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A systematic study is carried out on the angular distribution and polarization of photons emitted following radiative-recombination of bare and He-like ions of Ne, Ar, Ni and Mo with a unidirectional electron beam. In order to incorporate the screening effect due to inner-shell electrons, a distorted wave method is used. Scaling rules for polarization of the photon following radiative recombinatio
In this review, we provide a short outlook of some of the current most popular pictures and promising approaches to non-perturbative physics and confinement in gauge theories. A qualitative and by no means exhaustive discussion presented here covers such key topics as the phases of QCD matter, the order parameters for confinement, the central vortex and monopole pictures of the QCD vacuum structur
In this talk we discuss a number of ChPT calculations relevant for lattice QCD. These include the finite volume corrections at two-loop order for masses and decay constants. The second part is about hadronic vacuum polarization where we present the two-loop ChPT estimate for the disconnected and strange quark contributions. We also present the finite volume corrections at two-loop order. The final
Charge balance functions reflect the evolution of charged pair correlations throughout the stagesof pair production, dynamical diffusion, and hadronization in heavy-ion collisions. Microscopic mod-eling of these correlations in the full collision volume shows that the balance functions are sensitiveto the diffusivity of light quarks when studied as functions of relative azimuthal angle. By restric
We propose a novel mechanism for the production of gravitational waves in the early Universe that originates from the relaxation processes induced by the QCD phase transition. While the energy density of the quark-gluon mean-field is monotonously decaying in real time, its pressure undergoes a series of violent oscillations at the characteristic QCD time scales that generate a primordial multi-pea
It is shown that Technicolor model can be formulated having vector-like interaction of Techniquarks with the Standard Model bosons and Dirac mass term. Oblique corrections values for the case agree with experimental restrictions. The model Lagrangian is based on σ−model scheme introducing Techni-meson and Techni-baryon states. Neutral component of a "triplet" of heavy scalar Techni-baryons can be
We investigate how the uncertainties in σνN due the different QCD dynamic models would modify the neutrino absorption while they travel across the Earth. We compare the predictions of models based on the solution of the linear DGLAP equations at small-x and large-Q2 with those which impose the Froissart bound at large energies, taking into account the unitarity effects in the neutrino - nucleon cr
A search for the K+ → π+X decay, where X is a long-lived feebly interacting particle, is performed through an interpretation of the K+ → π+νν¯ analysis of data collected in 2017 by the NA62 experiment at CERN. Two ranges of X masses, 0–110 MeV/c2 and 154–260 MeV/c2, and lifetimes above 100 ps are considered. The limits set on the branching ratio, BR(K+ → π+X), are competitive with previously repor
We investigate the implication of uncertainties in the unintegrated gluon distribution for the predictions for central exclusive production of scalars at hadron colliders. We use parameterizations of the k(perpendicular to)-unintegrated gluon density obtained from the Linked Dipole Chain model, applying different options for the treatment of non-leading terms. We find that the luminosity function
Stamcellsforskning har på senare tid lett till förhoppningar om att bota alla möjliga sorters sjukdomar. De stamceller som är mest flexibla och därför mest användbara finns i embryo. Att få tag på mänskliga embryon kan dock både vara dyrt och moraliskt problematiskt. Därför har forskare försökt att istället omprogrammera celler från vuxna individer. En sådan teknik som nyligen tagit fart är direkt
Perturbative QCD corrections to leptoproduction events can be introduced either in the form of matrix elements or of parton showers. Each of these approaches has its advantages and disadvantages, making a comparison of the two interesting. At present energies, both methods can be made to agree reasonably well with data, whereas differences appear at higher energies. The influence of these QCD effe
Based on the chiral perturbation theory, we investigate the low-energy dynamics of nucleon parton distributions. We show that in different regions of the momentum fraction x the chiral expansion is significantly different. For nucleon parton distributions these regions are characterized by x similar to 1, x similar to m(pi)/M-N and x similar to (m(pi)/M-N)(2). We derive extended counting rules for
We report on recent studies of the phenomenon of color decoherence in jets in QCD media. The effect is most clearly observed in the radiation pattern of a quark-antiquark antenna, created in the same quantum state, traversing a dense color deconfined plasma. Multiple scattering with the medium color charges gradually destroys the coherence of the antenna. In the limit of opaque media, this ultimat
We investigate soft gluon radiation off a quark-antiquark antenna in both color singlet and octet configurations traversing a dense medium. We demonstrate that, in both cases, multiple scatterings lead to a gradual decoherence of the antenna radiation as a function of the medium density. In particular, in the limit of a completely opaque medium, total decoherence is obtained, i.e., the quark and t
In this Letter we analyze the relation between the triple-pomeron and Good-Walker formalism's for diffractive excitation in DIS and hadronic collisions. In both approaches gap events are interpreted as the shadow of absorption into inelastic channels. We here argue that the two formalisms are just different views of the same phenomenon. We first demonstrate how this relation works in a simple toy
HERA provides a unique possibility to investigate the dependence of multiple interactions on transverse interaction sizes through variation of the photon virtuality Q2. In order to observe effects of multiple interactions at Q2 substantially different from zero we have to look into regions of phase space where resolved processes dominate over direct ones. The forward jet production at small values
I will describe the current status of the PYTHIA7 project to completely rewrite the 'Lund family' of event generators in C++. The PYTHIA7 program is a general platform for implementing event generator models and is not limited to the standard Lund programs (PYTHIA, JETSET, ARIADNE,...). Also the future C++ version of the HERWIG program will be implemented in the PYTHIA7 framework. The underlying f
We apply hard pion Chiral Perturbation Theory to charmonium decays to pi pi, KK and eta eta. We first discuss why we expect to be able to provide results for the chiral logarithms in chi(c0) and chi(c2) decays to two pseudoscalars while for the decays from J/psi, psi(nS) and chi(c1) no simple prediction is possible. The leading chiral logarithm turns out to be absent for chi(c0), chi(c2) -> PP. Th
