RE: Citizen science: Using MG5aMC to simulate top quark production at CERN's LHC

[lemouth]

I apologise for having missed your blog. For some weird reasons the notification system failed and I only noticed it 30 hours after you posted it. Anyway, here I am (better late than never!). First of all, I must admit that your report is super clear and easy to follow. I totally appreciated reading it and it was a real pleasure to discover it.

Let me now move on with a few minor comments, before addressing the answer to the question you raised at the end of your blog. Or at least, before beginning to address it (I am sure the discussion will be continued soon).

That is also the reason why I named the working directory of the output from the simulation as wobble, from Feynman's wobbling plate story, where his work that earned him a Nobel Prize began.

I had a lot of fun in remembering the wobbling plate story. It is important to always have fun with what we do! Always! I am telling this to my sons day after day, and I hope this is something they will remember during their entire lives.

the tutorial also reminded me that it's not yet necessary to understand how to interpret these results

Don’t worry, this is for next week, when we will play with event reconstruction and detector simulators.

I wasn't sure what editor was used by my command prompt

From what you wrote, this is definitely VIM or VI. I like it a lot, personally. It is however very non-intuitive (as some other editors are too).

And now the major point of this reply...

The goal of the experiments is to measure the neutrino masses (determining the upper limit?) and the so-called mixing parameters which dictate the flavour content of each neutrino (there are 6 of those parameter, what are those?)

First of all, I would like to emphasise that we do not aim to make any measurement in this project, as we only plan to work with simulations. If our results are promising, then experimentalists may initiate the tasks that will lead to the corresponding measurements in data.

What we will do instead is to try to see how well the parameters of neutrino sector can be assessed through a specific signature studied at the Large Hadron Collider. In terms of free parameters, the idea is to target the neutrino effective mass matrix that consists of a function of all the parameters of the neutrino sector (the three neutrino masses, the three mixing angles and some potential CP-violating parameters) into six more global quantities that can be directly targeted at the LHC.

I am unsure that this fully answers your question, but it probably partly does it. From there, feel free to come back to me and we will pursue the discussion.

Cheers!

Comments

[travelingmercies]

The excerpt from the book is one of my favorite stories Feynman shared about his adventures. :) It's a great reminder for every curious minds of why they started pursuing science in the first place.

Oh, apologies, the last point was actually about the experiments in neutrino physics in general and also from your blog post mentioning about those 6 parameters. I have read this article about new upper limit on the mass of neutrinos while trying to learn more about neutrino mass models. Sometimes, I think about how the scientific community is both fast and slow in making discoveries. Like how a few years ago, neutrinos were considered massless and now, when I look at my printed copy of the table of SM, there's a corresponding mass for the neutrinos, albeit their upper limits only. It's great to be at the present where technology is catching up and brilliant minds are coming together giving it a push.

This is a more specific answer to my question from my previous report, as I was a bit clueless on what simulations this project aims to do.

What we will do instead is to try to see how well the parameters of neutrino sector can be assessed through a specific signature studied at the Large Hadron Collider. In terms of free parameters, the idea is to target the neutrino effective mass matrix that consists of a function of all the parameters of the neutrino sector (the three neutrino masses, the three mixing angles and some potential CP-violating parameters) into six more global quantities that can be directly targeted at the LHC. I am unsure that this fully answers your question, but it probably partly does it. From there, feel free to come back to me and we will pursue the discussion.

I really appreciate it that the idea is getting finer to me that I am little by little getting a grasp of it. I hope it won't frustrate you if I keep on getting sidetracked or if I'm getting ahead of the tasks. 😅 I'd surely come back to this thread/to you when I stumble on more questions as I go on with my reading materials for this week, but right now, I got my answer about those 6 parameters. Again, thank you very much in everything that you're doing in this project and in particle physics. ☺️

[lemouth]

Mmmh today I learned something :)

have read this article about new upper limit on the mass of neutrinos while trying to learn more about neutrino mass models.

The article you mentioned discusses the limits obtained from the KATRIN experiment that study beta decays (I discuss this in the third section of this neutrino blog). In short, KATRIN studies a process in which a given atomic nucleus decays into another nucleus, an electron and an invisible neutrino. By studying the kinematic properties of the electron, it becomes possible to constrain the (effective electron) neutrino mass. The experiment obtained a limit on the electron neutrino mass scale of 0.8 eV.

As a side note, I had in mind a value of 1.1 eV as a limit, but the link you mentioned refer to 0.8 eV. I somehow missed the 2022 update. This explains the first sentence of my reply ;)

Now:, I would like to come back on the following sentence.

Sometimes, I think about how the scientific community is both fast and slow in making discoveries.

To emphasise this a little bit more, the first article mentioning a potential LHC project dates from the 1980s. The construction of the machine started in the early 2000s, and the first data taking period was in 2007. The LHC is supposed to operate until 2035-2040. This time scale is inherent to what we aim to do, and there is nothing to be done about it (except by having infinite funding).

I hope it won't frustrate you if I keep on getting sidetracked or if I'm getting ahead of the tasks. 😅 I'd surely come back to this thread/to you when I stumble on more questions as I go on with my reading materials for this week, but right now, I got my answer about those 6 parameters. Again, thank you very much in everything that you're doing in this project and in particle physics. ☺️

I will never be frustrated and I will always be happy to answer anything. So feel free to shout out any question at me!

Have a nice week!