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A brief review is given for the use of feed-back artificial neural networks (ANN) to obtain good approximate solutions to combinatorial optimization problems. The key element is the mean field approximation (MFT), which differs from conventional methods and "feels" its ways towards good solutions rather than fully or partly exploring different possible solutions. The methodology, which is illustra
Parton shower algorithms are key components of theoretical predictions for high-energy collider physics. Work toward more accurate parton shower algorithms is thus pursued along many different avenues. The systematic treatment of subleading color corrections in parton shower algorithms is, however, technically challenging and remains elusive. In this article, we present an efficient and numericall
We consider the central exclusive production of qq̄ pairs and Higgs boson in proton-proton collisions at LHC. The amplitude for the process is derived within the k -factorization approach and considered in different kinematical asymptotics, in particular, in the important high quark transverse momenta and massless quark limits. Quark helicity and spin-projection amplitudes in two different frames
We report on the status of efforts to improve the reinterpretation of searches and measurements at the LHC in terms of models for new physics, in the context of the LHC Reinterpretation Forum. We detail current experimental offerings in direct searches for new particles, measurements, technical implementations and Open Data, and provide a set of recommendations for further improving the presentati
Radiative lifetimes of 17 excited levels of Nb i, in the energy range 27 400-47 700 cm-1 (5p y 6D degrees(9/2), 5p x 6D degrees(7/2), 5p w 4G degrees(7/2,9/2,11/2), 5s5p v 4D degrees(1/2,3/2,5/2,7/2), 5s6p n 4D degrees(1/2,3/2,5/2,7/2), 5s6p o 4F degrees(3/2,5/2,7/2,9/2)), have been measured. For 15 of these levels, the lifetimes are obtained for the first time. The lifetimes were measured using t
Have you ever wondered what astronomers do?Join us on Astronomy Day and Night as we launch our brand new astronomy podcast; The Meridian. In this first episode of the podcast Nic and Rebecca - a couple of curious and energetic astronomy PhD students - invite Michiel Lambrechts to the mic and chat to him about planet formation. Thereafter they take a closer look at one of their favourite astronomicIn this first episode of the podcast Nic and Rebecca invite Michiel Lambrechts to the mic and chat to him about planet formation. Thereafter they take a closer look at one of their favourite astronomical objects: Le Verrier's planet.
Den tekniska utvecklingen på betalningsmarknaden har resulterat i att bedragare använder alltmer sofistikerade metoder för att lura sina offer på pengar. I Sverige har särskilt bankbedrägerier genom social manipulation ökat de senaste åren. Enligt 5a kap. 1 § betaltjänstlagen bär banken som huvudregel det ekonomiska ansvaret för obehöriga transaktioner. För att bestämmelsen ska vara tillämplig kräTechnological developments in the payment market have resulted in fraudsters using increasingly sophisticated methods to defraud their victims of money. In Sweden, bank fraud through social engineering has increased in recent years. According to Chapter 5a, Section 1 of the Payment Services Act, the bank bears, as a general rule, the financial responsibility for unauthorized transactions. However,
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
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
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
The LHC Higgs data are showing a gradual inclination towards the standard model (SM) result, and realization of a SM-like limit becomes essential for beyond the SM scenarios to survive. Considering the accuracy that can be achieved in future colliders, models beyond the standard model that acquire the alignment limit with a SM-like Higgs boson can surpass others in the long run. Using a convenient
We investigate the possibility of detection of the VHE gamma-ray counterparts to the neutrino astrophysical sources within the Neutrino Target of Opportunity (NToO) program of CTA using the populations simulated by the FIRESONG software to resemble the diffuse astrophysical neutrino flux measured by IceCube. We derive the detection probability for different zenith angles and geomagnetic field conf
An unexpected explanation for neutrino mass, Dark Matter (DM) and Dark Energy (DE) from genuine Quantum Chromodynamics (QCD) of the Standard Model (SM) is proposed here, while the strong CP problem is resolved without any need to account for fundamental axions. We suggest that the neutrino sector can be in a double phase in the Universe: i) relativistic neutrinos, belonging to the SM; ii) non-rela
The NA62 experiment at CERN reports searches for K+→μ+N and K+→μ+νX decays, where N and X are massive invisible particles, using the 2016–2018 data set. The N particle is assumed to be a heavy neutral lepton, and the results are expressed as upper limits of O(10−8) of the neutrino mixing parameter |Uμ4|2 for N masses in the range 200–384 MeV/c2 and lifetime exceeding 50 ns. The X particle is consi
The NA62 experiment at the CERN SPS reports a study of a sample of 4 × 109 tagged π0 mesons from K+ → π+π0(γ), searching for the decay of the π0 to invisible particles. No signal is observed in excess of the expected background fluctuations. An upper limit of 4.4 × 10−9 is set on the branching ratio at 90% confidence level, improving on previous results by a factor of 60. This result can also be i
Over the past years, the LHC experiments have reported experimental evidence for processes associated to photon-photon and photon-hadron interactions, showing their potential to investigate the production of low- and high-mass systems in exclusive events. In the particular case of the photoproduction of vector mesons, the experimental study of this final state is expected to shed light on the desc
A phenomenological study of the isolated photon production in high energy pp and pA collisions at RHIC and LHC energies is performed. Using the color dipole formalism, we investigate the impact of the saturation effects on the production cross sections considering three different phenomenological models for the universal dipole cross section. Predictions for the rapidity dependence of the ratio of
Parton showers are crucial components of high-energy physics calculations. Improving their modelling of QCD is an active research area since shower approximations are stumbling blocks for precision event generators. Naively, the interference between subdominant Standard-Model interactions and QCD can be of similar size to subleading QCD corrections. This article assesses the impact of QCD/QED inte
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
We complete here our work on isospin violation in the K -> 3 pi system. We first calculate K -> 2 pi to the same order as we did K -> 3 pi in papers I and II of this series. This adds the effects of order G(27)p(2)(m(u) - m(d)) and G(27)p(2)e(2) to earlier work. We calculate also the lowest order bremsstrahlung contributions, K -> 2 pi gamma, 3 pi gamma. With these and our earlier results we perfo
