FIZIKA B 8 (1999) 2, 395-400

LETTER TO THE EDITOR

LONG VS. SHORT DISTANCE DISPERSIVE TWO-PHOTON K _L®m⁺ m^- AMPLITUDE

JAN O. EEG^a, KREŠIMIR KUMERIČKI^b and IVICA PICEK^b

^aDepartment of Physics, University of Oslo, Norway
^bDepartment of Physics, Faculty of Science, University of Zagreb, Croatia

Received 21 January 1999; Accepted 7 June 1999

We report on the calculation of the two-loop electroweak, two-photon mediated short-distance dispersive K_L®m⁺m^- decay amplitude. QCD corrections change the sign of this contribution and reduce it by an order of magnitude. The resulting amplitude enables us to provide a constraint on the otherwise uncertain long-distance dispersive amplitude.

PACS numbers: 12.15.-y, 12.39.Fe
UDC: 539.126

Keywords: kaon decay, muon, dispersive amplitude, QCD corrections

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