Inclusive $\Lambda^0$ Polarization in Proton Nucleus Collisions at 12-{GeV}

Abe, F. ; Hara, K. ; Kim, S. ; et al.
Phys.Rev.D 34 (1986) 1950-1959, 1986.
Inspire Record 237791 DOI 10.17182/hepdata.23459

The polarization of Λ0 hyperons in inclusive production by 12-GeV protons on nuclei has been measured for beryllium, copper, and tungsten targets. Data are obtained at five production angles, 3.5°, 5.0°, 6.5°, 8.0°, and 9.5°, covering the kinematic range 0.26≤xF≤0.77 and 0.4≤pT≤1.5 GeV/c. The dependence of the polarization on target nuclei is investigated by statistical analyses of the data. The polarization at fixed pT increases roughly linearly with xF. The present results are compared with other work at higher energies in terms of the A dependence and the (xF,pT) dependence.

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Polarization of $\Omega^-$ Hyperons Produced in 800 GeV Proton - Beryllium Collisions

Luk, K.B. ; James, C. ; Rameika, R. ; et al.
Phys.Rev.Lett. 70 (1993) 900-903, 1993.
Inspire Record 345978 DOI 10.17182/hepdata.19740

The polarization of 103 211 Ω− hyperons produced in 800 GeV proton-beryllium inclusive reactions has been measured. Between 0.3<xF<0.7 and 0.5<pt<1.3 GeV/c, the Ω− polarization is found to be consistent with zero, with a mean value of -0.01±0.01 at 〈xF〉=0.5 and 〈pt〉=0.95 GeV/c. This behavior is similar to that of Λ¯0, which also does not have any quarks in common with the incident proton, but is different from Ξ¯+, which is significantly polarized in the same kinematic region.

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Analyzing power A(y) for omega meson production in proton-proton collisions

Abdel-Bary, M. ; Brinkmann, K.Th. ; Clement, H. ; et al.
Phys.Lett.B 662 (2008) 14-18, 2008.
Inspire Record 784829 DOI 10.17182/hepdata.26964

We report on a determination of the analyzing power Ay in the reaction studied with the TOF spectrometer located at the COSY-accelerator (Forschungszentrum Juelich, Germany). This spectrometer is very well suited for polarization measurements due to its rotational symmetry and full coverage of the azimuthal angle. For a beam momentum of p=3065MeV/c corresponding to an excess energy of epsilon (Porson) =129MeV Ay is found to be compatible with zero.

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Measurement of J / psi and psi(2S) polarization in p anti-p collisions at S**(1/2) = 1.8-TeV

The CDF collaboration Affolder, T. ; Akimoto, H. ; Akopian, A. ; et al.
Phys.Rev.Lett. 85 (2000) 2886-2891, 2000.
Inspire Record 526553 DOI 10.17182/hepdata.42989

We have measured the polarization of J/Psi and Psi(2S) mesons produced in p\bar{p} collisions at \sqrt{s} = 1.8 TeV, using data collected at CDF during 1992-95. The polarization of promptly produced J/Psi [Psi(2S)] mesons is isolated from those produced in B-hadron decay, and measured over the kinematic range 4[5.5] < P_T < 20 GeV/c and |y| < 0.6. For P_T \gessim 12 GeV/c we do not observe significant polarization in the prompt component.

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Neutral strange particle production in sulphur sulphur and proton sulphur collisions at 200-GeV/nucleon

The NA35 collaboration Bartke, J. ; Bialkowska, H. ; Bock, R. ; et al.
Z.Phys.C 48 (1990) 191-200, 1990.
Inspire Record 304994 DOI 10.17182/hepdata.15177

The production of Λ,\(\bar \Lambda\) andKs0 has been studied in 200 GeV/nucleonp+S and S+S collisions in the streamer chamber of the NA35 experiment at the CERN SPS. Significant enhancement of the multiplicities of all observed strange particles relative to negative hadrons was observed in central S+S collisions, as compared top+p andp+S collisions. The latter collisions show no overall (relative) strangeness enhancement overp+p, but the rapidity distributions and hadron multiplicities indicate some secondary cascading production of Λ particles in thep+S andp+Au collisions. The Λ polarization in central S+S collisions was found to be compatible with zero up topT=2 GeV/c.

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Upsilon production and polarization in p anti-p collisions at s**(1/2) = 1.8-TeV

The CDF collaboration Acosta, D. ; Affolder, T. ; Akimoto, H. ; et al.
Phys.Rev.Lett. 88 (2002) 161802, 2002.
Inspire Record 569269 DOI 10.17182/hepdata.42894

We report on measurements of the ϒ(1S), ϒ(2S), and ϒ(3S) differential cross sections (d2σ/dpTdy)|y|<0.4, as well as on the ϒ(1S) polarization in pp¯ collisions at s=1.8TeV using a sample of 77±3pb−1 collected by the collider detector at Fermilab. The three resonances were reconstructed through the decay ϒ→μ+μ−. The measured angular distribution of the muons in the ϒ(1S) rest frame is consistent with unpolarized meson production.

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Angular distributions of leptons from J/psi's produced in 920- GeV fixed-target proton-nucleus collisions

The HERA-B collaboration Abt, I. ; Adams, M. ; Agari, M. ; et al.
Eur.Phys.J.C 60 (2009) 517-524, 2009.
Inspire Record 810555 DOI 10.17182/hepdata.57473

A study of the angular distributions of leptons from decays of J/psi's produced in p-C and p-W collisions at sqrt{s}=41.6 GeV has been performed in the Feynman-x region -0.34 < x_F < 0.14 and for transverse momentum up to 5.4 GeV/c. The data were collected by the HERA-B experiment at the HERA proton ring of the DESY laboratory. The results, based on a clean selection of 2.3 x 10^5 J/psi's reconstructed in both the e^+ e^- and mu^+ mu^- decay channels, indicate that J/psi's are produced with longitudinal polarization. The magnitude of the effect is maximal at low p_T. For p_T >1 GeV/c a significant dependence on the reference frame is found: the polar anisotropy is more pronounced in the Collins-Soper frame and almost vanishes in the helicity frame, where, instead, a significant azimuthal anisotropy arises.

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Measurement of single spin asymmetry for direct photon production in p p collisions at 200-GeV/c

The E704 collaboration Adams, D.L. ; Achurin, N. ; Belikov, N.I. ; et al.
Phys.Lett.B 345 (1995) 569-575, 1995.
Inspire Record 399938 DOI 10.17182/hepdata.28766

The single spin asymmetry for inclusive direct-photon production has been measured using a polarized proton beam of 200 GeV/c with an unpolarized proton target at −0.15 < xf < 0.15 and 2.5 < pt < 3.1 GeV/c at Fermilab. The data on the cross section for pp → γX at 2.5 < pt < 3.8 GeV/c are also provided. The measurement was done using lead-glass calorimeters and photon detectors which surrounded the fiducial area of the calorimeters. Background rejection has been done using these surrounding photon detectors. The cross section obtained is consistent with the results of previous measurements assuming a nuclear dependence of A 1.0 . The single spin asymmetry, A N , for the direct-photon production is consistent with zero within experimental uncertainty.

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Observation of significant spin effects in hard collisions at 40-GeV/c

Apokin, V.D. ; Arestov, Yu.I. ; Astafev, O.V. ; et al.
Phys.Lett.B 243 (1990) 461-464, 1990.
Inspire Record 303587 DOI 10.17182/hepdata.29694

A single-spin asymmetry in the inclusive π 0 production at small x F was measured. In the experiment 40 GeV/c π − mesons were incident on transversely polarized protons and deutrons. An asymmetry of (40–50)% has been revealed in the hard scattering region.

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Polarization of J / psi and psi(2S) mesons produced in p anti-p collisions at s**(1/2) = 1.96-TeV

The CDF collaboration Abulencia, A. ; Adelman, Jahred A. ; Affolder, T. ; et al.
Phys.Rev.Lett. 99 (2007) 132001, 2007.
Inspire Record 747876 DOI 10.17182/hepdata.42742

We have measured the polarizations of J/ψ and ψ(2S) mesons as functions of their transverse momentum pT when they are produced promptly in the rapidity range |y|<0.6 with pT≥5  GeV/c. The analysis is performed using a data sample with an integrated luminosity of about 800  pb−1 collected by the CDF II detector. For both vector mesons, we find that the polarizations become increasingly longitudinal as pT increases from 5 to 30  GeV/c. These results are compared to the predictions of nonrelativistic quantum chromodynamics and other contemporary models. The effective polarizations of J/ψ and ψ(2S) mesons from B-hadron decays are also reported.

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