Showing papers by "Abhay Deshpande published in 1998"
TL;DR: In this article, the spin asymmetries A1 and the spin structure functions g1 of the proton and the deuteron in the kinematic range 0.0008
Abstract: We present the final results of the spin asymmetries A1 and the spin structure functions g1 of the proton and the deuteron in the kinematic range 0.0008
250 citations
TL;DR: In this article, a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range 0.003 x Q 2 >1 GeV 2 was presented.
130 citations
TL;DR: In this article, the photoproduction reaction γp→ μ + μ − p has been studied in ep interactions using the ZEUS detector at HERA, which corresponds to an integrated luminosity of 43.2 pb −1.
93 citations
TL;DR: In this paper, the authors measured the diffractive cross-section of a dijet as a function of the fraction of the photon and pomeron momentum participating in the production of the dijet system.
Abstract: Differential dijet cross sections have been measured with the ZEUS detector for photoproduction events in which the hadronic final state containing the jets is separated with respect to the outgoing proton direction by a large rapidity gap. The cross section has been measured as a function of the fraction of the photon (ϰγOBS) and pomeron (βOBS) momentum participating in the production of the dijet system. The observed ϰγOBS dependence shows evidence for the presence of a resolved- as well as a direct-photon component. The measured cross section da/dβOBS increases as βOBS increases indicating that there is a sizeable contribution to dijet production from those events in which a large fraction of the pomeron momentum participates in the hard scattering. These cross sections and the ZEUS measurements of the diffractive structure function can be described by calculations based on parton densities in the pomeron which evolve according to the QCD evolution equations and include a substantial hard momentum component of gluons in the pomeron.
21 citations
TL;DR: In this article, the cross section for the photoproduction of events containing three jets with a three-jet invariant mass of M3J>50 GeV has been measured with the ZEUS detector at HERA.
19 citations
University of Santiago de Compostela1, Istanbul Technical University2, Uppsala University3, Ludwig Maximilian University of Munich4, French Alternative Energies and Atomic Energy Commission5, University of Trieste6, Ruhr University Bochum7, University of Mainz8, University of Virginia9, Delft University of Technology10, University of California, Los Angeles11, Yale University12, University of Bonn13, Fermilab14, Bielefeld University15, University of Wisconsin-Madison16, Northwestern University17, University of Houston18, University of Freiburg19, Stanford University20, Nagoya University21, University of Miyazaki22, Paul Scherrer Institute23, CERN24, University of California, Santa Cruz25, Joint Institute for Nuclear Research26, Aalto University27, Tel Aviv University28, Warsaw University of Technology29, University of Oslo30, University of Mons31
11 Dec 1998-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this article, a line shape for spin-1 systems with large quadrupolar broadening was developed which allowed the nitrogen polarization in the ammonia to be determined with a 10% relative error.
Abstract: The 1996 data taking of the SMC experiment used polarized protons to measure the spin-dependent structure function g(1) of the proton. Three liters of solid granular ammonia were irradiated at the Bonn electron linac in order to create the paramagnetic radicals which are needed for polarizing the protons. Proton polarizations of +/- (90 +/- 2.5)% were routinely reached. An analysis based on a theoretical line shape for spin-1. systems with large quadrupolar broadening was developed which allowed the nitrogen polarization in the ammonia to be determined with a 10% relative error. The measured quadrupolar coupling constant of N-14 agrees well with earlier extrapolated values. The polarization of the nitrogen nuclei was measured as a function of the proton polarization in order to provide a test of the equal spin temperature (EST) hypothesis. It was found to be closely valid under the dynamic nuclear polarization conditions with which the protons are polarized. Large deviations from EST could be induced by cross relaxing the proton and nitrogen spin systems at low fields. Nitrogen polarizations up to 40% were reached by these means. (C) 1998 Elsevier Science B.V. All rights reserved.
17 citations
01 Jan 1998
12 citations
TL;DR: In this article, the authors search for the production of a selectron and a squark in e + p collisions at a center-of-mass energy of 300 GeV using the ZEUS detector at HERA.
4 citations
TL;DR: In this paper, the spin-dependent asymmetries of high-energy polarized electrons by high energy polarized protons at HERA with their statistical errors were used to reduce the uncertainty in the determination of the first moment of the polarized gluon distribution.
Abstract: We present estimates of possible data on spin-dependent asymmetries in inclusive scattering of high energy polarized electrons by high energy polarized protons at HERA with their statistical errors and discuss systematic errors. We show that these data will provide important information on the low-x behavior of the polarized structure function g_1, and will reduce the uncertainty in the determination of the first moment of the polarized gluon distribution Delta g(x,Q^2) obtained from the QCD analysis of g_1 in NLO. Furthermore, using asymmetries for di-jet events from a polarized HERA would substantially reduce the uncertainty in the shape of Delta g(x,Q^2). Using the information on Delta g(x,Q^2) from the di-jet analysis in conjunction with the NLO QCD analysis of g_1 will provide an accurate determination of Delta g(x,Q^2) and its first moment.
3 citations
Journal Article•
TL;DR: A next-to-leading order QCD analysis of the presently available data on the spin structure function g(1) including the final data from the Spin Muon Collaboration is presented in this article.
Abstract: We present a next-to-leading order QCD analysis of the presently available data on the spin structure function g(1) including the final data from the Spin Muon Collaboration. We present results for the first moments of the proton, deuteron, and neutron st