Journeys in the Dark Sectors, via science and fiction

Guest post by: Andrea Giammanco

One day in summer 2021, all people with a CERN e-mail address received an unusual e-mail. Most of the recipients have no recollection anymore of it; we all receive so many e-mails, and this was not specifically targeted to anyone (just to “the CERN community”). But its topic was very intriguing to me: two members of the CERN family, Rob Appleby and Connie Potter, were looking for scientists and engineers to collaborate with professional fiction writers. We were invited to propose short science-inspired ideas for stories, to be eventually published by Comma Press, a not-for-profit British publisher. This resulted in the sci-fi anthology “Collision”, published in 2023, available at the CERN library.

I was immediately eager to participate and submitted two proposals. My main motivation was to get a chance to learn something about writing from a professional author. In my teenage years (we are talking about a previous millennium!), I was an avid reader of both fiction and scientific essays, so quite naturally I daydreamed of either becoming a scientist or a writer. I had no particular preference among the two dreams but, having to pick one, I wisely chose the path that felt most likely to eventually give me a job! And although I never regretted that choice, I kept writing as a hobby during my university years. I resumed that hobby a few years ago, writing a novel whose chapters I shared via a blog.

The contributions from CERN people were collected by Rob and Connie, and dispatched to a pool of authors collaborating with Comma Press. One of the two that I had submitted (which happened to be the one that constituted the scientific backdrop of my own novel) was selected by Adam Marek, a UK-based writer who had already published a few short-novel anthologies (which I recommend, by the way). We were put in contact and given a lot of freedom for how to organize this collaboration in practice. Marek and I had a few Zoom calls, with several mail exchanges in between. Each call lasted way longer than planned because we always reached a point where we were rather excited by the brainstorming.

From left to right: Spencer Kelly (BBC Click host), Andrea Giammanco and Adam Marek, during an interview for BBC Click at CERN.
From left to right: Spencer Kelly (BBC Click host), Andrea Giammanco and Adam Marek, during an interview for BBC Click at CERN. Picture source:
Copyright: BBC.

The idea that I had proposed, and that Marek had chosen, has to do with a category of beyond-Standard-Model hypotheses which go by the collective name of “hidden sectors” (also known as “hidden valleys” in part of the literature). Suppose that the (still unknown) ‘Theory of Everything’ is such that the various elementary particles are grouped in well-defined sectors, meaning that all particles within a sector easily interact with each other, but there is only some very tenuous interaction between particles belonging to different sectors. One of the sectors would be the Standard Model, i.e. all the particles that we already know, interacting through the forces that we already know about (electromagnetism, weak nuclear force, strong nuclear force and, finally, gravity, which is by far the weakest force at the microscopic scale). Nothing prevents the possibility that other particles from the other “sectors” permeate the very same space that we occupy, but we do not notice them because their interactions with us (i.e. with the Standard Model) are extremely feeble. However, all sectors are expected to feel at least gravitational interactions with each other (because whatever has mass should feel gravity), and this would provide a neat explanation of the mystery of Dark Matter, which is estimated to constitute about 80% of the matter of the Universe. We could even imagine a handful of different sectors that coexist in the same space and almost equally share the mass of the Universe. If at least some of the particles in the hidden sectors also have additional (non-gravitational) feeble interactions with the Standard Model particles, there is some hope to observe those interactions in a laboratory.

CMS data analysts have been looking for hints of hidden sectors (see for example this or this recent publication). And long, long ago (mostly 2007-2009), when I was a young researcher, the LHC start-up was imminent, and CMS scientists were busy integrating and commissioning the detector components and running Monte Carlo simulations, I had myself been involved in the preparation for this type of search: I had developed an algorithm for estimating the energy loss of charged particles in the CMS tracker and, among various things that one could do with such algorithm, I was also checking how it fared in the search for hypothetical new particles with a large mass, long lifetime and electrical charge. These kinds of particles are commonly predicted in dark-sector models, but not in the most mainstream new physics models that are searched for at the LHC (e.g. SUSY), so this was definitely a niche. But I was also working on some more popular topics, which ended up becoming the whole of my research. So, I eventually abandoned the Dark Sectors, but I kept finding that topic interesting and I was pleased when I could see it grow in popularity among particle physicists. This is still a niche, but it is being taken more and more seriously by the particle physics community, up to the point that now these kinds of searches guide the design of new detectors and of upgrades of the existing ones.

One way that I kept in contact with the topic was by occasionally fantasizing about it. Many colleagues definitely agree that Dark Sectors are a fertile idea from the scientific point of view: a simple concept from which many practical consequences descend. I find them fertile also from the narrative point of view. Dark Sectors can be more than one, and each sector would have a different chemistry: chemistry descends from the properties of the electron and of the proton – which is made of quarks - and of electromagnetism: each sector might have some look-alike of the electron and of the quarks, and some completely different set of fundamental forces, some of which may play the role of electromagnetism. If you could see a hidden sector, maybe you would see hidden planets with exotic chemistry and, of course, exotic biology. In my aforementioned online novel, I didn’t explore any of those hypothetical and unfathomable worlds, just the way I imagine their discovery by a team of LHC data analysts (whose human interactions, instead, I went to great lengths describing, humbly aiming at making this the most sociologically accurate novel ever devoted to CERN – a concern that Dan Brown certainly never had). Marek, for his short story, similarly chose to abstain from describing what is exactly in the Dark Sectors, and to describe instead the process of their discovery – not at the LHC though, but I will not spoil it!

Collision book
The moment I received the finished product!
Copyright: Andrea Giammanco

Amusingly, although I was supposed to be the one providing scientific ideas, two key scientific elements of the story were suggested by him. Those are the production of an extra flux of “dark-sector” particles by the Sun during anomalous solar activity events (plausible enough that it might actually deserve a dedicated simulation study, unless someone has already done it), and the amplification of the signal of these “dark particles” by some meta-materials. My first reaction to the latter idea, actually, was rather dismissive: I deemed it too much of a stretch. Then, by chance, I stumbled upon an article saying that Frank Wilczek, a Nobel Laureate (and very highly respected in our field, even regardless of the Nobel prize), is teaming up with a material scientist for the development of a meta-material optimized for the observation of axions, which is an example of hypothetical “dark particle” … Everything checked out!

Once it was published, it was then also very interesting to read the other stories in the book, and see how other author-scientist pairs had interacted. One of my favourite ones was by Luan Goldie, based on an idea by Carole Weydert, and is about the work-family balance struggles of the protagonist, something with which many scientist readers can easily relate to. Another great one, which seems to have attracted some publicity to the book thanks to the renown of its author Steven Moffat, of Doctor Who and Sherlock fame, is based on the premise that the Universe itself may deliberately act to change its own past in order to hamper the scientists’ attempts to unveil its secrets. And the scientific backdrop of this story, suggested by Peter Dong, is based on an actual string of papers from serious physicists!
In conclusion, it was a very rewarding experience to participate in this book. I was lucky to be paired with an author who listened with sincere interest, respected my insistence on scientific accuracy, and came up with a completely original narrative idea. He shared early drafts with me – apparently something that he had never done with previous collaborators, an exception because I had stated my interest in writing – and I was fascinated by witnessing his creative process. Like the other scientists involved in the book (including John Ellis, Gino Isidori and many others), I also had the opportunity to explain the science behind the story myself in the form of a short essay following Marek’s story.

The book is available from the CERN library, CERN shop, online, and in selected bookshops globally!



Adam Marek’s story: “End titles”

Andrea Giammanco’s afterword: “Don’t shoot the messenger particle!”

Included in “Collision”, Comma Press (2023),


Book’s webpage at Comma Press:

My novel:

Adam Marek’s website:

Symmetry interview, including me and Adam Marek:

BBC interview, including me and (mostly) Adam Marek:  - Note: this link is only accessible from the UK and will expire in July 2024.


Disclaimer: The views expressed in CMS blogs are personal views of the author and do not necessarily represent official views of the CMS collaboration.