Improved measurement of the form factors in the decay lambda+c-->lambda + nue

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) +/-...

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Published in:Physical review letters 2005-05, Vol.94 (19), p.191801-191801
Main Authors: Hinson, J W, Huang, G S, Lee, J, Miller, D H, Pavlunin, V, Rangarajan, R, Sanghi, B, Shibata, E I, Shipsey, I P J, Cronin-Hennessy, D, Park, C S, Park, W, Thayer, J B, Thorndike, E H, Coan, T E, Gao, Y S, Liu, F, Stroynowski, R, Artuso, M, Boulahouache, C, Blusk, S, Dambasuren, E, Dorjkhaidav, O, Mountain, R, Muramatsu, H, Nandakumar, R, Skwarnicki, T, Stone, S, Wang, J C, Csorna, S E, Danko, I, Bonvicini, G, Cinabro, D, Dubrovin, M, McGee, S, Bornheim, A, Lipeles, E, Pappas, S P, Shapiro, A, Sun, W M, Weinstein, A J, Briere, R A, Chen, G P, Ferguson, T, Tatishvili, G, Vogel, H, Watkins, M E, Adam, N E, Alexander, J P, Berkelman, K, Boisvert, V, Cassel, D G, Duboscq, J E, Ecklund, K M, Ehrlich, R, Galik, R S, Gibbons, L, Gittelman, B, Gray, S W, Hartill, D L, Heltsley, B K, Hsu, L, Jones, C D, Kandaswamy, J, Kreinick, D L, Magerkurth, A, Mahlke-Krüger, H, Meyer, T O, Mistry, N B, Patterson, J R, Peterson, D, Pivarski, J, Richichi, S J, Riley, D, Sadoff, A J, Schwarthoff, H, Shepherd, M R, Thayer, J G, Urner, D, Wilksen, T, Warburton, A, Weinberger, M, Athar, S B, Avery, P, Breva-Newell, L, Potlia, V, Stoeck, H, Yelton, J, Benslama, K, Cawlfield, C, Eisenstein, B I, Gollin, G D, Karliner, I, Lowrey, N, Plager, C, Sedlack, C, Selen, M, Thaler, J J, Williams, J, Edwards, K W
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Language:English
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Summary: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(-).
ISSN:0031-9007