For new analyses, the track is predetermined anyway (tune your object identification, tune your event selection, estimate backgrounds, plug in some analysis method specific to the case at hand, estimate systematic uncertainties, calculate the final numbers representing your result).

That’s all fine, but the unintended consequence of this workflow is, in my opinion and experience, that academic writing ends up relegated to the role of a task you have to do pretty quickly and is a mere accessory to an analysis that you have already done.

Things are made worse by the latest stage of the workflow; the review of the paper text made by the collaboration (usually in the form of a Publication Committee) is designed to standardize the text of all the Collaboration’s papers and to ensure the highest standards of quality of the resulting text. The problem is that, while iterating with the internal reviewers on the text, you will often feel that your authorship is taken away from you. What I mean is that the set of rules and comments is designed to produce a perfect Collaboration text, and this will strip most of your personality (reflected in your personal writing style) away from the paper. Unless you discuss a lot and manage to slip some lively bits into it.

Just to make things clear, I am not complaining about the existence of these rules; it is certainly desirable that the Collaboration outputs papers with the highest standard of text quality, and setting internal reviews and writing rules is a necessity. It’s just that the papers end up being the Collaboration’s papers, not your papers.

In any case, my point is that this kind of workflow unwittingly teaches us that writing is the last thing you do after having done everything else, and that the final result is not entirely under your control, because it will be the product of the Collaboration.

If you look at other fields, maybe even going into social sciences or the humanities, writing tends to be seen more as a necessary tool to organize your thoughts. This generally applies to the point of using writing to organize your thoughts into a paper-like format, which helps you at any stage identifying what do you need from an analysis point of view, but it also applies in general to taking random notes to fix your thoughts and reorganize them.

Once I started writing for my own projects regularly, I realized that what in high school was a vague unidentified feeling is actually a clear truth: writing is probably the best way of interacting with your own mind, and that is true regardless of what you are writing about (work, feelings, life in general). Writing activates your mind and enhances its capabilities.

In addition to the projects I am working on, I started to regularly jot down notes on pretty much anything (meetings, random thoughts, summaries of papers I have read, etc). The result is that I feel more focussed, I feel like I am thinking more clearly about pretty much anything, and I am retaining information in an extremely easier way. A bonus is also that I can retrieve from my notes any information I have forgotten or not retained!

In high school I could write pretty easily, but I guess my ability has atrophied in the years; now I think I regained it and pushed it even further. I can now probably be defined a writing junkie. A resource that helped me quite a lot in regaining momentum is Joli Jensen’s Write No Matter What,  a very nice book whose main point is that in order to write you should have frequent, low-stress, and high-reward contacts with your writing.

How does all of this apply to this blog? Well, for long I thought that to write regularly I would need to regularly produce very long pieces of text, mainly because the blogs I usually enjoy reading are made of very long posts. Recently I started to follow and enjoy a lot a blog which mixes longer posts and very short random posts, and I finally came to terms with the idea that a blog can be entertaining and useful even if a post is very short or consists in the jotting down of a single random idea. I will try this new format. I actually started this post with the idea of writing just a few lines to kick off the blog again and look, here I am at 1310 words and a couple more paragraphs to go.

I even have plans for a whole series of posts. The COVID-19 boredom induced me to slip a couple slides about The interesting paper of the week in the news slides of the weekly meeting I chair at my institution. It’s a meeting about the group’s CMS efforts, but all the papers I am slipping in are about Bayesian statistics or Machine learning because that’s where my interests lie right now. Yesterday it suddenly dawned to me that porting those weekly slides to weekly posts would make for a great low-stress series.

So, basically, I’m back and with plans of finally kicking this blog truly off on its intended course.

Turok, Dark Matter, and the Issue of Telephone Games in Science

Chinese Whispers is a children’s game; according to the linked Wikipedia article, it’s called Telephone Game in American English, which better resembles the Italian telefono senza fili (literally, wireless phone).

Regardless of the name, which might stir up some discussion in its British version due to stereotype, the point is it’s a game in which information gets progressively distorted at each step—or I should rather say that opportunity for distortion at each step is embedded in the rules of the game.

Information is usually distorted by the environment (i.e. by the challenge of quickly whispering words one player to each other), but there’s always the chance that a player intentionally changes the message. This makes often the game a bit less funny (the funniest realizations—at least to me—are the ones in which the changes are unintentional), but results in no big deal; the message has no real utility.

In the real world, messages are usually important in being meant to have some effect on the recipient, and intentional distortion becomes an issue because the distortion is motivated by the hidden agenda of the player (or in general actor, in this context) that distorts the message.

In science this issues can rise in the way scientific results are presented to the general public, and also in the way results are presented to a public of peers; I will discuss two recent examples that bothered me a bit.

The first example is the popular book The Order of Time by Carlo Rovelli. In the book, Rovelli argues essentially that time is a sort of emergent property rather than a fundamental entity. The book has been followed by a series of interviews and articles in the press, which helped popularize it and certainly pumped up sales.

The book—and the general attitude shown in press articles and interviews—creates huge harm, though, because the notion that sticks with the layman is precisely that time does not exist. While this is certainly an interesting theory, worth discussion and scientific exploration (if feasible), it is a theory. A fancy, interesting theory that is not supported by any evidence whatsoever, at this moment in time (pun intended).

I think that selling (because the issue here is selling) a theory as if it was a fact is seriously damaging both the public and the community, with the aggravating factor that the public is defenseless; the public just trusts whatever is written in a popular book or in a press article, regardless of the truth—as the Trump campaign taught us. Furthermore, unfortunately the general public does not go and check more informed reports such as an article from Nature which points out that the theory is just Rovelli’s theory and that the layman should not buy the theory as if it was the truth.

If you think that I am exaggerating, consider that I am one of the administrators of what is probably the major Italian Facebook group on outreach on the topic of Quantum Mechanics, Meccanica Quantistica; Gruppo Serio; every couple days we have users that keep posting their thoughts “on the fact that time does not exist”, to the point that we stopped allowing those posts to pass through our filters. When we still accepted those discussions, I have been able to experience firsthand that these people have read the book (or a press article about it) and have taken home the message that the state of the art of scientific knowledge is that time does not exist. And this is very bothering. I think Rovelli messed up very badly in this, and I have the impression (I hope the incorrect impression) that he is unwilling or not caring about correcting this mistake.

Rovelli’s book is not the only example of a book that does a disservice to outreach by projecting the theory or the biases of the author into the general public; another recent example would be the book (and blog post about FCC) by Sabine Hossenfelder in which she claims that a new particle collider would be a waste of money, but I think that others have already written extensively about the topic, so I won’t delve into the topic in this blog post (I already did on Twitter, though), and my second example won’t be Sabine’s book.

My second example will be a sneakier example I have assisted to last week in a seminar in my institution, Université catholique de Louvain. In the context of the assignment of some PhDs honoris causa to renown scientists, Neil Turok has been invited and gave a couple lectures. One lecture was to the general public, and I missed it because of other commitment; you can find the full video of it in my institution’s website. The second lecture, the one I will focus on, was to a semi-general public; not only researchers like me from the CP3 (Centre for Cosmology, Particle Physics and Phenomenology—kudos for centre, Oxford comma is missing though), but also bachelor and master students in Physics.

A seminar for specialists is pretty much an open field, where it’s assumed that the spectators will be actively engaged and will critically evaluate any bit of information transmitted by the speaker.

A lecture with bachelor and master students—who were encouraged to participate and make questions—is a more delicate scenario, in which I would argue that you want to make sure that everything will be communicated with the necessary caveats. Either well-established theories should be presented, or new, bizarre, untested theories; in the case of the latter, there should be ample warnings about the theories not being part of the scientific consensus. I am not saying that new/bizarre/untested theories should not be presented; on the contrary, it is good for the formation of the critical mind of the students that debate is stirred up and that exciting possibilites are presented to them. What I am saying is that such possibilities should be presented as such, and not as the unquestionable truth; here is where I think Turok messed up pretty badly.

The lecture was about a CPT-symmetric universe; a couple slides into the talk, he presented a slide in which he wrote an equation and outlined the different components and the scientists that solved those pieces of the puzzle. There was an almost invisible (dark violet on black) bit of the equation that I was not able to read but that turned out to be pretty crucial; he claimed that he used to put disclaimers about that piece of the equation, because it referred to dark matter, but that recently he removed the disclaimer because that part of the puzzle has been solved.

At that point, I kind of woke up, because to this day we are pretty far from being able to state that “we solved Dark Matter”.

It became clear a few slides later that what he meant is that his theory is that Dark Matter is constituted by right-handed (RH) neutrinos, and that consequently the standard model plus right-handed neutrinos is enough to explain all the universe.

He then went on to state that competing theories such as freeze-out and freeze-in are full of ad-hoc assumptions, whereas his theory was simple and elegant; he even threw in the middle some paternalistic comments saying that in astrophysics/cosmology lately people just produce bad papers for the sake of it, whereas he prefers simple solutions based on works from 50 years ago.

Now, it might be true that some people produce bad papers just for the sake of it, and it might be true that going back to the roots of a discipline can result in ideas with a newly found strength and solidity. But using this argument to bash at competing models seems to me a bit arrogant and uncalled for. Particularly in front of undergraduate students.

During the Q&A, a couple colleagues of mine argued on two different fronts; one argued that freeze-in mechanisms—contrary to what stated by Turok—do not assume a huge number of new fields and ad-hoc assumptions. I am no expert on astrophysics, but we had in the past weeks two or three seminars about freeze-out and freeze-in mechanisms at CP3, and I am pretty sure my colleague was right; yet, Turok dismissed him basically saying that he was sure my colleague was wrong, and the moderator in the end had to use the traditional diplomatic let’s continue discussing this during the coffee break before things went awry.

The other colleague argued that the “very simple and standard-model only” model by Turok assumed not just the Standard Model but also right-handed neutrinos, to which a small exchange followed about whether RH neutrinos can be considered practically-Standard-Model or not. The discussion dragged on a bit, and at some point Turok admitted—although very en-passant—that also his model is affected by totally ad-hoc assumptions such the Z2 symmetry that makes one and only one of the RH neutrinos stable. And yes, that assumption is totally ad-hoc and is apparently the only way in which the theory can explain why of all RH neutrinos only one should be stable and give rise to Dark Matter. Again, I think that while it’s healthy that students are exposed to debate and to new ideas, the way in which the theory has been presented before the critics has been very problematic.

Screenshot from 2019-02-12 22-27-35
Screenshot from the Turok fandom wiki

Summarizing, I think our duty as scientists is to give both the public and the students the most objective picture about whatever new theory we fancy at the moment—even if we ourselves devised that theory.

It is good to expose the public to some degree of the professional debate about some topics—although it probably depends on the topic; debate about CPT has not the same impact on the layman as a debate about black holes—remember when people believed the LHC would have destroyed the Earth?—or vaccines.

However, when speaking to—or writing for—people that have not the capabilities of critically sieving through information, we should be very careful to not misrepresent the difference between the current scientific consensus and yet untested theories.

After all, not everything is about Turok (the Neil); the image above teaches us that Dark Matter is a pretty delicate issue in Turok (the game) as well 😀

Welcome to This New Beginning

[EDIT: if you want to know what I am up to in a given moment, you can find updated biographical information in the About page. This post will NOT be updated with new affiliations and ventures.]

My name is Pietro, and I have a PhD in physics, but my current main research interest is statistics, with a focus on statistical learning techniques.

In my daily job, I am a researcher in Universidad de Oviedo, Spain, where I work as a particle physicist within the CMS experiment, and am the delegated node PI for the AdvancedMVA4NewPhysics ITN network (you can find me blogging there as well, by the way). I am active in Standard Model (ttH search, WZ cross section, ttbar cross section) and BSM physics (2HDM in the Higgs sector, and SUSY in top sector).

Drawing from my experiences in CMS data analysis, however, I grew fond of statistical techniques, both on the matter of their foundations and on the field of statistical learning. As a consequence, my research focus began to shift from the same usual physics to these more interesting, fundamental, methodological topics. I joined the CMS Statistics Committee, where I found a rich landscape of interesting use cases and a fertile field for discussion. However, there is a specific area of statistics that is rarely applied or discussed in HEP: Bayesian statistics. I felt this is really a pity, so I started roaming extensively this exciting area.

I hope to be able, in this blog, to spark in you some interest for statistical learning and for Bayesian statistics, or at least to give you a good time in reading my random thoughts about these topics.

If you are reading this post, you can safely skip reading the About page, which contains mostly a cut-and-paste of this post, unless you want to find a list of my publications, which is actually present in that page.

Oh, and the look-n-feel of the blog might change a bit in the next days: I am not entirely satisfied with the tinkering I have done so far, so I will most likely tinker with fonts and colours some more.

To conclude, and without further ado, welcome to my new small project: I hope you will enjoy it 🙂