Search results for "ddc:5"
showing 10 items of 1717 documents
Dynamics of an unbalanced two-ion crystal in a Penning trap for application in optical mass spectrometry
2019
In this article, the dynamics of an unbalanced two-ion crystal comprising the 'target' and the 'sensor' ions confined in a Penning trap has been studied. First, the low amplitude regime is addressed. In this regime, the overall potential including the Coulomb repulsion between the ions can be considered harmonic and the axial, magnetron and reduced-cyclotron modes split up into the so-called 'stretch' and 'common' modes, that are generalizations of the well-known 'breathing' and 'center-of-mass' motions of a balanced crystal made of two ions. By measuring the frequency modes of the crystal and the sensor ion eigenfrequencies using optical detection, it will be possible to determine the targ…
Surpassing the Energy Resolution Limit with Ferromagnetic Torque Sensors
2021
We discuss the fundamental noise limitations of a ferromagnetic torque sensor based on a levitated magnet in the tipping regime. We evaluate the optimal magnetic field resolution taking into account the thermomechanical noise and the mechanical detection noise at the standard quantum limit (SQL). We find that the Energy Resolution Limit (ERL), pointed out in recent literature as a relevant benchmark for most classes of magnetometers, can be surpassed by many orders of magnitude. Moreover, similarly to the case of a ferromagnetic gyroscope, it is also possible to surpass the standard quantum limit for magnetometry with independent spins, arising from spin-projection noise. Our finding indica…
Stern-Gerlach splitting of low-energy ion beams
2019
We present a feasibility study with several magnetic field configurations for creating spin-dependent forces that can split a low-energy ion beam by the Stern-Gerlach effect. To the best of our knowledge, coherent spin-splittings of charged particles have yet to be realised. Our proposal is based on ion source parameters taken from a recent experiment that demonstrated single-ion implantation from a high-brightness ion source combined with a radio-frequency Paul trap. The inhomogeneous magnetic fields can be created by permanently magnetised microstructures or from current-carrying wires with sizes in the micron range, such as those recently used in a successful implementation of the Stern-…
A relation between screening masses and real-time rates
2014
Thermal screening masses related to the conserved vector current are determined for the case that the current carries a non-zero Matsubara frequency, both in a weak-coupling approach and through lattice QCD. We point out that such screening masses are sensitive to the same infrared physics as light-cone real-time rates. In particular, on the perturbative side, the inhomogeneous Schrodinger equation determining screening correlators is shown to have the same general form as the equation implementing LPM resummation for the soft-dilepton and photon production rates from a hot QCD plasma. The static potential appearing in the equation is identical to that whose soft part has been determined up…
Identifying spin and parity of charmonia in flight with lattice QCD
2019
The spectrum of charmonium resonances contains a number of unanticipated states along with several conventional quark-model excitations. The hadrons of different quantum numbers $J^P$ appear in a fairly narrow energy band, where $J^P$ refers to the spin-parity of a hadron at rest. This poses a challenge for Lattice QCD studies of (coupled-channel) meson-meson scattering aimed at the determination of scattering amplitudes and resonance pole positions. A wealth of information for this purpose can be obtained from the lattice spectra in frames with nonzero total momentum. These are particularly dense since hadrons with different $J^P$ contribute to any given lattice irreducible representation.…
Measurement of the top quark mass in the dilepton channel using mT2 at CDF
2010
We present measurements of the top quark mass using mT2, a variable related to the transverse mass in events with two missing particles. We use the template method applied to tt̅ dilepton events produced in pp̅ collisions at Fermilab’s Tevatron Collider and collected by the CDF detector. From a data sample corresponding to an integrated luminosity of 3.4 fb-1, we select 236 tt̅ candidate events. Using the mT2 distribution, we measure the top quark mass to be Mtop=168.0-4.0+4.8(stat)±2.9(syst) GeV/c2. By combining mT2 with the reconstructed top quark mass distributions based on a neutrino weighting method, we measure Mtop=169.3±2.7(stat)±3.2(syst) GeV/c2. This is the first application of …
Resonances in QCD
2015
We report on the EMMI Rapid Reaction Task Force meeting 'Resonances in QCD', which took place at GSI October 12-14, 2015. A group of 26 people met to discuss the physics of resonances in QCD. The aim of the meeting was defined by the following three key questions: What is needed to understand the physics of resonances in QCD? Where does QCD lead us to expect resonances with exotic quantum numbers? What experimental efforts are required to arrive at a coherent picture? For light mesons and baryons only those with ${\it up}$, ${\it down}$ and ${\it strange}$ quark content were considered. For heavy-light and heavy-heavy meson systems, those with ${\it charm}$ quarks were the focus. This docum…
Axion quark nuggets and how a global network can discover them
2020
We advocate an idea that the presence of the daily and annual modulations of the axion flux on the Earth surface may dramatically change the strategy of the axion searches. Our computations are based on the so-called Axion Quark Nugget (AQN) dark matter model which was originally put forward to explain the similarity of the dark and visible cosmological matter densities $\Omega_{\rm dark}\sim \Omega_{\rm visible}$. In our framework, the population of galactic axions with mass $ 10^{-6} {\rm eV}\lesssim m_a\lesssim 10^{-3}{\rm eV}$ and velocity $\sim 10^{-3} c$ will be always accompanied by the axions with typical velocities $\sim 0.6 c$ emitted by AQNs. We formulate the broadband detection …
Study of the $^{15}$O(2p, γ )$^{17}$Ne cross section by Coulomb dissociation of $^{17}$Ne for the rp process of nucleosynthesis
2014
Acta physica Polonica / B 45(2), 229 - 234 (2014). doi:10.5506/APhysPolB.45.229
Production of Exotic Nuclei via MNT Reactions Using Gas Cells
2020
The use of multi-nucleon transfer (MNT) reactions to produce neutron-rich nuclei in the heavy region has received an increased attention in the last decade. The feasibility of employing such reactions at the FRS Ion Catcher facility at GSI and the IGISOL facility at JYFL is studied using a combination of theoretical calculations and experiment simulations. The reactions are computed within a Langevin-type model, and the Geant program is used to simulate the transport of the resulting products within the experimental setups of the above-mentioned facilities. The angular distribution of ion release, possible target choices and target-to-beam-dump distances are discussed. peerReviewed