Search results for "Satu"
showing 10 items of 1367 documents
From minijet saturation to global observables in A + A collisions at the LHC and RHIC
2014
We review the recent results from the computation of saturated next-to-leading order perturbative QCD minijet intial conditions combined with viscous hydrodynamical evolution of ultrarelativistic heavy-ion collisions at the LHC and RHIC. Comparison with experimental data is shown.
Understanding saturation and AA collisions with an eA collider
2009
The initial conditions in high energy nucleus-nucleus collisions are determined by the small momentum fraction part of the nuclear wavefunction. This is the regime of gluon saturation and the most direct way to experimentally study it would be deep inelastic scattering at a high energy electron ion collider (EIC). This talk discusses some of the connections between physics at the EIC and the initial stage of relativistic heavy ion collisions. We argue that measurements at an EIC will provide detailed high-precision information about the parameters for the initial conditions, transverse geometry and longitudinal correlations that will be crucial in understanding the initial stage of a heavy …
Measurement of the response of Silicon Photomultipliers from single photon detection to saturation
2019
Abstract The development of Silicon Photomultipliers (SiPM) is very dynamic and a large variety of types exists. Important SiPM characteristics include the size and number of pixels, the gain, the photon detection efficiency (PDE), the recovery time, and correlated noise. SiPMs are particularly suitable for single-photon detection and low-intensity exposures. For photon numbers (PDE corrected) reaching the number of pixels, however, the sensors saturate. In this work, we present comprehensive response measurements for state-of-the-art SiPMs using an experimental setup based on a tunable picosecond laser. Several models are applied to the measured response curves, taking particularly correla…
Direct measurements of the lifetime of medium-heavy hypernuclei
2018
Abstract The lifetime of a Λ particle embedded in a nucleus (hypernucleus) decreases from that of free Λ decay mainly due to the opening of the Λ N → N N weak decay channel. However, it is generally believed that the lifetime of a hypernucleus attains a constant value (saturation) for medium to heavy hypernuclear masses, yet this hypothesis has been difficult to verify. This paper presents a direct measurement of the lifetime of medium-heavy hypernuclei that were hyper-fragments produced by fission or break-up from heavy hypernuclei initially produced with a 2.34 GeV photon-beam incident on thin Fe, Cu, Ag, and Bi target foils. For each event, fragments were detected in coincident pairs by …
Continued fraction approximation for the nuclear matter response function
2008
A continued fraction approximation is used to calculate the Random Phase Approximation (RPA) response function of nuclear matter. The convergence of the approximation is assessed by comparing it with the numerically exact response function obtained with a typical effective finite-range interaction used in nuclear physics. It is shown that just the first order term of the expansion can give reliable results at densities up to the saturation density value.
Instabilities of infinite matter with effective Skyrme-type interactions
2002
The stability of the equation of state predicted by Skyrme-type interactions is examined. We consider simultaneously symmetric nuclear matter and pure neutron matter. The stability is defined by the inequalities that the Landau parameters must satisfy simultaneously. A systematic study is carried out to define interaction parameter domains where the inequalities are fulfilled. It is found that there is always a critical density $\rho_{cr}$ beyond which the system becomes unstable. The results indicate in which parameter regions one can find effective forces to describe correctly finite nuclei and give at the same time a stable equation of state up to densities of 3-4 times the saturation de…
Out-of-plane emission of nuclear matter in Au+Au collisions between 100 and 800 AMeV
1997
We present new experimental results concerning the azimuthal distributions of proton-likes, light and intermediate mass fragments at midrapidity for Au(100-800 AMeV)+Au collisions measured with the FOPI phase-I detector at GSI in Darmstadt. The azimuthal distributions are investigated as a function of the collision centrality, the incident energy, the fragment charge and transverse momentum. The azimuthal anisotropy is maximum for impact parameters around 7 fm. Intermediate mass fragments present a stronger out-of-plane emission signal than light fragments and a saturation is reached for Z greater than or equal to 4. The azimuthal anisotropy increases with the fragment transverse momentum a…
Frequency Deviation Due to a Sample Insertion Hole in a Cylindrical Cavity by Circuital Analysis
2007
One of the most widely used techniques for dielectric material characterization is the partially filled circular cavity. The exact analysis of this structure is well known in the bibliography. But in practice when the measured material is introduced through a circular pipe below its cut off frequency a problem arises. Traditionally the tube effect is neglected, but then some errors appear, whose magnitude depends on the material properties and the cavity and tube dimensions. In some cases, the errors introduced are noticeable and the tube effect should not be neglected. Some authors have tried to evaluate in a simple way this effect, but their equations are valid only in a restricted range …
Control of field-free molecular alignment by phase-shaped laser pulses
2005
We report an experimental study of the control of molecular alignment of ${\mathrm{N}}_{2}$ by use of spectrally modulated pulses at an intensity regime below the intrinsic saturation of the alignment. By manipulating the relative timing of the alignment revival pattern arising from the even subset of the thermal ensemble as compared to the odd subset, we demonstrate that the angular distribution of the aligned molecule can be converted into planar delocalization at specific times. We also show that the angular focusing of the molecular axis can be switched off by applying a specific bipulse.
Chiral approach to antikaons in dense matter
2008
Antikaons in dense nuclear matter are studied using a chiral unitary approach which incorporates the s- and p-waves of the \( \bar K \) N interaction. We include, in a self-consistent way, Pauli blocking effects, meson self-energies modified by nuclear short-range correlations and baryon binding potentials. We show that the on-shell factorization cannot be applied to evaluate the in-medium corrections to p-wave amplitudes. We also obtain an attractive shift for the Λ and Σ masses of −30 MeV at saturation density while the Σ* width gets sensibly increased to about 80 MeV. The moderate attraction developed by the antikaon does not support the existence of very deep and narrow bound states.