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Measurement of the gamma gamma* to eta_c transition form factor

Description: The authors study the reaction e{sup +}e{sup -} {yields} e{sup +}e{sup -} {eta}{sub c}, {eta}{sub c} {yields} K{sub S}K{sup {+-}}{pi}{sup {-+}} and obtain {eta}{sub c} mass and width values 2982.2 {+-} 0.4 {+-} 1.6 MeV/c{sup 2} and 31.7 {+-} 1.2 {+-} 0.8 MeV, respectively. They find {Lambda}({eta}{sub c} {yields} {gamma}{gamma}){Beta}({eta}{sub c} {yields} K{bar K}{pi}) = 0.374 {+-} 0.009 {+-} 0.031 keV, and measure the {gamma}{gamma}* {yields} {eta}{sub c} transition form factor in the momentum transfer range from 2 to 50 GeV{sup 2}. The analysis is based on 469 fb{sup -1} of integrated luminosity collected at PEP-II with the BABAR detector at e{sup +}e{sup -} center-of-mass energies near 10.6 GeV.
Date: April 28, 2010
Creator: Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J. et al.
Partner: UNT Libraries Government Documents Department

Measurements of the Semileptonic Decays \Bb\to D\ell\nub and \Bb\to D^*\ell\nub Using a Global Fit to D X\ell\nub Final States

Description: Semileptonic {bar B} decays to DX{ell}{bar {nu}} ({ell} = e or {mu}) are selected by reconstructing D{sup 0}{ell} and D{sup +}{ell} combinations from a sample of 230 million {Upsilon}(4S) {yields} B{bar B} decays recorded with the BABAR detector at the PEP-II e{sup +}e{sup -} collider at SLAC. A global fit to these samples in a 3-dimensional space of kinematic variables is used to determine the branching fractions {Beta}(B{sup -} {yields} D{sup 0}{ell}{bar {nu}}) = 2.36 {+-} 0.03 {+-} 0.12% and {Beta}(B{sup -} {yields} D*{sup 0}{ell}{bar {nu}}) = (5.37 {+-} 0.02 {+-} 0.21)% where the errors are statistical and systematic, respectively. The fit also determines form factor parameters in a HQET-based parameterization, resulting in {rho}{sub D}{sup 2} = 1.22 {+-} 0.04 {+-} 0.07 for {bar B} {yields} D{ell}{bar {nu}} and {rho}{sub D*}{sup 2} = 1.21 {+-} 0.02 {+-} 0.07 for {bar B} {yields} D*{ell}{bar {nu}}. These values are used to obtain the product of the CKM matrix element |V{sub cb}| times the form factor at the zero recoil point for both {bar B} {yields} D{ell}{bar {nu}} decays, G(1)|V{sub cb}| = (43.8 {+-} 0.8 {+-} 2.3) x 10{sup -3}, and for {bar B} {yields} D*{ell}{bar {nu}} decays, F(1)|V{sub cb}| = (35.7 {+-} 0.2 {+-} 1.2) x 10{sup -3}.
Date: August 28, 2008
Creator: Aubert, Bernard; Bona, M.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prencipe, E. et al.
Partner: UNT Libraries Government Documents Department