B. Badelek

Measurement of the proton and deuteron structure functions, F2p and F2d, and of the ratio sigmaL/sigmaT.

The muon-proton and muon-deuteron inclusive deep inelastic scattering cross sections were measured in the kinematic range 0.002 < x < 0.60 and 0.5 < Q(2) < 75 GeV2 at incident muon energies of 90, 120, 200 and 280 GeV. These results are based on the full data set collected by the New Muon Collaboration, including the data taken with a small angle trigger. The extracted values of the structure functions F-2(p) and F-2(d) are in good agreement with those from other experiments. The data cover a sufficient range of y to allow the determination of the ratio of the longitudinally to transversely polarised virtual photon absorption cross sections, R = sigma(L)/sigma(T), for 0.002 < x < 0.12. The values of R are compatible with a perturbative QCD prediction; they agree with earlier measurements and extend to smaller x.The muon-proton and muon-deuteron inclusive deep inelastic scattering cross sections were measured in the kinematic range 0.002<x<0.60 and 0.5<Q2<75 GeV2 at incident muon energies of 90, 120, 200 and 280 GeV. These results are based on the full data set collected by the New Muon Collaboration, including the data taken with a small angle trigger. The extracted values of the structure functions F2p and F2d are in good agreement with those from other experiments. The data cover a sufficient range of y to allow the determination of the ratio of the longitudinally to transversely polarised virtual photon absorption cross sections, R= sigma(L)/sigma(T), for 0.002<x<0.12 . The values of R are compatible with a perturbative QCD prediction; they agree with earlier measurements and extend to smaller x.

Measurement of the proton and the deuteron structure functions, F2p and F2d

The proton and deuteron structure functions F2p and F2d were measured in the kinematic range 0.006<x<0.6 and 0.5<Q^2<75 GeV^2, by inclusive deep inelastic muon scattering at 90, 120, 200 and 280 GeV. The measurements are in good agreement with earlier high precision results. The present and earlier results together have been parametrised to give descriptions of the proton and deuteron structure functions F2 and their uncertainties over the range 0.006<x<0.9.The proton and deuteron structure funtions F2p and F2d were measured in the kinematic range 0.006 < x < 0.6 and 0.5 < Q2 < 75 GeV2, by inclusive deep inelastic muon scattering at 90, 120, 200 and 280 GeV. The measurements are in good agreement with earlier high precision results. The present and earlier results together have been parametrised to give descriptions of the proton and deuteron structure functions F2 and their uncertainties over the range 0.006 < x < 0.9.

The Q2 dependence of the structure function ratio F2Sn/F2C and the difference RSn - RC in deep inelastic muon scattering

The Q(2) dependence of the structure function ratio F-2(Sn)/F-2(C) for 0.01 < x < 0.75 and 1 < Q(2) < 140 GeV2 is reported. For x < 0.1 the size of shadowing decreases linearly with In Q(2) and the maximum rate is about 0.04 at x = 0.01. The rate decreases with x and is compatible with zero for x greater than or equal to 0.1. The difference R(Sn) - R(C), where R is the ratio of longitudinally to transversely polarised virtual photon absorption cross sections, is also given. No dependence on x is seen and the average value is 0.040 +/- 0.021 (stat.) +/- 0.026 (syst.) at a mean Q(2) of 10 GeV2.

Unified description of the non-singlet spin dependent structure function g1 incorporating Altarelli-Parisi evolution and the double logarithmic ln2(1/x) effects at low x

Abstract A unified equation for the non-singlet spin dependent structure function g 1 ns ( x , Q 2 )= g 1 p ( x , Q 2 )− g 1 n ( x , Q 2 ) which incorporates the complete leading order Altarelli-Parisi evolution at finite x and double logarithmic ln 2 (1/ x ) effects at x →0 is formulated. This equation is solved assuming simple phenomenological parametrisation of the non-perturbative part of the structure function. Reasonable agreement is obtained with the recent data obtained by the Spin Muon Collaboration. Predictions for the small x behaviour of g 1 ns ( x , Q 2 ) in the kinematical range which may be relevant for the possible HERA measurements are given. The contribution to the Bjorken sum coming from the region of very small values of x is quantified. Extrapolation of g 1 ( x , Q 2 ) to the region of small x and small Q 2 is also discussed.

The structure function ratios F2C/F2D and F2C/F2D at small x

We present the structure function ratios F2(Li)/F2(D) and F2(C)/F2(D) measured in deep inelastic muon-nucleus scattering at a nominal incident muon energy of 200 GeV. The kinematic range 0.0001 s x s 0.7 and 0.01 s Q˜2 s 70 GeV˜2 is covered. For values of

Radiative correction schemes in deep inelastic muon scattering

x

A model of F2γ at arbitrary Q2 and the total photon–photon cross-sections at high energies

less than

Parametrization of F 2 γ at low Q 2 and of σ γ γ and σ γ * γ at high energies

0.002

Accurate measurement of Fd2/Fp2 and Rd - Rp

both ratios indicate saturation of shadowing at values compatible with photoabsorption results.

Shadowing in deuteron and the new F2n/F2p measurements

A description and a detailed comparison of the Mo and Tsai and the Dubna radiative correction schemes is presented. Numerical comparisons made in the kinematical region of the NMC high energy deep inelastic electroproduction experiment are discussed. An overall agreement between the two approaches in the region of lowx and highy, where the radiative corrections are largest, is better than 2%.