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

Apokin, V.D.; Arestov, Yu.I.; Astafiev, O.; Belikov, N.I.; Chujko, B. V.; Derevshchikov, A.A.; Grachev, O.A.; Matulenko, Yu. A.; Meshchanin, A.P.; Morozov, A. A.; Mochalov, V. V.; Mysnik, A.I.; Nurushev, S. B.; Patalakha, D. I.; Prudkogliad, A. F.; Rykov, V. L.; Soloviev, L. F.; Solovianov, V. L.; Vasiliev, A.; Borisov, N. S.; Kazarinov, Yu.M.; Khachaturov, B.; Liburg, M.Yu.; Matafonov, V.N.; Neganov, A. B.; Usov, Yu. A.; Bagaturia, Y.; Glonti, L.N.; Macharashvili, G.; Ocherashvili, A.I.; Sakhelashvili, T.

doi:10.1016/0370-2693(90)91414-7

Cited by 39 publications

(10 citation statements)

References 9 publications

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“…However, the reanalysis of that data [11] showed the asymmetry consistent with zero in the whole x T range covered. Former experiments, at 13.3, 18.5, 24 and 40GeV, [12] observed significant asymmetries in the central region and high p ⊥ . In this paper we shall concentrate only on the forward fragmentation region.…”

Section: Main Features Of Single Spin Asymmetry In Inclusive Pion Promentioning

confidence: 94%

Single spin asymmetry in inclusive pion production, Collins effect and the string model

Artru

Czyzewski

Yabuki

1997

Zeitschrift f�r Physik C Particles and Fields

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We calculate the single spin asymmetry in the inclusive pion production in protonproton collisions. We generate the asymmetry at the level of fragmentation function (Collins effect) by the Lund coloured string mechanism. We compare our results with the Fermilab E704 data from p↑p collisions at 200 GeV. We show that the transversely polarized quark densities at high Bjorken x strongly differ from these predicted by the SU(6) proton wave function.

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Section: Main Features Of Single Spin Asymmetry In Inclusive Pion Promentioning

confidence: 94%

Single spin asymmetry in inclusive pion production, Collins effect and the string model

Artru

Czyzewski

Yabuki

1997

Zeitschrift f�r Physik C Particles and Fields

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“…More recently, striking left-right asymmetries (A N ) have been observed [4][5][6][7] in singlespin hadron-hadron collisions. The available data for inclusive production of different mesons and of Λ hyperon show very much the same characteristics as those for P H : we can simply replace P H by A N in (1)-(3) above.…”

mentioning

confidence: 99%

“…(I) The existence of A N in single-spin reactions shows that the polarization of the valence quark and the transverse moving direction of the produced hadron containing this valence quark are closely related to each other: the data [4][5][6][7] shows that meson (e.g. π, η or K) containing q P v and a suitable anti-sea-quarkq T s has a large probability to go left if q P v is upwards polarized.…”

mentioning

confidence: 99%

Hyperon Polarization and Single Spin Left-Right Asymmetry in Inclusive Production Processes at High Energies

Liang

Boros

1997

Phys. Rev. Lett.

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It is shown that the polarization of hyperons observed in high energy collisions using unpolarized hadron beams and unpolarized nucleon or nuclear targets is closely related to the left-right asymmetries observed in single spin inclusive hadron production processes. The relationship is most obvious for the production of the hyperons which have only one common valence quark with the projectile. Examples of this kind are given. Further implications of the existence of large polarization for hyperon which has two valence quarks in common with the projectile and their consequences are discussed. A comparison with the available data is made. Further tests are suggested.

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“…It is known that single-spin asymmetries for majority of the studied reactions are close to zero in the fragmentation region of unpolarized protons. Surprisingly, in collisions of mesons with polarized targets, the non-zero single-spin asymmetries have been observed as in central [16,17] as well as in unpolarized beam fragmentation [18][19][20][21] regions. This might be due to the asymmetry of initial states with respect to permutation of colliding particles.…”

Section: The Main Objectives Of the Experimentsmentioning

confidence: 99%

Systematic Study of Spin Effects at SPASCHARM Experiment at 70-GeV Accelerator in Protvino

Mochalov

Abramov

Bazhanov

et al. 2016

Int. J. Mod. Phys. Conf. Ser.

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A new experiment SPASCHARM for systematic study of polarization phenomena in the inclusive and exclusive hadronic reactions in the energy range of IHEP accelerator U-70 (12-50 GeV) is currently under development. The universal experimental setup will detect dozens of various resonances and stable particles produced in collisions of unpolarized beams with the polarized target, and at the next stage, using polarized proton and antiproton beams. At the beginning, the final states consisting of light quarks (u, d, s) will be reconstructed, and later on the charmonium states will be studied. Measurements are planned for a variety of beams: π ± , K ± , p, antiprotons. Hyperon polarization and spin density matrix elements of the vector mesons will be measured along with the singlespin asymmetry (SSA). The 2π-acceptance in azimuth, which is extremely useful for reduction of systematic errors in measurements of spin observables, will be implemented in the experiment. The solid angle acceptance of the setup, ∆θ ≈ 250 mrad vertically and 350 mrad horizontally in the beam fragmentation region, covers a wide range of kinematic variables p T and x F . This provides the opportunity for separating dependences on these two variables which is usually not possible in the setups with a small solid angle acceptance. Unlike some previous polarization experiments, the SPASCHARM will be able to simultaneously accumulate and record data on the both, charged and neutral particle production.

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

Cited by 39 publications

References 9 publications

Single spin asymmetry in inclusive pion production, Collins effect and the string model

Single spin asymmetry in inclusive pion production, Collins effect and the string model

Hyperon Polarization and Single Spin Left-Right Asymmetry in Inclusive Production Processes at High Energies

Systematic Study of Spin Effects at SPASCHARM Experiment at 70-GeV Accelerator in Protvino

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