# XX International Workshop on Deep-Inelastic Scattering and Related Subjects

26-30 March 2012
University of Bonn
Europe/Berlin timezone

## Measurement of Photon Production in the Very Forward Direction in Deep-Inelastic Scattering at HERA [H1]

28 Mar 2012, 08:50
20m
Small Lecture Hall, Mathematical Institute (University of Bonn)

### Small Lecture Hall, Mathematical Institute

#### University of Bonn

Hadronic final states/diffraction and vector mesons

Hamlet Zohrabian

### Description

The production of photons at very small angles with respect to the proton beam direction is studied in deep-inelastic positron-proton scattering at HERA. The data are taken with the H1 detector in the years 2006 and 2007 and correspond to an integrated luminosity of $126 \mathrm{pb}^{-1}$. The analysis covers the range of negative four momentum transfer squared at the positron vertex $6<Q^2<100$ GeV$^2$ and inelasticity $0.05<y<0.6$. Cross sections are measured for the most energetic photon with pseudorapidity $\eta>7.9$ as a function of its transverse momentum $p_T^{lead}$ and longitudinal momentum fraction of the incoming proton $x_L^{lead}$. In addition, the cross sections are studied as a function of the sum of the longitudinal momentum fraction $x_L^{sum}$ of all photons in the pseudorapidity range $\eta>7.9$. The cross sections are normalised to the inclusive deep-inelastic scattering cross section and compared to the predictions of models of deep-inelastic scattering and models of the hadronic interactions of high energy cosmic rays.

### Presentation materials

 Proceedings Slides