Citizen science on Hive - The first ever calculation of same-sign di-muon total rates at the LHC run 3!

in StemSociallast year

Three weeks have spent since the release of the fifth episode of our citizen particle physics project on Hive. Whereas only one community member (@agreste) managed to finish all proposed tasks, two others are well advanced (@eniolw, @travelingmercies). I recommend them to consider writing an updated report when they will be fully done. Moreover, I am sure that @gentleshaid will soon write a complete or partial report.

I unfortunately have no information about anyone else participating (@isnochys? @mengene? @metabs? @servelle?). I hope everybody is fine…

This being written, it is never too late to join us in our study of neutrino mass models at CERN’s Large Hadron Collider (LHC) as a non-scientific actor from the Hive community. For this purpose, it is sufficient to go through all previous episodes, which should take a few hours of work per episode. The list of all released episodes is given below, and don’t hesitate to write reports on your progress.

In the context of this fifth episode, I am proud to say that @agreste was the first ever person in the world to provide total production rates for double-beta process at the LHC run 3. Extra work is required before getting to results in a publishable form, but these first steps are excellent ones! As can be guessed from this amazing result, our citizen science project rocks!

The present blog has the goal to provide solutions to the assignments proposed in this post. In fact, I will provide answers to all assignments, except for the last one for which I will let the participants self-checking each other, before deciding whether they are correct. I will nevertheless validate everything after my break, in about 3 or 4 weeks.

[Credits: Original image from geralt (Pixabay)]

Here is the usual recap of the previous episodes of our citizen science adventure on Hive.

As usual, I include in this introduction a list of acknowledgements to all participants to this project, and supporters from our community: @agmoore, @agreste, @aiovo, @alexanderalexis, @amestyj, @darlingtonoperez, @eniolw, @firstborn.pob, @gentleshaid, @gtg, @isnochys, @ivarbjorn, @linlove, @mengene, @mintrawa, @robotics101, @servelle, @travelingmercies and @yaziris. Please let me know if you want to be added or removed from this list.

Feynman diagrams describing our signal - assignment 1

[Credits: CMS-EXO-21-003 (CMS @ CERN)]

The figure above describes the process we consider. At the left of the figure, we see two quarks q1 and q2 that are two of the constituents of the protons that collide in the LHC. These energetic quarks convert into other quarks (the ‘primed’ quarks on the right) by emitting W bosons (in purple in the middle of the figure). Those two W bosons then lead to the production of two charged leptons l1 and l2 in the final state (that we took as muons in the exercise considered) through the exchange of a heavy neutrino N.

We observed that MG5aMC generated 80 diagrams (see the image below), and the question was about why we had so many of them.

[Credits: @lemouth]

The reason is as follows. An accelerated proton contains several flavours of quarks (four in our case: up, down, strange and charm), together with the corresponding antiquarks. Consequently, we have many possibilities for the initial quarks q1 and q2 in the above diagrams. Correspondingly, we also have different possibilities for the final-state ’primed quarks’. This is what we observe in the above image.

Signal rate at the LHC run 2 - assignment 2

The second assignment required the calculation of the rate of the new physics signal considered as a function of the heavy neutrino mass, reproducing somehow the purple line in figure 2 of the reference publication. You can find below my numbers and my plot.

Neutrino mass [GeV] Cross section [fb]
50 3.561
100 7.975
250 14.88
500 16.15
1,000 12.3
2,500 4.938
5,000 1.712
10,000 0.4864
20,000 0.1254

[Credits: @lemouth]

We can check that we have slight differences relative to the plot shown in the reference scientific publication (i.e. figure 2). This is related to the fact that we are using different parton densities dictating how to relate the colliding protons to their content, and that our calculations are accurate only at the leading order accuracy. In the reference paper, next-to-leading-order predictions are presented, in contrast.

This will be the topic of the next episode of our series: going from a leading order precision to the next-to-leading order one.

Signal rate at the LHC run 3 - assignment 3

I won’t provide solutions for this assignment and let you think about it during the summer. The numbers should however be similar to those above.

Summary: simulations of a neutrino mass signal at the LHC

In this post, I provided the solution to the assignments given in the fifth episode of our citizen science project on Hive. This episode targeted an LHC signal relevant for a neutrino mass model and had the goal to produce production rates for the LHC run 3, at a collision energy of 13.6 TeV.

This precise goal consisted of the third assignment for which I didn’t provide any solution yet, as I would like to keep the participants a bit busy during the summer break. This being written, I must admit that @agreste already produced his results, being hence the first person ever to calculate them on the planet.

In the next episode, we will start discussing precision predictions for the signal, and we will investigate the impact of precision on our results.

As I will be offline (not necessarily away, but really offline) for 3 or 4 weeks, there won’t be more tasks proposed during before my return. I hope this will leave some time to anyone interested to join the project and have fun with us.

Have a nice summer!


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Greetings dear friend @lemouth, I hope you have a good rest in these weeks that you will be offline, I see that @agreste has done a good job. It is satisfying to see how they have progressed in this project.
Greetings brother, have a great week

I let you imagine how happy I was when I read the report from @agreste and saw the plots he made. Those were precisely what I was expecting the participants to obtain, and they are the true proof our project can be a winning one!

Thatd be cool to see hive used as a sensible way to post data on a blockchain for the lowest price at cern lol all univeristies should use it

This would not be possible. The chain is way too slow and too small for the LHC. We are talking about hundreds of MB per second. Instead, we use a dedicated computing system, and decentralisation is not an option (too slow, too small in terms of space). We can only go with an expensive solution targeting the problem we need to solve (that is expensive because we need speed, space, backups, high-speed communication between universities and dedicated data centres from all over the world, etc.).

As I already mentioned it, blockchains are not suitable to solve any problem.

@agreste was the first ever person in the world to provide total production rates for double-beta process at the LHC run 3.

Congratulations to him, and to you for having the project yield such a result.

As I will be offline (not necessarily away, but really offline) for 3 or 4 weeks, there won’t be more tasks proposed during before my return

I am looking forward to your vacation 😇 Although you will be missed, your wife and your friends will be relieved to see you rest.

Have fun with the family this summer🏊‍♀🌅

Thanks a lot for this message. Still two days of work, two days of preparation, and then the computer will stay mostly offline (and I am not a "very phony person", so that my phone won't be very useful to stay connected ;)


Thank you very much for the mentions! I'm glad to be of service to this fascinating project. Have a good rest and see you in the next episode. Cheers!

Thanks again for your participation. I am super impressed by your achievements!


I actually have a plan of concluding the report today. However, power supply has hampered my plan. Maybe it will be restored later today though. Let's see what will happen. I've got a couple of questions but cant even ask now until I open my pc.

Good luck with electricity! This is indeed a problem for that kind of work that requires some computing power.

Are we talking about folding @ home style stuff here??

Not really. The idea is that anyone runs code, produces data and analyses it (and thus understands what they do). Everyone is thus acting as any professional researcher would do.

In the "[@]home paradigm", I think (I am unsure as I never checked this out) that people only provide computing power to research, and never do any computation by themselves.

Are we talking about folding @ home style stuff here??

Good morning @lemouth and how are you doing today? I hope you feel better?
Please take good care of yourself during your break too. Don’t be tempted to work in the slightest too.

Well done on this project too…. And @agreste, this is super amazing 🔥

Thanks for passing by. I am still tired, but I think this will go away when vacation time will start (i.e. when I will be far from the computer screen). My planning is so full of outdoor activities that it is clear that I won't work! Therefore, please don't worry for me (although your concerns are appreciated)!


Far from computer screen.... I like that.
You're welcome too


Thank you!

I am proud to say that @agreste was the first ever person in the world to provide total production rates for double-beta process at the LHC run 3.

A great @agreste milestone and accomplishment I must say.
A big congratulations to you and also everyone that has made the citizen science a success this far.

Thanks for your support to this (amazing ;) ) project, and your nice words!

Thank you!

Hive user science? Lets all compare our ancestry dna results and see if theres any trends that make some genetics better at dpos lol find the queen

That's not for me. Remember that I am a particle physicist. That limits the scope of possibilities for projects I would be able to lead. Anyone else with the right skills is however welcome to start any other initiative (I hope that this project will set up a precedent).

Wow i must commend you on your work, am a taxidermist at Thank you for you knowledge. Keep up the good works.
Thank you.

Thanks or passing by and your support. Note that we would be happy to see blogs on taxidermy at STEMsocial. I have never read anything on this.


Sure! I'll catch up as soon as I get some free time.

As I will be offline for a couple of weeks, you will have plenty of time to catch up ^^

Désolé j'ai lâché le projet par manque de temps et aussi car je suis un peu dépassé par la complexité.
Je ne trouverais pas honnête de faire des rapports sur des calculs que je ne comprends pas suffisamment.
Je suis cependant la progression et si je me motive assez je raccrocherai les wagons après les vacances, en Septembre.

Okidooki je vois. Pas de soucis. N'hesite pas a revenir vers moi si jamais tu revenais vers nous. Ca serait avec plaisir :)

Great Post!


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You will be missed too
Have an amazing summer😃

Thanks! You too!


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