Status of the FOPI pp Beamtime -Motivation -Particle Reconstruction -Inclusive Reconstruction...

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p Kaonic bound states Λ(1405) Doorway Mechanism   p  Λ  p  p + 3 T. Yamazaki et T. Akahishi, Phys. Rev. C 76 (2007) p–K - Potential Robert Münzer Leannis Meeting – Prag – May 2012

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Status of the FOPI pp Beamtime -Motivation -Particle Reconstruction -Inclusive Reconstruction -Exclusive Reconstruction with kinematical Refit -Summary and Outlook Motivation p Kaonic bound states (1405) Doorway Mechanism p p p + 3 T. Yamazaki et T. Akahishi, Phys. Rev. C 76 (2007) pK - Potential Robert Mnzer Leannis Meeting Prag May 2012 N* - Resonances Robert Mnzer Leannis Meeting Prag May Production Mechanism: p + p -> p + K + + M. S.-W. : Eu. Phys. Jou. A 46 The Experiment (Start RPC) : 200 ps S(Start PLAWA) : 400 ps Exclusive measurement: GeV Target: 2cm Liquid Hydrogen 80 Million LVL2 Trigger Events p + p - + p + K + ppK - + p (1405) + p + K GeV Beam Magnet CDC Barrel RPC Helitron PLAWA Robert Mnzer Leannis Meeting Prag May SiLViO Beam Magnet CDC Barrel RPC Helitron PLAWA Robert Mnzer Leannis Meeting Prag May Polar angle of particles from decay (pK + / K + in RPC acceptance) LVL1 / LVL2: Signal (pK + ): 5.8 Background (UrQMD pp 3.1GeV): 20.3 LVL1 / LVL2: Signal (pK + ): 5.8 Background (UrQMD pp 3.1GeV): 20.3 Trigger conditions LVL1: M(TOF) > 1 LVL2: LVL1 + SiVIO Trigger conditions LVL1: M(TOF) > 1 LVL2: LVL1 + SiVIO Silicon -Vertexing and Identification Online SiViO 8 M>0 M>1 NIMA617: ,2010 SiViO Acceptance Robert Mnzer Leannis Meeting Prag May 2012 Particle Selection Particle Identification 10 Backward Hemisphere CDC momentum + energy loss Backward Hemisphere CDC momentum + energy loss Forward Hemisphere Helitron momentum + Plawa TOF Forward Hemisphere Helitron momentum + Plawa TOF Preliminary Robert Mnzer Leannis Meeting Prag May 2012 Calibration not final Kaon Identification Time of Flight Detectors: Resistive Plate Chambers (RPC) Preliminary 11 Robert Mnzer Leannis Meeting Prag May 2012 -- p Inclusive Reconstruction Inclusive Reconstruction Data pp Simulation Preliminary 13 p CDC HELITRON Si ViO RPC Robert Mnzer Leannis Meeting Prag May 2012 Inclusive Reconstruction Data LVL2 Data LVL1 Enhancement: > 4,4 Fits to simulation Enhancement: > 4,4 Fits to simulation Preliminary 14 p CDC HELITRON Si ViO RPC Robert Mnzer Leannis Meeting Prag May 2012 Exlcusive Reconstruction K+K+ -- p Kinematical Refit Modify Particle Track Parameters (mom, phi, theta) within error to fulfill contraints. Results: New Particle Track Parameters, 16 Background Robert Mnzer Leannis Meeting Prag May 2012 Diploma Thesis D. Pleiner Diploma Thesis D. Pleiner Kinematical Refit Conservation Constraint 17 K+K+ p p p p (E,p) beam (E,p) target (E,p) kaon (E,p) pion (E,p) secproton (E,p) primproton p p p p -- -- K+K+ K+K+ E secproton + E pion + E primproton + E kaon = E beam + E target p secproton + p pion + p primproton + p kaon = p beam + p target E secproton + E pion + E primproton + E kaon = E beam + E target p secproton + p pion + p primproton + p kaon = p beam + p target Robert Mnzer Leannis Meeting Prag May 2012 Kinematical Refit Mass Constraint 18 K+K+ p p p p (E,p) beam (E,p) target (E,p) pion (E,p) secproton (E,p) primproton p p p p -- -- K+K+ K+K+ { (E,p) secproton + (E,p) pion } = M() (E,p) kaon Robert Mnzer Leannis Meeting Prag May 2012 Kinematical Refit Mass Constraint 19 K+K+ p p p p (E,p) beam (E,p) target (E,p) pion (E,p) secproton (E,p) primproton p p p p -- -- K+K+ K+K+ Vertex Constraints: Intersection p and (E,p) kaon Robert Mnzer Leannis Meeting Prag May 2012 Kinematical Refit Mass Constraint 20 K+K+ p p p p (E,p) beam (E,p) target (E,p) pion (E,p) secproton (E,p) primproton p p p p -- -- K+K+ K+K+ Vertex Constraints: Intersection p and K + (E,p) kaon Robert Mnzer Leannis Meeting Prag May 2012 Kinematical Refit Mass Constraint 21 K+K+ p p p p (E,p) beam (E,p) target (E,p) pion (E,p) secproton (E,p) primproton p p p p -- -- K+K+ K+K+ Vertex Constraints: Primary & Secondary Vertex (E,p) kaon Robert Mnzer Leannis Meeting Prag May 2012 Exlcusive Reconstruction pp Simulation (URQMD) K+K+ -- p Conservation Constraint E secproton + E pion + E primproton + E kaon = E beam + E target p secproton + p pion + p primproton + p kaon = p beam + p target E secproton + E pion + E primproton + E kaon = E beam + E target p secproton + p pion + p primproton + p kaon = p beam + p target pval> Conservation Constraint Robert Mnzer Leannis Meeting Prag May Invariant mass (p, ) With refit Without refit Robert Mnzer Leannis Meeting Prag May Conservation + Mass Constraint E secproton + E pion + E primproton + E kaon = E beam + E target p secproton + p pion + p primproton + p kaon = p beam + p target E secproton + E pion + E primproton + E kaon = E beam + E target p secproton + p pion + p primproton + p kaon = p beam + p target { (E,p) secproton + (E,p) pion } = M() Invariant mass (p, ) With refit Without refit Robert Mnzer Leannis Meeting Prag May pval>0.007 Missing Mass(p) Without Refit With Refit N* included in Urqmd Robert Mnzer Leannis Meeting Prag May pval>0.007 p+p -> p + N* ( -> + K + ) Exlcusive Reconstruction Data K+K+ -- p Data Original pval cut(>0.87) Original Invariant Mass (p,) Energy & Momentum Contraint N* MM (p) - refitted Pp UrQMD MM (p) - refitted Data Unrefitted refitted |Inv(p,pi)-1.116| 0.1 Conservation Constraint all pk Conservation Constraint all pk Best Value: Conservation Constraint Missing Mass (p, K) Different Contraints Conservation Conservation+ Mass Invariant Mass (p,) Invariant mass (p, ) Conservation Conservation+ Mass Missing Mass (p) Conservation Conservation+ Mass N* included in Urqmd Missing Mass(p) Conservation pKL - Phasespace N* included in Urqmd Missing Mass (p, K) Different Contraints Conservation Conservation+ Mass Exlcusive Reconstruction Data K+K+ -- p Data Original pval cut(>0.87) Original Invariant Mass (p,) Energy & Momentum Contraint Data Refitted Original Missing Mass pK+ =1.132 =0.039 =1.132 =0.039 =1.24 =0.050 =1.24 =0.050 |InvM(p,p)-1.116|