118465845
Recent results on charm from Fermilab experiment E-687
About 10{sup 4} charm decays have been reconstructed from first-run data of Fermilab experiment E687 using the Fermilab Wide-Band Photon Spectrometer with the world's highest energy photon beam. The success of techniques for isolating and reconstructing charm event samples based on two complementary vertexing strategies is illustrated. Preliminary results are presented. These include lifetime value of (0.50 {plus minus} 0.06 {plus minus} 0.03)ps for the D{sub s}{sup +}, and (0.20 {plus minus} 0.03 {plus minus} 0.03)ps for the {Lambda}{sub c}{sup +}. Preliminary values for the D{sup +} and D{sup 0} lifetimes are consistent with currently accepted world averages. Signals for the Cabibbo-suppressed decays D{sup 0} {yields} {pi}{sup +}{pi}{sup {minus}}{pi}{sup +}{pi}{sup {minus}}, D{sup +} {yields} K{sup +}K{sup {minus}}{pi}{sup +}, and D{sup +} {yields} {phi}{pi}{sup +} are shown; for B(D{sup 0} {yields} {pi}{sup +}{pi}{sup {minus}}{pi}{sup +}{pi}{sup {minus}})/B(D{sup 0} {yields} K{sup {minus}}{pi}{sup +}{pi}{sup +}{pi}{sup {minus}}) our preliminary value is 0.10 {plus minus} 0.02 {plus minus} 0.02. Preliminary values for ratios B(D{sup 0} {yields} {ovr K}{sup 0}K{sup +}K{sup {minus}})/B(D{sup 0} {yields} {ovr K}{sup 0}{pi}{sup +}{pi}{sup {minus}}) and B(D{sup 0} {yields} {ovr K}{sup 0}{phi})/B(D{sup 0} {yields} {ovr K}{sup 0}{pi}{sup +}{pi}{sup {minus}}) are 0.20 {plus minus} 0.06 and 0.16 {plus minus} 0.06. Preliminary results are givenmore » for cross sections of D*{sup {plus minus}} and D{sup {plus minus}} photoproduction on a Be target for the p{sup 2}{sub {tau}} dependence of D{sup {minus plus}} photoproduction and for the ratios D{double prime}/D*{sup +} and D*{sup {minus}}/D{sup {minus plus}}. The energy dependence of the total open charm photoproduction cross section is compared with model predictions for photon energies up to 350 GeV. 18 refs., 5 figs.« less
120539815
Experimental tests of discrete symmetries in the decays k+- ---> pi+ pi- e+- nu(e)
119779374
Neural network based neutral particles reconstruction with the E687 hadron calorimeter
Abstract We present a neutral particle reconstruction algorithm based on a neural network approach applied to the E687 hadron calorimeter. A measurement of the invariant mass of the Σ ± → nπ ± is presented to verify the reliability of the reconstruction. The reconstructed invariant mass of the charmed meson D + → K L 0 π + π + π − is also presented to show the possible application of this technique to charmed particles decaying into a neutral hadron. An example of this would be Λ c + → n K − π + π + .
110772906
The use of waveform digitizers with drift chambers for D0
Abstract A prototype drift chamber cell with good space resolution, d E d x , and two particle separation has been constructed. A 100 MHz, 11 bit waveform digitizer readout scheme has been used for the tests.
123787086
$D^0$ hot topics
The authors present recent D0 results based on approximately 1 fb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV recorded at the Fermilab Tevatron. Preliminary results on a search for the flavor changing neutral current process D{sup +} {yields} {pi}{sup +}{mu}{sup +}{mu}{sup -}, a measurement of the Cp violation parameter in B mixing, {epsilon}{sub B}, and a two sided limit on the B{sub s} oscillation frequency {Delta}m{sub s} are presented. The limits on {epsilon}{sub B} and {Beta}(D{sup +} {yields} {pi}{sup +}{mu}{sup +}{mu}{sup -}) are the world's best limits. The two sided bound on {Delta}m{sub s} is the first direct indication by a single experiment that {Delta}m{sub s} is bounded from above.
121765828
Pion pion phase shift and form-factors in the decays k+- ---> pi+ pi- e+- nu(e)
123655517
The universal structure of local algebras
It is shown that a few physically significant conditions fix the global structure of the local algebras appearing in quantum field theory: it is isomorphic to that of ℜ where ℜ is the unique hyperfinite factor of typeIII1 and the center of the respective algebra. The argument is based on results in [1, 2] relating to the type of the local algebras and an improvement of an argument in [3] concerning the “split property.”
116487953
The structure of local algebras in quantum field theory
122078833
Dirac versus wigner. Towards a universal particle concept in local quantum field theory
Abstract Based on the concept of particle weight a unified description of stable particle-like systems in local quantum field theory is given which applies also to so called infraparticles. Particle weights carry definite charge, four momentum and spin and give rise to characteristic mass shell singularities. A collision theory for these weights is proposed which allows to calculate transition probabilities directly from local gauge invariant operators.
119605647
Stable quantum systems in anti¿de Sitter space: Causality, independence, and spectral properties
If a state is passive for uniformly accelerated observers in n-dimensional (n⩾2) anti–de Sitter (Ads) space–time (i.e., cannot be used by them to operate a perpetuum mobile), they will (a) register a universal value of the Unruh temperature, (b) discover a PCT symmetry, and (c) find that observables in complementary wedge-shaped regions necessarily commute with each other in this state. The stability properties of such a passive state induce a “geodesic causal structure” on AdS and concommitant locality relations. It is shown that observables in these complementary wedge-shaped regions fulfill strong additional independence conditions. In two-dimensional AdS these even suffice to enable the derivation of a nontrivial, local, covariant net indexed by bounded space–time regions. All these results are model-independent and hold in any theory which is compatible with a weak notion of space–time localization. Examples are provided of models satisfying the hypotheses of these theorems.
125213305
AN ALGEBRAIC APPROACH TO THE CLASSIFICATION OF LOCAL CONFORMAL QUANTUM FIELD THEORIES