Measurements with HERA-II Data

The analysis of the HERA-I data has led to a tremendous increase in the understanding of the mechanisms of heavy quark production in $ep$ and $\gamma p$ scattering. In general, perturbative QCD has been proven to give reliable predictions. Experimentally, the HERA-I data are well understood and a large number of the important analyses have been performed and published or are in the process of being finished.

With HERA-II, the instantaneous luminosity has been increased by roughly a factor of 3 and the size and statistical precision of the data samples will be significantly improved. Furthermore a number of detector upgrades have been performed which open opportunities for new measurements in yet unexplored kinematic regions and will help reduce the systematic uncertainties. It is expected that the HERA-II data sample for heavy quark physics will be of order 500 pb$^{-1}$.

The main physics goals of Heavy Quark physics at HERA-II are

• to complete the picture of heavy quark production to large values of $p_t$ and $Q^2$, i.e. to gain statistics in regions in which both the charm and beauty masses are small in comparison to $p_t$ or $Q^2$ and massless models are expected to hold.
• to perform double differential measurements, allowing to study the differences between data and theory in detail.
• to cross check the results obtained with charm with precision measurements of beauty production.
• to extend the kinematic reach into the forward region. This is the kinematic region in which the largest differences between the data and the theory have been found. New and upgraded forward detectors will allow for measurements up to larger values of rapidity.
• to exploit more decay channels, e.g.by use of the new silicon detectors and larger statistics.
• to search for new states and to verify the findings of possible new states of HERA-I.

In the following the new detector components most relevant to heavy quark physics are described and possible future measurements are discussed.