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In the framework of the relativistic quantum dynamics approach we investigate antiproton observables in Au-Au collisions at 10.7A GeV. The rapidity dependence of the in-plane directed transverse momentum p(y) of p's shows the opposite sigh of the nucleon flow, which has indeed recently been discovered at 10.7A GeV by the E877 group. The "antiflow" of p's is also predicted at 2A GeV and at 160 A GeV and appears at all energies also for pi's and K's. These predicted p anticorrelations are a direct proof of strong p annihilation in massive heavy ion reactions.
We study the time scale for pressure equilibration in heavy ion collisions at AGS energies within the three-fluid hydrodynamical model and a microscopic cascade model (UrQMD). We find that kinetic equilibrium is reached in both models after a time of 5 fm/c (center-of-mass time). Thus, observables which are sensitive to the early stage of the reaction differ considerably from the expectations within the instant thermalization scenario (one-fluid hydrodynamical model).
Abstract: We study transverse expansion and directed flow in Au(11AGeV)Au reactions within a multi-fluid dynamical model. Although we do not employ an equation of state (EoS) with a first order phase transition, we find a slow increase of the transverse velocities of the nucleons with time. A similar behaviour can be observed for the directed nucleon flow. This is due to non-equilibrium e ects which also lead to less and slower conversion of longitudinal into transverse momentum. We also show that the proton rapidity distribution at CERN energies, as calculated within this model, agrees well with the preliminary NA44-data.
The study of (anti-)deuteron production in pp collisions has proven to be a powerful tool to investigate the formation mechanism of loosely bound states in high-energy hadronic collisions. In this paper the production of (anti-)deuterons is studied as a function of the charged particle multiplicity in inelastic pp collisions at s√=13 TeV using the ALICE experiment. Thanks to the large number of accumulated minimum bias events, it has been possible to measure (anti-)deuteron production in pp collisions up to the same charged particle multiplicity (dNch/dη∼26) as measured in p–Pb collisions at similar centre-of-mass energies. Within the uncertainties, the deuteron yield in pp collisions resembles the one in p–Pb interactions, suggesting a common formation mechanism behind the production of light nuclei in hadronic interactions. In this context the measurements are compared with the expectations of coalescence and statistical hadronisation models (SHM).
The study of (anti-)deuteron production in pp collisions has proven to be a powerful tool to investigate the formation mechanism of loosely bound states in high energy hadronic collisions. In this paper the production of (anti-)deuterons is studied as a function of the charged particle multiplicity in inelastic pp collisions at s√=13 TeV using the ALICE experiment. Thanks to the large accumulated integrated luminosity, it has been possible to measure (anti-)deuteron production in pp collisions up to the same charged particle multiplicity (dNch/dη∼26) as measured in p-Pb collisions at similar centre-of-mass energies. Within the uncertainties, the deuteron yield in pp collisions resembles the one in p-Pb interactions, suggesting a common formation mechanism behind the production of light nuclei in hadronic interactions. In this context the measurements are compared with the expectations of coalescence and Statistical Hadronisation Models (SHM).
The study of (anti-)deuteron production in pp collisions has proven to be a powerful tool to investigate the formation mechanism of loosely bound states in high energy hadronic collisions. In this paper the production of (anti-)deuterons is studied as a function of the charged particle multiplicity in inelastic pp collisions at s√=13 TeV using the ALICE experiment. Thanks to the large number of accumulated minimum bias events, it has been possible to measure (anti-)deuteron production in pp collisions up to the same charged particle multiplicity (dNch/dη∼26) as measured in p-Pb collisions at similar centre-of-mass energies. Within the uncertainties, the deuteron yield in pp collisions resembles the one in p-Pb interactions, suggesting a common formation mechanism behind the production of light nuclei in hadronic interactions. In this context the measurements are compared with the expectations of coalescence and Statistical Hadronisation Models (SHM).
The ALICE detector is ideally suited to study the production of anti- and hyper-matter due to its excellent particle identification capabilities. The measurement of the He¯4-nucleus in Pb–Pb collisons at sNN=2.76TeV is presented. We further show the performance for the reconstruction of the (anti-)hypertriton in the decay to He3+π− (He¯3+π+). In addition to this, two searches have been performed, one for the H-Dibaryon →Λpπ− and one for the Λn bound state (Λn¯→d¯π+). No signals are observed for these exotic states and upper limits have been determined.
We discuss deviations from the exponential decay law which occur when going beyond the BreitWigner distribution for an unstable state. In particular, we concentrate on an oscillating behavior, remisiscent of the Rabi-oscillations, in the short-time region. We propose that these oscillations can explain the socalled GSI anomaly, which measured superimposed oscillations on top of the exponential law for hydrogen-like nuclides decaying via electron-capture. Moreover, we discuss the possibility that the deviations from the Breit-Wigner in the case of the GSI anomaly are (predominantely) caused by the interaction of the unstable state with the measurement apparatus. The consequences of this scenario, such as the non-observation of oscillations in an analogous experiment perfromed at Berkley, are investigated.
We make predictions for the kaon interferometry measurements in Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC). A first order phase transition from a thermalized Quark-Gluon-Plasma (QGP) to a gas of hadrons is assumed for the transport calculations. The fraction of kaons that are directly emitted from the phase boundary is considerably enhanced at large transverse momenta K T ~ 1 GeV/c. In this kinematic region, the sensitivity of the R out/R side ratio to the QGP-properties is enlarged. Here, the results of the 1-dimensional correlation analysis are presented. The extracted interferometry radii, depending on K-Theta, are not unusually large and are strongly affected by momentum resolution effects.
11 262 keV 1+ state in 20Ne
(1983)
The excitation energy of the lowest 1+, T=1 state in 20Ne, which is important for parity nonconservation studies, has been determined in a photon scattering experiment to be 11 262.3 ± 1.9 keV. Values for the gamma -ray branching of this level to the ground state and to the first 2+ level in 20Ne are 84 ± 5% and 16 ± 5%, respectively. NUCLEAR REACTIONS 20Ne( gamma , gamma ), E gamma <18 MeV, bremsstrahlung; measured E gamma , gamma branching. Ne natural targets.