update

alefisico · Jan 4, 2024 · 44e0c88 · 44e0c88
1 parent 928bc55
commit 44e0c88
Show file tree

Hide file tree

Showing 5 changed files with 25 additions and 8 deletions.
diff --git a/_episodes/02-Pileup_jetID.md b/_episodes/02-Pileup_jetID.md
@@ -120,7 +120,6 @@ There are 12 interactions before and 3 after.
 
 Tracking is a major tool in CMS. We can identify most charged particles from non-leading primary vertices, CHS removes these particles. 
 
-<img src="../fig/episode2/pfenergyfractions.png" alt="" style="width:30%">
 
 ### PileUp Per Particle Identification (PUPPI)
 

diff --git a/_episodes/03-JEC_JER.md b/_episodes/03-JEC_JER.md
@@ -1,6 +1,6 @@
 ---
-title: "JEC and JER"
-teaching: 10
+title: "Jet energy corrections and resolution"
+teaching: 40
 exercises: 20
 questions:
 - "What are jet energy correction?"
@@ -13,10 +13,6 @@ keypoints:
 - "Jets are stochastic objects which its content fluctuates a lot. We measure the jet energy resolution to mitigate this effects."
 ---
 
-(Following slides 27-38 from these slides)  (FIXME)
-
----
-
 > ## After following the instructions in the setup (if you have not done it yet) :
 >
 > ~~~
@@ -32,9 +28,29 @@ keypoints:
 
 ## Jet Energy Corrections
 
+<img src="../fig/episode3/jet_response.svg" alt="" style="width:50%">
+
+Let's define the jet pt response $R$ as the ratio between the _measured_ and the _true_ pt of a jet
+from simulation. We expect that the average response is different from 1 because of pileup adding
+energy or non-linear calorimeter response. 
+
+__Jet energy corrections (JEC)__ corrects reconstructed jets (on average) back to particle level.
+This is done against many useful metrics, like $p_T^{gen}$, $\eta$, area, pileup. CMS uses a
+_factorized approach to JECs_:
+
+<img src="../fig/episode3/Run2-JERC.png" alt="" style="width:50%">
+
+ * Pileup corrections to correct for offset energy (noPU vs. PU jet matching). This is usually called L1FastJet.
+ * Correction to particle level jet vs. 𝑝𝑇 and η from simulation. This is called L2Relative and L3Absolute, or L2L3 together.
+ * Only for data: Small residual corrections (Pileup/relative and absolute) to correct for differences between data and simulation. This is called L2L3Residuals.
+
+<img src="../fig/episode3/l1l2_jecs.svg" alt="" style="width:70%">
+
+### Exercise 3.1
+
 > ## Open a notebook
 >
-> For this part open the notebook called `Jet_Energy_Corrections.ipynb` and run the Exercise 1 and 2.
+> For this part open the notebook called `Jet_Energy_Corrections.ipynb` and run the Exercise 3.1
 {: .checklist}
 
 > ## Discussion 1.1

diff --git a/fig/episode3/Run2-JERC.png b/fig/episode3/Run2-JERC.png
diff --git a/fig/episode3/jet_response.svg b/fig/episode3/jet_response.svg
diff --git a/fig/episode3/l1l2_jecs.svg b/fig/episode3/l1l2_jecs.svg
Original file line number	Diff line number	Diff line change
Expand Up		@@ -120,7 +120,6 @@ There are 12 interactions before and 3 after.

		Tracking is a major tool in CMS. We can identify most charged particles from non-leading primary vertices, CHS removes these particles.

		<img src="../fig/episode2/pfenergyfractions.png" alt="" style="width:30%">

		### PileUp Per Particle Identification (PUPPI)

Expand Down