RE: Particle physics on Steem - let’s start coding on the MadAnalysis 5 platform
Here are more questions. :-)
Currently looking at the diphoton channel.
I don't fully understand paragraph 3 of section 4.1.
I know how to calculate the summing of pTs using the sumIsolation method, but I don't know what I'm supposed to do with the results.
What is the isolation criteria?
Paragraph 4 seems to indicate 2 lists of cuts, one for "low pTmiss category" and one for the "hight pTmiss category".
Does this mean that the program should be supplied a configuration to indicate which category to apply in the analysis?
Does pT1 mean the transversal momentum of the leading photon, and pT2 mean the transversal of the subleading photon?
Should an event be selected if a diphoton passes all the cuts in one fiducial region, but none pass the cuts in the other fiducial region?
Thanks!
Here are my answers. Sorry for the delay, I had some troubles to find the information for the first question ^^
Unfortunately, the experimental documentation is often incomplete. You found one proof (an d there are many!) by yourself. After digging a little bit, the information is actually hidden in table 3 of this paper.
You should declare two signal regions (in the initialization part of the code) and then declare the cuts and associate them with one of the regions, the other region or both regions. You can then apply them sequentially. Examples of codes can be found here, if needed.
That is correct. Again, they could have specified it in the experimental paper... (Do you believe I am often arguing about the documentation being incomplete, unclear, confusing, etc?)
The code will automatically proceed as long as an event populates at least one region.
Hi,
Great, thanks!
Ok but I already have 2 signal regions (one for each η region).
So I guess that each one of the above region should also be associated with 2 regions (low and high pTmiss), so as a result there would be 4 signal regions in total. Is that OK?
Just to be clear, both photons of a diphoton must be detected in the same fiducial region, right?
We are not talking about the possibility of the leading photon being detected in fiducial region 1, and the subleading photon being detected in fiducial region 2, isn't it?
I will work on the above assumption for now.
Thanks!
This is not correct. You need one region in which several eta conditions are applied. In fact, all eta values smaller than 2.5 are OK, except for a small window between 1.44 and 1.57. This window corresponds to the transition region between the barrel and the endcap of the detector.
I am not too sure to follow on this one. Can you please elaborate?
I think I was under the impression that the two regions where
But if I understand you well, that is not correct.
Rather there should be one region for low pTmiss, and one region for high pTmiss.
Is this correct?
Sorry, I wasn't being very clear.
Is it possible for one photon of a diphoton to be detected in the barrel, and the other photon to be detected in the end-cap?
I think I was under the impression that the two regions where
region 1: |η| < 1.44
region 2: 1.57 < |η| < 2.5
But if I understand you well, that is not correct.
Rather there should be one region for low pTmiss, and one region for high pTmiss.
Is this correct?
Now this is correct. You have to check whether there are two photons, and that each of them satisfies one of the two pseudorapidity requirements :)
Yes. This is totally possible. The relative configuration of the two photons can a priori be anything.
OK, great. Thanks for the clarifications!
I think I have finished the diphoton channel.
Should I create a new program for the di-tau channel, or do you want both analysis to be done in the same executable?
Congratulations! Both in the same program is better (one just need to add new regions). This will make things easier later.
OK, I must confess I didn't find the time yet to start working on the tau channels...
Worryingly it looks a bit more difficult to understand than the diphoton channel. :-(
I'm hoping to get started soon but I may or may not have finished by Friday.
I'll do my best.
Hi @lemouth,
In section 5.1, there some formula to calculate the isolation of leptons.
I don't understand the following:
What is the "primary vertex"?
How do I calculate the isolation components for the "primary vertex" and "non-primary vertex"?
Thanks!