J/psi production in Jet at pp 500 GeV

Updated on Tue, 2022-04-19 01:40. Originally created by tc88qy on 2019-09-02 02:47.

The first dataset used in this analysis is run11 pp 500 GeV.

Jet reconstruction may case not of time, thus the strategy is reconstruct J/psi first, if there is a ee candidate the Jet reconstruction will be done on this event.

Part 1: J/psi-Jet correlation
J/psi-Jet correlation for Unlike-sign and Like-sign are very similar, It may doubt by using Unlike-sign - Jet correlation minus the like-sign correlation to get the J/psi correlation. In addition, the J/psi residual (~10%) is also hard to reduce. To get rid of this, I sliced dphi (phi_j/psi - phi_jet) in each of the dphi bin, I filled am invariant mass
distribution. In this invariant mass distribution, I can extract the J/psi yield.
The details of J/psi yield extraction are:
1. UnLike-sign - Like-sign
2. Residual background estimation, excluding J/psi mass counting range (2.7, 3.3).
3. Fixed Background shape and J/psi mean as well as sigma. Fitting the J/psi shape.
4. J/psi yield is (Unlike-sign -Like-sign - Residual)

Part 2: Z (J/psi pT / Jet pT) distribution
Jet (including J/psi)
Sliced Z in each Z bin, filled an invariant mass distribution. Extraction is done the same as Part 1:
Residual background
J/psi shape

Part 3: J/psi polarization in Jet
This part
J/psi shape in different Z at each cos(theta), phi bin

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Comments on the Jets pT, it is very close to J/psi pT, thus Z will peak around 1.
Part1 : J/psi yield extraction
residual background estimation
Fitting the J/psi shape
Efficiency corrected background and yield
residual background estimation with efficiency correction
Fitting the J/psi shape with efficiency correction