Improved upper limits on the flavor-changing neutral current decays B → Kℓ+ℓ- and B → K* (892)ℓ+ℓ-
Physical Review Letters 87:18 (2001) 1818031-1818035
Abstract:
The flavor-changing neutral current (FCNC) decay was studied using Monte Carlo simulations to determine the efficiency for detecting the signal modes. The upper limits on branching fractions were obtained and no indication of a signal were obtained for the decay. Systematic and statistical errors for the process were calculated numerically.Search for the decay upsilon(1S) --> gammaeta(').
Phys Rev Lett 87:14 (2001) 141801
Abstract:
We report on a search for the radiative decay Upsilon(1S)-->gammaeta(') in 61.3 pb(-1) of data taken with the CLEO II detector at the Cornell Electron Storage Ring. Three decay chains were investigated, all involving eta(')-->pi(+)pi(-)eta, followed by eta-->gammagamma, eta-->pi(0)pi(0)pi(0), or eta-->pi(+)pi(-)pi(0). We find no candidate events in any of the three cases and set a combined upper limit of 1.6x10(-5) at 90% C.L., significantly smaller than the previous limit. We compare our result to other radiative Upsilon decays, to radiative J/psi decays, and to theoretical predictions.Search for the decay Y(1S) → γη′
Physical Review Letters 87:14 (2001)
Abstract:
A study was carried out to search for the decay Υ → γη' with the decay mode η' → ηπ+π- and three decay modes of the η. Using simple, loose selection criteria, no candidates were found and the 90%C C.L. limit of B(Υ → γη') 1.6 × 10-5 was set.Rate measurement of D(0)-->K+pi(-)pi(0) and constraints on D(0) -- D(0) mixing.
Phys Rev Lett 87:7 (2001) 071802
Abstract:
We present an observation and time-integrated rate measurement of the decay D(0)-->K(+)pi(-)pi(0) produced in 9 fb(-1) of e(+)e(-) collisions near the Upsilon(4S) resonance. The signal is inconsistent with an upward fluctuation of the background by 4.9 standard deviations. We measured the time-integrated rate of D(0)-->K(+)pi(-)pi(0) normalized to the rate of D(0)-->K(+)pi(-)pi(0) to be 0.0043(+0.0011)(-0.0010) (stat)+/-0.0007 (syst). This decay can be produced by doubly Cabibbo-suppressed decays or by the D(0) evolving into a D(0) through mixing, followed by a Cabibbo-favored decay to K(+)pi(-)pi(0). We also found the CP asymmetry A = (9(+25)(-22))% be consistent with zero.Experimental investigation of the two-photon widths of the chi(c0) and the chi(c2) mesons.
Phys Rev Lett 87:6 (2001) 061801