Muon pair production in the process e+e- -> e+e-mu+mu- is studied using the data taken at LEP1 (sqrt(s) \simeq m_Z) with the DELPHI detector during the years 1992-1995. The corresponding integrated luminosity is 138.5 pb^{-1}. The QED predictions have been tested over the whole Q^2 range accessible at LEP1 (from several GeV^2/c^4 to several hundred GeV^2/c^4) by comparing experimental distributions with distributions resulting from Monte Carlo simulations using various generators. Selected events are used to extract the leptonic photon structure function F_2^\gamma. Azimuthal correlations are used to obtain information on additional structure functions, F_A^\gamma and F_B^\gamma, which originate from interference terms of the scattering amplitudes. The measured ratios F_A^\gamma/F_2^\gamma and F_B^\gamma/F_2^\gamma are significantly different from zero and consistent with QED predictions.
The measured QED photon structure function at Q**2 = 12.5 GeV for the combine SAT and STIC data.
The measured QED photon structure function at Q**2 = 120 GeV for the combine SAT and STIC data.
Ratio of the structure functions FA and FB to F2.
No description provided.
Low x domain.
Data from deep inelastic scattering of 200 GeV muons on a carbon target with squared four-momentum transfer 52 GeV2≤Q2≤200 GeV2 were analysed in the region of the Bjorken variable close tox=1, which is the kinematic limit for scattering on a free nucleon. At this value ofx, the carbon structure function is found to beF2C≈1.2·10−4. Thex dependence of the structure function forx>0.8 is well described by an exponentialF2C∞exp(−sx) withs=16.5±0.6.
No description provided.
Multiplicative factors by which F2 has to be multiplied or divided to allow for a systematic uncertainty in detector resolution.
Multiplicative factors by which F2 has to be multiplied or divided to allow for a systematic uncertainty in the beam energy.
High statistics data on the structure functions F 2 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 F 2 n / F 2 p and their difference F 2 p - F 2 n . Both measurements are consistent with predictions of the quark-parton model and of QCD.
No description provided.
No description provided.
We present results on a high statistics study of the nucleon structure functions F 2 ( x , Q 2 ) and R = σ L / σ T measured in deep inelastic scattering of muons on a deuterium target. The analysis is based on 8×10 5 events after all cuts, recorded at beam energies of 120, 200 and 280 GeV in the kinematic range 0.06⩽ × ⩽0.80 and 8GeV 2 ⩽ Q 2 ⩽260GeV 2 . Scaling violations observed in the data are in agreement with predictions of perturbative QCD and allow to determine the QCD mass scale parameter Λ.
No description provided.
R=SIG(L)/SIG(T) is taken to be zero.
R=SIG(L)/SIG(T) is taken to be zero.
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.
THE AVERAGE VALUES OF Q**2 AT EACH OF THE X VALUES LISTED IN THIS TABLE ARE 15,20,20,25,30,35,40,45,50,50.
R=SIG(L)/SIG(T) IS TAKEN TO BE ZERO.
R=SIG(L)/SIG(T) IS TAKEN TO BE ZERO.
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.).
R=SIG(L)/SIG(T).
No description provided.
No description provided.
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%.
Q**2 RANGE FOR EACH X BIN IS AS FOLLOWS: 14 TO 20, 16 TO 30, 18 TO 35, 18 TO 46, 20 TO 106, 23 TO 106, 23 TO 150, 26 TO 200, 26 TO 200, 26 TO 200 GEV**2.
None
VALUES OBTAINED USING ASSUMPTION R=0.
VALUES OBTAINED USING ASSUMPTION R=0.
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.
VALUES OF Q2 CORRESPONDING TO THE X-BINS IN THIS TABLE ARE:- 46-106,46-106,53-150,53-200,70-200,80-200 RESPECTIVELY.
VALUES OF Q2 CORRESPONDING TO THE X-BINS IN THIS TABLE ARE:- 26-40,26-61,30-80,30-106,30-106,30-150,30-200,35-200,46-200.
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