PYTHIA for GLUEX

PYTHIA has beed tuned by the HERMES team to reproduce the various particle photoproduction by a 28~GeV electron beam. I used their version of the code (PYTHIA 6.225), removing the radiation correction part, since GLUEX is using a photon beam. The other HERMES corrections to the code stay. I also used the flags and parameters tuned for HERMES.

The full photoproduction cross section at 9 GeV is about 0.12 mb, while PYTHIA gives 0.071 mb. I used the ratio of 1.69 to correct the partial cross section produced by PYTHIA in order to compare them with various measurements, summarized in a review by Baldini et al.

Comparison of photoproduction cross sections with PYTHIA calculations
process Measured PYTHIA

E_γ, GeV σ µb E_γ, GeV σ µb

γ+p → 1 prong 9.3 8.5±1.0 9.0 6.2

γ+p → 3 prongs 9.3 64.4±1.5 9.0 59.

γ+p → 5 prongs 9.3 34.2±0.9 9.0 44.

γ+p → 7 prongs 9.3 6.8±0.3 9.0 8.3

γ+p → pπ⁺π^-π^° 9.3 7.5±0.8 9.0 6.8

γ+p → pπ⁺π^- 9.3 14.7±0.6 9.0 14.5

γ+p → strange 5.6 8.7±0.9 9.0 24.

γ+p → pπ⁺π^-K⁺K^- 9.3 0.46±0.08 9.0 1.7

γ+p → pK⁺K^- 9.3 0.58±0.05 9.0 0.44

γ+p → pφ 9.3 0.55±0.07 9.0 0.53

**Comparison of photoproduction cross sections with PYTHIA calculations**
process	Measured	PYTHIA
E_γ, GeV	σ µb	E_γ, GeV	σ µb
γ+p → 1 prong	9.3	8.5±1.0	9.0	6.2
γ+p → 3 prongs	9.3	64.4±1.5	9.0	59.
γ+p → 5 prongs	9.3	34.2±0.9	9.0	44.
γ+p → 7 prongs	9.3	6.8±0.3	9.0	8.3
γ+p → pπ⁺π^-π^°	9.3	7.5±0.8	9.0	6.8
γ+p → pπ⁺π^-	9.3	14.7±0.6	9.0	14.5
γ+p → strange	5.6	8.7±0.9	9.0	24.
γ+p → pπ⁺π^-K⁺K^-	9.3	0.46±0.08	9.0	1.7
γ+p → pK⁺K^-	9.3	0.58±0.05	9.0	0.44
γ+p → pφ	9.3	0.55±0.07	9.0	0.53

E-Mail : gen@jlab.org
Last updated: June 13, 2007