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

• Published in: Physics letters. B 2016-06, Vol.757, p.362-367
• Main Authors: Anastasi, A., Babusci, D., Bencivenni, G., Berlowski, M., Bloise, C., Bossi, F., Branchini, P., Budano, A., Caldeira Balkeståhl, L., Cao, B., Ceradini, F., Ciambrone, P., Curciarello, F., Czerwiński, E., D'Agostini, G., Danè, E., De Leo, V., De Lucia, E., De Santis, A., De Simone, P., Di Cicco, A., Di Domenico, A., Di Salvo, R., Domenici, D., D'Uffizi, A., Fantini, A., Felici, G., Fiore, S., Gajos, A., Gauzzi, P., Giardina, G., Giovannella, S., Graziani, E., Happacher, F., Heijkenskjöld, L., Ikegami Andersson, W., Johansson, T., Kamińska, D., Krzemien, W., Kupsc, A., Loffredo, S., Mandaglio, G., Martini, M., Mascolo, M., Messi, R., Miscetti, S., Morello, G., Moricciani, D., Moskal, P., Papenbrock, M., Passeri, A., Patera, V., Perez del Rio, E., Ranieri, A., Salabura, P., Santangelo, P., Sarra, I., Schioppa, M., Silarski, M., Sirghi, F., Tortora, L., Venanzoni, G., Wiślicki, W., Wolke, M.
• Format: Article
• Language: English
• Subjects: [formula omitted] collisions; Conversion decay; Transition form factor
• ISSN: 0370-2693; 1873-2445; 1873-2445
• DOI: 10.1016/j.physletb.2016.04.015

A measurement of the vector to pseudoscalar conversion decay ϕ→π0e+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− collisions at s∼mϕ collected at the DAΦNE e+e− collider. These events were used to perform the first measurement of the transition form factor |Fϕπ0(q2)| and a new measurement of the branching ratio of the decay: BR(ϕ→π0e+e−)=(1.35±0.05−0.10+0.05)×10−5. The result improves significantly on previous measurements and is in agreement with theoretical predictions.