Angular reduction in multiparticle matrix elements

A general method for the reduction of coupled spherical harmonic products is presented. When the total angular coupling is zero, the reduction leads to an explicitly real expression in the scalar products within the unit vector arguments of the spherical harmonics. For non-scalar couplings, the reduction gives Cartesian tensor forms for the spherical harmonic products, with tensors built from the physical vectors in the original expression. The reduction for arbitrary couplings is given in closed form, making it amenable to symbolic manipulation on a computer. The final expressions do not depend on a special choice of coordinate axes, nor do they contain azimuthal quantum number summations, nor do they have complex tensor terms for couplings to a scalar. Consequently, they are easily interpretable from the properties of the physical vectors they contain.Comment: This version contains added comments and typographical corrections to the original article. Now 27 pages, 0 figure

Trends in the use of payment instruments in the United States

In 2003, for the first time, the number of electronic payments in the United States exceeded the number of check payments--a result of substantial growth in electronic payments (especially by debit card) and a decline in check payments. The shift toward electronic payments suggests that, as with other large economies, many payments formerly made by check are now being made with electronic payment instruments. As in past years, however, the value of checks far exceeded the value of commonly used electronic payments. ; Comparisons among groups of depository institutions of different types and sizes suggest that the distribution of payments of different types is linked in part to the types of customers those institutions tend to serve. For example, at credit unions, which generally serve individuals rather than businesses, checks accounted for a smaller proportion of account debits, and debit card payments and ATM withdrawals accounted for a larger proportion, than at institutions of other types. ; Overall, "on us" check payments, those for which the payer and payee used the same institution, declined slightly. The rate at which checks are returned also declined, while the rate of returned ACH payments--almost twice that of checks--increased, in part because of new types of ACH payments, including ACH transactions initiated with a check. ; Data gathered in 2004 also reveal some differences among geographic regions. Debit card use was substantially greater, and check use substantially lower, in the West than in other regions. In contrast, debit card use was considerably less common in the Northeast, and the decline in check payments since 2000 was less pronounced in that region. ; Indirect evidence--data on ATM withdrawals and cash back from debit card payments--suggests that cash remains a popular means of making payments. Industry data showing increases in ATMs and ATM transactions appear to reflect a shift toward greater use of ATMs and less use of checks to obtain cash, and do not necessarily indicate an increase in the use of cash.Payment systems ; Checks

Heavy Top Quark Searches in the Di-Lepton Mode at the Tevatron

We present the results of a detailed study of the effects of $b$-tagging on the heavy top-quark signal and backgrounds for the modes of the di-lepton plus two high transverse energy jets at the Fermilab Tevatron. The general characteristics of the heavy top-quark signal events are also discussed so that a comparison can be made between $b$-tagging and imposing stringent kinematical cuts to eliminate backgrounds.Comment: uses PHYZZX and TABLES macros, 10 pages, four figures not included (available by request), FERMILAB-Pub-93/105-

Angular Correlations in Top Quark Pair Production and Decay at Hadron Colliders

We show how to observe sizable angular correlations between the decay products of the top quark and those of the anti-top quark in top quark pair production and decay at hadron colliders. These correlations result from the large asymmetry in the rate for producing like-spin versus unlike-spin top quark pairs provided the appropriate spin axes are used. The effects of new physics at production or decay on these correlations are briefly discussed.Comment: 34 pages, revtex, including 12 uuencoded postscript figure

M\"ossbauer Antineutrinos: Recoilless Resonant Emission and Absorption of Electron Antineutrinos

Basic questions concerning phononless resonant capture of monoenergetic electron antineutrinos (M\"ossbauer antineutrinos) emitted in bound-state beta-decay in the 3H - 3He system are discussed. It is shown that lattice expansion and contraction after the transformation of the nucleus will drastically reduce the probability of phononless transitions and that various solid-state effects will cause large line broadening. As a possible alternative, the rare-earth system 163Ho - 163Dy is favoured. M\"ossbauer-antineutrino experiments could be used to gain new and deep insights into several basic problems in neutrino physics

Implications of New Gallex Results for the MSW Solution of the Solar Neutrino Problem

We compare the implications for 7Be and pp neutrinos of the two MSW fits to the new GALLEX solar neutrino measurements . Small mixing angle solutions tend to suppress the former as electron-neutrinos, but not the latter, and large angle solutions tend to reduce both by about a factor of 2. The consequences for BOREXINO and similar solar neutrino--electron scattering experiments are discussed.Comment: 7 pages (plus 3 figures available upon request) UTAPHY-HEP-

Weak Transitions in A=6 and 7 Nuclei

The $^6$He beta decay and $^7$Be electron capture processes are studied using variational Monte Carlo wave functions, derived from a realistic Hamiltonian consisting of the Argonne $v_{18}$ two-nucleon and Urbana-IX three-nucleon interactions. The model for the nuclear weak axial current includes one- and two-body operators with the strength of the leading two-body term--associated with $\Delta$-isobar excitation of the nucleon--adjusted to reproduce the Gamow-Teller matrix element in tritium $\beta$-decay. The measured half-life of $^6$. He is under-predicted by theory by $\simeq$ 8%, while that of $^7$Be for decay into the ground and first excited states of $^7$Li is over-predicted by $\simeq$ 9%. However, the experimentally known branching ratio for these latter processes is in good agreement with the calculated value. Two-body axial current contributions lead to a $\simeq$ 1.7% (4.4%) increase in the value of the Gamow-Teller matrix element of $^6$He ($^7$Be), obtained with one-body currents only, and slightly worsen (appreciably improve) the agreement between the calculated and measured half-life. Corrections due to retardation effects associated with the finite lepton momentum transfers involved in the decays, as well as contributions of suppressed transitions induced by the weak vector charge and axial current operators, have also been calculated and found to be negligible.Comment: 23 pages 8 tables. submitted to Phys. Rev.

Academic Librarianship and the Redefining Scholarship Project: A Report from the Association of College and Research Libraries Task Force on Institutional Priorities and Faculty Rewards

At the July, 1996 Annual Conference of the American Library Association, the Board of Directors of the Association of College and Research Libraries (ACRL) appointed a task force to write a formal statement defining and describing the kind of scholarship performed by academic librarians, using as a framework the taxonomy developed by Eugene Rice and elaborated by Ernest Boyer in his 1990 book Scholarship Reconsidered: Priorities of the Professoriate.(1) The task force\u27s statement, upon approval by the ACRL Board, is intended to become part of a larger movement established by Syracuse University\u27s Center for Instructional Development, entitled the Institutional Priorities and Faculty Rewards project. The project, which is being funded by the Lilly Endowment, with support from the Fund for the Improvement of Postsecondary Education, is providing assistance to academic associations for the development and dissemination of definitions of scholarship for their disciplines. The definitions are intended to extend the range of activities recognized as scholarly for the purposes of tenure, promotion, merit, or reward system guidelines. The following is the report of the ACRL task force

QCD Corrections to Spin Correlations in Top Quark Production at Lepton Colliders

Spin correlations, using a generic spin basis, are investigated to leading order in QCD for top quark production at lepton colliders. Even though, these radiative corrections induce an anomalous gamma/Z magnetic moment for the top quarks and allow for single, real gluon emission, their effects on the top quark spin orientation are very small. The final results are that the top (or anti-top) quarks are produced in an essentially unique spin configuration in polarized lepton collisions even after including the O(alpha_{s}) QCD corrections.Comment: 32 pages, REVTeX, 13 Postscript figures, psfig.sty and here.sty are required. Several references added, Tables 3, 4 and 5 are change

Microwave and Physical Electronics

Contains reports on six research projects.Office of Scientific Research and Development (OSRD) OEMsr-26