High statistics measurement of the K+-->pi0e+nu (K+e3) branching ratio.

E865 at the Brookhaven National Laboratory AGS collected about 70 000 K(+)(e3) events to measure the K(+)(e3) branching ratio relative to the observed K+-->pi(+)pi(0), K+-->pi(0)micro(+)nu, and K+-->pi(+)pi(0)pi(0) decays. The pi(0) in all the decays was detected using the e(+)e(-) pair from pi(0)-->e(+)e(-)gamma decay and no photons were required. Using the 2002 Particle Data Group branching ratios for the normalization decays, we obtain BR(K(+)(e3(gamma)))=(5.

Experimental study of the radiative decays K+-->mu(+)nue(+)e(-) and K+-->e(+)nue(+)e(-).

Experiment 865 at the Brookhaven Alternating Gradient Synchrotron obtained 410 K+-->e(+)nue(+)e(-) and 2679 K+-->mu(+)nue(+)e(-) events including 10% and 19% background. The branching ratios were measured to be [2.48+/-0.

New measurement of K(+)(e4) decay and the s-pave pi pi-scattering length a(0)(0).

A sample of 4 x 10(5) events from the decay K(+)-->pi(+)pi(-)e(+)nu(e) (K(e4)) has been collected in experiment E865 at the Brookhaven Alternating Gradient Synchrotron. The analysis of these data yields new measurements of the K(e4) branching ratio [(4.11+/-0.

New measurement of the rare decay K+ --> pi(+)&mgr;(+)&mgr;(-).

More than 400 K+-->pi(+)&mgr;(+)&mgr;(-) events were observed in a rare K+ decay experiment at the Brookhaven Alternating Gradient Synchrotron. Normalized to the K+-->pi(+)pi(+)pi(-) decay, the branching ratio is determined to be [9.22+/-0.

Search for lepton flavor violation in K+ decays into a charged pion and two leptons.

A search for lepton flavor violating decays, K+ --> mu+ mu+ pi-, K+ --> e+ e+ pi-, K+ --> pi+ e+ mu-, K+ --> mu+ e+ pi-, and pi0 --> e+ mu-, was performed using the data collected in Experiment E865 at the Brookhaven Alternating Gradient Synchrotron. No signal was found in any of the decay modes. At the 90% confidence level, the branching ratios are less than 3.

Improved limit on the rate of the decay K+ --> pi(+)&mgr;(+)e(-).

We report results of a search for the lepton-family number violating decay K+-->pi(+)&mgr;(+)e(-) from data collected by experiment E865 in 1996 at the Alternating Gradient Synchroton of Brookhaven National Laboratory. We place an upper limit on the branching ratio at 3.9x10(-11) ( 90% C.