Data driven polarization measurement at the ILC using the W+W- production

The ILC will be an e-e+ linear collider, operating at energies from 500 GeV up to 1 TeV. This accelerator, complementary to the LHC at CERN, will be a precision machine, allowing measurements of new physics and detailed investigations of the electroweak symmetry breaking mechanism, involving the Higgs and the couplings of Gauge bosons. The knowledge of the beam polarization is important for many measurements, with an aimed level of precision of the 0.2%. At the ILC dedicated polarimeters will be able to measure the polarization on a very short timescale, but they will need to be calibrated using a physics process. Due to its sensitivity to the polarization and its high cross section, the W+W- production fits perfectly this purpose. Two methods are presented. The first is a modified Blondel scheme, which makes use of the total cross section measurement for different signs of the incoming beam polarization. An alternative technique has also been studied, with the aim to reduce the high luminosity demand of the Blondel scheme. In this second method also the angular distribution information is exploited. Templates of the cosθW distributions are created for different polarizations, and the ''data'' are fitted to the templates in order to determine the polarization. This talk presents the results obtained for both the methods in the context of the optimization of the ILD detector concept for the ILC, using fully simulated Monte-Carlo Events