Upgraded DIRAC spectrometer at CERN PS for the investigation of pi pi and pi K atoms

0466587 - ÚJF 2017 RIV NL eng J - Článek v odborném periodiku
Adeva, B. - Benelli, A. - Čechák, T. - Doškářová, P. - Hons, Zdeněk - Klusoň, J. - Lednický, Richard - Martinčík, J. - Průša, P. - Smolík, J. - Trojek, T. - Urban, T. - Vrba, T. … celkem 70 autorů
Upgraded DIRAC spectrometer at CERN PS for the investigation of pi pi and pi K atoms.
Nuclear Instruments & Methods in Physics Research Section A. Roč. 839, DEC (2016), s. 52-85. ISSN 0168-9002. E-ISSN 1872-9576
Grant CEP: GA MŠMT(CZ) LG13031
Institucionální podpora: RVO:61389005 ; RVO:68378271
Klíčová slova: upgraded DIRAC spectrometer * CERN PS * pi pi and pi K atoms * Life-time measurement * long-lived excited states of pi pi atoms
Kód oboru RIV: BG - Jaderná, atomová a mol. fyzika, urychlovače; BF - Elementární částice a fyzika vys. energií (FZU-D)
Impakt faktor: 1.362, rok: 2016

The DIRAC spectrometer installed at CERN PS was upgraded in order to study simultaneously A(2 pi) and A(pi K) atoms, namely the bound states of two pi mesons, and of pi and K mesons, respectively. The detector system can now accept a high intensity beam of 2-6 x 10(11) primary protons per second. The electronics and the data-acquisition system can handle a very large amount of data to identify pi, K, p, e and mu, allowing the selection of pi pi and pi K pairs in the offline analysis. The resolution of the longitudinal and transverse components of the relative momentum Q of each meson pair in their center-of-mass system with respect to the direction of the pair was substantially improved. The analysis of their distributions allowed an reliable separation between the meson pairs originating from hadronic atoms and the backgrounds permitting the measurement of the lifetimes of hadronic atoms in the ground state and pi-pi, pi-K s-wave scattering lengths. The upgraded setup also allowed the study of the long-lived excited states of pi pi atoms.
Trvalý link: http://hdl.handle.net/11104/0264853