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

J. W. Hinson, G. S. Huang, J. Lee, D. H. Miller, V. Pavlunin, R. Rangarajan, B. Sanghi, E. I. Shibata, I. P.J. Shipsey, D. Cronin-Hennessy, C. S. Park, W. Park, J. B. Thayer, E. H. Thorndike, T. E. Coan, Y. S. Gao, F. Liu, R. Stroynowski, M. Artuso, C. BoulahouacheS. Blusk, E. Dambasuren, O. Dorjkhaidav, R. Mountain, H. Muramatsu, R. Nandakumar, T. Skwarnicki, S. Stone, J. C. Wang, S. E. Csorna, I. Danko, G. Bonvicini, D. Cinabro, M. Dubrovin, S. McGee, A. Bornheim, E. Lipeles, S. P. Pappas, A. Shapiro, W. M. Sun, A. J. Weinstein, R. A. Briere, G. P. Chen, T. Ferguson, G. Tatishvili, H. Vogel, M. E. Watkins, N. E. Adam, J. P. Alexander, K. Berkelman

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26 Scopus citations


Using the CLEO detector at the Cornell Electron Storage Ring, we have studied the distribution of kinematic variables in the decay Λc+→Λe+νe. By performing a four-dimensional maximum likelihood fit, we determine the form factor ratio, R=f2/f1=-0.31±0. 05(stat)±0.04(syst), the pole mass, Mpole=[2.21±0.08(stat) ±0.14(syst)]GeV/c2, and the decay asymmetry parameter of the Λc+, αΛc=-0.86±0.03(stat)±0.02(syst), forq2=0.67 (GeV/c2)2. We compare the angular distributions of the Λc+ and Λ̄c- and find no evidence for CP violation: AΛc= (αΛc+αΛ̄c)(αΛc- αΛ̄c)=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, AΛ, for Λ→pπ-.

Original languageEnglish (US)
Article number191801
JournalPhysical review letters
Issue number19
StatePublished - May 20 2005


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