Daum, M.
Polarization
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Kinetic energy spectrum and polarization of neutrons from the reaction C-12(p(pol.),n(pol.))X at 590-MeV.

Arnold, J. ; van den Brandt, B. ; Daum, M. ; et al.
Eur.Phys.J.A 2 (1998) 411-415, 1998.
Inspire Record 477089 DOI 10.17182/hepdata.43498

The kinetic energy spectrum and the polarization of the PSI neutron beam produced in the reaction 12C(p,n)X at 0° with 590 MeV polarized protons were investigated. A strong energy dependence of the ne

1 data table
Table 1

No description provided.


Polarization transfer observables in pi d elastic scattering

Suft, G. ; Amaudruz, P. ; Boschitz, E. ; et al.
Phys.Lett.B 425 (1998) 19-24, 1998.
Inspire Record 472904 DOI 10.17182/hepdata.28205

Polarization transfer observables in π + d elastic scattering have been measured for the first time. Four polarization transfer parameters were determined at pion energies T π =134 MeV and 180 MeV at scattering angles θ π ,C.M. between 100° and 140° using a deuteron target polarized perpendicular to the scattering plane and a deuteron tensor polarimeter. The data are compared to different predictions from the SAID phase shift analysis and Faddeev calculations.

2 data tables
Table 1

Systematic and statistical errors are added in quadrature.

Table 2

Systematic and statistical errors are added in quadrature.


Spin observables in neutron proton elastic scattering.

Ahmidouch, A. ; Arnold, J. ; van den Brandt, B. ; et al.
Eur.Phys.J.C 2 (1998) 627-641, 1998.
Inspire Record 471273 DOI 10.17182/hepdata.11376

The analyzing power,$A_{oono}$, and the polarization transfer observables$K_{onno}$,$K_{os''so}$

20 data tables
Table 1

Position 'A' (see text for explanation).

Table 2

Position 'A' (see text for explanation).

Table 3

Position 'A' (see text for explanation).

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Study of Lambda0 polarization in four different exclusive p p reactions at 27.5-GeV/c

Felix, J. ; Avilez, C. ; Christian, D.C. ; et al.
Phys.Rev.Lett. 82 (1999) 5213-5216, 1999.
Inspire Record 457464 DOI 10.17182/hepdata.19473

We have measured the xF and PT dependence of the polarization of Λ0 hyperons produced in exclusive final states pp→pΛ0K+π+π−, pp→pΛ0K+π+π−π+π−, pp→pΛ0K+π+π−π+π−π+π−, and pp→pΛ0K+π+π−π+π−π+π−π+π− at 27.5 GeV/ c. We present an empirical parametrization for Λ0 polarization as a function of xF and PT: P=(−0.443±0.037)xFPT for −1≤xF≤1 and 0≤PT≤1.8GeV/c. This parametrization is independent of the final state and provides a good description of the data. We note that the mechanism responsible for Λ0 polarization appears to be independent of the production mechanism.

1 data table
Table 1

Result of a linear fit to all the data in the XL and PT region.


Measurements of inclusive anti-Lambda0 production with large x(F) at the Spp(bar)S collider.

The UA8 collaboration Brandt, A. ; Erhan, S. ; Kuzucu, A. ; et al.
Nucl.Phys.B 519 (1998) 3-18, 1998.
Inspire Record 452309 DOI 10.17182/hepdata.32680

We report results of inclusive measurements of anti-Lambda, produced in the forward direction at the SPS with sqrt(s) = 630 GeV, using the UA8 small angle Roman Pot spectrometers. These measurements cover the range in Feynman-x_f and transverse momentum, 0.6 < x_f < 1.0 and 0.4 < p_t < 0.7 GeV, respectively. Within a systematic uncertainty of +-20% on the absolute cross section measurements, the results are indistinguishable from those made by some of us in two earlier experiments at the CERN Intersecting Storage Rings, with energies, sqrt(s) = 53 and 62 GeV. In the x_f-range, 0.6-0.9, the absolute cross sections are lower by a factor of 2 to 3 than the predictions of the Lund model as embodied in the PYTHIA 5.6 and JETSET 7.3 Monte Carlo programs, indicating inadequacies in knowledge of the baryon fragmentation function. For the largest x_f-range, 0.9-1.0, the measurements agree with the Monte Carlo predictions. We have measured the average anti-Lambda polarization for our events and find (6 +- 12%), consistent with previous measurements at the ISR in the present region of x_f - p_t.

3 data tables
Table 1

Invariant cross section for inclusive LAMBDABAR production, multiplied by a factor 2, from the UP spectrometer.

Table 2

Invariant cross section for inclusive LAMBDABAR production, multiplied by a factor 2, from the DOWN spectrometer.

Table 3

The measured LAMBDABAR polarization.


Elastic and proton dissociative rho0 photoproduction at HERA

The ZEUS collaboration Breitweg, J. ; Derrick, M. ; Krakauer, D. ; et al.
Eur.Phys.J.C 2 (1998) 247-267, 1998.
Inspire Record 452353 DOI 10.17182/hepdata.44331

Elastic and proton-dissociative rho0 photoproduction (gamma p-->rho0 p,gamma p -->rho0 N,with rho0-->pi+pi-) has been studied in ep interactions at HERA for gamma-p centre-of-mass energies in the range 50pi+pi- p cross section is 11.2\pm 0.1(stat.)+1.1-1.2 (syst.) mub at =71.7 GeV. The t dependence of the cross section can be described by a function of the type Ae^(-b|t|+ct^2) with b=10.9\pm0.3(stat.)+1.0-0.5(syst.)GeV-2 and c=2.7\pm0.9(stat.)+1.9-1.7(syst.) GeV-4. The t dependence has also been studied as a function of W and a value of the slope of the pomeron trajectory 0.23\pm0.15(stat.)+0.10-0.07(syst.)GeV-2 has been deduced. The rho spin density matrix elements r^04_00,r^04_1-1 and Re[r^04_10] have been measured and found to be consistent with expectations based on SCHC. For p-dissociative pi+pi- photoproduction in the rho0 mass range, the distributions of the two-pion invariant mass, W and the polar and azimuthal angles of the pions in the helicity frame are the same within errors as those for the elastic process. The t distribution has been fitted to an exponential function with a slope parameter 5.8\pm0.3(stat.)\pm0.5(syst.)GeV-2. The ratio of the elastic to p-dissociative rho0 photoproduction cross section is 2.0\pm0.2(stat.)\pm0.7(syst.).

19 data tables
Table 1

Integrated elastic rho0 photoproduction cross section.

Table 2

Integrated elastic pi+ pi- photoproduction cross section.

Table 3

Differential T distribution. Statistical errors only.

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Spin transfer in inclusive Lambda0 production by transversely polarized protons at 200-GeV/c.

The E704 collaboration Bravar, A. ; Adams, D.L. ; Akchurin, N. ; et al.
Phys.Rev.Lett. 78 (1997) 4003-4006, 1997.
Inspire Record 449327 DOI 10.17182/hepdata.19560

Surprisingly large polarizations in hyperon production by unpolarized protons have been known for a long time. The spin dynamics of the production process can be further investigated with polarized beams. Recently, a negative asymmetry AN was found in inclusive Λ0 production with a 200GeV/c transversely polarized proton beam. The depolarization DNN in p↑+p→Λ0+X has been measured with the same beam over a wide xF range and at moderate pT. DNN reaches positive values of about 30% at high xF and pT∼1.0GeV/c. This result shows a sizable spin transfer from the incident polarized proton to the outgoing Λ0.

6 data tables
Table 1

Errors are statistical only. The systematic errors are estimated to be negligible.

Table 2

Errors are statistical only. The systematic errors are estimated to be negligible.

Table 3

Errors are statistical only. The systematic errors are estimated to be negligible.

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Measurement of single spin asymmetry in eta meson production in p(pol.) p and in anti-p(pol.) p interactions in the beam fragmentation region at 200-GeV/c.

The Fermilab E704 collaboration Adams, D.L. ; Bonner, B.E. ; Corcoran, M.D. ; et al.
Nucl.Phys.B 510 (1998) 3-11, 1998.
Inspire Record 449811 DOI 10.17182/hepdata.51687

We present experimental results on measuring a single spin asymmetry in η-meson production in the interaction of transversely polarized protons and antiprotons at p lab = 200 GeV / c with a proton target in the region 0.2 < x F < 0.7 for p ↑ p , 0.3 < x F < 0.7 for p ̄ ↑p and 0.7 < p T < 2.0 GeV / c . A comparison of single spin asymmetries in π- and η-meson production is made.

2 data tables
Table 1

The true asymmetry for ETA production in proton-proton collisions.

Table 2

The true asymmetry for ETA production in antiproton-proton collisions.


Tensor analyzing power T(20) for cumulative pion production from deuterons in a GeV energy region.

Afanasev, S. ; Anisimov, Yu. ; Fujieda, M. ; et al.
Nucl.Phys.A 625 (1997) 817-831, 1997.
Inspire Record 454165 DOI 10.17182/hepdata.36286

The tensor analyzing power T 20 for the reaction d ↑ + 12 C → π ± (0°) + X has been measured with a polarized deuteron beam from 6.2 to 9.0 GeV/ c at a pion momentum3.0 GeV/ c . This experiment is focused on “cumulatively produced pions”, which are produced beyond the kinematically allowed limit for free nucleon-nucleon collisions. The measured values of T 20 turn out to be close to zero. They are in disagreement with the results of our impulse approximation calculation which is based on a single NN → πNN interaction and takes into account the internal motion of nucleons in the deuteron. Possible explanations of the result are discussed.

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.


Proton dissociative rho and elastic phi electroproduction at HERA

The H1 collaboration Adloff, C. ; Aid, S. ; Anderson, M. ; et al.
Z.Phys.C 75 (1997) 607-618, 1997.
Inspire Record 443293 DOI 10.17182/hepdata.44590

The electroproduction of rho mesons with proton diffractive dissociation for Q^2 > 7 GeV^2 and the elastic electroproduction of Phi mesons for Q^2 > 6 Gev^2 are studied in e^+ p collisions at HERA with the H1 detector, for an integrated luminosity of 2.8 pb-1. The dependence of the cross sections on P_t^2 and Q^2 is measured, and the vector meson polarisation obtained. The cross section ratio between proton dissociative and elastic production of rho mesons is measured and discussed in the framework of the factorisation hypothesis of diffractive vertices. The ratio of the elastic cross section for Phi and rho meson production is investigated as a function of Q^2.

11 data tables
Table 1

Corrected PT**2 distribution for RHO production from the proton dissociative sample. Statistical errors only.

Table 2

Cross sections and ratio of proton dissociative to elastic cross sections.

Table 3

Cross sections and ratio of proton dissociative to elastic cross sections.

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