The impact of ttbar cross-section measurement with the first LHC data

The measurement of ttbar cross-section will be a challenging but fruitful step for the LHC experiments when the first data is collected in 2009-2010. Analysis strategies have been carefully crafted to obtain measurements that are robust against uncertainties of the detector performance in the early data. The richness of top phenomenology enables cross- section measurements in a variety of channels providing vital information to understand the consistency of the data, laying an essential foundation to new physics discoveries. We will present the prospects of the ttbar cross-section measurement, which have been studied in detail using full detector simulation. We will then review the impact of early ttbar cross-section measurements in the broader perspective of the LHC physics.