Constraints on an enhanced sbar d Z vertex from epsilon'/epsilon
| dc.creator | Silvestrini, Luca | |
| dc.date | 1999-06-01 | |
| dc.date.accessioned | 2026-07-07T04:07:16Z | |
| dc.date.available | 2026-07-07T04:07:16Z | |
| dc.description | We analyze rare kaon decays in models in which the dominant new effect is an enhanced sbar d Z vertex Z_{ds}. We point out that in spite of large theoretical uncertainties the CP-violating ratio epsilon'/epsilon provides at present the strongest constraint on Im Z_{ds}. Assuming 1.5 10^{-3} < epsilon'/epsilon < 3 10^{-3} and Standard Model values for the CKM parameters we obtain the bounds BR(K_L -> pi^0 nu nubar) < 3.9 10^{-10} and BR(K_L -> pi^0 e^+ e^-)_{dir} < 7.9 10^{-11}. Using the bound on Re Z_{ds} from K_L -> mu^+ mu^- we find BR(K^+ -> pi^+ nu nubar) < 2.6 10^{-10}. We also discuss new physics scenarios in which in addition to an enhanced sbar d Z vertex also neutral meson mixing receives important new contributions. In this case our most conservative bounds are BR(K_L -> pi^0 nu nubar) < 1.8 10^{-9}, BR(K_L -> pi^0 e^+ e^-)_{dir} < 2.8 10^{-10} and BR(K^+ -> pi^+ nu nubar) < 6.1 10^{-10}. The dependence of the upper bound for BR(K_L -> pi^0 nu nubar) on the CKM parameters is also analyzed. | |
| dc.description | LaTeX, 7 pages, 1 figure. Talk given at the XXXIV Rencontres de Moriond "Electroweak interactions and unified theories", Les Arcs, France, 13-20 March 1999. Contains a numerical update of the analysis in hep-ph/9811471 | |
| dc.identifier | https://arxiv.org/abs/hep-ph/9906202 | |
| dc.identifier | http://arxiv.org/abs/hep-ph/9906202 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/49083 | |
| dc.subject | High Energy Physics - Phenomenology | |
| dc.title | Constraints on an enhanced sbar d Z vertex from epsilon'/epsilon | |
| dc.type | text |