Determination of the pionium lifetime in the DIRAC experiment at CERN

  1. FUNGUEIRIÑO PAZOS, JOSE LUIS
Supervised by:
  1. Bernardo Adeva Andany Co-director
  2. Antonio Romero Vidal Co-director
  3. Máximo Pló Casasús Co-director

Defence university: Universidade de Santiago de Compostela

Fecha de defensa: 26 April 2012

Committee:
  1. Armando Lanaro Chair
  2. Juan Jose Saborido Silva Secretary
  3. Oton Vázquez Doce Committee member
  4. Joan Soto Riera Committee member
  5. Cibrán Santamarina Ríos Committee member
Department:
  1. Department of Particle Physics

Type: Thesis

Teseo: 325243 DIALNET lock_openMINERVA editor

Abstract

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.