Measurement of the ϕ → π⁰e⁺e⁻ transition form factor with the KLOE detector

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• 作者：KLOE-2 CollaborationA. Anastasi^e ; ^d ; D. Babusci^d ; ^{danilo.babusci@lnf.infn.it" class="auth_mail" title="E-mail the corresponding author} ; G. Bencivenni^d ; M. Berlowski^u ; C. Bloise^d ; F. Bossi^d ; P. Branchini^r ; A. Budano^q ; ^r ; L. Caldeira Balkestå ; hl^t ; B. Cao^t ; F. Ceradini^q ; ^r ; P. Ciambrone^d ; F. Curciarello^e ; ^b ; ^l ; E. Czerwiński^c ; G. D'Agostini^m ; ⁿ ; E. Danè ; ^d ; V. De Leo^r ; E. De Lucia^d ; A. De Santis^d ; P. De Simone^d ; A. Di Cicco^q ; ^r ; A. Di Domenico^m ; ⁿ ; R. Di Salvo^p ; D. Domenici^d ; A. D'Uffizi^d ; A. Fantini^o ; ^p ; G. Felici^d ; S. Fiore^s ; ⁿ ; A. Gajos^c ; P. Gauzzi^m ; ⁿ ; G. Giardina^e ; ^b ; S. Giovannella^d ; E. Graziani^r ; F. Happacher^d ; L. Heijkenskjö ; ld^t ; W. Ikegami Andersson^t ; T. Johansson^t ; D. Kamińska^c ; W. Krzemien^u ; A. Kupsc^t ; S. Loffredo^q ; ^r ; G. Mandaglio^f ; ^g ; M. Martini^d ; ^k ; M. Mascolo^d ; ^{mascolo.matteo@gmail.com" class="auth_mail" title="E-mail the corresponding author} ; R. Messi^o ; ^p ; S. Miscetti^d ; G. Morello^d ; D. Moricciani^p ; P. Moskal^c ; M. Papenbrock^t ; A. Passeri^r ; V. Patera^j ; ⁿ ; E. Perez del Rio^d ; A. Ranieri^a ; P. Salabura^c ; P. Santangelo^d ; I. Sarra^d ; M. Schioppa^h ; ⁱ ; M. Silarski^d ; F. Sirghi^d ; L. Tortora^r ; G. Venanzoni^d ; W. Wiślicki^u ; M. Wolke^t
• 关键词：e+e&minus ; e+e&minus ; collisions ; Conversion decay ; Transition form factor
• 刊名：Physics Letters B
• 出版年：2016
• 出版时间：10 June 2016
• 年：2016
• 卷：757
• 期：Complete
• 页码：362-367
• 全文大小：483 K

文摘

A measurement of the vector to pseudoscalar conversion decay ϕ→π⁰e⁺e⁻$\varphi \to {\pi }^0{e}^{+}{e}^{-}$ with the KLOE experiment is presented. A sample of ∼9500 signal events was selected from a data set of 1.7 fb⁻¹ of e⁺e⁻$e^{+}{e}^{-}$ collisions at $\sqrt{s}\sim m_{\varphi }$ collected at the DAΦNE e⁺e⁻$e^{+}{e}^{-}$ collider. These events were used to perform the first measurement of the transition form factor |F_ϕπ⁰(q²)|$|F_{\varphi {\pi }^0}(q^2)|$ and a new measurement of the branching ratio of the decay: $\mathrm{BR}(\varphi \to {\pi }^0{e}^{+}{e}^{-})=(1.35\pm {0.05}_{-0.10}^{+0.05})\times {10}^{-5}$. The result improves significantly on previous measurements and is in agreement with theoretical predictions.