Measurement of elastic ρ 0 photoproduction at HERA
Document Type
Article
Publication Date
12-1-1995
Abstract
Elastic ρ 0 photoproduction has been measured using the ZEUS detector at HERA. Untagged photoproduction events from ep interactions were used to measure the reaction γp→ρ 0 p(ρ 0)→π +π-) at photon-proton centre-of-mass energies between 60 and 80 GeV and |t|<0.5 GeV2, where t is the square of the four-momentum transferred at the proton vertex. The differential cross section dσ/d M ππ where M ππ is the invariant mass of the two pions, and the integrated cross section, σγp→ρ{variant}0ρ{variant}, are presented; the latter was measured to be 14.7±0.4 (stat.) ±2.4 (syst.)μb. The differential cross section dσ/dt has an approximately exponential shape; a fit of the type A t ′ exp(-b t ′ |t|+c t ′ t 2) yields a t-slope b t ′ =9.9±1.2 (stat.) ±1.4 (syst.) GeV-2. The results, when compared to low energy data, show a weak energy dependence of both σγp→ρ{variant}0p and of the t-slope. The ρ 0 is produced predominantly with transverse polarisation, demostrating that s-channel helicity conservation holds at these energies. © 1996 Springer-Verlag.
Publication Source (Journal or Book title)
Zeitschrift für Physik C: Particles and Fields
First Page
39
Last Page
54
Recommended Citation
Derrick, M., Krakauer, D., Magill, S., Mikunas, D., Musgrave, B., Repond, J., Stanek, R., Talaga, R., Zhang, H., Ayad, R., Bari, G., Basile, M., Bellagamba, L., Boscherini, D., Bruni, A., Bruni, G., Bruni, P., Cara Romeo, G., Castellini, G., Chiarini, M., Cifarelli, L., Cindolo, F., Contin, A., Corradi, M., Gialas, I., Giusti, P., Iacobucci, G., Laurenti, G., Levi, G., Margotti, A., Massam, T., Nania, R., & Nemoz, C. (1995). Measurement of elastic ρ 0 photoproduction at HERA. Zeitschrift für Physik C: Particles and Fields, 69 (1), 39-54. https://doi.org/10.1007/BF02907384