Search results for "Camps"
showing 10 items of 75 documents
Orientational dynamics of fluctuating dipolar particles assembled in a mesoscopic colloidal ribbon
2017
We combine experiments and theory to investigate the dynamics and orientational fluctuations of ferromagnetic microellipsoids that form a ribbonlike structure due to attractive dipolar forces. When assembled in the ribbon, the ellipsoids display orientational thermal fluctuations with an amplitude that can be controlled via application of an in-plane magnetic field. We use video microscopy to investigate the orientational dynamics in real time and space. Theoretical arguments are used to derive an analytical expression that describes how the distribution of the different angular configurations depends on the strength of the applied field. The experimental data are in good agreement with the…
Determining the nuclear neutron distribution from Coherent Elastic neutrino-Nucleus Scattering: current results and future prospects
2020
Coherent Elastic neutrino-Nucleus Scattering (CEνNS), a process recently measured for the first time at ORNL’s Spallation Neutron Source, is directly sensitive to the weak form factor of the nucleus. The European Spallation Source (ESS), presently under construction, will generate the most intense pulsed neutrino flux suitable for the detection of CEνNS. In this paper we quantify its potential to determine the root mean square radius of the point-neutron distribution, for a variety of target nuclei and a suite of detectors. To put our results in context we also derive, for the first time, a constraint on this parameter from the analysis of the energy and timing data of the CsI detector at t…
Search for neutral Higgs bosons decaying into four taus at LEP2
2010
A search for the production and non-standard decay of a Higgs boson, h, into four taus through intermediate pseudoscalars, a, is conducted on 683 pb-1 of data collected by the ALEPH experiment at centre-of-mass energies from 183 to 209 GeV. No excess of events above background is observed, and exclusion limits are placed on the combined production cross section times branching ratio, β2 = σ(e+e -→Zh)/σSM(e+e-→Zh) ×B(h→aa)×B(a→τ+τ-) 2. For mh 1 is excluded at the 95% confidence level.
Tunable chirped fibre Bragg grating device controlled by variable magnetic fields
2002
A novel dynamic chirping fibre Bragg grating device based on a magnetic field applied to a magnetostrictive transducer capable of tuning its dispersion is presented. Chirping ranges up to 300 ps/nm have been demonstrated, which are suitable for several applications such as tunable transversal filtering and dynamic dispersion compensation.
Physics with the KLOE-2 experiment at the upgraded DAFNE
2010
Investigation at a $\phi$--factory can shed light on several debated issues in particle physics. We discuss: i) recent theoretical development and experimental progress in kaon physics relevant for the Standard Model tests in the flavor sector, ii) the sensitivity we can reach in probing CPT and Quantum Mechanics from time evolution of entangled kaon states, iii) the interest for improving on the present measurements of non-leptonic and radiative decays of kaons and eta/eta$^\prime$ mesons, iv) the contribution to understand the nature of light scalar mesons, and v) the opportunity to search for narrow di-lepton resonances suggested by recent models proposing a hidden dark-matter sector. We…
199 Causal Classes of Space-Time Frames
1992
It is shown that from the causal point of view Minkowskian space-time admits 199, and only 199, different classes of frames.
Reply to "Comment on 'Insensitivity of Hawking radiation to an invariant Planck-scale cutoff' "
2010
We clarify the relationship between the conclusions of the previous Comment of A. Helfer and that of our Brief Report.
The effective neutrino charge radius
2003
It is shown that at one-loop order a neutrino charge radius (NCR) may be defined, which is ultraviolet finite, does not depend on the gauge-fixing parameter, nor on properties of the target other than its electric charge. This is accomplished through the systematic decomposition of physical amplitudes into effective self-energies, vertices, and boxes, which separately respect electroweak gauge invariance. In this way the NCR stems solely from an effective proper photon-neutrino one-loop vertex, which satisfies a naive, QED-like Ward identity. The NCR so defined may be extracted from experiment, at least in principle, by expressing a set of experimental electron-neutrino cross-sections in te…
Switching the Magnetic Vortex Core in a Single Nanoparticle.
2016
Imaging and manipulating the spin structure of nano- and mesoscale magnetic systems is a challenging topic in magnetism, yielding a wide range of spin phenomena such as skyrmions, hedgehog-like spin structures, or vortices. A key example has been provided by the vortex spin texture, which can be addressed in four independent states of magnetization, enabling the development of multibit magnetic storage media. Most of the works devoted to the study of the magnetization reversal mechanisms of the magnetic vortices have been focused on micrometer-size magnetic platelets. Here we report the experimental observation of the vortex state formation and annihilation in individual 25 nm molecular-bas…
Bounding effective operators at the one-loop level: the case of four-fermion neutrino interactions
1994
The contributions of non-standard four-neutrino contact interactions to electroweak observables are considered at the one-loop level by using the effective quantum field theory. The analysis is done in terms of three unknown parameters: the strength of the non-standard neutrino interactions, $\tilde{F}$, an additional derivative coupling needed to renormalize the divergent contributions that appear when the four-neutrino interactions are used at the loop level and a non-standard non-derivative $Z$-${\bar\nu} \nu$ coupling. Then, the precise measurements of the invisible width of the $Z$-boson at LEP and the data on the neutrino deep-inelastic scattering yield the result $\tilde{F} = (-100 \…