arXiv subjects

G. Radel

Publications and source records attributed to G. Radel.

6 recordsLinked to original sources

arXiv2001

The polarised gluon density Delta G(x) from di-jet events at high energy ep-colliders

We present the potential to determine the polarised gluon density from boson-gluon fusion processes with di-jet events at future high energy ep-colliders. These include HERA at DESY operated with polarised electrons and protons, polarised protons from HERA colliding on polarised electrons from a future linear collider, and polarised protons from RHIC at BNL colliding on electrons from a future electron accelerator.

hep-ph↗

arXiv1999

The polarised gluon density Delta G from di-jet events in NLO

A feasibility study to extract the polarised gluon density from di-jet events at HERA in next-to-leading order is presented. It is shown that when taking next-to-leading order effects into account the asymmetries at HERA remain measurable and sensitive to the polarised gluon distribution. They can be used to extract the polarised gluon density in the proton in the region 0.005<x_g<0.4.

hep-ph↗

arXiv1998

A Study of the Polarized Structure Function g_1^p(x,Q^2) and the Polarized Gluon Distribution Delta g(x,Q^2) at HERA

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.

hep-ph↗

arXiv1998

Asymmetry distributions and mass effects in dijet events at a polarized HERA

The asymmetry distributions for several kinematic variables are considered for finding a systematic way to maximize the signal for the extraction of the polarized gluon density. The relevance of mass effects for the corresponding dijet cross section is discussed and the different approximations for including mass effects are compared. We also compare via the programs Pepsi and Mepjet two different Monte Carlo (MC) approaches for simulating the expected signal in the dijet asymmetry at a polarized HERA.

hep-ph↗

arXiv1997

Delta G(x) from high p_t hadrons in DIS at a polarised HERA

We investigate the possibility to identify photon-gluon fusion (PGF) events in polarised deep inelastic ep scattering, assuming the kinematics of the HERA collider, by a pair of charged high p_t particles. In a Monte Carlo study we find possible selection criteria and show the expected measurable asymmetries. We discuss the sensitivity to $ΔG(x)$ and compare the result to the one obtained using di-jets to tag PGF events.

hep-ph↗

arXiv1997

The polarised gluon density from di-jet events in DIS at a polarised HERA

We present a possible direct measurement of the polarised gluon density $ΔG(x)$ in LO from di-jet production in polarised deep inelastic ep scattering, assuming the kinematics of the HERA collider. We show the sensitivity to the x-dependence of $ΔG(x)$ and to the first moment $\int ΔG(x) dx$ in the range $0.002< x <0.2$, assuming the electron and proton beam of HERA being polarised to 70% and an integrated luminosity of at least 200 pb$^{-1}$. We include in our study hadronisation and higher order effects, as well as realistic detector smearing and acceptance. We find that the statistical and systematic uncertainties are small enough to distinguish between different parametrizations for $ΔG(x)$, which all are in accordance with present data. We stress that at HERA an x-range could be measured, that is not accessible to any other present or proposed experiment.

hep-ph↗