The ratio Rη=Γ(η→π+π−γ)/Γ(η→π+π−π0) has been measured by analysing 22 million ϕ→ηγ decays collected by the KLOE experiment at DAΦNE, corresponding to an integrated luminosity of 558 pb−1. The η→π+π−γ proceeds both via the ρ resonant contribution, and possibly a non-resonant direct term, connected to the box anomaly. Our result, Rη=0.1856±0.0005stat±0.0028syst, points out a sizable contribution of the direct term to the total width. The di-pion invariant mass for the η→π+π−γ decay could be described in a model-independent approach in terms of a single free parameter, α. The determined value of the parameter α is α = (1.32 ± 0.08stat(+0.1 -0.09, syst) ± 0.02theo) GeV-2.
Measurement of Γ(η → π+ π− γ)/Γ(η → π+ π− π0) with the KLOE detector / KLOE/KLOE-2, Collaboration; Loffredo, S. - In: PHYSICS LETTERS. SECTION B. - ISSN 0370-2693. - 718:3(2013), pp. 910-914. [10.1016/j.physletb.2012.11.032]
Measurement of Γ(η → π+ π− γ)/Γ(η → π+ π− π0) with the KLOE detector
Loffredo S
2013
Abstract
The ratio Rη=Γ(η→π+π−γ)/Γ(η→π+π−π0) has been measured by analysing 22 million ϕ→ηγ decays collected by the KLOE experiment at DAΦNE, corresponding to an integrated luminosity of 558 pb−1. The η→π+π−γ proceeds both via the ρ resonant contribution, and possibly a non-resonant direct term, connected to the box anomaly. Our result, Rη=0.1856±0.0005stat±0.0028syst, points out a sizable contribution of the direct term to the total width. The di-pion invariant mass for the η→π+π−γ decay could be described in a model-independent approach in terms of a single free parameter, α. The determined value of the parameter α is α = (1.32 ± 0.08stat(+0.1 -0.09, syst) ± 0.02theo) GeV-2.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
