Using data from the FOCUS (E831) experiment at Fermilab, we present new measurements for the Cabibbo-suppressed decay mode $D^0 \to \pi^-\pi^+\pi^-\pi^+$. We measure the branching ratio $\Gamma(D^0 \to\pi^+\pi^- \pi^+\pi^-)/\Gamma(D^0 \to K^-\pi^+\pi^-\pi^+) = 0.0914 \pm 0.0018 \pm 0.0022$. An amplitude analysis has been performed, a first for this channel, in order to determine the resonant substructure of this decay mode. The dominant component is the decay $D^0 \to a_1(1260)^+ \pi^-$, accounting for 60% of the decay rate. The second most dominant contribution comes from the decay $D^0 \to \rho(770)^0\rho(770)^0$, with a fraction of 25%. We also study the $a_1(1260)$ line shape and resonant substructure. Using the helicity formalism for the angular distribution of the decay $D^0 \to \rho(770)^0\rho(770)^0$, we measure a longitudinal polarization of $P_L = (71 \pm 4\pm 2)$%.
Study of the D°---> pi- pi+ pi- pi+ decay / J.M. Link, P.M. Yager, J.C. Anjos, I. Bediaga, C. Castromonte, C. Gobel, A.A. Machado, J. Magnin, A. Massafferri, J.M. de Miranda, I.M. Pepe, E. Polycarpo, A.C. dos Reis, S. Carrillo, E. Casimiro, E. Cuautle, A. Sanchez-Hernandez, C. Uribe, F. Vazquez, L. Agostino, L. Cinquini, J.P. Cumalat, B. O'Reilly, I. Segoni, K. Stenson, J.N. Butler, Falso Cheung, G. Chiodini, I. Gaines, P.H. Garbincius, L.A. Garren, E. Gottschalk, P.H. Kasper, A.E. Kreymer, R. Kutschke, M. Wang, L. Benussi, M. Bertani, S. Bianco, F.L. Fabbri, S. Pacetti, A. Zallo, M. Reyes, C. Cawlfield, D.Y. Kim, A. Rahimi, J. Wiss, R. Gardner, A. Kryemadhi, Y.S. Chung, J.S. Kang, B.R. Ko, J.W. Kwak, K.B. Lee, K. Cho, H. Park, G. Alimonti, S. Barberis, M. Boschini, A. Cerutti, P. D'Angelo, M. Di Corato, P. Dini, L. Edera, S. Erba, P. Inzani, F. Leveraro, S. Malvezzi, D. Menasce, M. Mezzadri, L. Moroni, D. Pedrini, C. Pontoglio, F. Prelz, M. Rovere, S. Sala, T.F. Davenport, V. Arena, G. Boca, G. Bonomi, G. Gianini, G. Liguori, D.L. Pegna, M.M. Merlo, D. Pantea, S.P. Ratti, C. Riccardi, P. Vitulo, H. Hernandez, A.M. Lopez, H. Mendez, A. Paris, J. Quinones, J.E. Ramirez, Y. Zhang, J.R. Wilson, T. Handler, R. Mitchell, D. Engh, M. Hosack, W.E. Johns, E. Luiggi, J.E. Moore, M. Nehring, P.D. Sheldon, E.W. Vaandering, M. Webster, M. Sheaff. - In: PHYSICAL REVIEW D. - ISSN 0556-2821. - 75:5(2007), pp. 052003.052003-1-052003.052003-17.
Study of the D°---> pi- pi+ pi- pi+ decay
F. Leveraro;G. Gianini;
2007
Abstract
Using data from the FOCUS (E831) experiment at Fermilab, we present new measurements for the Cabibbo-suppressed decay mode $D^0 \to \pi^-\pi^+\pi^-\pi^+$. We measure the branching ratio $\Gamma(D^0 \to\pi^+\pi^- \pi^+\pi^-)/\Gamma(D^0 \to K^-\pi^+\pi^-\pi^+) = 0.0914 \pm 0.0018 \pm 0.0022$. An amplitude analysis has been performed, a first for this channel, in order to determine the resonant substructure of this decay mode. The dominant component is the decay $D^0 \to a_1(1260)^+ \pi^-$, accounting for 60% of the decay rate. The second most dominant contribution comes from the decay $D^0 \to \rho(770)^0\rho(770)^0$, with a fraction of 25%. We also study the $a_1(1260)$ line shape and resonant substructure. Using the helicity formalism for the angular distribution of the decay $D^0 \to \rho(770)^0\rho(770)^0$, we measure a longitudinal polarization of $P_L = (71 \pm 4\pm 2)$%.
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