HEPData Search

We have observed a clear peak below the Σ+-production threshold in the 4He(K−,π−) reaction at 600MeV/c and θKπ=4∘. This is confirmation of the existence of the bound state of Σ4He, which was reported in the 4He(stoppedK−,π−) reaction. As in the case of stopped kaons, no such peak was found in the 4He(K−,π+) spectrum. Quantitatively reliable parameters for this level have been established. The binding energy and the width of the bound state are 4.4±0.3(stat)±1(syst) MeV and 7.0±0.7(stat)−0.0+1.2(syst) MeV, respectively.

1 data table

Table 1

$HE4/S represents the HE4/SIGMA+ bound state.

Elastic and inelastic scattering of K+ from Li-6 and C-12.

Chrien, R.E. ; Sawafta, R. ; Peterson, R.J. ; et al.

Nucl.Phys.A 625 (1997) 251-260, 1997.

Inspire Record 453025 DOI 10.17182/hepdata.36467

Cross sections for inelastic scattering of 635 and 715 MeV/ c K + from 12 C are compared with DWIA calculations in order to check for possible density-dependent effects on K + -nucleon cross sections within nuclei. New fits to 715 MeV/ c K + scattering spectra from 6 Li give elastic and inelastic cross sections and permit an evaluation of the density dependence of these effects. The same DWIA methods are also used to estimate quadrupole non-central contributions to elastic K + scattering from the 1 + ground state of 6 Li, and these are found to be very small.

8 data tables

Table 1

Axis error includes +- 0.0/0.0 contribution (?////NORMALIZATION UNCERTAINTIES ARE INCLUDED).

Table 2

Axis error includes +- 0.0/0.0 contribution (?////NORMALIZATION UNCERTAINTIES ARE INCLUDED).

Table 3

Axis error includes +- 0.0/0.0 contribution (?////NORMALIZATION UNCERTAINTIES ARE INCLUDED).

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The reaction e+ e- ---> gamma gamma (gamma) at Z0 energies

The DELPHI collaboration Abreu, P. ; Adam, W. ; Adami, F. ; et al.

Phys.Lett.B 268 (1991) 296-304, 1991.

Inspire Record 317825 DOI 10.17182/hepdata.29352

The total and differential cross-sections for the reaction e + e − → γγ ( γ ) are measured at centre of mass energies around 91 GeV using an integrated luminosity of 4.7 pb −1 . The aggreement with QED prediction is good. Consequently there is no evidence for non-standard channels which would have the same experimental signature. The lower limits on the QED cuttoff parameters are Λ + > 113 GeV and Λ − > 95 GeV. An upper limit on the effective coupling between a possible excited electron and the gamma is derived. At 95% confidence level the branching ratios for Z 0 decay into π 0 γ, ηψ and γγγ are below 1.5 × 10 −4 , 2.8 × 10 −4 and 1.4 × 10 −4 respectively.

2 data tables

Table 1

Radiative effects are subtracted.

Table 2

Radiative effects subtracted.

K+ elastic scattering from C and Li-6 at 715-MeV/c

Michael, R. ; Barakat, M.B. ; Bart, S. ; et al.

Phys.Lett.B 382 (1996) 29-34, 1996.

Inspire Record 328538 DOI 10.17182/hepdata.28355

Elastic differential cross sections for K + mesons scattered from nat C and 6 Li targets have been measured at an incident momentum of 715 MeV/c and at angles of 7° to 42° in the laboratory frame. The experimental cross sections agree, within errors, with two different parameter-free impulse approximation calculations. To reduce the effects of the systematic errors, the ratio of the experimental cross sections for nat C to 6 Li is compared to the theoretical values, and these ratios do not agree with theory. This discrepancy suggests either a density-dependent alteration of K + -nucleon amplitudes or a failure of the optical potential calculations to describe these nuclides adequately.

2 data tables

Table 1

No description provided.

Table 2

No description provided.