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J Lachniet,
A Afanasev,
H Arenhövel,
W K Brooks,
G P Gilfoyle,
D Higinbotham,
S Jeschonnek,
B Quinn,
M F Vineyard,
G Adams, [......],
M Williams,
E Wolin,
M H Wood,
A Yegneswaran,
J Yun,
M Yurov,
L Zana,
J Zhang,
B Zhao,
Z W Zhao
[show abstract]
[hide abstract]
ABSTRACT: The neutron elastic magnetic form factor was extracted from quasielastic electron scattering on deuterium over the range Q;{2}=1.0-4.8 GeV2 with the CLAS detector at Jefferson Lab. High precision was achieved with a ratio technique and a simultaneous in situ calibration of the neutron detection efficiency. Neutrons were detected with electromagnetic calorimeters and time-of-flight scintillators at two beam energies. The dipole parametrization gives a good description of the data.
Physical Review Letters 06/2009; 102(19):192001. · 7.37 Impact Factor
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M Battaglieri,
R De Vita,
A P Szczepaniak,
K P Adhikari,
M Aghasyan,
M J Amaryan,
P Ambrozewicz,
M Anghinolfi,
G Asryan,
H Avakian, [......],
D P Weygand,
M Williams,
E Wolin,
M H Wood,
A Yegneswaran,
M Yurov,
L Zana,
J Zhang,
B Zhao,
Z W Zhao
[show abstract]
[hide abstract]
ABSTRACT: We report on the results of the first measurement of exclusive f_{0}(980) meson photoproduction on protons for E_{gamma}=3.0-3.8 GeV and -t=0.4-1.0 GeV2. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. The resonance was detected via its decay in the pi;{+}pi;{-} channel by performing a partial wave analysis of the reaction gammap-->ppi;{+}pi;{-}. Clear evidence of the f_{0}(980) meson was found in the interference between P and S waves at M_{pi;{+}pi;{-}} approximately 1 GeV. The S-wave differential cross section integrated in the mass range of the f_{0}(980) was found to be a factor of about 50 smaller than the cross section for the rho meson. This is the first time the f_{0}(980) meson has been measured in a photoproduction experiment.
Physical Review Letters 04/2009; 102(10):102001. · 7.37 Impact Factor
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M Nozar,
C Salgado,
D P Weygand,
L Guo,
G Adams,
Ji Li,
P Eugenio,
M J Amaryan,
M Anghinolfi,
G Asryan, [......],
D P Watts,
L B Weinstein,
M Williams,
E Wolin,
M H Wood,
A Yegneswaran,
L Zana,
J Zhang,
B Zhao,
Z W Zhao
[show abstract]
[hide abstract]
ABSTRACT: A search for exotic mesons in the pi;{+}pi;{+}pi;{-} system photoproduced by the charge exchange reaction gammap-->pi;{+}pi;{+}pi;{-}(n) was carried out by the CLAS Collaboration at Jefferson Lab. A tagged-photon beam with energies in the 4.8 to 5.4 GeV range, produced through bremsstrahlung from a 5.744 GeV electron beam, was incident on a liquid-hydrogen target. A partial wave analysis was performed on a sample of 83 000 events, the highest such statistics to date in this reaction at these energies. The main objective of this study was to look for the photoproduction of an exotic J;{PC}=1;{-+} resonant state in the 1 to 2 GeV mass range. Our partial wave analysis shows production of the a_{2}(1320) and the pi_{2}(1670) mesons, but no evidence for the a_{1}(1260), nor the pi_{1}(1600) exotic state at the expected levels. An upper limit of 13.5 nb is determined for the exotic pi_{1}(1600) cross section, less than 2% of the a_{2}(1320) production.
Physical Review Letters 04/2009; 102(10):102002. · 7.37 Impact Factor
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R E Mitchell,
M R Shepherd,
D Besson,
T K Pedlar,
D Cronin-Hennessy,
K Y Gao,
J Hietala,
Y Kubota,
T Klein,
B W Lang, [......],
R Patel,
J Yelton,
P Rubin,
B I Eisenstein,
I Karliner,
S Mehrabyan,
N Lowrey,
M Selen,
E J White,
J Wiss
[show abstract]
[hide abstract]
ABSTRACT: Using 2.45x10;{7} psi(2S) decays collected with the CLEO-c detector at the Cornell Electron Storage Ring we present the most precise measurements of magnetic dipole transitions in the charmonium system. We measure B(psi(2S)-->gammaeta_{c})=(4.32+/-0.16+/-0.60)x10;{-3}, B(J/psi-->gammaeta_{c})/B(psi(2S)-->gammaeta_{c})=4.59+/-0.23+/-0.64, and B(J/psi-->gammaeta_{c})=(1.98+/-0.09+/-0.30)%. We observe a distortion in the eta_{c} line shape due to the photon-energy dependence of the magnetic dipole transition rate. We find that measurements of the eta_{c} mass are sensitive to the line shape, suggesting an explanation for the discrepancy between measurements of the eta_{c} mass in radiative transitions and other production mechanisms.
Physical Review Letters 02/2009; 102(1):011801. · 7.37 Impact Factor
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R E Mitchell,
M R Shepherd,
D Besson,
T K Pedlar,
D Cronin-Hennessy,
K Y Gao,
J Hietala,
Y Kubota,
T Klein,
B W Lang, [......],
J Yelton,
P Rubin,
C Cawlfield,
B I Eisenstein,
I Karliner,
D Kim,
N Lowrey,
M Selen,
E J White,
J Wiss
[show abstract]
[hide abstract]
ABSTRACT: Using a 281 pb-1 data sample collected at the psi(3770) resonance with the CLEO-c detector at the Cornell Electron Storage Ring, we report the first observation of D+ --> etae + nue. We also set upper limits for D+ --> eta'e + nue and D + --> varphie + nue that are about 2 orders of magnitude more restrictive than those obtained by previous experiments.
Physical Review Letters 02/2009; 102(8):081801. · 7.37 Impact Factor
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G. V. Fedotov,
V. I. Mokeev,
V. D. Burkert,
L. Elouadrhiri,
E. N. Golovatch,
B. S. Ishkhanov,
E. L. Isupov,
N. V. Shvedunov,
G. Adams,
M. J. Amaryan, [......],
M. F. Vineyard,
A. V. Vlassov,
L. B. Weinstein,
D. P. Weygand,
M. Williams,
E. Wolin,
M. H. Wood,
A. Yegneswaran,
L. Zana,
J. Zhang
[show abstract]
[hide abstract]
ABSTRACT: This paper reports on the most comprehensive data set obtained on differential and fully integrated cross sections for the process ep→e'pπ+π-. The data were collected with the CLAS detector at Jefferson Laboratory. Measurements were carried out in the as yet unexplored kinematic region of photon virtuality 0.2<Q2<0.6 GeV2 and invariant mass of the final hadron system W from 1.3 to 1.57 GeV. For the first time, nine independent one-fold differential cross sections were determined in each bin of W and Q2 covered by the measurements. A phenomenological analysis of the data allowed us to establish the most significant mechanisms contributing to the reaction. The nonresonant mechanisms account for a major part of cross sections. However, we find sensitivity to s-channel excitations of low-mass nucleon resonances, especially to the N(1440)P11 and N(1520)D13 states in kinematic dependencies of the one-fold differential cross sections.
Phys. Rev. C. 01/2009; 79(1).
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G. V. Fedotov,
V. I. Mokeev,
V. D. Burkert,
L. Elouadrhiri,
E. N. Golovatch,
B. S. Ishkhanov,
E. L. Isupov,
N. V. Shvedunov,
G. Adams,
M. J. Amaryan, [......],
M. F. Vineyard,
A. V. Vlassov,
L. B. Weinstein,
D. P. Weygand,
M. Williams,
E. Wolin,
M. H. Wood,
A. Yegneswaran,
L. Zana,
J. Zhang
[show abstract]
[hide abstract]
ABSTRACT: This paper reports on the most comprehensive data set obtained on differential and fully integrated cross sections for the process ep→e'pπ+π-. The data were collected with the CLAS detector at Jefferson Laboratory. Measurements were carried out in the as yet unexplored kinematic region of photon virtuality 0.2<Q2<0.6 GeV2 and invariant mass of the final hadron system W from 1.3 to 1.57 GeV. For the first time, nine independent one-fold differential cross sections were determined in each bin of W and Q2 covered by the measurements. A phenomenological analysis of the data allowed us to establish the most significant mechanisms contributing to the reaction. The nonresonant mechanisms account for a major part of cross sections. However, we find sensitivity to s-channel excitations of low-mass nucleon resonances, especially to the N(1440)P11 and N(1520)D13 states in kinematic dependencies of the one-fold differential cross sections.
Phys. Rev. C. 01/2009; 79(1).
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The CLAS Collaboration,
S. A. Morrow,
M. Guidal,
M. Garçon,
J. M. Laget,
E. S. Smith,
G. Adams,
K. P. Adhikari,
M. Aghasyan,
M. J. Amaryan, [......],
D. P. Weygand,
M. Williams,
E. Wolin,
M. H. Wood,
A. Yegneswaran,
M. Yurov,
L. Zana,
J. Zhang,
B. Zhao,
Z. W. Zhao
[show abstract]
[hide abstract]
ABSTRACT: The ep → e
′
pρ0 reaction has been measured using the 5.754GeV electron beam of Jefferson Lab and the CLAS detector. This represents the largest
ever set of data for this reaction in the valence region. Integrated and differential cross-sections are presented. The W , Q2 and t dependences of the cross-section are compared to theoretical calculations based on the t -channel meson-exchange Regge theory, on the one hand, and on quark handbag diagrams related to Generalized Parton Distributions
(GPDs) on the other hand. The Regge approach can describe at the » \approx 30% level most of the features of the present data while the two GPD calculations that are presented in this article which
succesfully reproduce the high-energy data strongly underestimate the present data. The question is then raised whether this
discrepancy originates from an incomplete or inexact way of modelling the GPDs or the associated hard scattering amplitude
or whether the GPD formalism is simply inapplicable in this region due to higher-twists contributions, incalculable at present.
European Physical Journal A 12/2008; 39(1):5-31. · 2.19 Impact Factor
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R. A. Briere,
T. Ferguson,
G. Tatishvili,
H. Vogel,
M. E. Watkins,
J. L. Rosner,
J. P. Alexander,
D. G. Cassel,
J. E. Duboscq,
R. Ehrlich, [......],
L. M. Zhang,
G. Bonvicini,
D. Cinabro,
M. Dubrovin,
A. Lincoln,
P. Naik,
J. Rademacker,
D. M. Asner,
K. W. Edwards,
J. Reed
[show abstract]
[hide abstract]
ABSTRACT: Using Υ(2S) and Υ(3S) data collected with the CLEO III detector we have searched for decays of χbJ to final states with open charm. We fully reconstruct D0 mesons with pD0>2.5 GeV/c in three decay modes (K-π+, K-π+π0, and K-π-π+π+) in coincidence with radiative transition photons that tag the production of one of the χbJ(nP) states. Significant signals are obtained for the two J=1 states. Recent nonrelativistic QCD (NRQCD) calculations of χbJ(nP)→cc̅ X depend on one nonperturbative parameter per χbJ triplet. The extrapolation from the observed D0X rate over a limited momentum range to a full cc̅ X rate also depends on these same parameters. Using our data to fit for these parameters, we extract results which agree well with NRQCD predictions, confirming the expectation that charm production is largest for the J=1 states. In particular, for J=1, our results are consistent with cc̅ g accounting for about one-quarter of all hadronic decays.
Phys. Rev. D. 11/2008; 78(9).
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Q. He,
J. Insler,
H. Muramatsu,
C. S. Park,
E. H. Thorndike,
F. Yang,
M. Artuso,
S. Blusk,
S. Khalil,
J. Li, [......],
B. Sanghi,
I. P. J. Shipsey,
B. Xin,
G. S. Adams,
M. Anderson, J. P. Cummings,
I. Danko,
D. Hu,
B. Moziak,
J. Napolitano
[show abstract]
[hide abstract]
ABSTRACT: We study exclusive χc0,1,2 decays to four-hadron final states involving two charged and two neutral hadrons: π+π-π0π0, K+K-π0π0, pp̅ π0π0, K+K-ηπ0, and K±π∓K0π0. The χc states are produced in radiative decays of 3.08×106 ψ(2S) resonance decays and observed in the CLEO detector. We also measure the largest substructure contributions to the modes π+π-π0π0 and K±π∓K0π0.
Phys. Rev. D. 11/2008; 78(9).
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Q He,
J Insler,
H Muramatsu,
C S Park,
E H Thorndike,
F Yang,
M Artuso,
S Blusk,
S Khalil,
J Li, [......],
D H Miller,
I P J Shipsey,
B Xin,
G S Adams,
M Anderson, J P Cummings,
I Danko,
D Hu,
B Moziak,
J Napolitano
[show abstract]
[hide abstract]
ABSTRACT: We report the first observation of Upsilon(2S)-->etaUpsilon(1S), with a branching fraction B=(2.1(-0.6)+0.7(stat)+/-0.3(syst)) x 10(-4) and a statistical significance 5.3sigma. Data were acquired with the CLEO III detector at the CESR e+e(-) symmetric collider. This is the first process observed involving a b-quark spin flip. For related transitions, 90% confidence limits in units of 10(-4) are B(Upsilon(2S)-->pi0Upsilon(1S)) < 1.8, B(Upsilon(3S)-->etaUpsilon(1S)) < 1.8, B(Upsilon(3S)-->pi0Upsilon(1S)) < 0.7, and B(Upsilon(3S)-->pi0Upsilon(2S)) < 5.1.
Physical Review Letters 11/2008; 101(19):192001. · 7.37 Impact Factor
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W Love,
V Savinov,
A Lopez,
S Mehrabyan,
H Mendez,
J Ramirez,
G S Huang,
D H Miller,
V Pavlunin,
B Sanghi, [......],
B W Lang,
R Poling,
A W Scott,
A Smith,
P Zweber,
S Dobbs,
Z Metreveli,
K K Seth,
A Tomaradze,
K M Ecklund
[show abstract]
[hide abstract]
ABSTRACT: In this Letter, we describe a search for lepton flavor violation (LFV) in the bottomonium system. We search for leptonic decays Upsilon(nS)-->mutau (n=1, 2, and 3) using the data collected with the CLEO III detector. We identify the tau lepton using its leptonic decay nu_{tau}nu[over ]_{e}e and utilize multidimensional likelihood fitting with probability density function shapes measured from independent data samples. We report our estimates of 95% C.L. upper limits on LFV branching fractions of Upsilon mesons. We interpret our results in terms of the exclusion plot for the energy scale of a hypothetical new interaction versus its effective LFV coupling in the framework of effective field theory.
Physical Review Letters 11/2008; 101(20):201601. · 7.37 Impact Factor
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S Dobbs,
Z Metreveli,
K K Seth,
A Tomaradze,
J Libby,
A Powell,
G Wilkinson,
K M Ecklund,
W Love,
V Savinov, [......],
T K Pedlar,
D Cronin-Hennessy,
K Y Gao,
J Hietala,
Y Kubota,
T Klein,
B W Lang,
R Poling,
A W Scott,
P Zweber
[show abstract]
[hide abstract]
ABSTRACT: A precision measurement of the mass of the h_{c}(1P1) state of charmonium has been made using a sample of 24.5x10;{6} psi(2S) events produced in e;{+}e;{-} annihilation at the Cornell Electron Storage Ring (CESR). The reaction used was psi(2S)-->pi;{0}h_{c}, pi;{0}-->gammagamma, h_{c}-->gammaeta_{c}, and the reaction products were detected in the CLEO-c detector. Data have been analyzed both for the inclusive reaction and for the exclusive reactions in which eta_{c} decays are reconstructed in 15 hadronic decay channels. Consistent results are obtained in the two analyses. The averaged results of the present measurements are M(h_{c})=3525.28+/-0.19(stat.)+/-0.12(syst.) MeV, and B(psi(2S)-->pi;{0}h_{c})xB(h_{c}-->gammaeta_{c})=(4.19+/-0.32+/-0.45)x10;{-4}. Using the ;{3}P_{J} centroid mass, DeltaM_{hf}(1P) identical withM(chi_{cJ})-M(h_{c})=+0.02+/-0.19+/-0.13 MeV.
Physical Review Letters 10/2008; 101(18):182003. · 7.37 Impact Factor
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J Libby,
L Martin,
A Powell,
G Wilkinson,
K M Ecklund,
W Love,
V Savinov,
H Mendez,
J Y Ge,
D H Miller, [......],
Y Kubota,
T Klein,
B W Lang,
R Poling,
A W Scott,
P Zweber,
S Dobbs,
Z Metreveli,
K K Seth,
A Tomaradze
[show abstract]
[hide abstract]
ABSTRACT: We measure the mass of the eta;{'} meson using psi(2S)-->pi;{+}pi;{-}J/psi, J/psi-->gammaeta;{'} events acquired with the CLEO-c detector operating at the CESR e;{+}e;{-} collider. Using three decay modes, eta;{'}-->rho;{0}gamma, eta;{'}-->pi;{+}pi;{-}eta with eta-->gammagamma, and eta;{'}-->pi;{+}pi;{-}eta with eta-->pi;{+}pi;{-}pi;{0}, we find M_{eta;{'}}=957.793+/-0.054+/-0.036 MeV, in which the uncertainties are statistical and systematic, respectively. This result is consistent with but substantially more precise than the current world average.
Physical Review Letters 10/2008; 101(18):182002. · 7.37 Impact Factor
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W Love,
V Savinov,
H Mendez,
J Y Ge,
D H Miller,
I P J Shipsey,
B Xin,
G S Adams,
M Anderson, J P Cummings, [......],
P Zweber,
S Dobbs,
Z Metreveli,
K K Seth,
A Tomaradze,
J Libby,
L Martin,
A Powell,
G Wilkinson,
K M Ecklund
[show abstract]
[hide abstract]
ABSTRACT: We search for a non-SM-like CP-odd Higgs boson (a(1)(0)) decaying to tau(+)tau(-) or mu(+)mu(-) in radiative decays of the Upsilon(1S). No significant signal is found, and upper limits on the product branching ratios are set. Our tau(+)tau(-) results are almost 2 orders of magnitude more stringent than previous upper limits. Our data provide no evidence for a Higgs state with a mass of 214 MeV decaying to mu(+)mu(-), previously proposed as an explanation for 3 Sigma(+)-->pmu(+)mu(-) events observed by the HyperCP experiment. Our results constrain NMSSM models.
Physical Review Letters 10/2008; 101(15):151802. · 7.37 Impact Factor
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B. I. Eisenstein,
I. Karliner,
S. Mehrabyan,
N. Lowrey,
M. Selen,
E. J. White,
J. Wiss,
R. E. Mitchell,
M. R. Shepherd,
D. Besson, [......],
A. Ryd,
A. J. Sadoff,
X. Shi,
S. Stroiney,
W. M. Sun,
T. Wilksen,
S. B. Athar,
R. Patel,
J. Yelton,
P. Rubin
[show abstract]
[hide abstract]
ABSTRACT: We measure the branching ratio of the purely leptonic decay of the D+ meson with unprecedented precision as B(D+→μ+ν)=(3.82±0.32±0.09)×10-4, using 818 pb-1 of data taken on the ψ(3770) resonance with the CLEO-c detector at the CESR collider. We use this determination to derive a value for the pseudoscalar decay constant fD+, combining with measurements of the D+ lifetime and assuming |Vcd|=|Vus|. We find fD+=(205.8±8.5±2.5) MeV. The decay rate asymmetry Γ(D+→μ+ν)-Γ(D-→μ-ν̅ )/Γ(D+→μ+ν)+Γ(D-→μ-ν̅ )=0.08±0.08, consistent with no CP violation. We also set 90% confidence level upper limits on B(D+→τ+ν)<1.2×10-3 and B(D+→e+ν)<8.8×10-6.
Phys. Rev. D. 09/2008; 78(5).
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G S Adams,
M Anderson, J P Cummings,
I Danko,
D Hu,
B Moziak,
J Napolitano,
Q He,
J Insler,
H Muramatsu, [......],
A Powell,
G Wilkinson,
K M Ecklund,
W Love,
V Savinov,
H Mendez,
J Y Ge,
D H Miller,
I P J Shipsey,
B Xin
[show abstract]
[hide abstract]
ABSTRACT: We report the first observation of the decay J/psi-->3gamma. The signal has a statistical significance of 6sigma and corresponds to a branching fraction of B(J/psi-->3gamma)=(1.2+/-0.3+/-0.2)x10;{-5}, in which the errors are statistical and systematic, respectively. The measurement uses psi(2S)-->pi;{+}pi;{-}J/psi events acquired with the CLEO-c detector operating at the CESR e;{+}e;{-} collider.
Physical Review Letters 09/2008; 101(10):101801. · 7.37 Impact Factor
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D. M. Asner,
K. W. Edwards,
P. Naik,
R. A. Briere,
T. Ferguson,
G. Tatishvili,
H. Vogel,
M. E. Watkins,
J. L. Rosner,
J. P. Alexander, [......],
N. Sultana,
T. Skwarnicki,
S. Stone,
J. C. Wang,
L. M. Zhang,
G. Bonvicini,
D. Cinabro,
M. Dubrovin,
A. Lincoln,
J. Rademacker
[show abstract]
[hide abstract]
ABSTRACT: We exploit the quantum coherence between pair-produced D0 and D̅ 0 in ψ(3770) decays to study charm mixing, which is characterized by the parameters x and y, and to make a first determination of the relative strong phase δ between doubly Cabibbo-suppressed D0→K+π- and Cabibbo-favored D̅ 0→K+π-. We analyze a sample of 1.0×106 D0D̅ 0 pairs from 281 pb-1 of e+e- collision data collected with the CLEO-c detector at Ecm=3.77 GeV. By combining CLEO-c measurements with branching fraction input and time-integrated measurements of RM≡(x2+y2)/2 and RWS≡Γ(D0→K+π-)/Γ(D̅ 0→K+π-) from other experiments, we find cosδ=1.03-0.17+0.31±0.06, where the uncertainties are statistical and systematic, respectively. In addition, by further including external measurements of charm mixing parameters, we obtain an alternate measurement of cosδ=1.10±0.35±0.07, as well as xsinδ=(4.4-1.8+2.7±2.9)×10-3 and δ=(22-12-11+11+9)°.
Phys. Rev. D. 07/2008; 78(1).
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D Cronin-Hennessy,
K Y Gao,
D T Gong,
J Hietala,
Y Kubota,
T Klein,
B W Lang,
R Poling,
A W Scott,
A Smith, [......],
D Kim,
N Lowrey,
P Naik,
C Sedlack,
M Selen,
E J White,
J Wiss,
M R Shepherd,
D Besson,
T K Pedlar
[show abstract]
[hide abstract]
ABSTRACT: By using 1.8x10{6} DDpairs, we have measured B(D{0}-->pi{-}e{+}nu{e})=0.299(11)(9)%, B(D{+}-->pi{0}e{+}nu{e})=0.373(22)(13)%, B(D{0}-->K{-}e{+}nu{e})=3.56(3)(9)%, and B(D{+}-->K{0}e{+}nu{e})=8.53(13)(23)% and have studied the q;{2} dependence of the form factors. By combining our results with recent lattice calculations, we obtain |V{cd}|=0.217(9)(4)(23) and |V{cs}|=1.015(10)(11)(106).
Physical Review Letters 06/2008; 100(25):251802. · 7.37 Impact Factor
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S. Dobbs,
Z. Metreveli,
K. K. Seth,
A. Tomaradze,
J. Ernst,
H. Severini,
S. A. Dytman,
W. Love,
V. Savinov,
O. Aquines, [......],
K. Y. Gao,
D. T. Gong,
J. Hietala,
Y. Kubota,
T. Klein,
B. W. Lang,
R. Poling,
A. W. Scott,
A. Smith,
P. Zweber
[show abstract]
[hide abstract]
ABSTRACT: Using a sample of 1.8 million DD̅ mesons collected at the ψ(3770) with the CLEO-c detector, we study the semileptonic decays D0→π-e+νe, D+→π0e+νe, D0→K-e+νe, and D+→K̅ 0e+νe. For the total branching fractions we find B(D0→π-e+νe)=0.299(11)(9)%, B(D+→π0e+νe)=0.373(22)(13)%, B(D0→K-e+νe)=3.56(3)(9)%, and B(D+→K̅ 0e+νe)=8.53(13)(23)%, where the first error is statistical and the second systematic. In addition, form factors are studied through fits to the partial branching fractions obtained in five q2 ranges. By combining our results with recent unquenched lattice calculations, we obtain |Vcd|=0.217(9)(4)(23) and |Vcs|=1.015(10)(11)(106), where the final error is theoretical.
Phys. Rev. D. 06/2008; 77(11).
