Related papers: Value of $\alpha_s$ and high twists from combined …
We extract the ratio of the down (d) and up (u) parton distribution functions (PDF's) from the ratio of NMC deuteron and proton structure function F_2(d)/F_2(p), using corrections for nuclear binding effects in the deuteron, which are…
We discuss the combination of NNLO standard QCD evolution and scheme-invariant analysis for unpolarized DIS structure functions data as a method to reduce the theoretical errors on the determination of $\alpha_s(M_Z^2)$ to $\sim 1$% in…
The prospects for a determination of the strong coupling constant $\alpha_s$ via scaling violations of fragmentation functions in deeply inelastic scattering are studied. The statistical error in the case of an integrated luminosity of $250…
The results of the more detailed NNLO QCD analysis of the CCFR data for $xF_3$ SF are presented. The factorization scale uncertainties are analysed. The NNLO results for $alpha_s(M_Z)$ and twist-4 contributions are obtained. Despite the…
We extract the ratio of the down (d) and up (u) parton distribution functions (PDF's) from the ratio of deuteron and proton structure function F_2(d)/F_2(p) measured by NMC. We use corrections for nuclear binding effects in the deuteron,…
The new theoretical input to the analysis of the experimental data of the CCFR collaboration for $F_3$ structure function of $\nu N$ deep inelastic scattering is considered. This input comes from the next-to-next-to-leading order…
We discuss the extension of a systematic perturbative QCD based analysis to the x -> 1 region. After subtracting a number of effects that transcend NLO pQCD evolution, such as target mass corrections and large x resummation effects, the…
The four-loop determination of the strong coupling from fully inclusive observables is reviewed. Special attention is given to the low-energy measurement extracted from the hadronic $\tau$ decay width. A recent exhaustive analysis of the…
A next--to--leading order QCD analysis of deep inelastic scattering data is performed allowing for contributions due to a light gluino. We obtain the values of $\alpha_s(M_Z^2) \pm \delta \alpha_s^{stat} = 0.108 \pm 0.002, 0.124 \pm 0.001,…
Results are presented of two studies addressing the scaling violations of deep-inelastic structure functions. Factorization-scheme independent fits to all ep and mu p data on F_2 are performed at next-to-leading order (NLO), yielding…
An exploratory study for a new determination of the strong coupling constant alpha_s(MZ) from existing world data on the proton structure function F2p in the Q**2-range from ~ 5 to ~ 120 (GeV/c)**2 is presented. The main features of our…
Higher twist effects in the deeply inelastic scattering are studied. We start with a short review of the theoretical results on higher twists in QCD. Within the saturation model we perform a twist analysis of the nucleon structure functions…
We show that standard next-to-leading order (NLO) perturbative QCD analyses used to extract $\alpha_{s}$ from LEP data do not serve to disentangle the completely unknown renormalization scheme (RS) invariant next-NLO (NNLO) and higher-order…
We determine the value of the strong coupling $\alpha_\text{s}$ and study its running over a wide range of scales as probed by the dijet production process at hadron colliders, based on an NNLO QCD analysis of LHC dijet data. From a large…
The higher twist corrections $h^N(x)/Q^2$ to the spin dependent proton and neutron $g_1$ structure functions are extracted from the world data on $g_1(x,Q^2)$ in a model independent way and found to be non-negligible. Their role in…
We present a new extraction of the effective strong coupling constant \alpha_{s,g_1}(Q^2). The result agrees with a previous determination and extends the measurement of the low and high Q^2 behavior of \alpha_{s,g_1}(Q^2) that was…
We report a robust constrain on the possible variation of fine-structure constant, alpha = e^2/(hbar*c), obtained using O III 4959,5007, nebular emission lines from QSOs. We find Delta-alpha/alpha=-(2.1 +/- 1.6) x 10^(-5) based on a well…
A QCD fit analysis to the combined HERA-I inclusive deep inelastic cross sections measured by the H1 and ZEUS collaborations for $e^\pm p$ scattering resulting into a competitive NLO PDF set, HERAPDF1.0 is presented. HERAPDF at NNLO fits…
We present an improved determination of the proton structure functions $F_{2}$ and $xF_{3}$ from the CCFR $\nu $-Fe deep inelastic scattering (DIS) experiment. Comparisons to high-statistics charged-lepton scattering results for $F_{2}$…
We investigate the influence of higher twist corrections to deep inelastic structure functions in the low-$Q^2$ and small-$x$ HERA region. We review the general features of the lowest-order QCD diagrams which contribute to twist-4 at…