124675549
PHYSICS OF HEAVY QUARKS
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.
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
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.
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.
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.
14629672
Multi-instanton check of the relation between the prepotential F and the modulus u in N = 2 SUSY Yang-Mills theory
Abstract By examining multi-instantons in N = 2 supersymmetric SU(2) gauge theory, we derive, on very general grounds, and to all orders in the instanton number, a relationship between the prepotential F (Φ), and the coordinate on the quantum moduli space u = 〈TrΦ2〉. This relation was previously obtained by Matone in the context of the explicit Seiberg-Witten low-energy solution of the model. Our findings can be viewed as a multi-instanton check of the proposed exact results in supersymmetric gauge theory.
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.
62799412
Constraining Dark Sectors at Colliders: Beyond the Effective Theory Approach
We outline and investigate a set of benchmark simplified models with the aim of providing a minimal simple framework for an interpretation of the existing and forthcoming searches of dark matter particles at the LHC. The simplified models we consider provide microscopic QFT descriptions of interactions between the Standard Model partons and the dark sector particles mediated by the four basic types of messenger fields: scalar, pseudoscalar, vector and axial-vector. Our benchmark models are characterized by four to five parameters, including the mediator mass and width, the dark matter mass and the effective coupling(s). In the gluon fusion production channel we resolve the top quark in the loop and compute full top-mass effects for scalar and pseudoscalar messengers. We show the LHC limits and reach at 8 and 14 TeV for models with all four messenger types. We also outline the complementarity of direct detection, indirect detection and LHC bounds for dark matter searches. Finally, we investigate the effects which arise from extending the simplified model to include potential new physics contributions in production. Using the scalar mediator as an example, we study the impact of heavy new physics loops which interfere with the top-mediated loops. Our computations are performed within the mcfm framework, and we provide fully flexible public Monte Carlo implementation.
123478544
Comment on thermal sphaleron transitions