A Quantum Diaries Survivor

In the final day of the ICNFP 2022 conference in Kolympari (Greece), we could listen to an enlightening presentation by Prof. Marek Karliner (Tel Aviv University), who is an absolute authority on the matter of the theory of hadron spectroscopy. 

A reader of this blog left an interesting question in the comments thread of the article I wrote on recent ATLAS results two days ago. As I tried to answer the question exhaustively, I think the material might be of interest of other readers here, so I decided to make an independent post of it, adding some more detail.John asks whether it is possible that what we see, when we plot the mass of a particle, is the true distribution of values of the particle - i.e. that the particle does not have only one mass, but a distribution of values. The question is not an idle one! So let us discuss it below. I will make a few points to clarify matters.1. We estimate by proxy

Bill Murray gave a nice summary of recent results from the ATLAS collaboration at the ICNFP conference this morning, and I will nit-pick a few graphs from his presentation to show the level of detail of investigations in subnuclear processes that the Large Hadron Collider (LHC) is providing these days, as seen from the lens of one of its two main microscopes, the wondrous ATLAS detector.The LHC is taking data. What, again?

I arrived to Kolymbari, a nice seaside resort on the western coast of the Greek island of Crete, late yesterday night, and am now already immersed in the morning session of the XI edition of the International Conference on New Frontiers in Physics. This event, which takes place at the Orthodox Academy of Crete in Kolymbari since 2012, takes a rather broad view on advances in both experimental results and theory of fundamental physics.

In over 15 years of blogging, in this and previous sites, I have mostly stayed away from the topic of climate change, the environmental catastrophe we are creating with our "perennial growth" myths and our disdain of our planet and the other species that inhabit it, and the continuous slaughter of over a billion animals every year for our unnecessarily opulent lunch tables. 

Today I am back from one of the most interesting workshops I ever attended to, and I wish to share some thoughts I had on possible ways to enhance our research of new ideas for future particle detectors with you. Those ideas come from discussions with other participants to the workshop, or just from re-digesting things I have been pondering over for a while. 

To appreciate what B mesons are, and what is the magic of their behaviour, which is the topic of this article, I need to give you a three-paragraph introduction below.At the smallest distance scales, matter is made of quarks and leptons, which we consider as point-like objects endowed with different properties and interactions. Most of the matter around us is in fact made up of three-quark systems: protons and neutrons, organized in tightly packed nuclei kept together by the strong force; with electrons (which are the lightest charged leptons) orbiting around them thanks to the electromagnetic force attracting them to the protons. 

Physicists from the CMS experiment at CERN's Large Hadron Collider have used the total data sample of 13 TeV proton-proton collisions collected in the past few years to search for resonant decays of heavy hadrons into pairs of J/Psi mesons, and they found three of them. One of the three new resonances is likely to be the same as a particle already identified for the first time by the competitor LHCb experiment, while the other two are new finds. LHCb is also a LHC detector, but it is one optimized for heavy hadron spectroscopy; while CMS is a "general purpose" detector built with the primary goal of finding the Higgs boson (a 2012 success) and searching for new phenomena at the highest-energy frontier. 

Yes, I know - I have touched on this topic already a couple of times in this blog, so you have the right to be bored and surf away. I am bound to talk about this now and then anyway, though, because this is the focus of my research these days. Recently I was in the Elba island (a wonderful place) for a conference on advanced detectors for fundamental physics, and I presented a poster there on the topic of artificial-intelligence-assistend design of instruments for fundamental physics. Below is the poster (I hope it's readable in this compressed version - if you really want a better pic just ask).

Neural networks are everywhere today. They are used to drive vehicles, classify images, translate texts, determine your shopping preferences, or finding your quickest route to the supermarket. Their power at making sense of small or large datasets alike is enabling great progress in a number of areas of human knowledge, too. Yet there is nothing magical about them, and in fact what makes them powerful is something that has been around for century: differential calculus.

When I explain to the public (in this blog, or at public conferences or schools) how the Large Hadron Collider operates, I have to gloss over a lot of detail that is unnecessary to grasp the important concepts, which enable other discussions on interesting subnuclear physics. This is good practice, and it also saves me from having to study details I have forgotten along the way - they say that what you are left with when you forget everything is culture, and I tend to agree. I have a good culture in particle physics and that's all I need to do some science popularization ;-)

As the twentythree regular readers of this blog know [(c) A.Manzoni], in recent times I have moved the main focus of my research to advanced applications of deep learning to fundamental science. That does not mean that I am not continuing to participate in the CMS experiment at the CERN Large Hadron Collider - that remains the main focus of my research; but it does mean that what remains of my brain functionalities is mostly invested in thinking about future applications of today's and tomorrow's computer science innovations.