摘要:

It is known that the hadroproduction of &psgr; is dominated bygg→&khgr;0,2→&ggr;&psgr; andgg→g&psgr;. The helicity amplitude method allows for the calculation of the necessary polarized parton level processesgg→qq¯ andgg→gqq¯. Techniques exist which can be used to relate the relatively well understood non‐relativistic potential model quarkonium wavefunctions to thegg&khgr; andggg&psgr; couplings. Thus it is possible to isolate the polarized gluon contribution to the spin‐spin asymmetry from other sources of asymmetry, and study the polarized gluon distribution function directly.

ISSN:0094-243X    

DOI:10.1063/1.40482

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The need for polarized beams at hadron‐hadron colliders is reviewed. As an example, lowest order Drell‐Yan is examined at the resonance for a new scalar or vector boson. Assuming only scalar and pseudoscalar couplings in the case of a spin zero boson or vector and pseudovector couplings for a new vector boson, it is clear that polarization is required if complete information on the interactions is desired from hadron‐hadron collisions. For this case, a study with one beam carrying longitudinal polarization combined with a study wherebothbeams have a transverse polarization is required.

ISSN:0094-243X    

DOI:10.1063/1.40483

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Spin effects observed in proton‐proton and meson‐proton elastic scattering at large angle show that hadron helicity flip survives at large energies. This may be traced back to the lack of rotational symmetry of the independent scattering processes known to dominate at asymptotic energies. We suggest experiments with nuclear targets to test this and the independent scattering contribution to the pp angular distribution.

ISSN:0094-243X    

DOI:10.1063/1.40484

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The effective transverse size of hadrons in leading perturbative contributions to elastic wide angle hadron‐hadron scattering is discussed. The leading perturbative contribution toANN, the spin asymmetry, at &pgr;/2 scattering angle is evaluated as a function of the center of mass energy.

ISSN:0094-243X    

DOI:10.1063/1.40485

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We present a dynamical explanation of the single transverse‐spin asymmetry for the processpN→&Lgr;0↑X, with the &Lgr;0observed at large angles. The polarisation arises by considering the &Lgr;0to be produced either directly or via the virtual dissociation of a parent baryon. Our results reproduce very well both the measuredpTandxFdependence of the polarisation. We also include a discussion of the left‐right asymmetry in pion production off a polarised target:pN↑→&pgr;X.

ISSN:0094-243X    

DOI:10.1063/1.40486

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Transverse, single‐spin asymmetries offer a chance to test QCD at the level of ‘‘twist‐3’’ observables. Early suggestions that such asymmetries necessarily vanish asmq→0 or involve an extra power of &agr;scan be refuted with a simple example. Recent experimental results support the interpretation of these data in hard‐scattering QCD. The asymmetry in the scattering on nuclear targets can provide new, nontrivial information the space‐time structure of the interaction.

ISSN:0094-243X    

DOI:10.1063/1.40487

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We analyze the first nonleading power corrections to inclusive hadron‐hadron scattering cross sections. Such corrections decrease as 1/Qrelative to leading power in the case of polarized hadronic collisions, or as 1/Q2in the case of unpolarized hadronic collisions. We show why such corrections may be treated in perturbative QCD, in terms of generalized factorization theorems.

ISSN:0094-243X    

DOI:10.1063/1.40488

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

We predict that probability for a nucleon to traverse nucleus in the central collisions should noticeably increase with energy increase between BNL and CERN energies due to color screening phenomenon. At RHIC energies this effect should practically disappear if perturbative QCD scenario is applicable.

ISSN:0094-243X    

DOI:10.1063/1.40489

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

In this talk we review the experimental and theoretical situation, and then describe a calculation of the induced, anomalouus gluonic contribution by means of a lattice QCD simulation. We will discuss some necessary theoretical and lattice preliminaries to the calculation, and the algorithm that was used. We will also mention some important issues having to do with gauge invariance. The main conclusion that we report here is that, based on the lattice calculation, the anomalous gluonic contribution is much too small to change the interpretation of the EMC experiment. Finally we will address some of the limitations of the calculation, and provide an estimate of its accuracy.

ISSN:0094-243X    

DOI:10.1063/1.40490

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

I address the issue of the properties of the first moments of the polarized structure functions. I demonstrate that consistency with the Altarelli‐Parisi analysis requires an introduction of a new gluon operator which is not present in the OPE expansion. The proton matrix element of this operator normalizes the first moment of the polarized gluon density.

ISSN:0094-243X    

DOI:10.1063/1.40491

出版商:AIP    

年代:1991

数据来源: AIP