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We calculate the relativistic six-meson scattering amplitude at low energy within the framework of QCD-like theories with n degenerate quark flavors at next-to-leading order in the chiral counting. We discuss the cases of complex, real and pseudoreal representations, i.e. with global symmetry and breaking patterns SU(n)×SU(n)/SU(n) (extending the QCD case), SU(2n)/SO(2n), and SU(2n)/Sp(2n). In cas
In this work, we perform a detailed study of transition form factors for axial- vector meson production via the two-photon fusion process γ*γ* → 1++, with space-like virtual photons in the initial state and a P-wave axial-vector quarkonium in the final state. In this analysis, we employ the formalism of light-front quarkonium wave functions obtained from a solution of the Schrödinger equation for
Interactions of hard partons in the Quark Gluon Plasma (QGP) created with relativistic heavy ion collisions lead to characteristic modifications of the internal structure of reconstructed jets. A large part of the observed jet sub-structure modifications stem from the QGP’s response to energy and momentum deposited by hard partons. Good control over medium response in theoretical calculations is t
We extract the heavy quark diffusion coefficient k and the resulting momentum broadening h p2i of a heavy quark embedded in a far-from-equilibrium gluon plasma using classical-statistical lattice simulations. We find several features in the time dependence of the momentum broadening: a short initial rapid growth of h p2i, followed by linear growth with time due to Langevin-type dynamics and damped
This paper discusses a general class of ladder resummation inspired hadronic approximations. It is found that this approach naturally reproduces many successes of single meson per channel saturation models (e.g. VMD) and NJL based models. In particular the existence of a constituent quark mass and a gap equation follows naturally. We construct an approximation that satisfies a large set of QCD sho
Using the large N-C approximation we have constructed the most general chiral resonance Lagrangian in the odd-intrinsic parity sector that can generate low-energy chiral constants up to O(p(6)). Integrating out the resonance fields these O(p(6)) constants are expressed in terms of resonance couplings and masses. The role of eta' is discussed and its contribution is explicitly factorized. Using the
We have in earlier papers presented an extension of Mueller's dipole cascade model, which includes subleading effects from energy conservation and running coupling as well as color-suppressed saturation effects from pomeron loops via a "dipole swing". The model was applied to the description of the total and diffractive cross sections in pp and gamma * p collisions, and also the elastic cross sect
The medium-induced one-gluon radiation spectrum off a massive quark-antiquark (q (q) over bar) antenna traversing a colored QCD medium is calculated in this contribution. The gluon spectrum off the antenna computed at first order in the opacity expansion is collinear finite but infrared divergent, which is different from the result obtained from an independent emitter which is both infrared and co
We consider a model for the Higgs sector with two scalar doublets and a softly broken Z(2) symmetry, the Stealth Doublet Model. This model can be seen as a generalization of the Inert Doublet Model. One of the doublets is the Higgs doublet that participates in electroweak symmetry breaking and couples to fermions. The other doublet does not couple to fermions at tree level and does not acquire a v
Abstract in UndeterminedThe PYTHIA program is a standard tool for the generation of high-energy collisions, comprising a coherent set of physics models for the evolution from a few-body hard process to a complex multihadronic final state. It contains a library of hard processes and models for initial-and final-state parton showers, multiple parton-parton interactions, beam remnants, string fragmen
We investigate some recent measurements of Fermi-Dirac correlations by the LEP collaborations indicating surprisingly small source radii for the production of baryons in e(+)e(-) annihilation at the Z(0) peak. In hadronization models there is besides the Fermi-Dirac correlation effect also a strong dynamical (anti-) correlation. We demonstrate that the extraction of the pure FD effect is highly de
We review the theoretical motivations and experimental status of searches for stable massive particles (SMPs) which could be sufficiently long-lived as to be directly detected at collider experiments. The discovery of such particles would address a number of important questions in modern physics including the origin and composition of dark matter in the universe and the unification of the fundamen
We study the electromagnetic form factor of the pion and kaons at low-energies with the use of Chiral Perturbation Theory. The analysis is performed within the three flavour framework and at next-to-next-to-leading order. We explain carefully all the relevant consistency checks on the expressions, present full analytical results for the pion form factor and describe all the assumptions in the anal
We make a thorough comparison between different schemes of merging fixed-order tree-level matrix element generators with parton-shower models. We use the most basic benchmark of the O(alpha_S) correction to e+e- -> jets, where the simple kinematics allows us to study in detail the transition between the matrix-element and parton-shower regions. We find that the CKKW-based schemes give a reasonably
We discuss γ∗γ∗ → ηc(1S), ηc(2S) transition form factors for both virtual photons. The general formula is given. We use different models for the cc¯ wave function obtained from the solution of the Schrödinger equation for different cc¯ potentials: harmonic oscillator, Cornell, logarithmic, power-law, Coulomb and Buchmüller-Tye. We showed some examples of wave functions in the Light Front represent
In this paper, we discuss the exclusive photoproduction of ground and excited states of ψ(1S,2S) and ϒ(1S,2S) in ultraperipheral collisions (UPCs). Using the potential model in order to obtain the vector meson wave function, we find a good agreement of our calculations with data from the LHC and HERA colliders for J/ψ(1S,2S) and ϒ(1S) in γp collisions. We extend the calculations to the nuclear tar
We construct families, and concrete examples, of simple extensions of the Standard Model that can yield ultralight real or complex vectors or scalars with potential astrophysical relevance. Specifically, the mass range for these putative fundamental bosons (∼ 10-10-10-20 eV) would lead dynamically to both new non-black hole compact objects (bosonic stars) and new non-Kerr black holes, with masses
We introduce an improvement to the FxFx matrix element merging procedure for pp →tt¯ W production at NLO in QCD with one and/or two additional jets. The main modification is an improved treatment of jets that are not logarithmically enhanced in the low transverse-momentum regime. We provide predictions for the inclusive cross section and the tt¯ W differential distributions including parton-shower
Denna uppsats behandlar det straffrättsliga begreppet samtycke som är en av ansvarsfrihetsgrunderna i svensk rätt. Syftet i uppsatsen är att besvara när samtycke blir relevant att åberopa och när det tillämpas. I ansvarsfrihetsgrunden samtycke innefattas två centrala rekvisit: att samtycket är giltigt samt att gärningen inte är oförsvarlig. Arbetet koncentrerar sig på samtycke till våldsbrott och This paper examines and analyzes the conception of consent in Swedish criminal law. The purpose of the paper is to answer the question when consent becomes relevant to discuss and to examine when it should be applicable. The conception of consent contents two necessary prerequisites: it has to be a valid consent and the criminal act can’t be indefensible. The work of the paper concentrates in crim
