Nanoparticles magnetization switching by Surface Acoustic Waves

Treballs Finals de Grau de Física, Facultat de Física, Universitat de Barcelona, Curs: 2016, Tutor: Javier Tejada PalaciosIn this project we present a simulation which allows the prediction of the spin-phonon interaction in magnetic nanoparticle samples. The study of new techniques to manipulate the magnetic moment of nanostructures are being increasingly demanded [1{5]. For this purpose, surface acoustic waves (SAWs) are excellent candidates since they offer a dynamic and tuneable mechanism for the control of low energy excitations. The goal of the project is to better understand the mechanism of magnetization switching produced by SAWs, developing a numerical solution of the theoretical model previously proposed by Professor Eugene M. Chudnovsky [6]. We have developed our theoretical calculations used to predict the magnetization jump dependency on different parameters such as system temperature, SAWs power and frequency and sample magnetic properties. Some of these dependencies have been experimentally verified using a Superconducting Quantum Interference Device magnetometer (SQUID) at the Laboratory of Magnetism and Superconductivity of the University of Barcelon

Exotic hadrons in the Λb → J/Ψ φ Λ decay

We study the weak decay of the Λb baryon into J/ψϕΛ, a process that is particularly well suited to analyze the physics of some of the recently observed or theoretically predicted exotic hadrons, as one expects to see their signature in all three final two-body channels. In the J/ψϕ invariant mass spectrum we study the interplay between the X(4140) and the X(4160) resonances. The J/ψΛ mass spectrum may help to identify the strange partner of the hidden-charm pentaquark recently observed by the LHCb collaboration, the existence of which has been predicted by a chiral unitary approach. We conclude that this strange pentaquark has a good chance of experimental detection if it is present in the range between 4450-4500 MeV. Finally, in the ϕΛ spectrum we expect a contribution from a dynamically generated resonance at around 2160 MeV, but with the present model parameters there is little chance for its experimental detection

AGKY Hadronization Model Tuning in GENIE v3

The GENIE neutrino Monte Carlo describes neutrino-induced hadronization with an effective model, known as AGKY, which is interfaced with PYTHIA at high invariant mass. Only the low-mass AGKY model parameters were extracted from hadronic shower data from the FNAL 15 ft and BEBC experiments. In this paper, the first hadronization tune on averaged charged multiplicity data from deuterium and hydrogen bubble chamber experiments is presented, with a complete estimation of parameter uncertainties. A partial tune on deuterium data only highlights the tensions between hydrogen and deuterium datasets

Neutrino-nucleon cross-section model tuning in GENIE v3

We summarize the results of a study performed within the GENIE global analysis framework, revisiting the GENIE bare-nucleon cross-section tuning and, in particular, the tuning of (a) the inclusive cross section, (b) the cross section of low-multiplicity inelastic channels (single-pion and double-pion production), and (c) the relative contributions of resonance and nonresonance processes to these final states. The same analysis was performed with several different comprehensive cross-section model sets available in GENIE Generator v3. In this work we perform a careful investigation of the observed tensions between exclusive and inclusive data, and install analysis improvements to handle systematics in historic data. All tuned model configurations discussed in this paper are available through public releases of the GENIE Generator. With this paper we aim to support the consumers of these physics tunes by providing comprehensive summaries of our alternate model constructions, of the relevant datasets and their systematics, and of our tuning procedure and results

Neutrino-nucleus CC0π\mathrm{CC}0{\pi} cross-section tuning in GENIE v3

International audienceThis article summarizes the state of the art of νμ and ν¯μ CC0π cross-section measurements on carbon and argon and discusses the relevant nuclear models, parametrizations and uncertainties in GENIE v3. The CC0π event topology is common in experiments at a few-GeV energy range. Although its main contribution comes from quasielastic interactions, this topology is still not well understood. The GENIE global analysis framework is exploited to analyze CC0π datasets from MiniBooNE, T2K and MINERνA. A partial tune for each experiment is performed, providing a common base for the discussion of tensions between datasets. The results offer an improved description of nuclear CC0π datasets as well as data-driven uncertainties for each experiment. This work is a step towards a GENIE global tune that improves our understanding of neutrino interactions on nuclei. It follows from earlier GENIE work on the analysis of neutrino scattering datasets on hydrogen and deuterium

First combined tuning on transverse kinematic imbalance data with and without pion production constraints

International audienceWe present the first global tuning, using GENIE, of four transverse kinematic imbalance measurements of neutrino-hydrocarbon scattering, both with and without pion final states, from the T2K and MINERvA experiments. As a proof of concept, we have simultaneously tuned the initial state and final-state interaction models (SF-LFG and hA, respectively), producing a new effective theory that more accurately describes the data

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved