HEPData Search

Showing 10 of 10000 results

Scalar and vector meson production and two-step processes in the (K-,K+) reaction on C-12.

The E224 collaboration Ahn, J.K. ; Aoki, S. ; Chung, K.S. ; et al.

Nucl.Phys.A 625 (1997) 231-250, 1997.

Inspire Record 439760 DOI 10.17182/hepdata.36465

The double strangeness exchange reaction ( K − , K + ) is investigated with respect to the sub-threshold production of scalar and vector mesons ( f 0 / a 0 / φ ) decaying into K + K − and the two-step processes induced by intermediate mesons and Ξ − hyperons at p k − = 1.66 GeV/ c using a scintillating fiber active target. The differential cross section ( 〈 dσ dΩ L 〉) averaged over the angular interval (2.3° ⩽ θ K + L ⩽ 14.7°) for the sub-threshold f 0 / a 0 / φ meson production with the K + K − decay is 11 ± 6 μ b/sr at 0.6 ⩽ p K 1 < 0.95 GeV/ c . The present result differs significantly from the theoretical calculation which predicts the contribution of the f 0 / a 0 / φ meson production to be predominant in the ( K − , K + ) reaction below p K + = 0.95 GeV/ c . We found a sizable contribution from two-step ( K − , K + processes, characterized by production of two S = −1 hyperons, consistent with the result of the intra-nuclear cascade (INC) model calculation with respect to the meson-induced hyperon (or hyperon resonance) pair production in the momentum region 0.6 ⩽ p K + < 0.95 GeV/ c . The observed enhancement of the cross section for the two-step ΛΛ production beyond the prediction of the INC model at p K + ⋍ 1.1 GeV /c could be due to the Ξ − p → ΛΛ reaction in 12 C.

6 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

More…

Multinucleon contributions to the C-12(pi+,p p) reaction at 100-MeV and 165-MeV incident pion energies

Huber, G.M. ; Lolos, G.J. ; Papandreou, Z. ; et al.

Nucl.Phys.A 624 (1997) 623-654, 1997.

Inspire Record 459427 DOI 10.17182/hepdata.36491

Differential and total cross sections for π + absorption on 12 C are presented at incident pion energies of 100 and 165 MeV. This is the first time that this reaction has been measured with a combination of good energy and angle information over an extensive region of phase space. Results are compared to extensive Monte Carlo simulations in order to investigate the role of two- and multinucleon absorption processes in this nucleus. Signatures of ISI and FSI in the pion absorption process are also investigated, in order to explain the complex reaction mechanism implied by the data.

2 data tables

Table 1

Axis error includes +- 20/20 contribution (Relative systematic uncertainty).

Table 2

Axis error includes +- 20/20 contribution (Relative systematic uncertainty).

Compton scattering by the proton through Theta(CMS) = 75-degrees and 90-degrees in the Delta resonance region

Hünger, A ; Peise, J ; Robbiano, A ; et al.

Nucl.Phys.A 620 (1997) 385-416, 1997.

Inspire Record 458618 DOI 10.17182/hepdata.36349

Differential cross sections for Compton scattering by the proton have been measured in the energy interval between 200 and 500 MeV at scattering angles of θ cms = 75° and θ cms = 90° using the CATS, the CATS/TRAJAN, and the COPP setups with the Glasgow Tagger at MAMI (Mainz). The data are compared with predictions from dispersion theory using photo-meson amplitudes from the recent VPI solution SM95. The experiment and the theoretical procedure are described in detail. It is found that the experiment and predictions are in agreement as far as the energy dependence of the differential cross sections in the Δ-range is concerned. However, there is evidence that a scaling down of the resonance part of the M 1+ 3 2 photo-meson amplitude by (2.8 ± 0.9)% is required in comparison with the VPI analysis. The deduced value of the M 1+ 3 2 - photoproduction amplitude at the resonance energy of 320 MeV is: |M 1+ 3 2 | = (39.6 ± 0.4) × 10 −3 m π + −1 .

2 data tables

Table 1

No description provided.

Table 2

No description provided.

Threshold measurements at the internal experimental facility COSY-11

Balewski, J. ; Brauksiepe, S. ; Budzanowski, A. ; et al.

Nucl.Phys.A 626 (1997) 85C-92C, 1997.

Inspire Record 463151 DOI 10.17182/hepdata.36361

The experimental setup and detection technique of the COSY-11 installation, an internal experimental facility at the cooler synchrotron and storage ring COSY Jülich, are described. The detection system has been designed for meson production studies with full geometrical acceptance close to threshold. Preliminary results of first measurements are presented, emphasis is put on strangeness production in the reactions pp → ppK + K − and pp → pK + Λ .

2 data tables

Table 1

Excess energy of 6.1 MeV above threshold 3.3016 GeV.

Table 2

Excess energy of 2 MeV above threshold 2.339 GeV.

Neutron-proton differential cross-section measurements for En from 28 to 75 MeV

Benck, S. ; Slypen, I. ; Meulders, J-P. ; et al.

Nucl.Phys.A 615 (1997) 220-228, 1997.

Inspire Record 459311 DOI 10.17182/hepdata.36360

Experimental measurements of differential cross-sections for neutron-proton scattering are reported for 12 incident neutron energies between 28 and 75 MeV. Data are compared with predictions of different theoretical models and with other experimental results.

6 data tables

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.