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We discuss the Melosh spin rotation effects in diffractive photo- and electroproduction of heavy quarkonia off a nucleon target in the dipole picture. The quarkonium light-front wave functions are obtained in the Schroedinger equation based formalism using the realistic interquark interaction potentials. A strong onset of spin rotation effects predicted in the case of J/ψ(1S) photoproduction enabl
In this work we investigate the spin correlation effect of the interference between signal and irreducible background events present in top quark pair production at the LHC at LO in the dilepton channel. To simulate the high energy proton-proton collisions of the LHC, MadGraph5_aMC@NLO framework is used as an event generator. The spin correlations are explicitly measured via the lepton kinematics
High energy particle collisions often produce large numbers of partons in the final state, which are clustered together in collimated sprays called jets. A recent paper [1] introduces the concept of jet entropy, which is an observable that quantifies the entanglement between the resolved and unresolved parts of a jet. We derive an analytic expression for the entropy of a gluon jet and compare the
We report lifetime measurements of the five levels in the 3d(4)(a(5)D)5s e(6)D term in Cr II at an energy around 83 000 cm(-1), and log(gf) values for 38 transitions from the investigated levels. The lifetimes are obtained using time-resolved, laser-induced fluorescence on ions from a laser-produced plasma. Since the levels have the same parity as the low-lying states directly populated in the pla
The intensity-calibrated spectra of W II have been recorded in the spectral interval 23 000-51 300 cm(-1) (1950-4350 angstrom), using the FT500 UV Fourier Transform Spectrometer at Lund Observatory. Combining the intensity data in this work with lifetimes previously measured using the time-resolved laser-induced-fluorescence (TR-LIF) technique resulted in transition probabilities and log gf values
The K → ππ system is analyzed in the chiral limit within the Standard Model. We discuss how to connect the short-distance running in the |ΔS| = 1 case to the matrix-elements calculated in a low-energy approximation in a scheme-independent fashion. We calculate this correction and the resulting Wilson Coefficients. The matrix elements are calculated to next-to-leading order in the 1/Nc expansion an
We propose a low-scale renormalizable trinification theory that successfully explains the flavor hierarchies and neutrino puzzle in the Standard Model (SM), as well as provides a dark matter candidate and also contains the necessary means for efficient leptogenesis. The proposed theory is based on the trinification SU(3)C×SU(3)L×SU(3)R gauge symmetry, which is supplemented with an additional flavo
We propose the Positive Resampler to solve the problem associated with event samples from state-of-the-art predictions for scattering processes at hadron colliders typically involving a sizeable number of events contributing with negative weight. The proposed method guarantees positive weights for all physical distributions, and a correct description of all observables. A desirable side product of
We have developed a phenomenological effective quantum-field theoretical model describing the "hadron gas" of the lightest pseudoscalar mesons, scalar σ-meson and σ-vacuum, i.e. the expectation value of the σ-field, at finite temperatures. The corresponding thermodynamic approach was formulated in terms of the generating functional derived from the effective Lagrangian providing the basic thermody
We report new time-resolved laser-induced fluorescence lifetime measurements for 22 highly excited even-parity levels in singly ionized yttrium (Y II). To populate these levels belonging to the configurations 4d6s, 5s6s 4d5d, 5p2, 4d7s and 4d6d, a two-step laser excitation technique was used. Our previous pseudo-relativistic Hartree-Fock model (Biémont et al. 2011) was improved by extending the co
We discuss the matching between long-distance and short-distance at next-to-leading in 1/Nc and show how the scheme-dependence from the two-loop renormalization group running can be treated. We then use this method to study the three O(p2) terms contributing to non-leptonic kaon decays, namely the usual octet and 27-plet derivative terms as well as the weak mass term using the Extended Nambu Jona-
We present new algorithms for simulating Bose–Einstein correlations among final-state bosons in an event generator. The algorithms are all based on introducing Bose–Einstein correlations as a shift of final-state momenta among identical bosons, and differ only in the way energy and momentum conservation is ensured. The benefits and shortcomings of this approach, that may be viewed as a local rewei
A real photon has a complicated nature, whereby it may remain unresolved or fluctuate into a vector meson or a perturbative qq̄ pair. In γγ events, this gives three by three combinations of the nature of the two incoming photons, and thus six distinct event classes. The properties of these classes are partly constrained by the choices already made in our related γp model. It is therefore possible
As the current nuclear PDF analyses are mainly constrained by fixed-target Drell-Yan and deeply inelastic scattering data only the quark nuclear modifications at fairly large x values are in a good control. Inclusive pion production in d+Au collisions at RHIC provides some constraints for gluons but due to the limited kinematic reach of the data the gluon modifications remain uncertain especially
A new release of the Monte Carlo event generator Herwig (version 7.2) is now available. This version introduces a number of improvements over the major version 7.0, notably: multi-jet merging with the dipole shower at LO and NLO QCD; spin correlations in both the dipole and angular-ordered parton showers; an improved choice of evolution variable in the angular-ordered parton shower; improvements t
We show how a careful analysis of the behaviour of a parton shower Monte Carlo in the vicinity of the soft and collinear regions allows one to formulate a modified MC@NLO-matching prescription that reduces the number of negative-weight events with respect to that stemming from the standard MC@NLO procedure. As a first practical application of such a prescription, that we dub MC@NLO-∆, we have impl
We present a generalisation of the flavour-ordering method applied to the chiral nonlinear sigma model with any number of flavours. We use an extended Lagrangian with terms containing any number of derivatives, organised in a power-counting hierarchy. The method allows diagrammatic computations at tree-level with any number of legs at any order in the power-counting. Using an automated implementat
Microsoft Word - Kursbokslut MATA21 VT2020.docx Course analysis MATA21 Spring 2020 Lecturer: Jan-Fredrik Olsen (second half) Seminar teachers: Jonathan Holmqvist, Adem Limani, Douglas Svensson (first half) Registered students: • 67 first time registered and 58 re-registered = 125 registered. Result diagnostic test: 62 students took the diagnostic test at the start of the term (the results in paren
https://www.maths.lu.se/fileadmin/maths/Matematik_NF/Kursutvaerderingar/VT2020/Kursbokslut_MATA21_VT2020.pdf - 2026-05-25
I AM GRATEFUL TO Dien Ho and James Phillips for their comments on my article (Mulinari, 2018). Although they approach the topic from different perspectives, they both seem to find my account of the evolution of monoamine theories into neuroplasticity theories to be compelling. They especially seem to find my principal argument to be persuasive: Until quite recently, the use of drugs to generate an
