120745044
Phenomenology of the particle spectra in QCD jets in a modified leading logarithmic approximation
Inclusive energy spectra of hadrons produced ine+e− annihilation are compared to predictions of the model independent perturbative approach based on the modified leading logarithmic approximation for description of QCD parton cascades and the local parton-hadron duality concept.
119379184
Radiative corrections to the hadronic cross-section measurement at DA$\Phi$NE
Abstract. The hadronic invariant mass distribution for the process of electron–positron annihilation into a pair of charged pions accompanied by a photon radiated from the initial state has been studied for the region of DA$\Phi$NE energies. The Born cross–section and the electromagnetic radiative corrections to it are calculated for realistic conditions of the KLOE detector. The dependence on the physical parameters which define the event selection is obtained.
124029542
On the sensitivity of the inclusive distributions in parton jets to the coherence effects in QCD gluon cascades
The KNO multiplicity distributions and properties of two-particle correlations in QCD jets are considered in the framework of the perturbative approach accounting for effects of the coherence in the soft gluon bremsstrahlung.
119436494
QCD Interconnection Effects
Heavy objects like the W, Z and t are short-lived compared with typical hadronization times. When pairs of such particles are produced, the subsequent hadronic decay systems may therefore become interconnected. We study such potential effects at Linear Collider energies.
125850380
Multiple Hadron Production in Parton {QCD} Jets
117871006
Pomeron universality from identical pion correlations at the LHC
Abstract Bose–Einstein correlations of identical pions produced in high-energy pp collisions at the LHC allow a probe of the Pomeron exchange mechanism. The size of the domain which emits the pions depends on the multiplicity of events, but not on the collider energy. This confirms the universal structure of Pomeron exchange. The data at relatively low multiplicities indicate that the size of the source created by one-Pomeron exchange is much less than the size of the proton.
118956578
Baryon number violation and instantons in the standard model
We report on the recent developments in the theory of high energy collisions mediated by an instanton. Theoretical methods of studying the nonperturbative dynamics of the Standard Model at high energies in association with multi-particle-production and (B+L)-violation are reviewed. Particularly, we concentrate on the optical theorem approach based on the valley method. A pre-history and a current status of the theory of electroweak (B+L)-violation in high energy collisions are discussed.
123478544
Comment on thermal sphaleron transitions
122485626
Multi-instantons do not stop the cross-section at half the 't Hooft suppression
Abstract Using the (1+1)-dimensional abelian Higgs model as a toy model we study the non-perturbative semiclassical behaviour of the total cross-section in the limit of large Higgs mass mh as compared to the vector boson mass mw. In the single-instanton approximation the total cross-section rises steeply with energy. The leading-order exponential suppression by the 't Hooft factor (twice the instanton action) disappears at energies near the sphaleron energy. Above the sphaleron energy semiclassical methods based on the instanton/anti-instanton valley break down. The influence of multi-instanton contributions is found to be completely negligible up to energies of the order of the sphaleron energy.
15145483
Instantons, Higher-Derivative Terms, and Nonrenormalization Theorems in Supersymmetric Gauge Theories
Abstract We discuss the contribution of ADHM multi-instantons to the higher-derivative terms in the gradient expansion along the Coulomb branch of N = 2 and N = 4 supersymmetric SU (2) gauge theories. In particular, using simple scaling arguments, we confirm the Dine-Seiberg nonperturbative nonrenormalization theorems for the 4-derivative/8-fermion term in the two finite theories ( N = 4, and N = 2 with N F = 4).
15251851
Tree amplitudes in gauge theory as scalar MHV diagrams
It was proposed in [2] that all tree amplitudes in pure Yang-Mills theory can be constructed from known MHV amplitudes. We apply this approach for calculating tree amplitudes of gauge fields and fermions and find agreement with known results. The formalism amounts to an effective scalar perturbation theory which offers a much simpler alternative to the usual Feynman diagrams in gauge theory and can be used for deriving new simple expressions for tree amplitudes. At tree level the formalism works in a generic gauge theory, with or without supersymmetry, and for a finite number of colours.