Author:
,Babusci D.,Badoni D.,Balwierz-Pytko I.,Bencivenni G.,Bini C.,Bloise C.,Bossi F.,Branchini P.,Budano A.,Caldeira Balkeståhl L.,Capon G.,Ceradini F.,Ciambrone P.,Czerwinski E.,Danè E.,De Lucia E.,De Robertis G.,De Santis A.,Di Domenico A.,Di Donato C.,Di Salvo R.,Domenici D.,Erriquez O.,Fanizzi G.,Fantini A.,Felici G.,Fiore S.,Franzini P.,Gauzzi P.,Giardina G.,Giovannella S.,Gonnella F.,Graziani E.,Happacher F.,Heijkenskjöld L.,Höistad B.,Iafolla L.,Jacewicz M.,Johansson T.,Kupsc A.,Lee-Franzini J.,Leverington B.,Loddo F.,Loffredo S.,Mandaglio G.,Martemianov M.,Martini M.,Mascolo M.,Messi R.,Miscetti S.,Morello G.,Moricciani D.,Moskal P.,Nguyen F.,Passeri A.,Patera V.,Prado Longhi I.,Ranieri A.,Redmer C. F.,Santangelo P.,Sarra I.,Schioppa M.,Sciascia B.,Silarski M.,Taccini C.,Tortora L.,Venanzoni G.,Wislicki W.,Wolke M.,Zdebik J.
Abstract
Abstract
We present a measurement of η meson production in photon-photon interactions produced by electron-positron beams colliding with
$ \sqrt{s}=1 $
GeV. The measurement is done with the KLOE detector at the ϕ-factory DAΦNE with an integrated luminosity of 0.24 fb−1. The e
+
e
− → e
+
e
−
η cross section is measured without detecting the out-going electron and positron, selecting the decays η → π
+
π
−
π
0 and η → π
0
π
0
π
0. The most relevant background is due to e
+
e
− → ηγ when the monochromatic photon escapes detection. The cross section for this process is measured as σ(e
+
e
− → ηγ) = (856 ± 8stat ± 16syst) pb. The combined result for the e
+
e
− → e
+
e
−
η cross section is σ(e
+
e
− → e
+
e
−
η) = (32.72 ± 1.27stat ± 0.70syst) pb. From this we derive the partial width Γ(η → γγ) = (520 ± 20stat ± 13syst) eV. This is in agreement with the world average and is the most precise measurement to date.
Publisher
Springer Science and Business Media LLC
Subject
Nuclear and High Energy Physics