A Multi-Phase Transport Model for Relativistic Heavy Ion Collisions

We describe in detail how the different components of a multi-phase transport (AMPT) model, that uses the Heavy Ion Jet Interaction Generator (HIJING) for generating the initial conditions, Zhang's Parton Cascade (ZPC) for modeling partonic scatterings, the Lund string fragmentation model or a quark coalescence model for hadronization, and A Relativistic Transport (ART) model for treating hadronic scatterings, are improved and combined to give a coherent description of the dynamics of relativistic heavy ion collisions. We also explain the way parameters in the model are determined, and discuss the sensitivity of predicted results to physical input in the model. Comparisons of these results to experimental data, mainly from heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC), are then made in order to extract information on the properties of the hot dense matter formed in these collisions.Comment: 33 pages, 38 figures, revtex. Added 9 figures, version published in Phys. Rev. C. The full source code of the AMPT model in the Fortran 77 language and instructions for users are available from the EPAPS ftp site (ftp://ftp.aip.org/epaps/phys_rev_c/E-PRVCAN-72-781512/) and the OSCAR website (http://www-cunuke.phys.columbia.edu/OSCAR/

Nothing but Relativity, Redux

Here we show how spacetime transformations consistent with the principle of relativity can be derived without an explicit assumption of the constancy of the speed of light, without gedanken experiments involving light rays, and without an assumption of differentiability, or even continuity, for the spacetime mapping. Hence, these historic results could have been derived centuries ago, even before the advent of calculus. This raises an interesting question: Could Galileo have derived Einsteinian relativity

A tapered multi-gap multi-aperture pseudospark-sourced electron gun based X-band slow wave oscillator

The experimental study of a tapered, multi-gap, multi-aperture pseudospark-sourced electron gun based X-band plasma assisted slow wave oscillator is presented. The designed electron gun is based on the pseudospark discharge concept and has been used to generate a high current density and high energy electron beam simultaneously. The distribution of apertures has been arranged such that the field penetration potency inside the backspace of the hollow-cathode is different while passing through the tapered gap region. This leads to non-concurrent ignition of the discharge through all the channels which is, in general, quite challenging in the case of multi-aperture plasma cathode electron gun geometries. Multiple and successive hollow cathode phases are reported from this electron gun geometry, which have been confirmed using simulations. This geometry also has led to the achievement of ∼71% fill factor inside the slow wave oscillator for an electron beam of energy of 20 keV and a beam current density in the range of 115-190 A/cm2 at a working argon gas pressure of 18 Pa. The oscillator has generated broadband microwave output in the frequency range of 10-11.7 GHz with a peak power of ∼10 kW for ∼50 ns

CASE STUDY ON BETA BLOCKERS INDUCED PSORIASIS

Drug-induced Psoriasis is one among the common etiological factors of Psoriasis reported worldwide. Familiar drugs known to cause psoriasiform eruptions include Anti-malarials, Beta blockers, NSAIDs, Lithium. etc. Certain antihypertensives like ACE inhibitors, diuretics are also documented to have caused psoriatic episodes. A 57 y old South-Indian male patient with a history of Hypertension, Diabetes Mellitus, Atrial Fibrillation for 4 y; was on antihypertensive therapy for Hypertension and Atrial Fibrillation with proponolol for past 2 y and metoprolol initially. He was presented to the hospital two weeks after switching on to Metoprolol therapy for chief complaints of erythematous scaly lesions especially over both the extremities and paronydrial appearance of nails. Initially, he was on Propranolol therapy which was then shifted to Metoprolol due to an appearance of oral lesions in the mouth. Metoprolol was now discontinued and switched on to Atenolol. After 1-2 w of therapy with Atenolol, the lesions were found to disappear and no recurrence of psoriatic conditions were found. Proper reviewing of medical history for any allergic reactions and the optimization of drug therapy through Therapeutic Drug Monitoring could be initiated by Clinical Pharmacist in order to avoid such drug-induced flares

Relativistic coupled-cluster single-double method applied to alkali-metal atoms

A relativistic version of the coupled-cluster single-double (CCSD) method is developed for atoms with a single valence electron. In earlier work, a linearized version of the CCSD method (with extensions to include a dominant class of triple excitations) led to accurate predictions for energies, transition amplitudes, hyperfine constants, and other properties of monovalent atoms. Further progress in high-precision atomic structure calculations for heavy atoms calls for improvement of the linearized coupled-cluster methodology. In the present work, equations for the single and double excitation coefficients of the Dirac-Fock wave function, including all non-linear coupled-cluster terms that contribute at the single-double level are worked out. Contributions of the non-linear terms to energies, electric-dipole matrix elements, and hyperfine constants of low-lying states in alkali-metal atoms from Li to Cs are evaluated and the results are compared with other calculations and with precise experiments.Comment: 12 page

SU(16) grandunification: breaking scales, proton decay and neutrino magnetic moment

We give a detailed renormalization group analysis for the SU(16) grandunified group with general breaking chains in which quarks and leptons transform separately at intermediate energies. Our analysis includes the effects of Higgs bosons. We show that the grandunification scale could be as low as $\sim 10^{8.5}$ GeV and give examples where new physics could exist at relatively low energy ($\sim 250$ GeV). We consider proton decay in this model and show that it is consistent with a low grandunification scale. We also discuss the possible generation of a neutrino magnetic moment in the range of $10^{-11}$ to $10^{-10}\mu_B$ with a very small mass by the breaking of the embedded SU(2)$_\nu$ symmetry at a low energy.Comment: (16 pages in REVTEX + 6 figures not included) OITS-49

Interacting Brownian Motion with Resetting

We study two Brownian particles in dimension $d=1$, diffusing under an interacting resetting mechanism to a fixed position. The particles are subject to a constant drift, which biases the Brownian particles toward each other. We derive the steady-state distributions and study the late time relaxation behavior to the stationary state.Comment: 13 pages, 4 figure

Implications of LEP Results for SO(10) Grandunification with Two Intermediate Stages

We consider the breaking of the grand unification group $SO(10)$ to the standard model gauge group through several chains containing two intermediate stages. Using the values of the gauge coupling constants at scale $M_Z$ derived from recent LEP data, we determine the range of their intermediate and unification scales. In particular, we identify those chains that permit new gauge structure at relatively low energy $(\sim 1\, {\rm TeV})$.Comment: (LATEX, 9 pages + 3 pages of figures not included) OITS-48