Resumen de Determination of the pionium lifetime in the DIRAC experiment at CERN
This work presents the latest and most accurate measurement of the pionium lifetime accomplished by the DIRAC experiment at CERN. The pionium breakup probability in a Nickel targe was measured and the pionium lifetime was extracted after precise simulation of the atom interactions with matter, leading to the result tau = (3,15 + 0,20 - 0,19) femtoseconds.
Much previous activity has been devoted to the determination of the pionium lifetime in DIRAC, but the present work has accomplished a new selection method using the upstream position detectors yielding an enhanced data sample, and a refined simulation of the detector and trigger response. As a consequence of the latter, a most complete and meticulous description of the systematic errors involved in the lifetime measurement has been provided. The result has been a reduction of the systematic uncertainties with respect to our previous publication.
