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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

SLIDE 1

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

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SLIDE 2

Dec 06, 2016

p. 2

Albrecht Gillitzer

Antiproton-Nucleus Physics for „Day-1“

Nuclear potential of Λ

Mean pT in correlated ΛΛ

pairs

Missing mass in of forward Λ

Color Transparency Short Range Correlations ΔΔ component in the deuteron (and in nuclei) Additional ideas (?)

SLIDE 3

Dec 06, 2016

p. 3

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

SLIDE 4

Dec 06, 2016

p. 4

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

SLIDE 5

Dec 06, 2016

p. 5

Albrecht Gillitzer

Decay File for EvtGen

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 # End

decay model parameters

SLIDE 6

Dec 06, 2016

p. 6

Albrecht Gillitzer

Decay Model

momentum distribution:

∝ exp −

$ %&'$ + %exp − $ %&$$ ;

) ∝ %

, * = 115 MeV 0

⁄ , *% = 220 MeV 0 ⁄ ,

3$ 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

SLIDE 7

Dec 06, 2016

p. 7

Albrecht Gillitzer

̅ = 8.0 GeV/0

SLIDE 8

Dec 06, 2016

p. 8

Albrecht Gillitzer

SLIDE 9

Dec 06, 2016

p. 9

Albrecht Gillitzer

SLIDE 10

Dec 06, 2016

p. 10

Albrecht Gillitzer

Ne-20 Ne-20 He-3 He-3

SLIDE 11

Dec 06, 2016

p. 11

Albrecht Gillitzer

PandaRoot Simulation & Analysis

trunk versions 29122, 29475 p = 8.0 GeV/c target: 20Ne (A = 20) final state: ̅ − 1 ; in addition: ̅ D − 1 1 M events / 0.4 M events MC truth match ideal PID

SLIDE 12

Dec 06, 2016

p. 12

Albrecht Gillitzer

SLIDE 13

Dec 06, 2016

p. 13

Albrecht Gillitzer

SLIDE 14

Dec 06, 2016

p. 14

Albrecht Gillitzer

Status

Tested with simpleEvtGen for various nuclei: 3He, 20Ne, 40Ca,

208Pb, 238U

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 !