The eta(c)gamma gamma* transition form factor in the decay eta(c)->gamma l(+)l(-) and in the crossed channels gamma e(-)->eta(c)e(-) and e(+)e(-)->eta(c)gamma

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Di Salvo E., Rekalo M., Tomasi-Gustafsson E.

EUROPEAN PHYSICAL JOURNAL C, cilt.16, sa.2, ss.295-302, 2000 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 16 Sayı: 2
  • Basım Tarihi: 2000
  • Doi Numarası: 10.1007/s100520050022
  • Dergi Adı: EUROPEAN PHYSICAL JOURNAL C
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.295-302
  • Orta Doğu Teknik Üniversitesi Adresli: Hayır

Özet

The Dalitz distribution and the effective mass spectrum of the lepton pair produced in the decay eta(c) --> gamma l(+)l(-), as well as the differential cross sections for the crossed channels gamma e(-) --> eta(c)e(-) and e(+)e(-) --> eta(c)gamma, are calculated in terms of the sole electromagnetic transition form factor for the vertex eta(c) --> gamma gamma*, where gamma* is a virtual photon with a space-like (for gamma e(-) --> eta(c)e(-)) or a time-like (for e(+)e(-) --> eta(c)gamma and eta(c) --> gamma l(+)l(-)) four-momentum. Explicit parameterizations of the transition form factor are found in two different approaches, namely in the vector dominance model and in a QCD-inspired consideration on the basis of the process c (c) over bar --> gamma l(+)l(-), with zero relative three-momentum of the annihilating quarks.