Large gluon polarization from correlated high-pT hadron pairs in polarized electro-production

HERMES is a second generation experiment to study the spin structure of the nucleon, in which measurements of the spin dependent properties of semi-inclusive deep-inelastic lepton scattering are emphasized. Data have been accumulated for semi-inclusive pion, kaon, and proton double-spin asymmetries, as well as for high-pT hadron pairs, and single-spin azimuthal asymmetries for pion electroproduction and deep virtual Compton scattering. These results provide information on the flavor decomposition of the polarized quark distributions in the nucleon and a first glimpse of the gluon polarization, while the observation of the azimuthal asymmetries show promise for probing the tensor spin of the nucleon and isolating the total angular momentum carried by the quarks.

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Exploring the Gluon Polarization with Inclusive and Correlation Measurements at RHIC

10.3360/dis.2009.207 ◽

2009 ◽

Author(s):

Bernd Surrow

Keyword(s):

Gluon Polarization

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SLAVNOV–TAYLOR IDENTITY FOR NONEQUILIBRIUM QUARK–GLUON PLASMA

Modern Physics Letters A ◽

10.1142/s0217732301003553 ◽

2001 ◽

Vol 16 (08) ◽

pp. 531-540 ◽

Cited By ~ 2

Author(s):

K. OKANO

Keyword(s):

Quark Gluon Plasma ◽

Gluon Plasma ◽

Polarization Tensor ◽

Gluon Polarization ◽

Time Path

Within the closed-time-path formalism of nonequilibrium QCD, we derive a Slavnov–Taylor (ST) identity for the gluon polarization tensor. The ST identity takes the same form in both Coulomb and covariant gauges. Application to quasi-uniform quark–gluon plasma (QGP) near equilibrium or nonequilibrium quasistationary QGP is made.

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CHIRAL QUARK MODEL (χQM) AND THE NUCLEON SPIN

International Journal of Modern Physics A ◽

10.1142/s0217751x04019949 ◽

2004 ◽

Vol 19 (29) ◽

pp. 5027-5041 ◽

Cited By ~ 13

Author(s):

HARLEEN DAHIYA ◽

MANMOHAN GUPTA

Keyword(s):

Angular Momentum ◽

Magnetic Moments ◽

Distribution Functions ◽

Gluon Polarization ◽

Spin Distribution ◽

Polarization Functions ◽

Singlet Component ◽

Configuration Mixing ◽

The Right ◽

E866 Data

Using χ QM with configuration mixing, the contribution of the gluon polarization to the flavor singlet component of the total spin has been calculated phenomenologically through the relation [Formula: see text] as defined in the Adler–Bardeen scheme, where ΔΣ on the right-hand side is Q2 independent. For evaluation the contribution of gluon polarization [Formula: see text], ΔΣ is found in the χ QM by fixing the latest E866 data pertaining to [Formula: see text] asymmetry and the spin polarization functions whereas ΔΣ(Q2) is taken to be 0.30±0.06 and αs=0.287±0.020, both at Q2=5 GeV 2. The contribution of gluon polarization Δg' comes out to be 0.33 which leads to an almost perfect fit for spin distribution functions in the χ QM . When its implications for magnetic moments are investigated, we find perfect fit for many of the magnetic moments. If an attempt is made to explain the angular momentum sum rule for proton by using the above value of Δg', one finds the contribution of gluon angular momentum to be as important as that of the [Formula: see text] pairs.

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