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G. Parente

Publications and source records attributed to G. Parente.

41 records · Page 3Linked to original sources

Next-to-next-to-leading order QCD analysis of the CCFR data for xF_3 and F_2 structure functions of the deep-inelastic neutrino-nucleon scattering

The next-to-next-to-leading order (NNLO) non-singlet QCD analysis of the experimental data of the CCFR collaboration for the $xF_3$ and $F_2$ structure functions of the deep-inelastic scattering of neutrinos and antineutrinos on the nucleon by means of the Jacobi polinomial expansion method is made. The target mass corrections are also taken into account. We demonstrate that the NNLO corrections have the important: they are decreasing the difference between the values of $α_s(M_Z)$, extracted from the NLO fit of $xF_3$ data and from the NLO non-singlet fit of the combined $xF_3$ and $F_2$ CCFR data. The obtained NNLO results for $α_s(M_Z)$ are :$α_s(M_Z)=0.109 \pm 0.003(stat) \pm 0.005(syst) \pm 0.003 (theor)$ (from $xF_3$ data) and $α_s(M_Z)=0.111\pm 0.002 (stat) \pm 0.003 (syst) \pm 0.003 (theor)$ (from the combined $xF_3$ and $F_2$ data). We also estimate the values of the order $O(α_s^2)$-corrections to the Gottfried sum rule.

hep-ph↗

The Longitudinal Structure Function F$_L$ as a Function of F$_2$ and dF$_2$/dlnQ$^2$ at small x. The Next-to-Leading Analysis

We present a set of formulae to extract the longitudinal deep inelastic structure function $F_L$ from the transverse structure function $F_2$ and its derivative $dF_2/dlnQ^2$ at small $x$. Our expressions are valid for any value of $δ$, being $x^{-δ}$ the behavior of the parton densities at low $x$. Using $F_2$ HERA data we obtain $F_L$ in the range $10^{-4} \leq x \leq 10^{-2}$ at $Q^2=20$ GeV$^2$. Some other applications of the formulae are pointed out.

hep-ph↗

The Gluon Distribution as a Function of F$_2$ and dF$_2$/dlnQ$^2$ at small x. The Next-to-Leading Analysis

We present a set of formulae to extract the gluon distribution function from the deep inelastic structure function F$_2$ and its derivative dF$_2$/dlnQ$^2$ at small x in the leading and next-to-leading order of perturbation theory. The detailed analysis is given for new HERA data. The values of the gluon distribution are found in the range $10^{-4} \leq x \leq 10^{-2}$ at $Q^2=20$ GeV$^2$.

hep-ph↗

Next-to-Next-to-Leading Order QCD Analysis of DIS Structure Functions

It is performed for the first time a next-to-next-to-leading order analysis of deep inelastic structure functions $F_2$ and $F_L$ using the recently determined first moments of the non-singlet anomalous dimensions and the corresponding Wilson coefficients. {}From a comparison to BCDMS data we found a slight decrease in the energy scale of perturbative QCD with respect to the next-to-leading order analysis, which brings the scale closer to the value predicted from a scheme invariant approach.

hep-ph↗

Light Gluinos and the Longitudinal Structure Function

The leading effect of light gluinos on the deep inelastic longitudinal structure function is calculated. We present the explicit analitic expression for the Wilson coefficient. After convolution with quark, gluon and gluino distributions we found that the size of the contribution is of order a few percent of the total $F_L$. Some phenomenological implications for HERA and LEP/LHC are given.

hep-ph↗