| Scientific Committee Paper | |
| Report number | CERN-SPSC-2011-001 ; SPSC-P-284-ADD-5 ; DIRAC-DOC-2011-01 |
| Title | Search for Long-Lived States of $\pi^+\pi^-$ Atoms : Addendum to the DIRAC Proposal |
| Project Manager/Technical Coordinator | Nemenov, Leonid |
| Author(s) |
Adeva, B ; Afanasyev, L ; Amsler, C ; Anania, A ; Aogaki, S ; Augsten, K ; Benelli, A ; Brekhovskikh, V ; Cechak, T ; Chiba, M ; Ciortea, C ; Ciocarlan, C ; Constantinescu, S ; Curceanu, C ; Doskarova, P ; Dudarev, A ; Dumitriu, D ; Drijard, D ; Enulescu, A ; Fluerasu, D ; Gortchakov, O ; Gritsay, K ; Guaraldo, C ; Gugiu, M ; Hansroul, M ; Hosek, R ; Hons, Z ; Karpukhin, V ; Kluson, J ; Kobayashi, M ; Kulikov, A ; Kulish, E ; Kuptsov, A ; Kruglov, V ; Kruglova, L ; Kuroda, K ; Lamberto, A ; Lednicky, R ; Martincik, J ; Nemenov, L ; Nikitin, M ; Okada, K ; Pentia, M ; Plo, M ; Prusa, P ; Rappazzo, G ; Ryazantsev, A ; Romero, A ; Ronzhin, V ; Rykalin, V ; Saborido, J ; Schacher, J ; Shlyapnikov, P ; Smolik, J ; Takeutchi, F ; Tarasov, A ; Trojek, T ; Urban, T ; Vrba, T ; Vazquez, P ; Yazkov, V ; Yoshimura, Y ; Zhabitsky, M ; Zrelov, P |
| Corporate author(s) | CERN. Geneva. SPS and PS Experiments Committee ; SPSC |
| Series | (Addendum (Proposal)) |
| Note | PS212 Addendum 5 |
| Submitted by | [email protected] on 05 Jan 2011 |
| Referee | [email protected] on 09 Feb 2011 |
| Subject category | Detectors and Experimental Techniques |
| Accelerator/Facility, Experiment | CERN PS ; DIRAC PS212 |
| Abstract | The proposed experiment is a further development of the DIRAC experiment already running at CERN PS. Up to now more than 21000 $\pi^+\pi^-$ pairs originated from the $\pi^+\pi^-$ atom ($A_{2\pi}$) breakup were identified and the overall accuracy of the $A_{2\pi}$ lifetime is about 9% in accordance with the DIRAC proposal. This measurement allowed to extract the difference $|a_0-a_2|$ of $s$-wave $\pi\pi$-scattering length with accuracy of 4.3%. The observation of long-lived (metastable) $A_{2\pi}$ states will be performed with the same setup. This observation opens a possibility to measure the energy difference between $ns$ and $np$ states and to determine the value of another combination $2a_0+a_2$ of $\pi\pi$ scattering length in a model-independent way. In combination with the first measurement it allows to get $a_0$ and $a_2$ separately. An additional measurement of the multiple scattering angles in different materials with accuracy better than 1% will be performed in parallel with the observation. This measurement is needed to improve the systematic accuracy in the $A_{2\pi}$ lifetime for the data already collected in 2008--2010. |
| Copyright/License | Report: © 2011-2025 CERN (License: CC-BY-3.0) |
Email contact(s) : [email protected]
Registre creat el 2011-01-05, darrera modificació el 2016-06-30
