_ A Simple Generator for pA Collisions Dec 6, 2016 | - PowerPoint PPT Presentation

Mitglied der Helmholtz-Gemeinschaft _ A Simple Generator for pA Collisions Dec 6, 2016 | Albrecht Gillitzer LIX PANDA Collaboration Meeting, GSI Darmstadt, 5-9 Dec 2016

Antiproton-Nucleus Physics for „Day-1“ � � Nuclear potential of Λ � pairs • Mean p T in correlated ΛΛ • Missing mass in of forward Λ � Color Transparency � Short Range Correlations � ΔΔ component in the deuteron (and in nuclei) � Additional ideas (?) Dec 06, 2016 p. 2 Albrecht Gillitzer

Existing Event Generators for � � A � URQMD • background generator • little flexibility, no access to source code(?) • I‘ve never used it � GiBUU • use for both background and signal • flexibility, many options, access to source code, very complex �� � → � � � � �, � � � � � ⁄ • I‘ve used it for �̅ Ca → � � � FTF • both for �̅� and �̅� , emphasis on background • some flexibility • I‘ve used it for �̅� only Dec 06, 2016 p. 3 Albrecht Gillitzer

Need Simple Signal Generator in � � A � Idea: implement �̅� collisions in EvtGen � Physics model: quasi-free �̅� reactions with (A-1) spectator nucleus on nuclear proton or neutron with internal momentum Dec 06, 2016 p. 4 Albrecht Gillitzer

Decay File for EvtGen decay model pbarNe20_pbarpX.dec : noPhotos # Decay pbarASystem 1.0 A-1System pbarpSystem NucleusSpectator 20.0 1.0 1.88; Enddecay # Decay pbarpSystem 1.0 p+ anti-p- PHSP; Enddecay # parameters End Dec 06, 2016 p. 5 Albrecht Gillitzer

Decay Model � $ � $ �� � � � � ∝ � � exp − %& '$ + � % exp − � momentum distribution: %& $$ ; ) � ∝ � % �� 3 $ ⁄ , * % = 220 MeV 0 ⁄ , � � � � , * � = 115 MeV 0 3 ' = 0.0146 � select absolute momentum of A-1 spectator � select isotropic cos :, ; � calculate p4 of target nucleon: � < = = −� < >�� , ? = = @ > − ? >�� � calculate p4 of �̅� system and boost to initial �̅� system � then �̅� system decays as specified in decay file Dec 06, 2016 p. 6 Albrecht Gillitzer

� �̅ = 8.0 GeV/0 Dec 06, 2016 p. 7 Albrecht Gillitzer

Dec 06, 2016 p. 8 Albrecht Gillitzer

Dec 06, 2016 p. 9 Albrecht Gillitzer

Ne-20 Ne-20 He-3 He-3 Dec 06, 2016 p. 10 Albrecht Gillitzer

PandaRoot Simulation & Analysis � trunk versions 29122, 29475 � p = 8.0 GeV/c � target: 20 Ne (A = 20) � final state: �̅ � � − 1 ; in addition: �̅ � D � � − 1 � 1 M events / 0.4 M events � MC truth match � ideal PID Dec 06, 2016 p. 11 Albrecht Gillitzer

Dec 06, 2016 p. 12 Albrecht Gillitzer

Dec 06, 2016 p. 13 Albrecht Gillitzer

Status � Tested with simpleEvtGen for various nuclei: 3 He, 20 Ne, 40 Ca, 208 Pb, 238 U � Full simulation & analysis: 1 M events �̅� → �̅� � − 1 � Full simulation & analysis: 0.4 M events �̅� → �̅�D � � − 1 � Relevant files uploaded to the repository � Should work from present trunk – Try it ! Dec 06, 2016 p. 14 Albrecht Gillitzer