Search results for "Satu"
showing 10 items of 1367 documents
Rapidity dependence of particle production in ultrarelativistic nuclear collisions
2002
We compute the rapidity dependence of particle and transverse energy production in ultrarelativistic heavy ion collisions at various beam energies and atomic numbers using the perturbative QCD + saturation model. The distribution is a broad gaussian near $y=0$ but the rapid increase of particle production with the beam energy will via energy conservation strongly constrain the rapidity distribution at large $y$.
A Temperature Dependent Non-Linear Inductor Model for a DC/DC Boost Converter
2018
This paper is focused on the use of non-linear inductors in DC/DC switching converters, as well as their behaviour due to changes in current and temperature. The model of an inductor is set up on the basis of experimental data, which are automatically acquired by a virtual instrument; from those data, a polynomial curve describing the inductance variations is obtained. The analysis of the converter, performed by including the proposed model, is validated by experimental tests.
Evidence of shadowing in inelastic nucleon-nucleon cross section
2021
The Glauber modeling plays a key role in centrality-dependent measurements of heavy-ion collisions. A central input parameter in Glauber models is the inelastic nucleon-nucleon cross section $\sigma_{\text{nn}}^{\text{inel}}$ which is nearly always taken from proton-proton measurements. At the LHC energies $\sigma_{\text{nn}}^{\text{inel}}$ depends on the QCD dynamics at small $x$ and low interaction scales where the shadowing/saturation phenomena are expected to become relatively more important for larger nuclei than for the proton. Thus, $\sigma_{\text{nn}}^{\text{inel}}$ e.g. in Pb+Pb collisions may well be lower than what is seen in proton-proton collisions. In this talk, we demonstrate…
The electromagnetic mass difference of pions from asymptotic QCD
1983
We show how the asymptotic behaviour of an analytic amplitude can yield information on the amplitude at small space-like momenta. Applying this to QCD two-point functions, we are able to obtain low energy parameters without using resonance saturation. In the special case considered here, we have calculated the electromagnetic mass difference of pions using only the asymptotic QCD amplitude. The result, in very good agreement with experiment is\(\Delta m_\pi = 5.3 \pm 1.5MeV.\)
Taming the higher power corrections in semileptonic B decays
2016
We study the effect of dimension 7 and 8 operators on inclusive semileptonic B decays and the extraction of |Vcb|. Using moments of semileptonic B decay spectra and information based on the Lowest-Lying State saturation Approximation (LLSA) we perform a global fit of the nonperturbative parameters of the heavy quark expansion including for the first time the O(1/mb^{4,5}) contributions. Higher power corrections appear to have a very small effect on the extraction of |Vcb|, independently of the weight we attribute to the LLSA.
Semi-global simulations of the magneto-rotational instability in core collapse supernovae
2009
Possible effects of magnetic fields in core collapse supernovae rely on an efficient amplification of the weak pre-collapse fields. It has been suggested that the magneto-rotational instability (MRI) leads to rapid field growth. Although MRI studies exist for accretion discs, the application of their results to core collapse supernovae is inhibited as the physics of supernova cores is substantially different from that of accretion discs. We address the problem of growth and saturation of the MRI by means of semi-global simulations, which combine elements of global and local simulations by taking the presence of global background gradients into account and using a local computational grid. W…
X-ray rotational modulation of a supersaturated star in IC 2391
2003
We present evidence of X-ray rotational modulation on VXR45, a young fast rotator star, member of IC 2391. It is a dG9 spectral type star whose rotational period and X-ray luminosity make it a supersaturated star. Our X-ray observation, made with EPIC/PN on XMM-Newton, covers about two photometric rotational periods. The detection of rotational modulation implies the presence of structural inhomogeneities. Possible interpretations are presented and discussed.
Formation Conditions of Titan's and Enceladus's Building Blocks in Saturn's Circumplanetary Disk
2021
Abstract The building blocks of Titan and Enceladus are believed to have formed in a late-stage circumplanetary disk (CPD) around Saturn. Evaluating the evolution of the abundances of volatile species in this disk as a function of the migration, growth, and evaporation of icy grains is then of primary importance to assess the origin of the material that eventually formed these two moons. Here we use a simple prescription of Saturn’s CPD in which the location of the centrifugal radius is varied, to investigate the time evolution of the icelines of water ice, ammonia hydrate, methane clathrate, carbon monoxide, and dinitrogen pure condensates. To match their compositional data, the building b…
Inverse amplitude method in pi pi scattering in chiral perturbation theory to two loops
2002
The inverse amplitude method is used to unitarize the two loop $\pi\pi$ scattering amplitudes of SU(2) Chiral Perturbation Theory in the $I=0,J=0$, $I=1,J=1$ and $I=2,J=0$ channels. An error analysis in terms of the low energy one-loop parameters $\bar l_{1,2,3,4,}$ and existing experimental data is undertaken. A comparison to standard resonance saturation values for the two loop coefficients $\bar b_{1,2,3,4,5,6} $ is also carried out. Crossing violations are quantified and the convergence of the expansion is discussed.
Double modulation sideband spectroscopy: μ0, μ24, and μ44 of 28SiH4
1992
Abstract The linear Stark effect within the ν 2 ν 4 dyad of the main isotopomer of silane, 28 SiH 4 , has been investigated by applying the saturation technique as well as IR-IR double resonance. From 35 transitions, two vibration-induced dipole moment parameters and the centrifugal distortion moment have been determined as μ 0 = 1.357(12) × 10 −5 D, μ 24 = 2.391(31) × 10 −2 D, and μ 44 = −1.261(17) × 10 −2 D employing the Stark coefficients calculated by the procedure of Loete.