Andreev, V.
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Total photoabsorption cross-section for He-4 from 200-MeV to 800-MeV

MacCormick, M. ; Habermann, J. ; Ahrens, J. ; et al.
Phys.Rev.C 55 (1997) 1033-1038, 1997.
Inspire Record 457684 DOI 10.17182/hepdata.25723

The total photoabsorption cross section for 4He has been measured for the first time over a wide photon energy range (200 MeV<~Eγ<~800 MeV). By using the large acceptance detector DAPHNE at the tagged photon facility of the MAMI microtron in Mainz high precision results with small systematic errors were obtained. This measurement shows that 4He has a behavior similar to heavy nuclei and, in particular, a reduction of the cross section with respect to the lighter nuclei is found for Eγ>600 MeV.

1 data table
Table 1

No description provided.


Spin asymmetries from O-16(gamma(pol.),p pi-) near Delta resonance energies

Hicks, K. ; Baghaei, H. ; Caracappa, A. ; et al.
Phys.Rev.C 55 (1997) R12-R15, 1997.
Inspire Record 456890 DOI 10.17182/hepdata.25766

Spin asymmetries for the 16O(γ→,pπ−) reaction are reported for incident photon energies of 293 ± 20 MeV, proton angles ranging from 28° to 140° (lab), and pion angles of 35° to 115°. The data are compared with calculations in a quasifree plane-wave impulse approximation model. This model is in good agreement with the data at small momentum transfer q, but does not follow the trend of the data at large q. Sensitivity to the Δ-nucleus potential and to modification of the Δ lifetime from nuclear medium effects are explored using a simple modification of the Δ propagator in the calculations.

6 data tables
Table 1

The data are extracted from the figures by S.Slabospitsky. ASYM is the spin asymmetry. It is the ratio of the difference to the sum of the cross sections with the photon's linear polarization oriented parallel or perpendicular to the scattering plane.

Table 2

The data are extracted from the figures by S.Slabospitsky. ASYM is the spin asymmetry. It is the ratio of the difference to the sum of the cross sections with the photon's linear polarization oriented parallel or perpendicular to the scattering plane.

Table 3

The data are extracted from the figures by S.Slabospitsky. ASYM is the spin asymmetry. It is the ratio of the difference to the sum of the cross sections with the photon's linear polarization oriented parallel or perpendicular to the scattering plane.

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Spin transfer measurements of the pi anti-d ---> anti-p p reaction at energies spanning the Delta resonance

Feltham, A. ; Jones, G. ; Olszewski, R. ; et al.
Phys.Rev.C 55 (1997) 19-41, 1997.
Inspire Record 456889 DOI 10.17182/hepdata.25720

The first spin-transfer experiment performed for the πd→→p→p reaction is described. Three spin-transfer parameters for this π-absorption process were determined, KLSa, KSSa, and KNNa, which correspond to the π-production parameters, KSLp, KSSp, and KNNp, of the time-reversed p→p→d→π process. Each observable was measured at a single angle for a number of energies spanning the Δ resonance of this system. The results are compared with the predictions of published partial wave amplitude fits which are primarily based on existing data for the time-reversed pp→dπ reaction, and also with the predictions of two current theories. The failure of these theories to describe the fundamental features of the data clearly demonstrates the need for further theoretical work in this area.

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.


Study of anti-neutron proton annihilation in two mesons in the momentum range between 50 to 400 MeV/c with OBELIX

The OBELIX collaboration Bertin, A. ; Bruschi, M. ; Capponi, M. ; et al.
Phys.Lett.B 410 (1997) 344-352, 1997.
Inspire Record 459313 DOI 10.17182/hepdata.28243

We measured the in flight annihilation frequencies and cross sections of reactions n p → π + π 0 ,π + η and K + K S in the antineutron momentum range between 50 and 400 MeV/c. The annihilation frequencies of these channels from the different allowed initial states were calculated and some information about the n p annihilation dynamics were obtained. The first determination of the D-wave contribution in this momentum range was also obtained.

1 data table
Table 1

No description provided.


Charged particle production in S S collisions at 200-GeV/c per nucleon

The WA94 collaboration Andrighetto, A. ; Antinori, F. ; Bayes, A.C. ; et al.
Phys.Lett.B 412 (1997) 148-154, 1997.
Inspire Record 460283 DOI 10.17182/hepdata.28242

Charged particle production in central S-S collisions at 200 GeV/ c per nucleon has been studied by the WA94 experiment at the CERN-SPS. Particle identification has been provided by the Omega RICH, while a silicon telescope in the Omega spectrometer and an array of MultiWire Proportional Chambers have been used to trace particles through the RICH detector. Production ratios and transverse mass spectra for π ± , K ± and p( p ) at central rapidity and p T > 1.3 GeV/ c are presented.

3 data tables
Table 1

Distributions are fitted with (1/MT**1.5)*DSIG/DMT = CONST*EXP(-MT/SLOPE).

Table 2

1.54 GeV ratio is calculated from the fit to the MT distribution.

Table 3

1.54 GeV ratio is calculated from the fit to the MT distribution.


Anomalous J / psi suppression in Pb - Pb interactions at 158 GeV/c per nucleon

The NA50 collaboration Abreu, M.C. ; Alessandro, B. ; Alexa, C. ; et al.
Phys.Lett.B 410 (1997) 337-343, 1997.
Inspire Record 459314 DOI 10.17182/hepdata.28260

The Drell-Yan and J ψ cross-sections measured in PbPb collisions are compared with the values extrapolated from the results obtained in proton and light ion induced reactions. While the Drell-Yan production exhibits the normal expected behaviour, the yield of J ψ in PbPb interactions is abnormally low, as it lies 9 standard deviations below the expected value. Moreover, the departure from the expected behaviour increases significantly from peripheral to central collisions.

2 data tables
Table 1

The results from other experiments are also presented.

Table 2

Different data are rescaled at 200 GeV.


Pion and proton production in proton tungsten and sulphur tungsten interactions at 200-GeV/c per nucleon

The WA85 collaboration Antinori, F. ; Barnes, R.P. ; Bayes, A.C. ; et al.
Phys.Lett.B 412 (1997) 407-413, 1997.
Inspire Record 459722 DOI 10.17182/hepdata.28265

Production of charged particles identified by a multi cell threshold Čerenkov counter in proton-tungsten and central sulphur-tungsten collisions at 200 GeV/ c per nucleon is discussed. The π ± , p and p production ratios and transverse mass spectra at central rapidity and p T > 0.6 GeV/ c are presented and compared with results from other experiments at the same beam energy.

4 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

The slope evaluated from the D(N)/D(MT)/(MT**1.5) distribution (denoted as D(N)/D(MT)).

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Study of the pi0 pi0 eta-prime final state in anti-p p annihilation at rest

The Crystal Barrel collaboration Abele, A. ; Adomeit, J. ; Amsler, C. ; et al.
Phys.Lett.B 404 (1997) 179-186, 1997.
Inspire Record 457856 DOI 10.17182/hepdata.28292

A partial wave analysis of p̄p → π 0 π 0 η ′ has been performed using the η′ → π 0 π 0 η and η ′ → γγ decay modes. The data are dominated by an η ′ recoiling against the ( ππ ) S-wave. In addition, α 2 (1320) → η′π 0 is needed. There is evidence for contributions from α 0 (1450) → η′π 0 . The branching ratio of α 0 (1450) → η′π 0 with respect to ηπ 0 is consistent with the prediction of SU(3).

1 data table
Table 1

No description provided.


Tensor analyzing power T(20) in backward elastic d p scattering and breakup at 0-degrees between 3.5-GeV/c and 6.5-GeV/c

Azhgirey, L.S. ; Chernykh, E.V. ; Kobushkin, A.P. ; et al.
Phys.Lett.B 391 (1997) 22-28, 1997.
Inspire Record 456818 DOI 10.17182/hepdata.28323

The tensor analyzing power T 20 for the p ( d , p d) and p ( d , p ) pn reactions θ cm p = 180° have been measured at incident deuteron momenta from 3.5 to 6.5 GeV/ c . For both reactions T 20 remains negative up to internal momentum k ⋍ 0.85 GeV/ c and show a rich structure beyond the region where T 20 is expected to be determined by the S - and D -states of the deuteron. The T 20 data for deuteron breakup without pion production, close to the backward elastic kinematics, were obtained simultaneously with the elastic data.

1 data table
Table 1

K is the internal momentum of the nucleon.


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.