scholarly journals HIGH ENERGY PHOTON-PHOTON AND ELECTRON-PHOTON COLLISIONS

1998 ◽  
Vol 13 (14) ◽  
pp. 2417-2427 ◽  
Author(s):  
STANLEY J. BRODSKY

The advent of a next linear e±e- collider and back-scatterd laser beams will allow the study of a vast array of high energy processes of the Standard Model through the fusion of real and virtual photons and other gauge bosons. As examples, I discuss virtual photon scattering γ*γ*→X in the region dominated by BFKL hard Pomeron exchange and report the predicted cross sections at present and future e±e- colliders. I also discuss exclusive γγ reactions in QCD as a measure of hadron distribution amplitudes and a new method for measuring the anomalous magnetic and quadrupole moments of the W and Z gauge bosons to high precision in polarized electron-photon collisions.

Author(s):  
Ivan A. Shershan ◽  
Tatiana V. Shishkina

In this paper the analysis of W-boson production process in high-energy electron-photon collisions as a tool to search for deviations from the Standard Model is considered. In particular, a set of extended gauge models, including anomalous multi-boson interactions, are discussed as a promising way for «new physics» study. A numerical analysis of the total cross sections of the processes was carried out. The lowest order radiative corrections in the soft-photon approximation within the Standard Model are taken into account. Calculations beyond the Standard Model was performed, the kinematic features of the cross sections were identified. The restrictions on the anomalous triple gauge boson coupling constants were analyzed and the kinematic areas to the search for their manifestations were obtained during the experiments at the International Linear Collider. The paper shows that the search for «new physics» effects based on electron-photon collisions around the W-boson production peak is the maximal promising. It was also shown that future experiments at high luminosity linear colliders will significantly clarify the constraints on anomalous gauge coupling constants.


2021 ◽  
Vol 24 (4) ◽  
pp. 317-325
Author(s):  
I. A. Shershan ◽  
T. V. Shishkina

Differential and total cross sections of single gauge boson production in high energy electron-photon collisions obtained within the Standard Model in leading order and next-to-leading order are presented. Soft photon bremsstrahlung as well as hard photon bremsstrahlung parts were considered using the dimensional regularization procedure. Special features of receiving the hard bremsstrahlung convergent contribution are discussed. The corresponding anomalous gauge boson couplings were studied in the effective Lagrangian approach. Best conditions for registration of effects beyond the Standard Model are determined.


2019 ◽  
Vol 22 (4) ◽  
pp. 318-329 ◽  
Author(s):  
I. A. Shershan Shershan ◽  
T. V. Shishkina Shishkina

The differential and total cross sections of the single gauge boson production in quasielastic high energy electron-photon scattering are obtained within the Standard Model in leading order and next-to-leading order of the perturbative theory. The contribution of divergent part of hard photon bremsstrahlung was included. The anomalous gauge boson coupling in the effective Lagrangian approach were studied. It is shown the analysis of neutral gauge couplings can be fully performed for two constants with different types of symmetries. Numerical analysis has been done. The best conditions were determined for registration of generated effects beyond the Standard Model.


1989 ◽  
Vol 04 (17) ◽  
pp. 4551-4565 ◽  
Author(s):  
JOANNE L. HEWETT ◽  
THOMAS G. RIZZO

We discuss and contrast search limits for and properties of new Z′ gauge bosons which can be probed at high energy e+e− colliders within the context of several E6 superstring-inspired models. In particular, we discuss the probability of distinguishing these various models from one another and determining the Z′ coupling parameters uniquely. Using the deviations from the standard model predictions for asymmetries and cross sections for various final state fermions, we set discovery limits for new Z′ bosons at [Formula: see text] and 1 TeV e+e− colliders. We find quite generally that cross section deviations provide the strongest limits on the existence of new Z′ bosons below threshold even when 100% beam polarization is available. The possibility of using Z′ pair production as a sensitive probe of the e+e−Z′ coupling is also examined.


2005 ◽  
Vol 20 (22) ◽  
pp. 5164-5173 ◽  
Author(s):  
BEATE HEINEMANN

Recent searches for physics beyond the Standard Model at high energy colliders are presented. The main focus is on searches for supersymmetry, extra dimensions and new gauge bosons. In all search analyses the data are found to agree well with the Standard Model background expectation and no evidence for contributions from physics beyond the Standard Model is found. The data are thus used to place limits on new physics scenarios.


2003 ◽  
Vol 18 (16) ◽  
pp. 2871-2892 ◽  
Author(s):  
Stanley J. Brodsky

The advent of back-scattered laser beams for e±e-colliders will allow detailed studies of a large array of high energy γγ and γe collision processes with polarized beams. These include tests of electroweak theory in photon-photon annihilation such as γγ → W+W-, γγ → Higgs bosons, and higher-order loop processes, such as γγ → γγ, Zγ, H0Z0and ZZ. Methods for measuring the anomalous magnetic and quadrupole moments of the W and Z gauge bosons to high precision in polarized electron-photon and photon-photon collisions are discussed. Since each photon can be resolved into a W+W-pair, high energy photon-photon collisions can also provide a remarkably background-free laboratory for studying WW collisions and annihilation. I also review high energy γγ and eγ tests of quantum chromodynamics, including the production of two gluon jets in photon-photon collisions, deeply virtual Compton scattering on a photon target, and leading-twist single-spin asymmetries for a photon polarized normal to a production plane. Exclusive hadron production processes in photon-photon collisions provide important tests of QCD at the amplitude level, particularly as measures of hadron distribution amplitudes which are also important for the analysis of exclusive semi-leptonic and two-body hadronic B-decays.


2021 ◽  
Vol 81 (9) ◽  
Author(s):  
G. R. Boroun ◽  
B. Rezaei

AbstractWe present nonlinear corrections (NLCs) to the distribution functions at low values of x and $$Q^{2}$$ Q 2 using the parametrization $$F_{2}(x,Q^{2})$$ F 2 ( x , Q 2 ) and $$F_{L}(x,Q^{2})$$ F L ( x , Q 2 ) . We use a direct method to extract nonlinear corrections to the ratio of structure functions and the reduced cross section in the next-to-next-to-leading order (NNLO) approximation with respect to the parametrization method (PM). Comparisons between the nonlinear results with the bounds in the color dipole model (CDM) and HERA data indicate the consistency of the nonlinear behavior of the gluon distribution function at low x and low $$Q^{2}$$ Q 2 . The nonlinear longitudinal structure functions are comparable with the H1 Collaboration data in a wide range of $$Q^{2}$$ Q 2 values. Consequently, the nonlinear corrections at NNLO approximation to the reduced cross sections at low and moderate $$Q^{2}$$ Q 2 values show good agreement with the HERA combined data. These results at low x and low $$Q^{2}$$ Q 2 can be applied to the LHeC region for analyses of ultra-high-energy processes.


2019 ◽  
Vol 208 ◽  
pp. 09001
Author(s):  
Spencer Klein

Although they are best known for studying astrophysical neutrinos, neutrino telescopes like IceCube can study neutrino interactions, at energies far above those that are accessible at accelerators. In this writeup, I present two IceCube analyses of neutrino interactions at energies far above 1 TeV. The first measures neutrino absorption in the Earth, and, from that determines the neutrino-nucleon cross-section at energies between 6.3 and 980 TeV. We find that the cross-sections are 1.30 +0.21 -0.19 (stat.) +0.39 -0.43 (syst.) times the Standard Model crosssection. We also present a measurement of neutrino inelasticity, using νμ charged-current interactions that occur within IceCube. We have measured the average inelasticity at energies from 1 TeV to above 100 TeV, and found that it is in agreement with the Standard Model expectations. We have also performed a series of fits to this track sample and a matching cascade sample, to probe aspects of the astrophysical neutrino flux, particularly the flavor ratio.


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