Abstract
The photoproduction of isolated photons has been measured in diffractive events recorded by the ZEUS detector at HERA. Cross sections are evaluated in the photon transverse-energy and pseudorapidity ranges 5 < ETγ < 15 GeV and -0.7 < ηγ < 0.9, inclusively, and also with a jet with transverse energy and pseudorapidity in the ranges 4 < ETjet < 35 GeV and -1.5 < ηjet < 1.8, using a total integrated electronproton luminosity of 456 pb-1. A number of kinematic variables were studied and compared to predictions from the RAPGAP Monte Carlo model. An excess of data is observed above the RAPGAP predictions for z ℙmeas > 0.9, where z ℙmeas is the fraction of the longitudinal momentum of the colorless "Pomeron" exchange that is transferred to the photon-jet final state, giving evidence for direct Pomeron interactions.
| Original language | English |
|---|---|
| Article number | 032006 |
| Journal | Physical Review D |
| Volume | 96 |
| Issue number | 3 |
| DOIs | |
| Publication status | Published - 31 Aug 2017 |
Funding
We appreciate the contributions to the construction, maintenance and operation of the ZEUS detector made by many people who are not listed as authors. The HERA machine group and the DESY computing staff are especially acknowledged for their success in providing excellent operation of the collider and the data-analysis environment. We thank the DESY directorate for their strong support and encouragement. We also thank H. Jung for providing invaluable assistance with the use of RAPGAP. S. A., A. B., M. C., A. P., M. C., A. M., M. S., E. T., A. B., S. D., A. L., L. S., R. B., A. G., A. S., and M. R. were supported by the Italian National Institute for Nuclear Physics (INFN). I. B. and E. P. were supported by the German Federal Ministry for Education and Research (BMBF), under Contract No. 05 H09PDF. Z. A. I., N. Z. J., F. M., N. M., and W. A. T. W. were supported by High Impact Research (HIR) Grant No. UM.C/625/1/HIR/ 149 and University Malaya Research Grant (UMRG) Grants No. RU006-2013, No. RP012A-13AFR and No. RP012B-13AFR from Universiti Malaya, and Exploratory Research Grant Scheme (ERGS) Grant No. ER004-2012A from the Ministry of Education, Malaysia. P. J. B., D. H. S., I. O. S., A. M. C., R. C. E. D., C. G., N. H. B., and M. W. were supported by the Science and Technology Facilities Council, UK. B. F., E. G., R. K., N. K., E. L., J. S., and M. T. were supported by the German Federal Ministry for Education and Research (BMBF), under Contract No. 05h09GUF, and the SFB 676 of the Deutsche Forschungsgemeinschaft (DFG). R. H., K. N., K. T., S. Y., Y. Y., T. T., Y. I., M. I., and M. K. were supported by the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT) and its grants for Scientific Research. R. K. D., L. K. G., Yu. A. G., I. A. K., B. B. L., O. Yu. L., and L. M. S. were partially supported by RF Presidential Grant No. NSh-7989.2016.2. H. A., S. K., A. L., and A. S. were supported by the Israel Science Foundation. C. D. C. was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC). B. F., V. M., O. T., and K. W. were supported by the Alexander von Humboldt Foundation. M. W. was also supported by DESY and the Alexander von Humboldt Foundation.
All Science Journal Classification (ASJC) codes
- Nuclear and High Energy Physics