Self-Energy of Decuplet Baryons in Nuclear Matter

We calculate, in chiral perturbation theory, the change in the self-energy of decuplet baryons in nuclear matter. These self-energy shifts are relevant in studies of meson-nucleus scattering and of neutron stars. Our results are leading order in an expansion in powers of the ratio of characteristic momenta to the chiral symmetry-breaking scale (or the nucleon mass). Included are contact diagrams generated by 4-baryon operators, which were neglected in earlier studies for the $\Delta$ isomultiplet but contribute to the self-energy shifts at this order in chiral perturbation theory.Comment: 11 pages, 2 eps figures, REVTe

Outskirts of Distant Galaxies In Absorption

QSO absorption spectroscopy provides a sensitive probe of both the neutral medium and diffuse ionized gas in the distant Universe. It extends 21cm maps of gaseous structures around low-redshift galaxies both to lower gas column densities and to higher redshifts. Combining galaxy surveys with absorption-line observations of gas around galaxies enables comprehensive studies of baryon cycles in galaxy outskirts over cosmic time. This Chapter presents a review of the empirical understanding of the cosmic neutral gas reservoir from studies of damped Lya absorbers (DLAs). It describes the constraints on the star formation relation and chemical enrichment history in the outskirts of distant galaxies from DLA studies. A brief discussion of available constraints on the ionized circumgalactic gas from studies of lower column density Lya absorbers and associated ionic absorption transitions is presented at the end.Comment: 45 pages, 7 figures, invited review, Book chapter in "Outskirts of Galaxies", Eds. J. H. Knapen, J. C. Lee and A. Gil de Paz, Astrophysics and Space Science Library, Springer, in pres

Charmless Two-body Baryonic B Decays

We study charmless two-body baryonic B decays in a diagramatic approach. Relations on decay amplitudes are obtained. In general there are more than one tree and more than one penguin amplitudes. The number of independent amplitudes can be reduced in the large m_B limit. It leads to more predictive results. Some prominent modes for experimental searches are pointed out.Comment: 15 pages, 2 figures. To appear in Phys. Rev.

Exact Diagonalization of Two Quantum Models for the Damped Harmonic Oscillator

The damped harmonic oscillator is a workhorse for the study of dissipation in quantum mechanics. However, despite its simplicity, this system has given rise to some approximations whose validity and relation to more refined descriptions deserve a thorough investigation. In this work, we apply a method that allows us to diagonalize exactly the dissipative Hamiltonians that are frequently adopted in the literature. Using this method we derive the conditions of validity of the rotating-wave approximation (RWA) and show how this approximate description relates to more general ones. We also show that the existence of dissipative coherent states is intimately related to the RWA. Finally, through the evaluation of the dynamics of the damped oscillator, we notice an important property of the dissipative model that has not been properly accounted for in previous works; namely, the necessity of new constraints to the application of the factorizable initial conditions.Comment: 19 pages, 2 figures, ReVTe

Probing CP Violation with the Deuteron Electric Dipole Moment

We present an analysis of the electric dipole moment (EDM) of the deuteron as induced by CP-violating operators of dimension 4, 5 and 6 including theta QCD, the EDMs and color EDMs of quarks, four-quark interactions and the Weinberg operator. We demonstrate that the precision goal of the EDM Collaboration's proposal to search for the deuteron EDM, (1-3)\times 10^{-27} e cm, will provide an improvement in sensitivity to these sources of one-two orders of magnitude relative to the existing bounds. We consider in detail the level to which CP-odd phases can be probed within the MSSM.Comment: 5 pages, 4 figures; precision estimates clarified, to appear in Phys. Rev.

SU(3) Predictions for Weak Decays of Doubly Heavy Baryons -- including SU(3) breaking terms

We find expressions for the weak decay amplitudes of baryons containing two b quarks (or one b and one c quark -- many relationship are the same) in terms of unknown reduced matrix elements. This project was originally motivated by the request of the FNAL Run II b Physics Workshop organizers for a guide to experimentalists in their search for as yet unobserved hadrons. We include an analysis of linear SU(3) breaking terms in addition to relationships generated by unbroken SU(3) symmetry, and relate these to expressions in terms of the complete set of possible reduced matrix elements.Comment: 49 page

Homodyne Bell's inequalities for entangled mesoscopic superpositions

We present a scheme for demonstrating violation of Bell's inequalities using a spin-1/2 system entangled with a pair of classically distinguishable wave packets in a harmonic potential. In the optical domain, such wave packets can be represented by coherent states of a single light mode. The proposed scheme involves standard spin-1/2 projections and measurements of the position and the momentum of the harmonic oscillator system, which for a light mode can be realized by means of homodyne detection. We discuss effects of imperfections, including non-unit efficiency of the homodyne detector, and point out a close link between the visibility of interference and violation of Bell's inequalities in the described scheme.Comment: 6 pages, 3 figures. Extended version, journal reference adde

Detection of Supernova Neutrinos by Neutrino-Proton Elastic Scattering

We propose that neutrino-proton elastic scattering, $\nu + p \to \nu + p$, can be used for the detection of supernova neutrinos in scintillator detectors. Though the proton recoil kinetic energy spectrum is soft, with $T_p \simeq 2 E_\nu^2/M_p$, and the scintillation light output from slow, heavily ionizing protons is quenched, the yield above a realistic threshold is nearly as large as that from $\bar{\nu}_e + p \to e^+ + n$. In addition, the measured proton spectrum is related to the incident neutrino spectrum, which solves a long-standing problem of how to separately measure the total energy and temperature of $\nu_\mu$, $\nu_\tau$, $\bar{\nu}_\mu$, and $\bar{\nu}_\tau$. The ability to detect this signal would give detectors like KamLAND and Borexino a crucial and unique role in the quest to detect supernova neutrinos.Comment: 10 pages, 9 figures, revtex

X-ray standing wave and reflectometric characterization of multilayer structures

Microstructural characterization of synthetic periodic multilayers by x-ray standing waves have been presented. It has been shown that the analysis of multilayers by combined x-ray reflectometry (XRR) and x-ray standing wave (XSW) techniques can overcome the deficiencies of the individual techniques in microstructural analysis. While interface roughnesses are more accurately determined by the XRR technique, layer composition is more accurately determined by the XSW technique where an element is directly identified by its characteristic emission. These aspects have been explained with an example of a 20 period Pt/C multilayer. The composition of the C-layers due to Pt dissolution in the C-layers, Pt$_{x}$C$_{1-x}$, has been determined by the XSW technique. In the XSW analysis when the whole amount of Pt present in the C-layers is assumed to be within the broadened interface, it l eads to larger interface roughness values, inconsistent with those determined by the XRR technique. Constraining the interface roughness values to those determined by the XRR technique, requires an additional amount of dissolved Pt in the C-layers to expl ain the Pt fluorescence yield excited by the standing wave field. This analysis provides the average composition Pt$_{x}$C$_{1-x}$ of the C-layers .Comment: 12 pages RevTex, 10 eps figures embedde

Analysis of Two-Body Decays of Charmed Baryons Using the Quark-Diagram Scheme

We give a general formulation of the quark-diagram scheme for the nonleptonic weak decays of baryons. We apply it to all the decays of the antitriplet and sextet charmed baryons and express their decay amplitudes in terms of the quark-diagram amplitudes. We have also given parametrizations for the effects of final-state interactions. For SU(3) violation effects, we only parametrize those in the horizontal $W$-loop quark diagrams whose contributions are solely due to SU(3)-violation effects. In the absence of all these effects, there are many relations among various decay modes. Some of the relations are valid even in the presence of final-state interactions when each decay amplitude in the relation contains only a single phase shift. All these relations provide useful frameworks to compare with future experiments and to find out the effects of final-state interactions and SU(3) symmetry violations.Comment: 28 pages, 20 Tables in landscape form, 4 figures. Main changes are: (i) some errors in the Tables and in the relations between the quark-diagram amplitudes of this paper and those of Ref.[10] are corrected, (ii) improvements are made in the presentation so that comparisons with previous works and what have been done to include SU(3) breaking and final-state interactions are more clearly stated; to appear in the Physical Review