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Spin correlation measurements for p (polarized) + p (polarized) elastic scattering at 497.5-MeV

Hoffmann, G.W. ; Barlett, M.L. ; Kielhorn, W. ; et al.
Phys.Rev.C 49 (1994) 630-632, 1994.
Inspire Record 383760 DOI 10.17182/hepdata.25964

The spin correlation parameter A00NN for 497.5 MeV proton + proton elastic scattering was determined over the center-of-momentum scattering angle region 23.1°–64.9 °. The new A00NN extend to more forward angles than existing A00NN and have significantly smaller statistical errors (±0.01–0.04). The A00NN are qualitatively described by recent phase shift analyses, but a quantitative shape and normalization discrepancy remains in the forward angle region. These new data provide important constraints for nucleon-nucleon spin-dependent amplitudes at forward angles which are used in theoretical models of nucleon-nucleus scattering.

1 data table
Table 1

Errors include statistical and systematic uncertainties.


Composite particle production in relativistic Au + Pt, Si + Pt, and p + Pt collisions

The E886 collaboration Saito, N. ; Bassalleck, B. ; Burger, T. ; et al.
Phys.Rev.C 49 (1994) 3211-3218, 1994.
Inspire Record 383739 DOI 10.17182/hepdata.25998

Recently, highly relativistic Au beams have become available at the Brookhaven National Laboratory, Alternating Gradient Synchrotron. Inclusive production cross sections for composite particles, d, t, He3, and He4, in 11.5A GeV/c Au+Pt collisions have been measured using a beam line spectrometer. For comparison, composite particle production was also measured in Si+Pt and p+Pt collisions at similar beam momenta per nucleon (14.6A GeV/c and 12.9 GeV/c, respectively). The projectile dependence of the production cross section for each composite particle has been fitted to Aprojα. The parameter α can be described by a single function of the mass number and the momentum per nucleon of the produced particle. Additionally, the data are well described by momentum-space coalescence. Comparisons with similar analysis of Bevalac A+A data are made. The coalescence radii extracted from momentum-space coalescence fits are used to determine reaction volumes (‘‘source size’’) within the context of the Sato-Yazaki model.

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.


Study of the reaction anti-p p ---> Anti-lambda Lambda below 6-MeV excess energy

Barnes, P.D. ; Birien, P. ; Breunlich, W.H. ; et al.
Phys.Lett.B 331 (1994) 203-210, 1994.
Inspire Record 382628 DOI 10.17182/hepdata.28665

The reaction p p → Λ Λ → p π + pπ − is studied in the experiment PS185 at the CERN Low Energy Antiproton Ring (LEAR). A precise measurement of the excitation function in the immediate threshold region below 6 MeV excess energy was achieved. The total cross section shows an unexpected behaviour around 1 MeV excess energy.

2 data tables
Table 1

The values are calculated using M(p)=M(pbar) = 938.27231 Mev and M(lambda)=M(lambdabar) = 1115.63 MeV.

Table 2

D(SIG)/D(OMEGA) as a function of COS(THETA(RF=CM)) for the nine intervals of the excess energy. Excess energy is SQRT(S)-M(lambda)-M(lambdabar).


Measurement of the double spin asymmetry A-LL for inclusive multi gamma pair production with 200-GeV/c polarized proton beam and polarized proton target

The FNAL E581/704 collaboration Adams, D.L. ; Akchurin, N. ; Belikov, N.I. ; et al.
Phys.Lett.B 336 (1994) 269-274, 1994.
Inspire Record 378852 DOI 10.17182/hepdata.28569

The invariant double-differential cross section, E 1 E 2 d 6 σ / d p 3 1 d p 3 2 , and the double-spin asymmetry, A LL , for inclusive multi-γ pair production in which γ-rays came from neutral mesons were measured with a 200 GeV / c longitudinally-polarized proton beam and a longitudinally-polarized proton target. Most of the multi-γ pairs comes from two-jet type events which are sensitive to partonic interaction. The A LL values were found to be consistent with zero. The invariant double-differential cross section for inclusive π 0 π 0 production was also measured. These measured cross sections are consistent with LUND Monte Carlo simulations. Using the LUND Monte Carlo simulation package with the Carlitz-Kaur model of spin dependent distribution functions of valence quarks, the A LL values have been compared with theoretical predictions of gluon polarization, ΔG / G . The results put restrictions on the size of ΔG / G in the region of 0.05 ⪅ x ⪅ 0.35.

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.


Phi and omega meson production in anti-n p annihilation and the OZI rule

The OBELIX collaboration Ableev, V.G. ; Agnello, M. ; Balestra, F. ; et al.
Phys.Lett.B 334 (1994) 237-243, 1994.
Inspire Record 383126 DOI 10.17182/hepdata.28740

The φπ + /ωπ + ratio from n¯p annihilations on a liquid hydrogen target, for n¯ momenta between 64 and 297 MeV/ c , was measured using the OBELIX spectrometer at LEAR. The ratio R(ϕπ/ωπ)=σ(n¯p→ϕπ+)/σ(n¯p→ωπ+) turned out 0.110±0.015 stat ±0.006 syst . Implications of this result on the OZI rule are discussed.

1 data table
Table 1

Assumes branching ratios of (49.1 +- 0.8)% for phi --> K+ K- and (88.8 +- 0.6)% for omega --> pi+ pi- pi0.


A Study of the transverse polarization of Lambda0 and Anti-lambda0 hyperons produced in pi- Cu interactions at 230-GeV/c

The ACCMOR collaboration Barlag, S. ; Becker, H. ; Bożek, A. ; et al.
Phys.Lett.B 325 (1994) 531-535, 1994.
Inspire Record 377671 DOI 10.17182/hepdata.28729

We study the polarization with respect to the normal to the production plane for a very clean sample of 27217 Λ 0 / Λ 0 hyperons produced in 230 GeV/ c π −  Cu interactions. In general we find P(Λ 0 ) ≈ P( Λ 0 ap; 0 except for x F > 0, p T > 1GeV/ c where P ( Λ 0 ) = −0.28±0.09(stat.)±0.02(syst.).

4 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Mass dependence of pi0 production in heavy ion collisions at 1-A/GeV

Schwalb, O. ; Pfeiffer, M. ; Berg, F.-D. ; et al.
Phys.Lett.B 321 (1994) 20-25, 1994.
Inspire Record 376130 DOI 10.17182/hepdata.28781

The production of neutral pions has been studied in the reactions 40 Ar + nat Ca , 86 Kr + nat Zr and 197 Au + 197 Au at 1 A GeV. For high energy pions emitted from the heavier systems a steeper than linear rise of the pion multiplicity with the centrality of the reaction is observed, indicating a pion production process other than binary nucleon-nucleon collisions. At low transverse momenta an enhancement of the π 0 -multiplicity increasing with the mass of the collision system is found. Systematic discrepancies between the experimental results and recent BUU, QMD and Cascade calculations are discussed.

6 data tables
Table 1

No description provided.

Table 2

RESULTS OF AN EXTRAPOLATION TO THE FULL SOLID ANGLE TAKING THE EXPERIMENTALTEMPERATURES INTO ACCOUNT.

Table 3

No description provided.

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Projectile rapidity pions in 775-MeV/nucleon La-139 + C-12 and La-139 + La-139 reactions

Hashimoto, O. ; Hamagaki, H. ; Kobayashi, T. ; et al.
Phys.Rev.C 49 (1994) 420-427, 1994.
Inspire Record 383725 DOI 10.17182/hepdata.25980

Negative pion spectra emitted in the reactions of 775 MeV/nucleon La139+12C and La139+139La reactions have been measured in coincidence with the projectile fragments using the HISS spectrometer at the Bevalac. Prominent peaks near the beam velocity were observed in the pion spectra. Position and widths of the peaks were studied as a function of the ‘‘sum charge’’ of projectile fragments which is a good measure of impact parameter; the smaller the ‘‘sum charge,’’ the smaller the impact parameter. The peak position down shifts with the smaller ‘‘sum charge.’’ The pion peak is wider in the transverse than in the longitudinal direction, possibly mirroring the velocity dispersions of projectile fragments in the early stage of reactions.

2 data tables
Table 1

THE CHARGE IN THE TABLE IS THE SUM CHARGE OF OBSERVED FRAGB. A TWO-DIMENSIONAL SPECTRUM WAS FITTED BY A SINGLE TWO-DIMENSIONAL GAUSSIAN FUNCTION ON A FLAT BACKGROUND.

Table 2

THE CHARGE IN THE TABLE IS THE SUM CHARGE OF OBSERVED FRAGB. A TWO-DIMENSIONAL SPECTRUM WAS FITTED BY A SINGLE TWO-DIMENSIONAL GAUSSIAN FUNCTION ON A FLAT BACKGROUND.


Annihilation cross-sections of anti-neutrons on C, Al, Cu, Sn and Pb at low momenta (180-MeV/c - 280-MeV/c) with the OBELIX spectrometer

The OBELIX collaboration Ableev, V.G. ; Adamo, A. ; Agnello, M. ; et al.
Nuovo Cim.A 107 (1994) 943-953, 1994.
Inspire Record 384438 DOI 10.17182/hepdata.37841

Annihilation cross-sections σann for antineutrons on some nuclei (C, Al, Cu, Sn and Pb) at three antineutron momenta (180, 240 and 280 MeV/c) were measured at LEAR (CERN) with the OBELIX spectrometer. A behaviour σann=σ0Aν has been found withν≈2/3. The data are discussed following some models for antineutron-nucleus interaction.

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.


Measurement of the average cross-section of 0.06-GeV/c to 0.75-GeV/c anti-p annihilation on Xe nuclei

The DIANA collaboration Barmin, V.V. ; Barylov, V.G. ; Chernukha, S.F. ; et al.
Phys.Atom.Nucl. 57 (1994) 1835-1836, 1994.
Inspire Record 385048 DOI 10.17182/hepdata.17208

None

1 data table
Table 1

CROSS SECTION WAS ESTIMATED ASSUMING IT'S INDEPENDENCE OF THE ANTIPROTON M OMENTUM.