Estimating two-loop radiative effects in the MOLLER experiment

Within the on-shell renormalization scheme, two-loop electroweak corrections to the parityviolating polarization asymmetry in the reaction e ^? e ^? → e ^? e ^?(γ, γγ) were estimated for the MOLLER experiment at JLab. The infrared divergence and the imaginary part of the amplitude were taken completely under control. Relevant compact expressions obtained by using asymptotic methods are free from unphysical parameters and are convenient for analysis and for numerical estimations. A numerical analysis revealed a significant scale of two-loop effects and the need for taking them into account in the MOLLER experiment.     

Hadronic radiative corrections to asymmetries observable in the G0 and Q<Subscript>Weak</Subscript> experiments

One-loop hadronic radiative corrections to asymmetries in electron-proton scattering were calculated for the G0 and Q_Weak experiments in the range Q ² = 0.01–1.0 GeV². The formalism of the monopole approximation and the formalism of the dipole approximation were employed for the form factors in hadronic vertices, and no significant distinctions between the asymmetries calculated on the basis of these two approaches were revealed. The result obtained here is in good agreement with the results of previous calculations, but it does not comply very well with data from the G0 experiment. In all probability, this disagreement stems primarily from incompletely taking into account the contribution of strange quarks in the proton. Our theoretical prediction for the asymmetry in question is commensurate with the preliminary estimate of the Q_Weak Collaboration.     

QCD corrections to the Drell-Yan process for the Large Hadron Collider (LHC): Vertex functions and gluon bremsstrahlung

With an eye to future experiments at the Large Hadron Collider (LHC), $ \mathcal{O}\left( {\alpha \alpha _s } \right) $ \mathcal{O}\left( {\alpha \alpha _s } \right) QCD corrections to the Drell-Yan process are calculated for vertex functions and gluon bremsstrahlung. Use is made of fully differential cross sections, so that the result obtained in the present study can readily be applied in analyzing experimental data (in correcting data from future experiments at LHC). It is shown both analytically and numerically that the results are independent of unphysical parameters, including the parameter separating the regions of soft and hard gluons and the quark mass. A numerical analysis of radiative effects was performed by means of the FORTRAN code READY with allowance for the experimental cuts used at the Compact Muon Solenoid (CMS) detector.     

One-loop chiral amplitudes of Møller scattering process

The high energy amplitudes of the large angles Møller scattering are calculated in the frame of chiral basis in Born and 1-loop QED level. Taking into account as well the contribution from emission of soft real photons the compact relations free from infrared divergences are obtained. The expressions for the contributions to the cross section of individual chiral amplitudes are in agreement with renormalization group predictions.     

Radiative corrections to the Drell-Yan process at large dilepton invariant masses

Electroweak radiative corrections to the neutral-current Drell-Yan process at large dilepton invariant masses are calculated. Asymptotic expressions are obtained for diagrams involving two-boson exchange, which represent one of the most significant contributions to the reaction being studied. The contributions of vertex diagrams and “soft” bremsstrahlung are also taken into account. A numerical analysis of electroweak effects with allowance for experimental constraints at the CMS facility is given. The result obtained from this analysis makes it possible to ensure a high precision in the region of high energies; therefore, it is applicable to future experiments at LHC.     

Precise calculations of observables of polarized møller scattering: From JLAB to ILC energies

One-loop electroweak corrections to observables of the reaction e ⁻ e ⁻ → e ⁻ e ⁻(γ) were calculated over a broad range of energies: from conditions of the MOLLER experiment at the Thomas Jefferson Laboratory (JLab) to those of planned experiments at the International Linear Collider (ILC). The dependence of various contributions to the observable polarization asymmetry on various renormalization conditions was studied within the scheme of on-shell renormalization. The results were obtained by two methods: precisely, by applying the FeynArts, FormCalc, LoopTools, and Form computer codes, and approximately, with the aid of the asymptotic-estimation methods. The resulting compact formulas are absolutely free from nonphysical parameters and are convenient for deducing numerical estimates. It is shown that the total one-loop correction is independent of renormalization conditions and takes an identical value within different computational schemes.     

Leading-order electroweak corrections to the Drell-Yan process in the CMS experiment at LHC

The leading part of electroweak radiative corrections to the Drell-Yan process in the CMS (compact muon solenoid detector) experiment at LHC were calculated. Analytic and numerical tests indicate that the results are independent of all nonphysical parameters. A numerical analysis of radiative effects was performed by using the FORTRAN code READY with allowance for experimental constraints at the CMS detector. The results presented for the relative correction to the fully differential cross section for the Drell-Yan process over the entire kinematical region of the CMS detector would hopefully be helpful in handling experimental data.     

Final-State Two-Loop Radiative Corrections to the Drell-Yan Process at the LHC in the Soft-Photon Approximation

In the soft-photon approximation, compact expressions for two-loop final-state electromagnetic radiative corrections to the four-fermion process in the s channel are obtained on the basis of the on-shell renormalization scheme. As applied to the Drell—Yan process, an efficient procedure for numerically estimating final-state radiative effects is proposed for experiments at the LHC for high invariant masses.

     

Two-Boson in a Charged-Current Polarized Process

Physics of Atomic Nuclei - By applying a new method, the contribution of the diagrams of two-boson exchange (boxes) with one and two complex-valued masses to the cross section for a four-fermion...     

Electroweak corrections to the observables of W-boson production at RHIC

The processes of the single W-production in hadron-hadron collisions are suggested for investigation of the nucleon spin. An approach is proposed for the determination of quark spin densities at low x. The lowest order electroweak radiative corrections to the observable quantities are calculated. The numerical calculations of the cross sections and the single spin asymmetries taking into consideration the electroweak corrections at RHIC energies have been made.