Particle physics on Steem - let’s start coding on the MadAnalysis 5 platform

in utopian-io •  3 months ago

I hope you all had a nice summer. Fall is almost there and it is timely to resume this particle physics project on Steem allowing non-physicist to contribute to state-of-the-art research in particle physics by contributing to the MadAnalysis 5 platform.


[image credits: Maximilian Brice (CC BY-SA 4.0)]

I will not enter into details, as everything has been largely documented in all the posts given below. For any newcomer, a good start is the 3-month status report that I posted right before leaving for my offline vacation place (and all references within).

Here, I instead solely focus on 3 LHC analyses which I would like the participants (so far, the main contributors are @crokkon, @effofex, @irelandscape, @mactro) to tackle.

Two of them (task requests 1 and 2) concern supersymmetry. Supersymmetry consists in one of the most studied theories extending the Standard Model of particle physics, and offers a bunch of new phenomena to use as handles for searching for it.

The last one (task request 3) focuses on dark matter, one of the key concept behind standard cosmology. The nature of dark matter is still unknown, assuming it exists, as alternative are still viable. Producing and observing it at particle colliders is thus vital for our understanding of nature.

Finally, as a bonus, anyone who would like to finish the dark matter analysis used in the exercises that we achieved is welcomed to do so.


General rules


After discussing with Utopian.io moderators, it has been decided that each contribution will have to be submitted in a fresh GitHub repository containing the C++ implementation, in the MadAnalysis 5 framework, of one or more of the analyses proposed below.

Please also do not forget to tag me in your post detailing your implementation and to leave a comment to this post (with the link) so that I could notice your work.


[image credits: geralt (CC0)]

On top of the various posts related to this project, an extensive documentation (of 100 pages) has been released last August. I recommend to browse it, and in particular its second technical appendix that contains all methods available within the MadAnalysis 5 package.

All submissions will be reviewed, and allowed to enter the second phase of the project if correct. The second phase of the project will address validation, which is by far not trivial and necessary for being included in the Public Analysis Database of MadAnalysis 5.

Such a validation procedure requires to simulate LHC collisions and to reproduce experimental predictions to some extent. This is what we will talk about in a month or so.

All contributions have to be submitted by September 28th. Good luck everyone!


TR1. Supersymmetry with ATLAS


The task request 1 focuses on a search for the supersymmetric partners of the Higgs bosons by the ATLAS collaboration. The sections 5 and 6 of this scientific article contain the description of the analysis.

  • Object definitions are detailed in Section 5 (very similar to the exercises).
  • 8 low-mass signal regions are defined in section 6.1.1 (summary in table 2)
  • 2 high-mass signal regions are defined in section 6.2.1 (summary in table 5).
  • The design of some of the variables may sound complicated. Feel free to ask for help.
  • Control regions can be ignored.

TR2. Supersymmetry with ATLAS - again


The task request 2 focuses on a search for the supersymmetric partners of the quarks and gluons by the ATLAS collaboration. The sections 5 and 6 of this scientific article contain the description of the analysis.

  • Object definitions are detailed in Section 5 (very similar to the exercises).
  • Section 6 details various signal regions: 3 classes of "high-pt" signal regions (see table 3) and 2 classes of "low-pt" signal regions (see table 4).
  • Each class of regions contains varied subregions according to the value of an mll variable (see tables 7 and 8). All those signal regions must be implemented independently.
  • Control regions can be ignored.

TR3. Dark matter with CMS


The task request 3 focuses on a search for dark matter by the CMS collaboration. The sections 4 and 5 of this scientific article contain the description of the analysis.

  • Diphoton channel: object definitions are detailed in Section 4.1 that also includes the analysis itself. There are two signal regions.
  • Ditau channel: object definitions are detailed in Section 5.1 that also includes the analysis itself. There are three signal regions.

References


  • Ref. 1: installation instructions and generalities on the MadAnalysis 5 framework.

  • Ref. 2: reconstructing photons, electron and muons in a detector; basic C++ programming in the MadAnalysis 5 framework.

  • Ref. 3: properties of all objects reconstructed in a detector; introducing jets.

  • Ref. 4: Histogramming and object isolation.

  • Ref. 5: implementing an analysis strategy, selection cuts and signal regions.

  • 3-month status report of the project.

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Thanks for the task request(s) and good luck finding people who can solve it/them.

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[utopian-moderator]

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Thanks for the feedback. I agree with all points and i really hope to see some contributions. For this, however, we will need to wait ^^

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Thank you for your review, @amosbastian!

So far this week you've reviewed 2 contributions. Keep up the good work!

OK, here are my first questions related to TR.3.

My understanding of the signal regions is:
For the diphoton channel: Signal regions are |η| < 1.44, and 1.57 < |η| < 2.50
For the τ+τ- channel: Signal regions are eτh, μτh and τhτh decay channels
Is this correct?

My undestandting of signal region eτh is that:
h (higgs) decays into τ+τ- (tau and anti-tau), and then that the τ+ decays into an electron (+neutrinos), while the +τ- decays into hadrons.
Is this correct?

Should the program generate histograms?

Show the program generate cut flow reports?

Do you have any sample data that I could run the program against?

That's it, I'm sure I'll have more questions in the future! :-)

Thanks!

Loading...

This application is the moment when I wish I know how to program in C++, but as my grandma used to tell me, "It is never too late to start.''

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No it is never too late. It is also pretty quick: a couple of afternoons. :)

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A couple of afternoons if you already are proficient in Matlab or Java :)
But yes, programming is easy, @greenrun, a lot of fun and has the ability to keep Mr.Alzheimer away :D
A lot of video tutorials out there, some you may even listen to in your car.
We actually have a success case with a young girl banker who wanted to be a programmer at 25. She enlisted in our paid-academy (we did the paying) projects. It took her 3-6 months to reach a comfortable level in .NET
She got an offer to work full time here afterwards.
So follow what you like and working people will usually be rewarded in life.

Cheers!

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@greenrun now we are two pushing you to start with! Please have a look to this post where one steemian got used to it in one week-end ^^

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Now, that sounds like an offer I cannot refuse :D

Posted using Partiko Android

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No you can't :D

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I know. Lol

Posted using Partiko Android

Ah, we are now reaching the main course. ;-)
I'll have a look at the reference documents when I get a chance.
Just to get an idea of the scope of work, would you say this is a much bigger task than previous exercises?

Cheers!

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Not necessarily. I think that the TR1 and TR2 are harder and may require an afternoon or two. TR3 is easier. But at the end of the day, the difficulty is the same as for the exercises. The only subtlety is that these analyses contain more than one signal region. Therefore not more complicated, but longer to implement.

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OK, I think I will try to work on TR3 in that case.
I'm really swamped at the moment so it probably makes sense that I pick the "lighter" task this time.
I had a look at section 4 and 5. As usual it's very hard to understand for me so I will probably have a few questions in the coming days!

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Don't hesitate to shoot questions here! :)

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t heve best stratecy...i think,,,

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I beg your pardon?

This project looks really interesting, I would love to dig more about it as soon as I get more free time.

Looks like it's time to renew my object-oriented programming knowledge :')

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Anytime is good! I would be more than happy to have more participants on board! :)

And so it begins. Again. I'll read up a bit and see if this is for me. Will you be fleshing out the TR's at all - things like example input data?

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This will be addressed when we will start validating the different pieces of code, which will come later. Validation is by far not trivial here, as it goes beyond just agreeing with a scientific article. But we first need to have something to be validated, i.e. working codes.

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I'm interested in trying to help out but how do I know if someone is already working on the task I would work on?

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To my knowledge, TR3 is taken by @irelanscape. The two others are still free.

Hey, @lemouth!

Thanks for contributing on Utopian.
We’re already looking forward to your next task request!

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i assume you won't be considering sourceforge as a microsoft-free alternative grin.png

it's great to see steemchain getting practical application in "the real world" in any case. Please discover something that enables FTL, corrects Einsteins framework and/or allows forward timetravel because i always feel ive been born 1000 years too soon (or maybe too late ... there's a certain charm at just bashing someone to a pulp to get what you want although its really something that should be considered only as a last resort dealing with those who don't understand anything but violence ofcourse)

j/k

great work, looking forward to the next lecture steemit lecture :D

everything's possible until proven otherwise, i am neither an atheist nor a believer and if there's an infinite number of here between this and that, why should i ?
(me, trying to get my fortune cookie on)

seriously, i dont understand why the Ned doesn't propagate this more " We are working WITH CERN on data for the large hadron collider

in a place full of self-proclaimed free thinkers, and a lot of i know better people, what could go down better, lol (i still think an educational free to download game on steam(not steem) that uses gpu and cpu resources like boinc would be a good idea but i'm not upper class so thats more for #utopian-io to decide is it not :p as i said previously, i doubt the Gaben wouldnt jump at a chance like that too)

and then some ... unfortunately, as always, the house doesn't clean itself.

yours truly,

sarcastiCat :p

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i assume you won't be considering sourceforge as a microsoft-free alternative

What??! No for god sake! :D

seriously, i dont understand why the Ned doesn't propagate this more " We are working WITH CERN on data for the large hadron collider

Well, this is a question for him and not for me...

in a place full of self-proclaimed free thinkers, and a lot of i know better people, what could go down better, lol (i still think an educational free to download game on steam(not steem) that uses gpu and cpu resources like boinc would be a good idea but i'm not upper class so thats more for #utopian-io to decide is it not :p as i said previously, i doubt the Gaben wouldnt jump at a chance like that too)

Here, I need help from people, not from computers. That is where the difference lies :)

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yea, well i'm not a first name basis with the upper-Ned here lol so you're right, but i just don't get it, its like a flashy neon-sign for a realworld blockchain application plus free advertising for steemit

but your people need computers to help you so i still think the game would be a good idea, maybe if i keep on the programming i can try myself in a year or two :) put my name on it and advertise myself with it hahah

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yea, well i'm not a first name basis with the upper-Ned here lol so you're right, but i just don't get it, its like a flashy neon-sign for a realworld blockchain application plus free advertising for steemit

I don't decide anything here, but I sometimes share your non-understanding.

but your people need computers to help you so i still think the game would be a good idea, maybe if i keep on the programming i can try myself in a year or two :) put my name on it and advertise myself with it hahah

Yes, and this is why many boinc for the LHC or cosmology exist already. For my project, people is the resource I need at most for now :)

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always the diplomat hahah ... i didnt know that came with the masters in physics ? a course in diplomacy ?

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Nope, this I learned after having been too rude (and paid the price for that) in my early days ;)

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early days :)
i doubt you're that ancient, i personally just have a lot of trouble with the required peacock dance in negotiations while everyone already knows what they want and you can just put the cards on the table lol. Some people seem to enjoy wasting time on hours and hours of conversation while you already know what the baseline is how far you will go and what exactly you want.
and it often gets me mistaken for rude , it does, but its just direct and doesnt fit in well with my sometimes prozaic and mostly chaotic nature i think its what people call "weird" :p
despite that, on the classic gary-gygax scale of disposition (which i think is a lot better than the standard one-dimensionel left-right people adhere to) i still think that despite appearences id come out as overall chaotic-good while it appears chaotic-neutral (old dungeons and dragons stuff from when life was different)

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One always has to play the game of the people above us... This being said, each of us has early days. It consists just in the early stage of the career/life, somehow.