Sebastian Ordoñez
jsordonezs@unal.edu.co
Supervisors: Alberto C. dos Reis & Diego A. Milanés C.
29th of November 2021
CERN Summer Student Programme 2021
The \(D\) meson is the lightest known particle containing charm quarks, its mass is known to be 1869.62\(\pm\)0.20 MeV
Tree-level diagram for the \(D^{+}\longrightarrow K^{-}K^{+}K^{+}\) decay
Dalitz Plot before and after cuts on the SDV
Invariant-mass spectrum of the \(K^{-}K^{+}K^{+}\) candidates
Before MVA it is necesasry to reduce the high levels of background: clone tracks and combinatorial.
and
Invariant-mass spectrum of the \(K^{-}K^{+}K^{+}\) candidates
Dalitz Plot before and after cuts on the PID variables
Background from data
Signal from Monte Carlo
Input variables for the MVA Algorithms
Classifier output distributions
ROC curve for all the classifiers
Area under the ROC curve
BDTG response
BDT response
Result of applying cuts in the classifiers that showed the best signal-background discrimination performance
\(D^{+}\longrightarrow K^{-}K^{+}K^{+}\) invariant-mass spectrum
This is the final invariant-mass distribution of the \(K^{-}K^{+}K^{+}\) candidates after applying the cut on the MLP classifier, the one with the best performance.
Final Dalitz Plot and Projections
Details and references can be found in CDS: https://cds.cern.ch/record/2781351