Matter induced charge symmetry breaking and pion form factor in nuclear medium

Medium modification of pion form factor has been evaluated in asymmetric nuclear matter. It is shown that both the shape and the pole position of the pion form factor in dense asymmetric nuclear matter is different from its vacuum counterpart with $\rho$-$\omega$ mixing. This is due to the density and asymmetry dependent $\rho$-$\omega$ mixing which could even dominate over its vacuum counterpart in matter. Effect of the in-medium pion factor on experimental observables {\it e.g.}, invariant mass distribution of lepton pairs has been demonstrated.Comment: Final Version to appear in Jour. Phys.

Fermi surface of an important nano-sized metastable phase: Al3_3Li

Nanoscale particles embedded in a metallic matrix are of considerable interest as a route towards identifying and tailoring material properties. We present a detailed investigation of the electronic structure, and in particular the Fermi surface, of a nanoscale phase ($L1_2$ Al$_3$Li) that has so far been inaccessible with conventional techniques, despite playing a key role in determining the favorable material properties of the alloy (Al\nobreakdash-9 at. %\nobreakdash-Li). The ordered precipitates only form within the stabilizing Al matrix and do not exist in the bulk; here, we take advantage of the strong positron affinity of Li to directly probe the Fermi surface of Al$_3$Li. Through comparison with band structure calculations, we demonstrate that the positron uniquely probes these precipitates, and present a 'tuned' Fermi surface for this elusive phase

Experimental determination of the state-dependent enhancement of the electron-positron momentum density in solids

The state-dependence of the enhancement of the electron-positron momentum density is investigated for some transition and simple metals (Cr, V, Ag and Al). Quantitative comparison with linearized muffin-tin orbital calculations of the corresponding quantity in the first Brillouin zone is shown to yield a measurement of the enhancement of the s, p and d states, independent of any parameterizations in terms of the electron density local to the positron. An empirical correction that can be applied to a first-principles state-dependent model is proposed that reproduces the measured state-dependence very well, yielding a general, predictive model for the enhancement of the momentum distribution of positron annihilation measurements, including those of angular correlation and coincidence Doppler broadening techniques

Quenching of light hadrons at RHIC in a collisional energy loss scenario

We evaluate the nuclear suppression factor, $R_{AA}(p_T)$ for light hadrons by taking into account the collisional energy loss. We show that in the measured $p_T$ domain of RHIC the elastic process is the dominant mechanism for the partonic energy loss.Comment: 4 pages with 3 figures, Quark Matter 2008 Proceeding

P6_5 The Flash and Quantum Tunneling

The Flash, a popular DC Comics superhero, is regarded as the fastest human alive. He has the power to run faster than light and phase through solid objects while doing so. Since his power to run faster than light is disputed by Einstein's Theory of Special Relativity, for this article we will assume that he is able to achieve a maximum velocity of 0:99 c . Given the high kinetic energy, in this paper we look at the possibility of him quantum tunneling through a solid object such as a wall

Urinary tract infection

Over two years, 9892 mid-stream urine samples from patients attending the Aga Khan University Hospital, Karachi were cultured. Significant bacterial growth was seen in 23.5% samples. Further iden­tification of these organisms Eevealed 40% of E.coli, 16% Pseudomonas aeruginosa, 11% Klebsiella aerogenes, 5.0% Enterobacter sp., 13% Protdus sp., 4.0% Serratia liquifaciens, 1.0% Acinetobacter sp., 3.0% Citrobacter sp., 4.0% Enterococci, 0.5% Staphylococcus aureus. Results of sensitivity tests performed with antibiotics Ampicillin, Cotrimoxa.zole, Nitrofurantoin, Nalidixic acid, Gentamicin, Amikacin, Pipemedic acid, Cefotaxime, Azactain and Carbenicillin did not reveal any distinct patter

Enskog Theory for Polydisperse Granular Mixtures II. Sonine Polynomial Approximation

The linear integral equations defining the Navier-Stokes (NS) transport coefficients for polydisperse granular mixtures of smooth inelastic hard disks or spheres are solved by using the leading terms in a Sonine polynomial expansion. Explicit expressions for all the NS transport coefficients are given in terms of the sizes, masses, compositions, density and restitution coefficients. In addition, the cooling rate is also evaluated to first order in the gradients. The results hold for arbitrary degree of inelasticity and are not limited to specific values of the parameters of the mixture. Finally, a detailed comparison between the derivation of the current theory and previous theories for mixtures is made, with attention paid to the implication of the various treatments employed to date.Comment: 26 pages, to be published in Phys. Rev.