scholarly journals PAIR PRODUCTION OF FUNDAMENTAL UNSTABLE PARTICLES IN MODIFIED PERTURBATION THEORY IN NNLO

2011 ◽  
Vol 26 (03) ◽  
pp. 223-234 ◽  
Author(s):  
M. L. NEKRASOV
Keyword(s):  
Exact Solution ◽  
Perturbation Theory ◽  
Pair Production ◽  
Cross Section ◽  
Massless Particles ◽  
Unstable Particles ◽  
The Cross

We consider pair production and decay of fundamental unstable particles in the framework of a modified perturbation theory (MPT) treating resonant contributions in the sense of distributions. The cross-section of the process is calculated within the NNLO of the MPT in a model that admits exact solution. Universal massless-particles contributions are taken into consideration. A comparison of the outcomes with the exact solution demonstrates excellent convergence of the MPT series at the energies near and above the maximum of the cross-section.

scholarly journals W-PAIR PRODUCTION IN MODIFIED PERTURBATION THEORY

2011 ◽  
Vol 26 (24) ◽  
pp. 1807-1816 ◽  
Author(s):  
M. L. NEKRASOV
Keyword(s):  
Perturbation Theory ◽  
Total Cross Section ◽  
Pair Production ◽  
Cross Section ◽  
Unstable Particles ◽  
Better Than

We examine capabilities of the modified perturbation theory (MPT) for description of the processes with productions and decays of fundamental unstable particles. We calculate total cross-section for e+e- → γ, Z → W+W- → 4f in a model with the Dyson-resummed and with the MPT-expanded up to the NNLO Breit–Wigner factors, and compare the outcomes. At the ILC energies a coincidence of the outcomes is detected with precision better than one per-mille.

scholarly journals MODIFIED PERTURBATION THEORY FOR PAIR PRODUCTION AND DECAY OF FUNDAMENTAL UNSTABLE PARTICLES

2009 ◽  
Vol 24 (32) ◽  
pp. 6071-6103 ◽  
Author(s):  
M. L. NEKRASOV
Keyword(s):  
Perturbation Theory ◽  
Asymptotic Expansion ◽  
Pair Production ◽  
Asymptotic Property ◽  
Cross Section ◽  
Arbitrary Order ◽  
Threshold Region ◽  
Coupling Constant ◽  
Unstable Particles ◽  
Kinematic Singularities

We construct an asymptotic expansion in powers of the coupling constant directly of the cross-section for pair production and decay of fundamental unstable particles. The resonant and kinematic singularities arising in the expansion we treat in the sense of distributions. This mode allows us to transform formally divergent integrals into absolutely convergent ones with keeping the asymptotic property of the expansion. The appropriate procedure is elaborated up to an arbitrary order of the expansion. The peculiarity of application of the procedure in the threshold region is analyzed. The scheme of the calculations within the NNLO approximation is explicitly discussed.

Biaxial bending of cold-formed angle members

1984 ◽  
Vol 11 (4) ◽  
pp. 933-942 ◽  
Author(s):  
Murty K. S. Madugula ◽  
Sujit K. Ray
Keyword(s):  
Exact Solution ◽  
Compressive Strength ◽  
Computer Program ◽  
Cross Section ◽  
Simultaneous Equations ◽  
Biaxial Bending ◽  
Total Stress ◽  
The Cross ◽  
The Galerkin Method ◽  
Shear Centre

Theoretical load–deflection relationships for cold-formed angles under biaxial bending using the Galerkin method are presented. The computational difficulties encountered in the exact solution of differential equations of equilibrium involving 12 unknown constants in 12 simultaneous equations are pointed out. A computer program for pinned-end boundary conditions was developed to estimate the deflection components of the shear centre, to calculate the total stress at various points in the cross section, and to predict the ultimate strength of the cold-formed angle sections connected by one leg. Failure is assumed to have occurred when the total stress at any point on the cross section reaches the value of yield stress, compressive or tensile, or when there is a change of sign for at least one of the deflection components. A table giving the ultimate compressive strength of two commonly used cold-formed angles for various gauge distances is included. The theoretical load–deflection curves are compared with experimental results and typical curves for three test specimens are also presented.

scholarly journals FACTORIZED FORMULA FOR THE CROSS-SECTION OF TWO-PARTICLE SCATTERING

2008 ◽  
Vol 23 (27n28) ◽  
pp. 4509-4516 ◽  
Author(s):  
V. I. KUKSA
Keyword(s):  
Cross Section ◽  
Intermediate State ◽  
Factorization Method ◽  
Phenomenological Analysis ◽  
Unstable Particle ◽  
Specific Structure ◽  
Particle Scattering ◽  
Unstable Particles ◽  
The Cross ◽  
Exact Factorization

We applied the factorization method to the processes of two-particle scattering with an unstable particle in the intermediate state. It was shown, that in the framework of this method, the cross-section can be represented in the universal factorized form for an arbitrary set of particles. An exact factorization is caused by a specific structure of unstable particles propagators. Phenomenological analysis of the factorization effect is performed.

scholarly journals Probing the Higgs sector in the nonrelativistic domain

2019 ◽  
Vol 2019 (7) ◽  
Author(s):  
Zhentao Zhang
Keyword(s):  
Pair Production ◽  
Cross Section ◽  
Higgs Sector ◽  
Threshold Region ◽  
Final State ◽  
Direct Information ◽  
The Cross ◽  
The One ◽  
Nonperturbative Contribution

AbstractAs a process that contains direct information from the Higgs self-coupling, we investigate the muon-induced Higgs pair production $\mu^-\mu^+\rightarrow HH$. We calculate the one-loop corrections to the cross section, and in the threshold region we take into account the nonperturbative contribution from the Higgs self-interactions in the final state. We point out that the Higgs pair production in the nonrelativistic domain might be a useful process for probing the Higgs sector.

scholarly journals Measurement of the cross section of W-boson pair production at LEP

2004 ◽  
Vol 600 (1-2) ◽  
pp. 22-40 ◽  
Author(s):  
P. Achard ◽  
O. Adriani ◽  
M. Aguilar-Benitez ◽  
J. Alcaraz ◽  
G. Alemanni ◽  
...  
Keyword(s):  
Pair Production ◽  
Cross Section ◽  
W Boson ◽  
Boson Pair ◽  
Boson Pair Production ◽  
The Cross

scholarly journals First measurement of the cross section for top-quark pair production in proton–proton collisions at s=7 TeV

2011 ◽  
Vol 695 (5) ◽  
pp. 424-443 ◽  
Author(s):  
V. Khachatryan ◽  
A.M. Sirunyan ◽  
A. Tumasyan ◽  
W. Adam ◽  
T. Bergauer ◽  
...  
Keyword(s):  
Pair Production ◽  
Cross Section ◽  
Top Quark ◽  
Proton Proton ◽  
Proton Collisions ◽  
The Cross ◽  
Proton Proton Collisions

Cross sections for the scattering of massless particles by graviton exchange

1970 ◽  
Vol 48 (8) ◽  
pp. 923-929 ◽  
Author(s):  
F. G. Peet
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Massless Particles ◽  
Scalar Particles ◽  
Two Component ◽  
Gravitational Scattering ◽  
The Cross

The gravitational scattering of various types of massless particles is considered. Cross sections are given for the gravitational scattering of scalar particles by: scalar particles, photons, four component neutrinos, and two component neutrinos; of photons by: photons, four component neutrinos, and two component neutrinos; of four component neutrinos by four component neutrinos; and of two component neutrinos by two component neutrinos. The cross section given by Barker et al. and by Boccaletti et al. for the scattering of photons by photons is confirmed. The cross section for the scattering of scalar particles by scalar particles given by DeWitt and the cross section for the scattering of photons by scalar particles given by Boccaletti et al. are found to be in error.

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