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Using COSY – 11 apparatus for the precise studies of the natural width of the η ′ meson
| Content Provider | Semantic Scholar |
|---|---|
| Author | Czerwinski, Eryk |
| Abstract | We present preliminary results and motivation of measurement of the total width of the η ′ meson (Γ η ′). The physics of the η ′ meson receives an increasing interest in view of the forthcoming measurements planned e.g. at the COSY, DAφ NE-2 and MAMI-C facilities where the η ′ will be produced in hadron-hadron, e +-e − , and γ-hadron reactions, respectively. Experimentally the emphasis will be put on the studies of the η ′ meson decays which are of interest on its own account and certainly will provide inputs to the phenomenology of the Quantum Chromo-Dynamics [1] in the non-perturbative regime. Specifically, precise determinations of the partial widths for the η ′ decay channels will be helpful for the development of the Chiral Perturbation Theory. However, the experimental precision of the partial width for various decay channels – where only the branching ratio is known or will be measured – is governed by the precision of the knowledge of the total width. In the case of the η ′ meson the branching ratios are typically known with precision better than 1.5%, while the total width is established about 10 times less accurate [2]. Therefore, we expect that the precise determination of the natural width of the η ′ meson will have a strong impact on the physics results which will be derived from measurements carried out by collaborations: WASA-at-COSY [3], CBall-at-MAMI [4] and KLOE-2 [5, 6]. In the last issue of the Review of Particle Physics only two direct measurements of the natural width of the η ′ meson are reported [2]. In the first experiment the width was established from the missing mass spectrum of the π − p → nX reaction measured close to the threshold for the production of the η ′ meson [7]. The experimental mass resolution achieved was equal to 0.75 MeV/c 2 (FWHM) and the extracted value of Γ η ′ amounts to 0.28 ± 0.10 MeV/c 2. In the second experiment the value of Γ η ′ was derived from the threshold excitation function of the pd → 3 He X reaction [8]. The study was performed at 20 different beam momenta, however, the error of the Γ η ′ was larger than in the previous |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://arxiv.org/pdf/0710.3248v1.pdf |
| Language | English |
| Access Restriction | Open |
| Subject Keyword | Adjudication Excitation Experiment Extraction Full Width at Half Maximum Large Mass Spectrometry Mesons Perturbation theory (quantum mechanics) Quantum pi-Mesons |
| Content Type | Text |
| Resource Type | Article |
