Szczegóły publikacji
Opis bibliograficzny
Photonic events with missing energy in $e^{+}e^{-}$ collisions at $\sqrt{s}$=189 GeV / G. Abbiendi [et al.], M. PRZYBYCIEŃ [et al.] // The European Physical Journal. C, Particles and Fields ; ISSN 1434-6044. — 2000 — vol. 18 iss. 2, s. 253–272. — Bibliogr. s. 272, Abstr. — Publikacja dostępna online od: 2000-11-27. — M. Przybycień - pierwsza afiliacja: CERN, European Organisation for Nuclear Research, Geneva, Switzerland
Autorzy (307)
- AGHPrzybycień Mariusz
- Abbiendi Giovanni
Dane bibliometryczne
| ID BaDAP | 8688 |
|---|---|
| Data dodania do BaDAP | 2002-03-28 |
| Tekst źródłowy | URL |
| DOI | 10.1007/s100520000522 |
| Rok publikacji | 2000 |
| Typ publikacji | artykuł w czasopiśmie |
| Otwarty dostęp |  |
| Czasopismo/seria | European Physical Journal, C |
Abstract
Photonic events with large missing energy have been observed in e(+)e(-) collisions at a centre-of-mass energy of 189 GeV using the OPAL detector at LEP. Results are presented for event topologies consistent with a single photon or with an acoplanar photon pair. Cross-section measurements are performed within the kinematic acceptance of each selection, and the number of light neutrino species is measured. Cross-section results are compared with the expectations from the Standard Model process e(+)e(-) –> nu<(<nu>)over bar> + photon(s). No evidence is observed for new physics contributions to these final states. Upper limits on sigma (e(+)e(-) –> XY) . BR(X –> Y-gamma) and sigma (e(+)e(-) –> XX) . BR2(X –> Y gamma) are derived for the case of stable and invisible Y. These limits apply to single and pair production of excited neutrinos (X = nu*,Y = nu), to neutralino production (X = <(<chi>)over tilde>(0)(2),Y = <(<chi>)over tilde>(0)(1)) and to supersymmetric models in which X = <(<chi>)over tilde>(0)(1) and Y = (G) over tilde is a Light gravitino. The case of macroscopic decay lengths of particle X is considered for e(+)e(-) –> XX, X –> Y gamma, when M-Y approximate to 0. The single-photon results are also used to place upper limits on superlight gravitino pair production as well as graviton-photon production in the context of theories with additional space dimensions.
