117943345
PHYSICS FROM COLLIDING e+ e- BEAMS OF THE NEW GENERATION
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.
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.
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.
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.
125850380
Multiple Hadron Production in Parton {QCD} Jets
15213237
Collinear limits in QCD from MHV rules
We consider multi-parton collinear limits of QCD amplitudes at tree level. Using the MHV formalism we specify the underlying analytic structure of the resulting multi-collinear splitting functions. We derive general results for these splitting functions that are valid for specific numbers of negative helicity partons and an arbitrary number of positive helicity partons (or vice versa).
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.
119258384
RG invariants, unification and the role of the messenger scale in General Gauge Mediation
In General Gauge Mediation (GGM) all MSSM soft sfermion masses at a high scale Mmess can be parameterised by three a priori independent scales ΛS; 1,2,3(Mmess). (Similarly the gaugino masses are given by ΛG; 1,2,3(Mmess).) For the first two generations this parameterisation in terms of a set of running ΛS; 1,2,3(μ) — conveniently obtained from appropriate RG invariants — continues to hold all the way down to the electroweak scale. This is not the case for the third generation because of the large Yukawa couplings. Together these two observations imply that the messenger scale is an additional parameter of GGM models.In models where all messengers are in complete GUT multiplets (without significant mass splittings), all ΛS,r are equal at Mmess. Starting from the observable mass spectrum at the electroweak scale we present a strategy to determine if this unification occurs and at which scale. This approach uses data accessible at colliders to gain insight into high scale unification physics beyond the unification of gauge couplings.
8182637
Recursion relations for gauge theory amplitudes with massive particles
We derive general tree-level recursion relations for amplitudes which include massive propagating particles. As an illustration, we apply these recursion relations to scattering amplitudes of gluons coupled to massive scalars. We provide new results for all amplitudes with a pair of scalars and n ≤ 4 gluons. These amplitudes can be used as building blocks in the computation of one-loop 6-gluon amplitudes using unitarity based methods.
14575937
The Instanton Hunter's guide to supersymmetric SU(N) gauge theories
Abstract We present a compendium of results for ADHM multi-instantons in SU ( N ) SUSY gauge theories, followed by applications to N = 2 supersymmetric models. Extending recent SU (2) work, and treating the N = 1 and N = 2 cases in parallel, we construct: (i) the ADHM supermultiplet, (ii) the multi-instanton action, and (iii) the collective coordinate integration measure. Specializing to N = 2, we then give a closed formula for F k , the k -instanton contribution to the prepotential, as a finite-dimensional collective coordinate integral. This amounts to a weak-coupling solution, in quadratures, of the low-energy dynamics of N = 2 SQCD, without appeal to duality. As an application, we calculate F 1 for all SU ( N ) and any number of flavors N F ; for N F N − 2 and N F = 2 N − 1 we confirm previous instanton calculations and agree with the proposed hyper-elliptic curve solutions. For N F = 2 N − 2 and N F = 2 N with N > 3 we obtain new results, which in the latter case we do not understand how to reconcile with the curves.