We present the measurements of the Λ c production cross section in proton-proton interactions at s =27.4 GeV and give new limits on the exclusive branching ratio Λ c →pK + π − .
No description provided.
Using the ARGUS detector at the e + e − storage ring DORIS II at DESY, we have observed parity violation in the decay Λ ± c → Λπ ± . We measure the coefficient of parity violation, α Λ c , to be −0.96±0.42. In addition, we measure σ BR ( Λ + c → Λπ + and σ BR ( Λ + c → Σ 0 π + ) to be, respectively, (2.2±0.3±0.4) pb and (2.0±0.7±0.4) pb.
No description provided.
The reaction γγ→K + K − π + π − π 0 has been observed for the first time, using the ARGUS detector at the e + e − storage ring DORIS II at DESY. The cross section shows an enhancement for W γγ close to 3 GeV/ c 2 . Searches for γγ→ωφ and for γγ→φφ leading to this final state, as well as for γγ→φφ→2K + 2K − , have been performed. The derived upper limits for ωφ and φφ production are compatible with q q q q model predictions.
TOPOLOGICAL CROSS SECTION.
95 PCT CL UPPER LIMITS.
In an experiment with the 1.5 m bubble chamber at the Rutherford Laboratory, the reaction K + d→K 0 pp has been studied at beam momenta of 2.2, 2.45 and 2.7 GeV/ c . The cross section for the reaction K + n→K 0 p has been estimated and found to be approximately twice that of the line-reversed reaction K − p → K 0 n at comparable energies. An SU(3) sum rule, due to Barger and Cline, has been tested and found not to be valid in this momentum range. The differential cross section for K + n→K 0 p has also been measured and a determination made of the imaginary to real ratio of the forward amplitude, using the optical theorem. Implications of these, and other results, for various Regge models are briefly discussed.
No description provided.
No description provided.
Results are given from a study of 15 518 events of the reaction K + d → K + π − pp. The K + π − spin density matrix and the constraints imposed on it by positivity have been studied. Analyses of K + π − → K + π − elastic scattering have been carried out using methods developed by Estabrooks and Martin and Ochs and Wagner for the analogous case of ππ scattering. Results are found to be in agreement with earlier K π scattering studies using the reaction K + p → K + π − Δ ++ at much higher energies. The S-wave scattering length is found to be in agreement with the prediction of current algebra.
No description provided.
Cross sections for p ̄ p → n ̄ n at 25 and 35 GeV/ c have been measured. The cross sections decrease with increasing momentum as 1/ P 2 . A narrow peak is observed in the momentum transfer interval 0 ⩽ − t ≲ 0.02 (GeV/ c 2 in the differential cross sections. Neither ϱ nor A 2 exchange contribute to the process in the investigated energy range.
K- CEX MEASURED BY STARS FROM KL AS A CHECK.
No description provided.
No description provided.
None
.
.
D(SIG)/D(T) AT T=0. OBTAINED FROM MODEL EXTRAPOLATION OF PRESENTED T DEPENDENCE OF D(SIG)/D(T).
Charged particles ($h^\pm$) and \kz mesons have been studied in photoproduced events containing at least one jet of $E_T > 8$ GeV in a pseudorapidity interval (--0.5, 0.5) in the ZEUS laboratory frame. Distributions are presented in terms of transverse momentum, pseudorapidity and distance of the particle from the axis of a jet. The properties of \hpm within the jet are described well using the standard settings of PYTHIA, but the use of the multiparton interaction option improves the description outside the jets. A reasonable overall description of the \kz behaviour is possible with PYTHIA using a reduced value of the strangeness suppression parameter. The numbers of $h^\pm$ and \kz within a jet as defined above are measured to be $3.25\pm0.02\pm0.28$ and $0.431\pm0.013\pm0.088$ respectively. Fragmentation functions are presented for $h^\pm$ and \kz in photoproduced jets; agreement is found with calculations of Binnewies et al. and, at higher momenta, with $p\bar p$ scattering and with standard PYTHIA. Fragmentation functions in direct photoproduced events are extracted, and at higher momenta give good agreement with data from related processes in $e^+e^-$ annihilation and deep inelastic $ep$ scattering.
Corrected multiplicities of charged particles and neutral K0 mesons per photoproduced jet.
Corrected distribution of charged particles per jet in events containing a hadron jet.
Corrected distribution of charged particles per jet in events containing a hadron jet.
A measurement of the spin alignment of charged D^* mesons produced in continuum e^+ e^- \to c \bar{c} events at \sqrt{s}=10.5 GeV is presented. This study using 4.72 fb^{-1} of CLEO II data shows that there is little evidence of any D^* spin alignment.
Systematic errors are not given.
Systematic errors are not given.
Two decay modes of D0 --> K- PI+ and D0 --> K- PI+ PI0 are combined.
We study the processes e+e- --> K+ K- pi+pi-gamma, K+ K- pi0pi0gamma, and K+ K- K+ K-gamma, where the photon is radiated from the initial state. About 84000, 8000, and 4200 fully reconstructed events, respectively, are selected from 454 fb-1 of BaBar data. The invariant mass of the hadronic final state defines the \epem center-of-mass energy, so that the K+ K- pi+pi- data can be compared with direct measurements of the e+e- --> K+ K- pi+pi- reaction. No direct measurements exist for the e+e- --> K+ K-pi0pi0 or e+e- --> K+ K-K+ K- reactions, and we present an update of our previous result with doubled statistics. Studying the structure of these events, we find contributions from a number of intermediate states, and extract their cross sections. In particular, we perform a more detailed study of the e+e- --> phi(1020)pipigamma reaction, and confirm the presence of the Y(2175) resonance in the phi(1020) f0(980) and K+K-f0(980) modes. In the charmonium region, we observe the J/psi in all three final states and in several intermediate states, as well as the psi(2S) in some modes, and measure the corresponding product of branching fraction and electron width.
The cross section for the reaction E+ E- --> K+ K- PI+ PI- measured with ISR data. Statistical errors only.
Cross section measurements for the reaction E+ E- --> K*(892)0 K- PI+. Statistical errors only.
Cross section measurements for the reaction E+ E- --> PHI PI+ PI-. Statistical errors only.
Forum