Measurements of the proton structure function F-2 for 0.6 < Q(2) < 17 GeV2 and 1.2 x 10(-5) < x < 1.9 x 10(-3) from ZEUS 1995 shifted vertex data are presented. From ZEUS F-2 data the slopes dF(2)/dln Q(2) at fixed x and dlnF(2)/dln(1/x) for x < 0.01 at fixed Q(2) are derived. For the latter, E665 data are also used. The transition region in Q(2) is explored using the simplest non-perturbative models and NLO QCD. The data at very low Q(2) less than or equal to 0.65 GeV2 are described successfully by a combination of generalised vector meson dominance and Regge theory. From a NLO QCD fit to ZEUS data the gluon density in the proton is extracted in the range 3 x 10(-5) < x < 0.7. Data from NMC and BCDMS constrain the fit at large x. Assuming the NLO QCD description to be valid down to Q(2) similar to 1 GeV2, it is found that the q (q) over bar sea distribution is still rising at small x and the lowest Q(2) values whereas the gluon distribution is strongly suppressed.

ZEUS results on the measurement and phenomenology of F-2 at low x and low Q(2)

CIRIO, Roberto;COSTA, Marco;MONACO, Vincenzo;PERONI, Cristiana;SACCHI, Roberto;SOLANO, Ada Maria;
1999-01-01

Abstract

Measurements of the proton structure function F-2 for 0.6 < Q(2) < 17 GeV2 and 1.2 x 10(-5) < x < 1.9 x 10(-3) from ZEUS 1995 shifted vertex data are presented. From ZEUS F-2 data the slopes dF(2)/dln Q(2) at fixed x and dlnF(2)/dln(1/x) for x < 0.01 at fixed Q(2) are derived. For the latter, E665 data are also used. The transition region in Q(2) is explored using the simplest non-perturbative models and NLO QCD. The data at very low Q(2) less than or equal to 0.65 GeV2 are described successfully by a combination of generalised vector meson dominance and Regge theory. From a NLO QCD fit to ZEUS data the gluon density in the proton is extracted in the range 3 x 10(-5) < x < 0.7. Data from NMC and BCDMS constrain the fit at large x. Assuming the NLO QCD description to be valid down to Q(2) similar to 1 GeV2, it is found that the q (q) over bar sea distribution is still rising at small x and the lowest Q(2) values whereas the gluon distribution is strongly suppressed.
1999
7
609
630
http://dx.doi.org/10.1007/s100520050432
ZEUS; STRUCTURE-FUNCTION F-2(X; Q(2)); DEUTERON STRUCTURE FUNCTIONS; PROTON STRUCTURE FUNCTIONS; HIGH-ENERGY COLLISIONS; PARTON DISTRIBUTIONS; QUANTUM CHROMODYNAMICS; PERTURBATION-THEORY; MUON SCATTERING; CROSS-SECTIONS
J. Breitweg;S. Chekanov;M. Derrick;D. Krakauer;S. Magill;D. Mikunas;B. Musgrave;J. Repond;R. Stanek;R. L. Talaga;R. Yoshida;H. Zhang;M. C....espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/109290
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