相关论文: New extraction of alpha_s(MZ) from proton DIS data
In this talk we summarize main results of a recent determination of the polarized deeply inelastic parton distributions to NLO from the world data. In the analysis the LO and NLO parton densities and their $1\sigma$ statistical errors were…
Astrophysical tests of the stability of fundamental couplings are becoming an increasingly important probe of new physics. Motivated by the recent availability of new and stronger constraints we update previous works testing the consistency…
Deep inelastic scattering data on F2 structure function from various fixed-target experiments were analyzed in the non-singlet approximation with a next-to-next-to-leading-order accuracy. The study of high statistics deep inelastic…
An update of measurements of the strong coupling constant $\alpha_s$ is given, representing the status of September 2002. The results convincingly prove the energy dependence of $\alpha_s$ and are in excellent agreement with the…
We determine the strong coupling from high-energy data for the Drell-Yan (DY) process and top-quark hadro-production collected at the Large Hadron Collider and the Tevatron combined with the world data on deep-inelastic scattering (DIS) and…
The deep inelastic scattering data on the nucleon F_2 structure function, accumulated by BCDMS, SLAC and NMC collaborations in fixed-target experiments, are analyzed in the non-singlet approximation within the frameworks of both…
We summarize the results of a recent global analysis of proton and deuteron F2 structure function world data performed over a large range of kinematics, including recent measurements done at JLab with the CLAS detector. From these data the…
We investigate the uncertainty in the value of the strong coupling $\alpha_S(M_Z^2)$ when allowing it to be a free parameter in the recent MMHT global analyses of deep-inelastic and related hard scattering data that was undertaken to…
The interplay between higher orders of the perturbative QCD (pQCD) expansion and higher-twist contributions in the analysis of recent Jefferson Lab data on the lowest moment of the spin-dependent proton $\Gamma_1^{p} (Q^2)$ at $0.05<Q^2< 3…
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…
The QCD coupling $\alpha_s$ is extracted from the energy evolution of the first two moments (multiplicity and mean) of the parton-to-hadron fragmentation functions at low fractional hadron momentum $z$. Comparisons of the experimental…
Using 3.9 $pb^{-1}$ of data from ep $\ra$ eX interactions recorded using the ZEUS detector in 1997,the proton structure function, F$_2$, has been measured in the range 0.015 GeV$^2$ $<$ Q$^2 <$ 0.65 GeV$^2$ and $6 \times 10^{-7} < x < 1…
From a fit to the experimental data on the $b\bar{b}$ fine structure, the two-loop coupling constant is extracted. For the 1P state the fitted value is $\alpha_s(\mu_1) = 0.33 \pm 0.01(exp)\pm 0.02 (th)$ at the scale $\mu_1 = 1.8 \pm 0.1$…
Calculations of deep inelastic processes (DIS) to next-to-next to leading order are discussed. Fitting $ep$ experiment in the range $2.5\leq Q^2\leq 230 GeV^2$, we find the coupling $\alpha_s(M_Z^2)=0.1163\pm0.0023$. We also get the gluon…
The reanalysis of all available world data on the longitudinal asymmetry A|| is presented. The proton structure function g1 was extracted within a unique framework of data inputs and assumptions. These data allowed for a reliable evaluation…
The available world deep-inelastic scattering data on proton and deuteron structure functions F2p, F2d, and their ratios, are leveraged to extract the free neutron F2n structure function, the F2n/F2p ratio, and associated uncertainties…
We determine a new set of parton distribution functions (ABMP16), the strong coupling constant $\alpha_s$ and the quark masses $m_c$, $m_b$ and $m_t$ in a global fit to next-to-next-to-leading order (NNLO) in QCD. The analysis uses the…
We present our QCD analysis of the proton structure function $F_2^p(x,Q^2)$ to determine the parton distributions at the next-to-leading order (NLO). The heavy quark contributions to $F_2^i(x,Q^2)$, with $i$ = $c$, $b$ have been included in…
Recent data on the (inelastic) Nachtmann moments of the unpolarized proton structure function F2p, obtained at low momentum transfer with the CLAS detector at Jefferson Lab, have been interpreted in terms of the dominance of the elastic…
Global fits for precision determinations of parton distributions, together with the highly correlated strong coupling $\alpha_s$, are presented up to next-to-next-to-leading order (NNLO) of QCD utilizing most world data (charm and jet…