Mitglied der HelmholtzGemeinschaft and with Box Generator Mar

Mitglied der Helmholtz-Gemeinschaft _ Λ and Λ with Box Generator Mar 17, 2015 | Albrecht Gillitzer, IKP Forschungszentrum Jülich _ LII PANDA Meeting, Giessen, March 2015

Box Generator Settings § Panda. Root version: 26413 (Oct 14 release) _ § # events: 1× 106 Λ and 1× 106 Λ _ § expected pπ- and pπ+ pairs: 639000 each § momentum range: 0. 5 Ge. V/c – 3. 0 Ge. V/c § theta range: 0 o – 35 o § phi range: 0 o – 360 o March 17, 2015 Albrecht Gillitzer p. 2

Statistics and Efficiencies Λ branch Λbar branch MC pπ event fraction 62. 7% 62. 3% # MC pπ events 626951 622500 p / pbar rec. eff. 78. 7% 70. 4% π- / π+ rec. eff. 83. 5% 86. 0% Λ / Λbar rec. eff. 50. 5% 47. 0% March 17, 2015 Albrecht Gillitzer p. 3

Particle Multiplicities _ Λ branch March 17, 2015 Albrecht Gillitzer p. 4

_ Λ and Λ Candidates March 17, 2015 M [Ge. V/c 2] Albrecht Gillitzer M [Ge. V/c 2] p. 5

θ [o] p [Ge. V/c] Protons: θ vs. p March 17, 2015 p [Ge. V/c] Albrecht Gillitzer p. 6

θ [o] p [Ge. V/c] Antiprotons: θ vs. p March 17, 2015 p [Ge. V/c] Albrecht Gillitzer p. 7

θ [o] p [Ge. V/c] π-: θ vs. p March 17, 2015 p [Ge. V/c] Albrecht Gillitzer p. 8

θ [o] p [Ge. V/c] π+: θ vs. p March 17, 2015 p [Ge. V/c] Albrecht Gillitzer p. 9

θ [o] p, π-: θ vs. Λ decay z March 17, 2015 z. Albrecht [cm] Gillitzer z [cm] p. 10

θ [o] _ _ p, π+: θ vs. Λ decay z March 17, 2015 z. Albrecht [cm] Gillitzer z [cm] p. 11

efficiency _ Comparison: p and p _ p efficiency ratio Reconstruction Efficiency March 17, 2015 p Albrecht Gillitzer _ p/p o] θ [p. 12

θ [o] _ Comparison: p and p p θ [o] Reconstruction Efficiency March 17, 2015 Albrecht Gillitzer _ p θ [o] p [Ge. V/c] p. 13

_ p annihilation π+ _ Λ _ p π+ πevt #8 March 17, 2015 Albrecht Gillitzer p. 14

_ p annihilation πγ π+ π+ _ Λ γ _ p π+ πMarch 17, 2015 Albrecht Gillitzer π- γ evt #11 p. 15

Summary _ § 1 million Λ and 1 million Λ generated with the Box Generator were simulated § the reconstruction efficiency for antiprotons is by about 10% lower than for protons § no systematic difference observed for π+ and for π§ annihilation of antiprotons is seen in Event Display § next: realistic pattern recognition March 17, 2015 Albrecht Gillitzer p. 16