Precision measurement of the mass of the hc(P11) state of charmonium
Physical Review Letters 101:18 (2008)
Abstract:
A precision measurement of the mass of the hc(P11) state of charmonium has been made using a sample of 24.5×106 ψ(2S) events produced in e+e- annihilation at the Cornell Electron Storage Ring (CESR). The reaction used was ψ(2S)→π0hc, π0→γγ, hc→γηc, 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 ηc 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(hc)=3525.28±0.19(stat.)±0.12(syst.)MeV, and B(ψ(2S)→π0hc)×B(hc→γηc)=(4.19±0. 32±0.45)×10-4. Using the PJ3 centroid mass, ΔMhf(1P) M(χcJ) -M(hc)=+0.02±0.19±0.13MeV. © 2008 The American Physical Society.Measurement of the η′-meson mass using J/ ψ→γη′
Physical Review Letters 101:18 (2008)
Abstract:
We measure the mass of the η′ meson using ψ(2S) →π+π-J/ψ, J/ψ→γη′ events acquired with the CLEO-c detector operating at the CESR e+e- collider. Using three decay modes, η′→ρ0γ, η′→π+π-η with η→γγ, and η′→π+π-η with η→π+π-π0, we find Mη′=957.793±0.054±0. 036MeV, in which the uncertainties are statistical and systematic, respectively. This result is consistent with but substantially more precise than the current world average. © 2008 The American Physical Society.Search for very light CP-odd Higgs boson in radiative decays of Υ(1S)
Physical Review Letters 101:15 (2008)
Abstract:
We search for a non-SM-like CP-odd Higgs boson (a10) decaying to τ+τ- or μ+μ- in radiative decays of the Υ(1S). No significant signal is found, and upper limits on the product branching ratios are set. Our τ+τ- 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 μ+μ-, previously proposed as an explanation for 3 Σ+→pμ+μ- events observed by the HyperCP experiment. Our results constrain NMSSM models. © 2008 The American Physical Society.Search for CP violation in the Dalitz-plot analysis of D±→K+K- π±
Physical Review D - Particles, Fields, Gravitation and Cosmology 78:7 (2008)
Abstract:
We report on a search for CP asymmetry in the singly Cabibbo-suppressed decay D+→K+K-π+ using a data sample of 818pb-1 accumulated with the CLEO-c detector on the ψ(3770) resonance. A Dalitz-plot analysis is used to determine the amplitudes of the intermediate states. We find no evidence for CP violation either in specific two-body amplitudes or integrated over the entire phase space. The CP asymmetry in the latter case is measured to be (-0.03±0.84±0.29)%. © 2008 The American Physical Society.Observation of χcJ radiative decays to light vector mesons
Physical Review Letters 101:15 (2008)