118394703
Leptonic decays of charged pseudoscalar mesons - 2012
We review the physics of purely leptonic decays of $\pi^\pm$, $K^\pm$, $D^{\pm}$, $D_s^\pm$, and $B^\pm$ pseudoscalar mesons. The measured decay rates are related to the product of the relevant weak-interaction-based CKM matrix element of the constituent quarks and a strong interaction parameter related to the overlap of the quark and antiquark wave-functions in the meson, called the decay constant $f_P$. The leptonic decay constants for $\pi^\pm$, $K^\pm$, $D^{\pm}$, $D_s^\pm$, and $B^\pm$ mesons can be obtained with controlled theoretical uncertainties and high precision from {\it ab initio} lattice-QCD simulations. The combination of experimental leptonic decay-rate measurements and theoretical decay-constant calculations enables the determination of several elements of the CKM matrix within the standard model. These determinations are competitive with those obtained from semileptonic decays, and also complementary because they are sensitive to different quark flavor-changing currents. They can also be used to test the unitarity of the first and second rows of the CKM matrix. Conversely, taking the CKM elements predicted by unitarity, one can infer "experimental" values for $f_P$ that can be compared with theory. These provide tests of lattice-QCD methods, provided new-physics contributions to leptonic decays are negligible at the current level of precision. This review is the basis of the article in the Particle Data Group's 2016 edition, updating the versions in Refs. [1-3].
125049924
A1 PRODUCTION IN CHARGE EXCHANGE REACTIONS
22176544
Measurement of the direct photon spectrum from the Upsilon (1S).
122981263
Limits on rare exclusive decays of B mesons
Abstract We have set upper limits for rare exclusive decays of B mesons arising from higher order processes in the standard model of electroweak interactions. Such decays may occur via “penguin diagrams” in B decay. We also set an upper limit on a lepton-number-violating decay mode of the neutral B meson.
118259341
Leptonic and Semileptonic Decays from CLEO‐c
The CLEO‐c measurement of the purely leptonic decay rate D+ → μ+v determines the value of the pseudoscalar decay constant fD+ = (222.6 ± 16.7−3.4+2.8) MeV, allowing for a precision test of strong interaction theories. Semileptonic decay branching ratios are also summarized.
122170479
Particle identification by ionization measurements: Description of the CLEO dEdx system
Abstract We describe the design, construction and performance of a pressurized proportional chamber system intended to identify particles by means of their energy loss in thin gas samples. The system is part of the CLEO detector at the Cornell Electron-Positron Storage Ring (CESR).
117517443
A FORM-FREE, SEMIPHENOMENOLOGICAL, ERROR-BOUNDED, POTENTIAL REPRESENTATION OF TWO-NUCLEON EXPERIMENTS.
118451431
COMPTON SCATTERING FROM RELATIVISTIC ELECTRONS
108012017
GRID DRIVEN POWER AMPLIFIER FOR MARK I MTA ACCELERATOR
A driven power amplifier r-f system was installed on thc Mark I linear accelerator for Run No. 10. The system, which used RCA A-2332 superpower, shield- grid triodes as final power amplifiers, is described. Problems associated with the initial excitation of the cavity and the techniques used to solve them are discussed. (auth)
210852321
MARK I MTA LINEAR ACCELERATOR RUN NO. 3
Experimental operation of Mark I from July 29 through Sept. 24, 1952 is reported. During the preceding two months shutdown, spark-damaged drift tubes No. 0, 1, and 2 were repaired and chemically cleaned. After a slow "bake-in" procedure, a cavity voltage of 20-Mv at 16% duty cycle was obtained. Although operation was not too steady, some preliminary beam evaluation tests were made. Proton acceleration threshold voltage was determined to be 18.5 Mv, based on the associated rapid increase in neutron flux beyond the D-8B target. The beam was found to be about 1 in. off from the cavity axis at the target. A pulsed beam current of 50 to 70 ma peak was reached. The results indicated that there was nothing to prevent a high-current pulsed beam from being produced. However, in spite of careful cleaning and slow bake-in methods, sparking in the 0-1 gap was still a problem. Since small scale tests indicated that Inconel had better resistance to spark damage than the deoxidized highphosphorous Cu originally used, Mark I was shut down to install Inconel overlays on the first two drift tubes. (For preceding report in series see LRL-71.) (auth)