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In the Next-to-Minimal SuperSymmetric Model (NMSSM) the lightest CP-odd Higgs bosons (a(1)) can be very light. As a consequence, in addition to the standard charged Higgs boson (h(+/-)) decays considered in the MSSM for a light charged Higgs (m(h +/-) < m(t)), the branching fraction for h(+/-) -> a(1)W can be dominant. We investigate how this signal can be searched for in t<(t)over bar> production

Diffractive excitation is usually described by the Good-Walker formalism for low masses, and by the triple-Regge formalism for high masses. In the Good-Walker formalism the cross section is determined by the fluctuations in the interaction. In this paper we show that by taking the fluctuations in the BFKL ladder into account, it is possible to describe both low and high mass excitation by the Good

We study the radiation of a highly energetic partonic antenna in a colored state traversing a dense QCD medium. Resumming multiple scatterings of all involved constituents with the medium we derive the general gluon spectrum which encompasses both longitudinal color coherence between scattering centers in the medium, responsible for the well known Landau-Pomeranchuk-Migdal (LPM) effect, and transv

Theoretical arguments, supported by other indirect evidence, suggest that the wave function of high-x partons should be narrower than that of low-x ones. In this article, we present a modification to the variable impact parameter framework of PYTHIA 8 to model this effect. In particular, a Gaussian hadronic matter profile is introduced, with a width dependent on the x value of the constituent bein

Production of heavy photons (Drell-Yan), gauge bosons, Higgs bosons, and heavy flavors, which is treated within the QCD parton model as a result of hard parton-parton collision, can be considered a bremsstrahlung process in the target rest frame. In this review, we discuss the basic features of the diffractive channels of these processes in the framework of color dipole approach. The main observat

We present a calculation of the finite volume corrections to meson masses and decay constants in three flavour Partially Quenched Chiral Perturbation Theory ( PQChPT) through two-loop order in the chiral expansion for the flavour-charged ( or off-diagonal) pseudoscalar mesons. The analytical results are obtained for three sea quark flavours with one, two or three different masses. We reproduce the

Radiative lifetimes of 17 high-lying excited states in Rh I aremeasured using the time-resolved laser-induced fluorescence method. Out of these lifetimes, 13 are new and the remaining four confirm previous measurements. Furthermore, we report the first theoretical investigation of Rh I, where the radiative decay properties of all experimentally known levels below 47 000 cm(-1) are calculated using

We study how general two Higgs doublet models can be constrained by considering their properties under renormalization group evolution of the Yukawa couplings. We take into account both the appearance of a Landau pole as well as off-diagonal Yukawa couplings leading to flavour changing neutral currents in violation with experimental constraints at the electroweak scale. We find that the latter con

We suggest one of the possible ways to compensate the large negative quantum-topological QCD contribution to the vacuum energy density of the Universe by means of a positive constant contribution from a cosmological Yang-Mills field. An important role of the exact particular solution for the Yang-Mills field corresponding to the finite-time instantons is discussed. An interesting connection of the

We present a dynamical study of the double parton distribution in impact parameter space, which enters into the double scattering cross section in hadronic collisions. This distribution is analogous to the generalized parton densities in momentum space. We use the Lund Dipole Cascade model, presented in earlier articles, which is based on BFKL evolution including essential higher order corrections

We discuss single diffractive gauge boson d (gamma*, W+/-, Z) production in proton-proton collisions at different (Large Hadron Collider and Relativistic Heavy Ion Collider) energies within the color dipole approach. The calculations are performed for gauge bosons produced at forward rapidities. The diffractive cross section is predicted as a function of the fractional momentum and invariant mass

The concept of multiple partonic interactions in hadronic events is vital for the understanding of both minimum-bias and underlying-event physics. The area is rather little studied, however, and current models off er a far from complete coverage, even of the effects we know ought to be there. In this article we address one such topic, namely that of rescattering, where an already scattered parton

After a brief review of how quantum mechanical weak measurements plus post-selection give rise to the weak value concept, I criticize an interpretation of a weak value as any sort of straightforward, bona fide property of the system under investigation.

We analyze a model for the Higgs sector with two scalar doublets and a Z(2) symmetry that is manifest in the Yukawa sector but broken in the potential. Thus, one of the doublets breaks the electroweak symmetry and has tree-level Yukawa couplings to fermions, whereas the other doublet has no vacuum expectation value and no tree-level couplings to fermions. Since the Z(2) parity is broken the two do

We present a method to match the multi-parton states generated by the High Energy Jets Monte Carlo with parton showers generated by the A riadne program using the colour dipole model. The High Energy Jets program already includes a full resummation of soft divergences. Hence, in the matching it is important that the corresponding divergences in the parton shower are subtracted, keeping only the co

We apply the resummed version of the Luscher formula to analyze finite volume corrections to the mass of the nucleon and of heavy mesons. We show that by applying the subthreshold expansion of the scattering amplitudes one can express the finite volume corrections in terms of only a few physical observables and the size of the box. In the case of the nucleon, the available information about the qu

We present a calculation of the meson masses, decay constants and quark-antiquark vacuum expectation value for the three generic QCD-like chiral symmetry breaking patterns SU(N-F) x SU(N-F) -> SU(N-F)(V), SU(N-F) -> SO(N-F) and SU(2N(F)) -> Sp(2N(F)) in the effective field theory for these cases. We extend the previous two-loop work to include effects of partial quenching and finite volume. The ca

We develop a general recipe for constructing orthogonal bases for the calculation of color structures appearing in QCD for any number of partons and arbitrary N-c. The bases are constructed using hermitian gluon projectors onto irreducible subspaces invariant under SU(N-c). Thus, each basis vector is associated with an irreducible representation of SU(N-c). The resulting multiplet bases are not on