* − with a Partial Reconstruction Technique

We present measurements of the decays B0 → D (∗)+ s D∗−, using data recorded by the BABAR detector in 1999 and 2000, consisting of 20.8 fb. The analysis is conducted with a partial reconstruction technique, in which only the D (∗)+ s and the soft pion from the D∗− decay are reconstructed. From the observed rates, we measure the branching fractions B(B0 → D+ s D ∗−) = (1.03 ± 0.14 ± 0.13 ± 0.26)% and B(B0 → D∗+ s D ∗−) = (1.97 ± 0.15 ± 0.30 ± 0.49)%, where the first error is statistical, the second is systematic, and the third is the error due to the D+ s → φπ + branching fraction uncertainty. From the B0 → D∗+ s D ∗− angular distributions, we measure the fraction of longitudinal polarization ΓL/Γ = (51.9 ± 5.0 ± 2.8)%, which is consistent with the theoretical prediction, based on factorization. These results are preliminary. Contributed to the 31st International Conference on High Energy Physics, 7/24—7/31/2002, Amsterdam, The Netherlands Stanford Linear Accelerator Center, Stanford University, Stanford, CA 94309 Work supported in part by Department of Energy contract DE-AC03-76SF00515. The BABAR Collaboration, B. Aubert, D. Boutigny, J.-M. Gaillard, A. Hicheur, Y. Karyotakis, J. P. Lees, P. Robbe, V. Tisserand, A. Zghiche Laboratoire de Physique des Particules, F-74941 Annecy-le-Vieux, France A. Palano, A. Pompili Università di Bari, Dipartimento di Fisica and INFN, I-70126 Bari, Italy J. C. Chen, N. D. Qi, G. Rong, P. Wang, Y. S. Zhu Institute of High Energy Physics, Beijing 100039, China G. Eigen, I. Ofte, B. Stugu University of Bergen, Inst. of Physics, N-5007 Bergen, Norway G. S. Abrams, A. W. Borgland, A. B. Breon, D. N. Brown, J. Button-Shafer, R. N. Cahn, E. Charles, M. S. Gill, A. V. Gritsan, Y. Groysman, R. G. Jacobsen, R. W. Kadel, J. Kadyk, L. T. Kerth, Yu. G. Kolomensky, J. F. Kral, C. LeClerc, M. E. Levi, G. Lynch, L. M. Mir, P. J. Oddone, T. J. Orimoto, M. Pripstein, N. A. Roe, A. Romosan, M. T. Ronan, V. G. Shelkov, A. V. Telnov, W. A. Wenzel Lawrence Berkeley National Laboratory and University of California, Berkeley, CA 94720, USA T. J. Harrison, C. M. Hawkes, D. J. Knowles, S. W. O’Neale, R. C. Penny, A. T. Watson, N. K. Watson University of Birmingham, Birmingham, B15 2TT, United Kingdom T. Deppermann, K. Goetzen, S. Ganzhur, H. Koch, B. Lewandowski, K. Peters, H. Schmuecker, M. Steinke Ruhr Universität Bochum, Institut für Experimentalphysik 1, D-44780 Bochum, Germany N. R. Barlow, W. Bhimji, J. T. Boyd, N. Chevalier, P. J. Clark, W. N. Cottingham, C. Mackay, F. F. Wilson University of Bristol, Bristol BS8 1TL, United Kingdom K. Abe, C. Hearty, T. S. Mattison, J. A. McKenna, D. Thiessen University of British Columbia, Vancouver, BC, Canada V6T 1Z1 S. Jolly, A. K. McKemey Brunel University, Uxbridge, Middlesex UB8 3PH, United Kingdom V. E. Blinov, A. D. Bukin, A. R. Buzykaev, V. B. Golubev, V. N. Ivanchenko, A. A. Korol, E. A. Kravchenko, A. P. Onuchin, S. I. Serednyakov, Yu. I. Skovpen, A. N. Yushkov Budker Institute of Nuclear Physics, Novosibirsk 630090, Russia D. Best, M. Chao, D. Kirkby, A. J. Lankford, M. Mandelkern, S. McMahon, D. P. Stoker University of California at Irvine, Irvine, CA 92697, USA C. Buchanan, S. Chun University of California at Los Angeles, Los Angeles, CA 90024, USA H. K. Hadavand, E. J. Hill, D. B. MacFarlane, H. Paar, S. Prell, Sh. Rahatlou, G. Raven, U. Schwanke, V. Sharma University of California at San Diego, La Jolla, CA 92093, USA