Two-spin asymmetries for χ productions at RHIC

Morii, Toshiyuki; Tanaka, Shun‐ichi; Yamanishi, Tadashi

doi:10.1016/0370-2693(96)00033-0

Cited by 10 publications

(6 citation statements)

References 26 publications

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“…The two-spin asymmetries for χ production have also been calculated. [120] These asymmetries are quite small unless the polarized gluon distribution is quite large ( ∆G ≈ 6). Thus, χ production could distinguish an extremely large distribution from other models.…”

Section: Gluon Sensitive Experimentsmentioning

confidence: 99%

Probing nucleon spin structure

Ramsey

1997

Progress in Particle and Nuclear Physics

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Section: Gluon Sensitive Experimentsmentioning

confidence: 99%

Probing nucleon spin structure

Ramsey

1997

Progress in Particle and Nuclear Physics

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“…In literature, a series of efforts have been made so far for measuring the polarized parton distributions through quarkonium production processes [13][14][15][16][17]. Unfortunately, most of previous investigations were not directly applied to the RHIC experiments and are spoiled by the uncertainties aforementioned.…”

Section: • Jet Production • Heavy Flavor Productionmentioning

confidence: 99%

Detect ΔG at BNL-RHIC via double quarkonium production

Kodaira

Qiao

2003

Physics Letters B

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The double spin asymmetry for exclusive J/ψ pair production in the polarized p − p collisions at RHIC is investigated. Our study shows that the asymmetry in this process is measurable at RHIC-SPIN experiments in the near future, and, hence it can be used to determine the gluon distribution function ∆G(x) in the polarized nucleon.PACS numbers: 13.88.+e, 21.10.Hw, 13.60.Le Since the first measurement of the polarized structure function by the European Muon Collaboration [1], an enormous amount of researches have been done on the nucleon spin structure both experimentally and theoretically. The unpolarized deep inelastic scattering (DIS) experiments show that the gluon shares a large portion of the parent proton's momentum. However, how the gluons share the spin of proton is still an open question. In the conventional DIS process, the gluon contributions are the Quantum Chromodynamics(QCD) higher order effects and we can not avoid some ambiguities coming from e.g. the factorization scheme dependence, when determining the polarized gluon distributions. Although there are some efforts [2,3] to parameterize them, it seems difficult to obtain clear understanding of the role of gluons.Therefore, it is desirable to study other processes than DIS in which a direct measurement of the polarized gluon is possible. It is now expected that the polarized protonproton collisions (RHIC-Spin) at BNL relativistic heavyion collider RHIC will provide copious experimental data to unveil the polarized parton distributions. Since the major emphasis and strength of RHIC-Spin is to measure the gluon polarization, it is important and interesting to investigate various processes which are attainable experimentally to this aim.Up to now, three processes are considered to be promising for measuring the polarized gluons, which are thought to be feasible at RHIC technically. Those are • High-p T Prompt Photon Production • Jet production • Heavy Flavor ProductionThere are some advantages and disadvantages in each of these processes. The prompt photon production with po-larized beams at RHIC is a useful process, but we must know precisely the quark distributions from the polarized DIS experiments. For jet and heavy flavor production, the effects of hadronization and higher order corrections are not yet well controlled theoretically. For detailed discussions, see recent review paper in Ref. [4]. Therefore, to develop more practical ways for measuring the gluon polarization at RHIC experiments is one of the urgent theoretical tasks today.The quarkonium production and decays have long been taken as ideal processes to investigate the nature of QCD. Due to the approximately non-relativistic nature, the heavy quark and antiquark bound state is considered as one of the simplest system in QCD. The very clean signals of quarkonium leptonic decays lead to the experimental observations with a high precision, and therefore the quarkonium may play a crucial role in investigating many quantities and phenomena, e.g. the parton distribution, the QGP and even n...

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“…Therefore one is looking for a suitable combination of the CSM and the COM formalism in the k ⊥ -factorization approach which may release the polarization problem of the final J/ψ and ψ ′ [18]. A discussion for the double spin asymmetry for RHIC energies in terms of the CSM formalism can be found in [19]. Higher order velocity corrections in the polarized case in terms of the COM formalism have been discussed in [20,21,22].…”

Section: Introductionmentioning

confidence: 99%

Quarkonium production through hard comover rescattering in polarized and unpolarized scattering

Maul

2001

Nuclear Physics B

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In this paper hadroproduction of charmonium states in polarized pp collisions is discussed. A thermal picture for the gluonic cloud of comovers is given making contact between the formalism and the measured unpolarized cross sections. The experimentally observed non-polarization of the final J/ψ states leads to the consequence that no correlations between the initial proton spin and the final charmonium spin should be existent. Hence the single spin asymmetries vanish to leading order in that model.

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Two-spin asymmetries for χ productions at RHIC

Cited by 10 publications

References 26 publications

Probing nucleon spin structure

Probing nucleon spin structure

Detect ΔG at BNL-RHIC via double quarkonium production

Quarkonium production through hard comover rescattering in polarized and unpolarized scattering

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