Search

We show that off-mass-shell effects arising from the internal structure of the proton provide a new proton polarization mechanism in the Lamb shift, proportional to the lepton mass to the fourth power. This effect is capable of resolving the current puzzle regarding the difference in the proton radius extracted from muonic compared with electronic hydrogen experiments. These off-mass-shell effects could be probed in several other experiments. A significant ambiguity appearing in dispersion relation evaluations of the proton polarizability contribution to the Lamb shift is noted.

Discussing the limitations on the validity of classical electrodynamics, we show that present day laser pulse technology applied to head-on-collisions with relativistic electrons generates fields strong enough to permit experimentation at the limits of validity of the Lorentz force, and the development of experimental tests of Mach's principle. We also discuss more distant opportunities for exploring the nature of laws of physics and the vacuum structure. We then conclude that the predictions of quantum electrodynamics in the presence of critical fields are not completely satisfactory and argue that the study of Laser materialization into particle pairs opens a new domain of quantum electrodynamics., Comment: 15 pages, to Appear in AIP proceedings of "Light at Extreme Intensities" (LEI 2009) meeting, held October 16-21, 2009 in Brasov

We use the statistical hadronization model (SHM) to describe hadron multiplicity yields and fluctuations. We consider 200 GeV Au-Au collisions, and show that both event averaged yields of stable particles and resonances, and event-by-event fluctuation of the $K/\pi$ ratio can be described within the SHM using the same set of thermal parameters, provided that the phase space occupancy parameter value is significantly above chemical equilibrium, and the freeze-out temperature is $\sim 140$ MeV. We present predictions that allow to test the consistency of our results., Comment: Proceedings for ISMD2005, Kromeriz, Czech republic

We discuss experimental features of identified particle production from nucleus-nucleus collisions. These features reflect hadronization from a deconfined partonic matter whose particle formation scheme is distinctly different from fragmentation phenomenology in elementary collisions. Multi-parton dynamics, such as quark coalescences or recombinations, appear to be essential to explain the experimental measurements at the intermediate transverse momentum of 2--5 GeV/c. Constituent quarks seem to be the dominant degrees of freedom at hadronization. Heavy quark production should help quantify deconfined matter properties., 18 pages, This report constitutes the combined contribution of the authors to the "VI Quark Confinement and the Hadron Spectrum" conference, held 21--25 September 2004 in Sardinia, Italy covering their oral presentations and the `Deconfinement' discussion session; proceedings to be published by the American Institute of Physics

We study as function of energy strangeness created in relativistic heavy ion collisions. We consider statistical hadronization with chemical freeze-out in both equilibrium and nonequilibrium. We obtain strangeness per baryon and per entropy in the energy range $8.75\lessim\sqrt{s_{NN}}\lessim 200 A$ GeV. A baryon density independent evaluation of the kaon to pion ratio is presented., 4 pages including one table and 4 figures; Stylistic changes, Improved figures, updated refernces

In order to recognize the new form of matter created at RHIC and SPS as the deconfined quark‐gluon plasma state (QGP), we need to understand the expected properties of this phase near to the conditions of its formation and disintegration. Thus, we first develop a model of QGP considering the constrains arising from QCD properties and lattice results, and explore its properties. In the second part, we describe the kinetic theory of strangeness production in the QGP phase. We show that gluon fusion dominate and evaluate the degree of equilibration expected at RHIC.

We argue for the applicability of the thermal model in the analysis of strange particle production in relativistic A‐A collisions. We describe the observable parameters in strange particle abundances, and discuss recent results, which point towards a deconfined QGP source of strange particles.

In this lecture we will study how the strange particle abundance in the final state is related to the conditions prevailing in the early moments of nuclear collisions. To do that we develop, within the thermal model, an approach that can describe these initial conditions. We compare the results we obtain with those derived for the S → W/Pb at SPS‐CERN and Au–Au interactions at AGS‐BNL, and we give our expectation regarding the abundance of strange antibaryons produced in the Pb–Pb collisions.

The non‐equilibrated dynamics of clustered qq‐pairs in the quark‐gluon plasma (QGP) near the hadronic gas (HG) state can introduce an asymmetry among the abundances of final‐state pions such that √〈π+〉〈π−〉 ≠ 〈π0〉.

Predictions suggesting that strange antibaryons are characteristic and descriptive signals of quark gluon plasma formation are confronted with recent experimental findings. A quantitative comparison between theory and experiment is presented.

We study nuclear fusion occurring according to conventional wisdom in the planet Jupiter. In particular, we consider if in a standard evolutionary model of Jupiter a significant part of Jupiter’s luminosity has been due to nuclear fusion at any time during its evolution. Nuclear rate equations in dense matter allowing for screening and pressure effects have been integrated in time.

We study the d‐d nuclear reaction cross section in a multi channel approach. An extrapolation of the existing cross sections to zero d‐d energy by means of a dynamical three channel model is given. In particular the correct velocity behavior at low energies is obtained for the Debye screened d‐d Coulomb interaction. We consider the d‐d threshold resonances.

We investigate the molecular processes involved in the muon catalysis of hydrogen isotope fusion with light nuclei Z≳1. We examine in some detail the expected fusion rates in (HZμ) molecules, and find the fusion rates to be significantly higher than previous estimates.

This is a survey of new and significant developments which promise to shape the future of muon catalyzed fusion, based on presentations made at the 1988 MuCF workshop. The new ideas about muon production, muon sticking, regeneration and the muomolecular reactions represent steady progress towards understanding of the basic physics of MuCF and reaching towards 1,000 fusions per muon. I will attempt to elucidates the progress made in the theory of MuCF and to illustrate the practical importance of some of the issues raised. In many instances I will follow my personal viewpoint, justifying as much as possible the reasons behind my judgement.

We study in turn the quantum theories of an otherwise free electron‐positron field and of a charged pion field in the presence of the electrostatic field of an extended charge distribution of arbitrary strength. In both instances, the standard quantization fails because of an instability of the vacuum as it is usually defined. The character of the instability, different in each case, is analyzed, and it is shown how a consistent quantization can be carried out. The possible observation of the instabilities, which appears feasible for the electron‐positron field, is discussed.

The properties of quark gluon plasma fireballs created in central inelastic interactions of high energy Oxygen and Sulphur nuclei are determined within a simple reaction model, and the expected rapidity distributions of strange baryons and antibaryons are given.

Annihilation of antiprotons on nuclei is capable to create highly excited states of nuclear matter. Conventional interpretation of recent data on strange particle production in 4 GeV/c antiproton annihilations on Ta has not been able to account for the high observed production of strangeness, and in particular the lambda particles. However, assuming quark gluon plasma formation at rather modest temperature T