Improved measurement of the form factors in the decay Λc+→ Λe+νe

/ Authors

J. Hinson, G. Huang, J. Lee, D. Miller, V. Pavlunin, R. Rangarajan, B. Sanghi, E. Shibata, I. Shipsey, D. Cronin-Hennessy

and 125 more authors

C. S. Park, W. Park, J. Thayer, E. Thorndike, T. Coan, Y. Gao, F. Liu, R. Stroynowski, M. Artuso, C. Boulahouache, S. Blusk, E. Dambasuren, O. Dorjkhaidav, R. Mountain, H. Muramatsu, R. Nandakumar, T. Skwarnicki, S. Stone, J. Wang, S. Csorna, I. Dankó, G. Bonvicini, D. Cinabro, M. Dubrovin, S. Mcgee, Adi Bornheim, E. Lipeles, S. Pappas, A. Shapiro, W. Sun, A. Weinstein, R. Briere, G. Chen, T. Ferguson, G. Tatishvili, H. Vogel, M. E. Watkins, N. Adam, J. Alexander, K. Berkelman, V. Boisvert, D. Cassel, J. Duboscq, K. Ecklund, R. Ehrlich, R. Galik, L. Gibbons, B. Gittelman, S. Gray, D. Hartill, B. Heltsley, L. Hsu, C. Jones, J. Kandaswamy, D. Kreinick, A. Magerkurth, H. Mahlke-Krüger, T. Meyer, N. Mistry, J. Patterson, D. Peterson, J. Pivarski, S. Richichi, D. Riley, A. Sadoff, H. Schwarthoff, M. Shepherd, J. Thayer, D. Urner, T. Wilksen, A. Warburton, M. Weinberger, S. Athar, P. Avery, L. Breva-Newell, V. Potlia, H. Stoeck, J. Yelton, Kamal Benslama, C. Cawlfield, B. Eisenstein, G. Gollin, I. Karliner, N. Lowrey, C. Plager, C. Sedlack, M. Selen, J. Thaler, J. Williams, K. Edwards, D. Besson, S. Anderson, V. Frolov, D. Gong, Y. Kubota, S. Li, R. Poling, A. Smith, C. Stepaniak, J. Urheim, Z. Metreveli, K. Seth, A. Tomaradze, P. Zweber, S. Ahmed, M. Alam, J. Ernst, L. Jian, M. Saleem, F. Wappler, K. Arms, E. Eckhart, K. Gan, C. Gwon, K. Honscheid, H. Kagan, R. Kass, T. Pedlar, E. Von Toerne, H. Severini, P. Skubic, S. Dytman, J. Mueller, S. Nam, V. Savinov

/ Abstract

Using the CLEO detector at the Cornell Electron Storage Ring, we have studied the distribution of kinematic variables in the decay lambda(+)(c)lambda--> e(+)nu(e). By performing a four-dimensional maximum likelihood fit, we determine the form factor ratio, R= f(2)/f(1) = -0.31 +/- 0.05(stat) +/- 0.04(syst), the pole mass, M(pole) = [2.21 +/- 0.08(stat) +/- 0.14(syst)] GeV/c(2), and the decay asymmetry parameter of the lambda(+)(c), alpha (lambda(c)) = -0.86 +/-0.03(stat) +/- 0.02(syst), for q(2) = 0.67 (GeV/c(2))(2). We compare the angular distributions of the lambda(+)(c) and lambda(-)(c) and find no evidence for CP violation: A(lambda(c)) = (alpha(lambda(c)) + alpha (lambda(c)))/(alpha(lambda(c))-alpha(lambda(c))) = 0.00 +/- 0.03(stat) +/- 0.01(syst) +/- 0.02, where the third error is from the uncertainty in the world average of the CP-violating parameter, A(lambda), for ppi(-).

Journal: Physical Review Letters

DOI: 10.1103/PhysRevLett.94.191801