G. Sultanov

A high statistics measurement of the proton structure functions F2(x, Q2) and R from deep inelastic muon scattering at high Q2

Abstract We present results on a high statistics study of the proton structure functions F 2 ( x , Q 2 ) and R = σ L / σ T measured in deep inelastic scattering of muons on a hydrogen target. The analysis is based on 1.8 × 10 6 events after all cuts, recorded at beam energies of 100, 120, 200 and 280 GeV and covering a kinematic range 0.06 ⩽ x ⩽ 0.80 and 7 GeV 2 ⩽ Q 2 ⩽260 GeV 2 . At small x , we find R to be different from zero in agreement with predictions of perturbative QCD.

A high statistics measurement of the deuteron structure functions F2(x, Q2) and R from deep inelastic muon scattering at high Q2

Abstract We present results on a high statistics study of the nucleon structure functions F2(x, Q2) and R=σL/σT measured in deep inelastic scattering of muons on a deuterium target. The analysis is based on 8×105 events after all cuts, recorded at beam energies of 120, 200 and 280 GeV in the kinematic range 0.06⩽ × ⩽0.80 and 8GeV2⩽Q2⩽260GeV2. Scaling violations observed in the data are in agreement with predictions of perturbative QCD and allow to determine the QCD mass scale parameter Λ.

A Measurement of Nuclear Effects in Deep Inelastic Muon Scattering on Deuterium, Nitrogen and Iron Targets

Abstract New data is presented on the ratios of structure functions F 2 ( x , Q 2 ) measured in deep inelastic muon scattering with deuterium, nitrogen, and iron targets. The existence of nuclear effects at large Q 2 is confirmed with improved systematic accuracy. The ratio F 2 Fe ( x ) F 2 D 2 ( x ) covers the range 0.20 ⩽ x ⩽ 0.70 and is in agreement with earlier measurements. The ratio F 2 N 2 ( x )/ F 2 D 2 ( x ) is measured over the range 0.08 ⩽ x ⩽ 0.70 and is compatible with unity below x = 0.3.

Nuclear effects in deep inelastic muon scattering on deuterium and iron targets

Abstract New Results are presented on nuclear effects in deep inelastic muon scattering on deuterium and iron targets at large Q 2 . The ratio F Fe 2 (x) F D 2 2 (x) measured in the kinematic range 0.06⩽ x ⩽0.70, 14GeV 2 ⩽ Q 2 ⩽70 GeV 2 is in good agreement with earlier measurements in the region of x > 0.25. At lower x , the structure function ratio exhibits an enhancement of ≈5%.

A comparison of the structure functions F2 of the proton and the neutron from deep inelastic muon scattering at high Q2

Abstract High statistics data on the structure functions F2 of the proton and the deutron measured with the same apparatus in deep inelastic muon scattering are used to study the ratio of structure functions of neutron and proton F2n/F2p and their difference F2p-F2n. Both measurements are consistent with predictions of the quark-parton model and of QCD.

A high statistics measurement of the nucleon structure function F2(x,Q2) from deep inelastic muon-carbon scattering at high Q2

Abstract We present results from a high statistics study of the nucleon structure function F 2 ( x , Q 2 ) measured in deep inelastic scattering of muons on carbon in the kinematic range 0.25⩽ x ⩽0.80 and Q 2 ⩾25 GeV 2 . The analysis is based on 1.5×10 6 reconstructed events recorded at beam energies of 120, 200 and 280 GeV. R = σ L / σ T is found to be independent of x in the range 0.25⩽ x ⩽0.07 and 40 GeV 2 ⩽ Q 2 ⩽200 GeV 2 with a mean value R =0.015±0.013 ( stat ) ±0.026 (syst.).

Test of QCD and a measurement of Λ from scaling violations in the proton structure function F2(x, Q2) at high Q2

Abstract Scaling violations in the proton structure function F 2 ( x , Q 2 ) measured with high statistics in deep inelastic scattering of muons on a hydrogen target are compared to predictions of perturbative QCD. Excellent agreement is observed with numerical solutions of the evolution equations in leading and next-to-leading order. The QCD mass scale parameter Λ is determined from these data both in a flavour nonsinglet approximation and with a complete flavour singlet and nonsinglet treatment. An estimate of the gluon distribution in the proton is given.

Test of QCD and a measurement of Λ from scaling violations in the nucleon structure function F2(x,Q2)

Scaling violations in the nucleon structure function F2(x,Q2) measured with high statistics in deep inelastic scattering of muons on a carbon target are compared to predictions of perturbative QCD. Excellent agreement is observed with numerical solutions of the Altarelli-Parisi evolution equations over the entire x and Q2 range of data. In a next-to-leading order nonsinglet approximation, the QCD mass scale parameter ΛMS is determined to be 230±20(stat.)±60(syst.) MeV. A singlet to the data favours a soft gluon distribution.

Measurement of the interference structure function xG3(x) in muon-nucleon scattering

Abstract The interference structure function xG 3 ( x ) has been measured for the first time scattering positive and negative muons of opposite helicity off a carbon target. The x dependence observed for Q 2 between 40 and 180 (GeV/c 2 ) is in good agreement with predictions of the quark-parton model. The measured ratio 2( a u Q u + a d Q d )/( Q u 2 + Q d 2 = 1.87 ± 0.25 (stat.) ± 0.24 (syst.) is consistent with the hypothesis of fractional quark charges and determines the sign of Q u − Q d to be positive.

Production of\(\bar D^0 \) andD− mesons in neutron-carbon interactions at 40–70 GeV

AbstractThe production of