Improvement and tuning of DPM model A. Galoyan and V. Uzhinsky, 7 Jun. 2017 1. Irregularities of invariant mass distributions in DPM generator found by Albrecht Gillitzer 2. Source of these irregularities in DPM Preliminary results of the DPM improvement All calculations with DPM were performed using PandaRoot installed in HybriLIT cluster in LIT JINR 4. Conclusion 1

2 April 27, 2017 | Albrecht Gillitzer IKP-1 PANDA Group Meeting Composite States in DPM & FTF (Test of DPM and FTF) 10^6 DPM events at momentum 4.6 GeV/c 10^6 FTF events events at momentum 4.6 GeV/c 2

Questions/problems In contrast to DPM, FTF creates zero-width composed states like Δ, ρ or K* -> Request to Geant4 DPM FTF Structures in pπ-, pπ+ and p pbar spectra seen in DPM are not present in FTF -> redesign of DPM DPM FTF 3

We have analyzed P-Pi mass distributions in DPM processes 4

Questions/problems Structures in pπ-, pπ+ and p pbar spectra seen in DPM are not present in FTF -> redesign of DPM Mpi-p > Ecms/2 Dominant process in DPM - fragmentation of di-quark and anti-diquark string Dominant process in FTF 5

We were trying to implement FTF algorithm in DPM Results 6

Cross sections of Pbar-P processes in DPM and FTF models Dynamics of the Pbar-P and Pbar-A reactions in the FTF model. A. Galoyan, A.Ribon, V. Uzhinsky //Contributions of the conference - IWNT35: 2016 http://ntl.inrne.bas.bg/workshop/2016/proc.html; arXiv:1610.08341 DPM cross sections FTF cross sections 7

8 Using FTF process cross sections we have preliminary results in DPM

Using FTF process cross sections we have preliminary results in DPM 9

Pair mass distributions in new version of DPM 10

Conclusion Sources of irregularities found by Albrecht are studied. The improvement of DPM generator has just started. Improved fragmentation functions are implemented in DPM generator 4. FTF cross sections of Pbar-P processes are installed 5. After tuning and complete testing, new improved DPM will be installed and commited in PandaRoot. 11