Publication
First Observation of the P-Wave Spin-Singlet Bottomonium States h(b)(1P) and h(b)(2P)
Résumé
We report the first observations of the spin-singlet bottomonium states h(b)(1P) and h(b)(2P). The states are produced in the reaction e(+)e(-) --> h(b)(nP)pi(+)pi(-) using a 121.4 fb(-1) data sample collected at energies near the Y(5S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. We determine M[h(b)(1P)] = (9898.2(-1.0-1.1)(+1.1+1.0)) MeV/c(2) and M[h(b)(2P)] = (10 259.8 +/- 0.6(-1.0)(+1.4)) MeV/c(2), which correspond to P-wave hyperfine splittings Delta M-HF = (+1.7 +/- 1.5) and (+0.5(-1.2)(+1.6)) MeV/c(2), respectively. The significances of the h(b)(1P) and h(b)(2P) are 5.5 sigma and 11.2 sigma, respectively. We find that the production of the h(b)(1P) and h(b)(2P) is not suppressed relative to the production of the Y(1S), Y(2S), and Y(3S).
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thumb|Exemple d'échantillonnage aléatoire En statistique, l'échantillonnage désigne les méthodes de sélection d'un sous-ensemble d'individus (un échantillon) à l'intérieur d'une population pour estimer les caractéristiques de l'ensemble de la population. Cette méthode présente plusieurs avantages : une étude restreinte sur une partie de la population, un moindre coût, une collecte des données plus rapide que si l'étude avait été réalisé sur l'ensemble de la population, la réalisation de contrôles destructifs Les résultats obtenus constituent un échantillon.
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Convenience sampling (also known as grab sampling, accidental sampling, or opportunity sampling) is a type of non-probability sampling that involves the sample being drawn from that part of the population that is close to hand. This type of sampling is most useful for pilot testing. Convenience sampling is not often recommended for research due to the possibility of sampling error and lack of representation of the population. But it can be handy depending on the situation. In some situations, convenience sampling is the only possible option.
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