Matthew Bellis: Alright, so we are now in need, let me go back to sharing my screen.
Matthew Bellis: Here we go.
Matthew Bellis: So we've now moved on to the online hands on portion This is again very similar to what you'll be doing in the other exercises as well.
Matthew Bellis: And if you go to.
Matthew Bellis: Now we're done with the break everybody earned it this next section is really, really just some basic questions.
Matthew Bellis: We only got so much time, I think we have allotted 40 minutes for this and there might be some questions that are not raised by this, but this is not a test, there is no grade given for this workshop.
Matthew Bellis: Instead of this, really, you know kind of self motivated how much you want to learn.
Matthew Bellis: And so I provided really basic questions for you to kind of remind yourself of what we covered, you can keep these notes for yourself, you do not have to share them with me.
Matthew Bellis: I would actually prefer that you don't share them with me, I will be posting solutions for this.
Matthew Bellis: Tomorrow sometime, so I will not post solutions on this today, but I will post solutions on this tomorrow, and we can use today as a point of discussion.
Matthew Bellis: If you can't answer and all of these questions the answers are in the previous lessons in the previous not.
Matthew Bellis: Like the pre exercises, but the previous section is in this lesson, so these questions are really designed to encourage people to go back through and read the some of them are very basic can you get to the starting page for the cms open data.
Matthew Bellis: What was the collision energy for some of these years for the bulk of the cms release data.
Matthew Bellis: And then there's a little bit more information about trying to find some collision data, how to understand what triggers are doing and then.
Matthew Bellis: Interestingly enough, as I was going through this last question about some of the simulated data I ran into some questions that I could not easily answer.
Matthew Bellis: And so I am actually going to use this as a learning exercise for myself as well, to find out more detailed information about some of the simulated data.
Matthew Bellis: And then the hands on activity does go a little bit deeper into this, but I thought this would be a nice kind of like easy review because there's a lot to cover today so i'm going to actually stop talking for a while i'm going to give everybody a chance to kind of just go through this.
Matthew Bellis: If you come across a question you don't know how to answer off the top of the BAT i'm going to ask you not to post a question right away i'm going to ask you to see if you can dig it out of any of the previous.
Matthew Bellis: sections of previous episodes of this lesson and then, if you spend some time really trying to dig around and you can't find it, you can post here just raise your hand or in the chat session, and we will try to monitor this.
Matthew Bellis: Every now and then, I may have asked for like a show of hands, however.
Matthew Bellis: To see how people are doing so maybe just for the first question, a show of hands, how many people can get to the cms open data portal or the CERN site CERN open data portal.
Matthew Bellis: How many people are able to get oh good few for a second like nobody raised their hand and I was like oh no no good good there's more people oh good I was like really worried i'm like no nobody can get there alright good people can get to the CERN open data portal.
Matthew Bellis: On tanks and Julie has posted in the chat i'm the direct link to the matter most discussion for this exercise.
Matthew Bellis: I good i'm glad people could get to the CERN open data portal, I would have failed as an instructor.
Matthew Bellis: If you weren't able to do that.
Matthew Bellis: And just out of curiosity, or any of the hands that are currently raised for questions or were you just raising your hands from before because about if you could get to the CERN open data portal.
Matthew Bellis: Okay cool great.
Matthew Bellis: I should have asked this um do you guys know how to raise your hand.
Matthew Bellis: i'm the host so I don't think I have the same functionality that you do.
Matthew Bellis: Julie, if someone wants to raise their hand, do they just mouse over their name and does that option pop up under participants, or is there a different way to do it.
Edgar Fernando Carrera Jarrin: there's a reactions and think.
Edgar Fernando Carrera Jarrin: button, that you can use.
Matthew Bellis: Oh there it is yeah yeah, thank you for that sorry so at the very bottom Thank you Edgar at the very bottom there's reactions it's a little SMILEY face one of them is raised hand, thank you.
Matthew Bellis: eugene add a comment can one get into the CERN open data portal through lx plus so I guess that question Alex plus is one of these certain machines.
Matthew Bellis: I don't actually know if the discs are accessible from Alex plus or if you always have to go through a vm or Dr terminal.
Matthew Bellis: Claudia Edgar do you have anything to say eugene asked this question in the zoom chat.
Kati Lassila-Perini: For the usage of open data and Alex plus.
Kati Lassila-Perini: The, we need to have the operating system which is compatible and Alex plus.
Kati Lassila-Perini: it's more recent.
Kati Lassila-Perini: than the than days as see six we using so that's why either people need to be using the open data container and.
Kati Lassila-Perini: And then or then well the the Alex we do have the singularity Shell that one can use in in in X plus but I don't think this is so much of the topic of this workshop can't really cover all the specific.
Matthew Bellis: specific aspects.
Matthew Bellis: yeah and I think one issue would be that so let's suppose you were an atlas user and you had an x plus account that at CERN.
Matthew Bellis: accessing the data files themselves on their own it's not necessarily useful unless you have the analysis, the cms is w software stack So even if you could you know CD to the directory where the files exist.
Matthew Bellis: You would be very limited in any type of analysis that you could do and that's why again that's coming environments being able to have a docker vm environment with all of the software that was used is really the only way to guarantee that you were processing the data correctly.
Matthew Bellis: hater or cartier comments there's there's no way to do polls as they're on zoom.
Matthew Bellis: Instead, something I feel like I could do that.
Matthew Bellis: At my school, but I don't see the option and.
Matthew Bellis: In this version of zoom.
venison.
Edgar Fernando Carrera Jarrin: Is a pulse Indymedia.
Matthew Bellis: Now Poles like doing like a quick.
Oh.
Edgar Fernando Carrera Jarrin: I see.
Edgar Fernando Carrera Jarrin: I actually it is version.
Matthew Bellis: yeah maybe not with this version Okay, no biggie.
Matthew Bellis: just wanted to make sure I wasn't missing anything.
Matthew Bellis: Also, if you are making great progress on this and feel free to go ahead and add your information to the pad let introduction, if you haven't already.
Matthew Bellis: meet each other, virtually and this new world.
Matthew Bellis: So, for the first three questions the getting to the starting page what collision energy difference between collision and simulated data.
Matthew Bellis: Could anybody raise their hand if they've had trouble with those first three questions or unsure of the first three questions I see one question about triggers which i'll answer in a moment, but, for the first three questions.
Matthew Bellis: Does anybody have any questions.
Edgar Fernando Carrera Jarrin: There are some questions in the chat window.
Matthew Bellis: them Okay, I will jump in with those So the question about triggers.
Matthew Bellis: So.
Matthew Bellis: cms is well the lsc experiments all have if they wanted to the ability to take.
Matthew Bellis: data for every collision those collisions are coming in either every 15 nanoseconds depending on the type of run period or every 25 nanoseconds, which means that you are basically getting this event trade of either 20 million times a second or 40 million times a second.
Matthew Bellis: That is far too much data to be recorded if you were to just record every position.
Matthew Bellis: and not every collision is interesting, what we're really looking for let's suppose you have an ATV collision, we would like, as much of that energy to go into the collision as possible.
Matthew Bellis: But we're not colliding protons were actually colliding corks and glue ons that make up all of.
Matthew Bellis: These protons and when you have a collision not all of the energy goes into the collision sometimes the protons just may or the courts may skip across each other.
Matthew Bellis: So they exchange some energy but they kind of it's almost like you have two balls coming and they just like clipped each other, a little bit and fly off.
Matthew Bellis: That may produce a bunch of energy going forward and backward in the detector.
Matthew Bellis: But it's not really always the physics that we're looking for it means that there was not enough energy maybe put into the collision to create new particles or other processes that we know you need much more effectively a head on collision.
Matthew Bellis: And so we design hardware, as well as software to very, very quickly, as the data is being recorded make a decision as to whether or not we should actually write that data to tape right that data to disk or basically throw it out erase everything start over and that is called a trigger.
Matthew Bellis: For each collision for each time something happens, we get something happening in our detector and very quickly, either in hardware, software decision is made as to whether or not to take all the information on the cms detector and write it to disk or just flush it and be done with it.
Matthew Bellis: These triggers might look for some deposition of energy in our view on system.
Matthew Bellis: Maybe that is consistent with either one or two milan's having gone through we're not doing any sort of tracking we're not trying to reconstruct to the exact path that a particle took we're just trying to say hey look, there was a bunch of energy here, that is.
Matthew Bellis: That is probably a new on that went in the system, or if it's an electromagnetic calorie mentor perhaps an electron or a photon.
Matthew Bellis: And so the data, not only when it gets written out do we do we set aside to keep it, but we have a little flag associated with it, like haha we are writing this because it past trigger a or trigger be or trigger see or maybe some combination of those.
Matthew Bellis: Are Monte Carlo are simulated data we can run a simulation of these triggers as well.
Matthew Bellis: And so, for each event in the Monte Carlo sample, we can say did it past trigger a B and C or did it pass none of those or did it past just trigger a.
Matthew Bellis: And now you as the analyst might be like haha i'm working with a trigger that looks for to museums, I should go through my simulated data and make sure each event past the flag for those two milan's.
Matthew Bellis: So that is the, that is, the concept of triggers that is not unique to the lsc there's not unique to CNS, it is a more general particle physics concept this idea of making a very quick determination as the data is coming in, as to whether or not you keep it.
Matthew Bellis: So hopefully that was helpful there's a bit more information on this in the trigger.
Matthew Bellis: In the trigger what's the word i'm looking for pre exercise as well.
Matthew Bellis: cool i'm glad that helped um the last question about the Z prime data set I believe there are.
Matthew Bellis: I think there are a couple I just found I just looked at the one particular data set when I was going through it.
Matthew Bellis: The one that I looked for if there's two of them, maybe there are two different became modes and I only found one of them, so i'll be curious to what people see and, yes, if there is a tag of lf V dylan ask this yeah that would be left on flavor violating.
Matthew Bellis: And I will actually bring up one of the ones that I had found in a little bit to to generate some discussion.
Matthew Bellis: erdem did you have a question as well, I saw your hand is raised.
Erdem Yi?it Ert?rer: Yes, I have a question, by the way, can you hear me loud and clear.
Matthew Bellis: I can hear you perfectly.
Okay.
Erdem Yi?it Ert?rer: i'm in i'm in physics senior undergrad so it may be a trivial question but, as I was looking through the open that data and searching for five different triggers I saw the like the term part like tall part level new part what is part me.
Matthew Bellis: Right so um This is something that i'm not as as familiar with i'm going to let cotton Edgar correct me on this in some of the newer data, you will only see like I think i'm hurt i'm you saw this with the double view there's a double mute park sample.
Erdem Yi?it Ert?rer: Yes.
Matthew Bellis: And right whole part yeah oh and there's a cow part as well right though.
Matthew Bellis: The w right in the in the new data sets for run to you will see this as double new on.
Matthew Bellis: And then just TAO the park, I believe, refers to.
Matthew Bellis: When you are doing a very, very early you take the data you set it aside you actually do a very quick reconstruction of it before you write it so it's a little bit more involved.
Matthew Bellis: than just doing a very quick hardware trigger and the data is staged for some period of time before it is written out to do this very quick pre processing on it.
Matthew Bellis: At least that's how i've heard it used in terms of actually the first term I heard that the first time I heard this term was actually from an llc be colleague of mine.
Matthew Bellis: But at during conti I was not actually part of cms during run one, so I am actually not.
Matthew Bellis: familiar with the details of the Web park samples, or if it means the same idea of kind of like cashing the data for a moment, doing a very quick processing of it before writing it out or a quick search, if you will.
Matthew Bellis: clements or cottier Edgar Julie, do you want to maybe provide a better explanation copy.
Kati Lassila-Perini: The web parked.
Kati Lassila-Perini: That was a question.
Matthew Bellis: yeah the park, what is the part three.
Kati Lassila-Perini: and eight, he said, it is the double new data set as was taking a time of data, taking was combined to what was a park data.
Kati Lassila-Perini: So, in that sense web parked contains more data that we have available at the time of the early data, taking the parked data indicates, something that we are not reconstructing immediately, but we are doing that.
Kati Lassila-Perini: Slightly afterwards to to.
Kati Lassila-Perini: to optimize the resources but it for the for the usage point of view, it is, it contains all the data that one would normally expect from a data set which is called upon me.
Erdem Yi?it Ert?rer: Okay Thank you so much.
Matthew Bellis: After you were gonna say something.
Edgar Fernando Carrera Jarrin: yeah just some.
Edgar Fernando Carrera Jarrin: Some some some input on this yeah we were actually working with the trigger at that time, and so I know about this kind of firsthand.
Edgar Fernando Carrera Jarrin: So that at the end of the day, was something like okay our trigger system in our acquisition system system can only handles.
Edgar Fernando Carrera Jarrin: couple of kilohertz of data, but you know people are pushing for more data, because they want to do more studies and have better sensitivities and control.
Edgar Fernando Carrera Jarrin: samples, and such and so these events where exactly as Kerry said, where it just the solution at the time was was just divert these events to certain repository area turn and reconstruct them.
Edgar Fernando Carrera Jarrin: right away, because that will take a lot of resources but later, you know, once the legacy has stopped for upgrades they will come back to those data and to raw data and reconstruct and in that way.
Edgar Fernando Carrera Jarrin: People will have more data and.
Edgar Fernando Carrera Jarrin: Then, can they can use it in their analysis that was the story about the part so as part in the sense that is is just.
Edgar Fernando Carrera Jarrin: hanging in there to be reconstructed at some place in.
Edgar Fernando Carrera Jarrin: Certain.
Edgar Fernando Carrera Jarrin: repositories two clusters, which.
Matthew Bellis: Banks and let me, let me emphasize airtime you mentioned, you are an undergrad I think there are a number of undergrads.
Matthew Bellis: Participating I would say that the undergraduate experience is actually similar to at least that the experimental understanding similar to many phenomenology and theorists So these are all fantastic questions for unambitious.
Matthew Bellis: there's a question in the zoom chat about how do you inspect the data found at a particular link with the edm dumped event content tool, I will show you that, so I am going to open, let me share my screen for a second.
Matthew Bellis: So I think this is the record that you went to you want to look at the the Z prime.
Matthew Bellis: And so, if you scroll down to the bottom, oh right, so this is one of the quite right, so this actually.
Matthew Bellis: This was actually one of the questions I was going to raise for my my peers my colleagues at this, so I had just grabbed a data set that I thought was interesting for this exercise, I said oh Z prime there's a lot of people looking for Z prime.
Matthew Bellis: If you are unsure if you're still trying to figure out how to understand some of these names, there is a link in all of the records all the simulated records about the description of the simulated data set name, and so you can click on about cms simulated data set names.
Matthew Bellis: And you find a little bit more breakdown of like understanding what some of these acronyms mean or maybe not acronyms but abbreviations little bit more information about the keywords that we generally tend to use tau l for charge leptons.
Matthew Bellis: Z Z prime for know photon.
Matthew Bellis: and so on and so on.
Matthew Bellis: And when I first grab this i'm like oh Z prime this looks like to TT i'm not sure what the EU is but i'm sure I can figure that out afterwards this looks like a mass of about 220 gv.
Matthew Bellis: I was not sure what this team meant and I thought I would be able to understand more, and then I did not quite appreciate that some of the data sets.
Matthew Bellis: Right, so the on demand, this is the the flag that we click.
Matthew Bellis: This data set is not available online as of yet, however, you can contact the.
Matthew Bellis: You can contact the organizers of the open data if you're interested in accessing the files, it may take weeks or months, so you could send an email to the open data support@cern.ch.
Matthew Bellis: There is some information, however, you can see, if you want to look at the who's files of how this was generated, you can go to this link right here.
Matthew Bellis: And there's information in here and looks like there was a file called Z prime to with 220 gv.
Matthew Bellis: Three of these files, but this actually does not give you more more exact information.
Matthew Bellis: And so to the question that was posed in the comments, because this is not currently stage you actually cannot examine it with the edm dump tool.
Matthew Bellis: So I will argue that, even though I had not put as much thought into this for for this exercise, it turned out to be a good learning tool, so I guess, not all of the files that you can see all the records, you can examine with edm dumb.
Matthew Bellis: But I will use this perhaps as a way to generate some discussion.
Matthew Bellis: Is there a way.
Matthew Bellis: For a user to try to find out more exact information, for example, this looks like Z prime decaying to TT which is TT bar.
Matthew Bellis: But if one wanted to know more about it, or if this was a little bit you know I don't know i'm not sure exactly what the you means i'm not sure if there's more information contour Edgar.
Matthew Bellis: What would be an appropriate way for someone to learn more about this if it was not staged or is this really the best information conti could you share some insight.
Kati Lassila-Perini: Yes, good said the selected this.
Kati Lassila-Perini: You pointed out the weak points right.
Matthew Bellis: Now i'm sorry.
Kati Lassila-Perini: This is, this is very good.
Kati Lassila-Perini: I think that he said, first of all, this is an important point in the sense that these are most of these on demand files, they are.
Kati Lassila-Perini: They have been used in very few analysis, so those were the first of the thought that will not be of immediate interest so that's why they were left on demand and in a certain sense that has proved proved to be true, because no one has yet.
Kati Lassila-Perini: demanded that, however.
Kati Lassila-Perini: We are currently working on the PETRA display of the of the generator information and indeed for the files which are produced through the lh is tap, we are not yet properly.
Kati Lassila-Perini: displaying them on the portal, but we working on that for the files which are actually.
Kati Lassila-Perini: generated by the generators that are building in the same software like btr hearing that we can immediately display the general parameters from from the portal.
Kati Lassila-Perini: But that's indeed the point that we are working on and we are happy to get complains if if you don't find the information, information that you find that we know that the information that product is not perfect.
Matthew Bellis: Okay, good i'm glad this turned out to be a teachable moment for all of us, then.
Matthew Bellis: Thanks scotty.
Matthew Bellis: And there's some for people who haven't seen there's some some good questions about the file formats in the zoom chat I won't repeat them, but Julie has.
Matthew Bellis: provided more clarifying context to some of the questions which is a great and helpful and Jamie i'm glad that was helpful for you as well.
Matthew Bellis: There was a question about tabula.
Matthew Bellis: took Toma Toma I can I only read that word I can't pronounce it.
Matthew Bellis: So I think ah, I can't remember if tesla is for the Tower decays if it's a way to simulate the Tower case or not coffee, do you want to comment on that I forgot.
Kati Lassila-Perini: Yes, precisely the it many times the data set name it indicates that this is there's something additional used in those cases it's precisely how all of which is a a tool to generate the towel House more precise, with a degenerate.
Matthew Bellis: Since there are some you know new you know younger collaborators and colleagues on this and participating i'll make mentioned.
Matthew Bellis: We often have different tools that simulate different stages of a physics process, so there is a tool commonly tool called mad graph that.
Matthew Bellis: Basically, produces particles at the level, you would write down a fireman diagram or what some people would refer to as the tree level diagram so a couple of glue ons coming together, creating some virtual particle that then.
Matthew Bellis: couples to fork antique work at that stage, we may use other tools, however, to simulate the hadron ization so how we create showers of particles how corks an Anti forks.
Matthew Bellis: Had denies into pions and protons and produce showers of particles and there are a series of post processing is not the right language but it's a different set of computer programs that simulate different physics.
Matthew Bellis: Pitsea is a very, very, very widely used ones that simulates this hybridization and then a copy mentality is for.
Matthew Bellis: A bit you know, has more precise physics information about how decays because that's something that we're looking into, you will see other terminology in this her wig is another more specific tool using for some of this.
Matthew Bellis: Some of the simulation of the physics, and this is physics that we're simulating before the electron goes through parts of the detector.
Matthew Bellis: This is really at some very, very you know femto scale level before it interacts with the detector how we simulate that process those tools are constantly being.
Matthew Bellis: updated as we get information from experiments as well as maybe more precise theoretical inputs and so you'll see this terminology pit the her where Teller Teller.
Matthew Bellis: In these names indicating which of these tools may have been used to simulate that that underlying physics.
Matthew Bellis: We only have a few minutes left before we go on to.
Matthew Bellis: Before we go on to julie's talk, so let me just for a moment just tell you what the online challenges that you will be doing, and then i'm going to hand it over.
Matthew Bellis: To Julie for objects, I think that's the schedule so here's your offline challenge, should you choose to accept it, and this will just be you know kind of a bit of a real life thing again without going into too much detail I claim, you could do this in about 30 to 45 minutes.
Matthew Bellis: So what you want to do is question right you want to make the next big discovery For those of you who are not as familiar, this is a shot from the unveiling of the higgs discovery from members of the Joint candela from cms.
Matthew Bellis: and
Matthew Bellis: Oh, my gosh I apologize i'm so I fabiola sorry from from atlas was also head of CERN right now, this is the audience, looking at the data from the higgs and this could be you, you could be one of these people who's made the next big discovery.
Matthew Bellis: And so I can talk to the very contrived exercise you've predicted a new particle this particle is called an ultimate on.
Matthew Bellis: The final particle to be discovered and you calculate most likely decay, is to to same sign charged leptons and two jet's of that could be any flavor.
Matthew Bellis: The predicted mass is in the 300 to 500 G range and you are going to look for it in the cms open data consider only the 2012 run period so here is the particle that you have predicted.
Matthew Bellis: So you need to determine what triggers might be most sensitive to this process we've talked about a few of them, but you could explore some others if you want their explanations in the.
Matthew Bellis: In the in the data sets how many records are there for each of these triggers and how many events will you be looking through when you go to look for these how many events will you have to search through.
Matthew Bellis: You also are concerned about background, so what standard model processes might contribute to the background and are there simulation samples that can help you study this.
Matthew Bellis: Now, again, I know that there are some new users and So the first thing you might want to do is remind yourself of what the top Cork decays to what a w bows on what is the bones on and what a trillion process refers to.
Matthew Bellis: And if any of these could be backgrounds can you ignore any of these, and so you should look at these standard model samples for the simulated data, and do you see any of these processes in there.
Matthew Bellis: And then I would like you to consider a particular sample that i've linked to there are many, many of these this is TT jets I will let you look up the details of this.
Matthew Bellis: And then, while I have not told you, the Cross section is the Cross section is large enough could this be a significant background.
Matthew Bellis: And so you're going to have to determine what process, this is could it be a significant background and I claim that a fair amount of that information should be on this page.
Matthew Bellis: You can post on matter most with your questions, but I hope that your peers will jump in, especially if it's questions about the physics and then tomorrow, we have some time blocked out to discuss the solutions.
Matthew Bellis: I think there's been enough time for questions and we have quite a bit more to cover so i'm going to stop the recording i'm going to hand it off to.
Matthew Bellis: To Julie and then I will restart their recording for her so I just want to say thank you everybody for your attention and your time and I will be seeing you virtually and on matter most over the course of this workshop Julie, I will stop and start, and then it is all yours.
Julie Hogan: sounds good.