Measurement of K-e3(0) form factors

Lai, A.; Marras, D.; Bevan, A.; Dosanjh, R. S.; Gershon, T. J.; Hay, B.; Kalmus, G. E.; Lazzeroni, C.; Munday, D. J.; Olaiya, E.; Parker, M. A.; White, T. O.; Wotton, S. A.; Barr, G.; Bocquet, G.; Ceccucci, A.; Cuhadar Dönszelmann, T.; Cundy, D.; D'Agostini, G.; Doble, N.; Falaleev, V.; Gatignon, L.; Gonidec, A.; Gorini, B.; Govi, G.; Grafström, P.; Kubischta, W.; Lacourt, A.; Norton, A.; Palestini, S.; Panzer Steindel, B.; Taureg, H.; Velasco, M.; Wahl, H.; Cheshkov, C.; Hristov, P.; Kekelidze, V.; Litov, L.; Madigojine, D.; Molokanova, N.; Potrebenikov, Y. U.; Stoynev, S.; Zinchenko, A.; Knowles, I.; Martin, V.; Sacco, R.; Walker, A.; Contalbrigo, M.; Dalpiaz, P.; Duclos, J.; Frabetti, P. L.; Gianoli, A.; Martini, M.; Petrucci, F.; Savrié, M.; Bizzeti, A.; Calvetti, Mario; Collazuol, G.; Graziani, G.; Iacopini, Enrico; Lenti, M.; Martelli, F.; Veltri, M.; Becker, H. G.; Eppard, K.; Eppard, M.; Fox, H.; Kalter, A.; Kleinknecht, K.; Koch, U.; Köpke, L.; Lopes Da Silva, P.; Marouelli, P.; Pellmann, I.; Peters, A.; Renk, B.; Schmidt, S. A.; Schönharting, V.; Schué, Y.; Wanke, R.; Winhart, A.; Wittgen, M.; Chollet, J. C.; Fayard, L.; Iconomidou Fayard, L.; Ocariz, J.; Unal, G.; Wingerter Seez, I.; Anzivino, G.; Cenci, P.; Imbergamo, E.; Lubrano, P.; Mestvirishvili, A.; Nappi, A.; Pepe, M.; Piccini, M.; Bertanza, L.; Carosi, R.; Casali, R.; Cerri, C.; Cirilli, M.; Costantini, F.; Fantechi, R.; Giudici, S.; Mannelli, I.; Pierazzini, G.; Sozzi, M.; Cheze, J. B.; Cogan, J.; De Beer, M.; Debu, P.; Formica, A.; Granier De Cassagnac, R.; Mazzucato, E.; Peyaud, B.; Turlay, R.; Vallage, B.; Holder, M.; Maier, A.; Ziolkowski, M.; Arcidiacono, R.; Biino, C.; Cartiglia, N.; Marchetto, F.; Menichetti, E.; Pastrone, N.; Nassalski, J.; Rondio, E.; Szleper, M.; Wislicki, W.; Wronka, S.; Dibon, H.; Fischer, G.; Jeitler, M.; Markytan, M.; Mikulec, I.; Neuhofer, G.; Pernicka, M.; Taurok, A.; Widhalm, L.

doi:10.1016/j.physletb.2004.08.076

The semileptonic decay of the neutral K meson, K-L(0) --> pi+/-e-/+upsilon (K-e3), was used to study the strangeness-changing weak interaction of hadrons. A sample of 5.6 million reconstructed events recorded by the NA48 experiment was used to measure the Dalitz plot density. Admitting all possible Lorentz-covariant couplings, the form factors for vector (f+(q(2))), scalar (f(S)) and tensor (f(T)) interactions were measured. The linear slope of the vector form factor lambda(+) = 0.0284 +/- 0.0007 +/- 0.0013 and values for the ratios |f(S)/f(+)(0)| = 0.015(-0.010)(+0.007) +/- 0.012 and |f(T)/f(+)(0)| = 0.05(-0.04)(+0.03) +/- 0.03 were obtained. The values for f(S) and f(T) are consistent with zero. Assuming only vector-axial-vector couplings, lambda(+) = 0.0288 +/- 0.0004 +/- 0.0011 and a good fit consistent with pure V-A couplings were obtained. Alternatively, a fit to a dipole form factor yields a pole mass of M = 859 +/- 18 MeV, consistent with the K*(892) mass.

Measurement of K-e3(0) form factors / A. Lai, D. Marras, A. Bevan, R.S. Dosanjh, T.J. Gershon, B. Hay, G.E. Kalmus, C. Lazzeroni, D.J. Munday, E. Olaiya, M.A. Parker, T.O. White, S.A. Wotton, G. Barr, G. Bocquet, A. Ceccucci, T. Cuhadar-Dönszelmann, D. Cundy, G. D'Agostini, N. Doble, et al.. - In: PHYSICS LETTERS. SECTION B. - ISSN 0370-2693. - STAMPA. - 604:(2004), pp. 1-10. [10.1016/j.physletb.2004.08.076]