Bounding the Tau Neutrino Magnetic Moment from Single Photon Searches at LEP

We show that single photon searches at LEP constrain the tau neutrino magnetic moment to be less than ${\cal O}(10^{-6})~\mu_B$. This bound is competitive with low energy ($s\simeq (30~GeV)^2$) single photon searches.Comment: 5 pgs. LaTeX, one reference fixed in revised version, JHU-TIPAC-940004, UM-TH-94-1

Serre Duality, Abel's Theorem, and Jacobi Inversion for Supercurves Over a Thick Superpoint

The principal aim of this paper is to extend Abel's theorem to the setting of complex supermanifolds of dimension 1|q over a finite-dimensional local supercommutative C-algebra. The theorem is proved by establishing a compatibility of Serre duality for the supercurve with Poincare duality on the reduced curve. We include an elementary algebraic proof of the requisite form of Serre duality, closely based on the account of the reduced case given by Serre in Algebraic Groups and Class Fields, combined with an invariance result for the topology on the dual of the space of repartitions. Our Abel map, taking Cartier divisors of degree zero to the dual of the space of sections of the Berezinian sheaf, modulo periods, is defined via Penkov's characterization of the Berezinian sheaf as the cohomology of the de Rham complex of the sheaf D of differential operators, as a right module over itself. We discuss the Jacobi inversion problem for the Abel map and give an example demonstrating that if n is an integer sufficiently large that the generic divisor of degree n is linearly equivalent to an effective divisor, this need not be the case for all divisors of degree n.Comment: 14 page

Effective field theory approach to Casimir interactions on soft matter surfaces

We utilize an effective field theory approach to calculate Casimir interactions between objects bound to thermally fluctuating fluid surfaces or interfaces. This approach circumvents the complicated constraints imposed by such objects on the functional integration measure by reverting to a point particle representation. To capture the finite size effects, we perturb the Hamiltonian by DH that encapsulates the particles' response to external fields. DH is systematically expanded in a series of terms, each of which scales homogeneously in the two power counting parameters: \lambda \equiv R/r, the ratio of the typical object size (R) to the typical distance between them (r), and delta=kB T/k, where k is the modulus characterizing the surface energy. The coefficients of the terms in DH correspond to generalized polarizabilities and thus the formalism applies to rigid as well as deformable objects. Singularities induced by the point particle description can be dealt with using standard renormalization techniques. We first illustrate and verify our approach by re-deriving known pair forces between circular objects bound to films or membranes. To demonstrate its efficiency and versatility, we then derive a number of new results: The triplet interactions present in these systems, a higher order correction to the film interaction, and general scaling laws for the leading order interaction valid for objects of arbitrary shape and internal flexibility.Comment: 4 pages, 1 figur

Simulations of the Disk-Jet Interaction in GRS 1915+105 and Other Systems

After an X-ray binary experiences a transient jet ejection, it undergoes a phase in which its X-ray light curve is dominated, for some time, by thermal emission from an accretion disk surrounding the black hole. The accretion physics in the thermal-dominant state is understood better than in any other, and it is therefore the best state for comparing observations to theoretical models. Here, I present simulations that study the way a thermally-emitting disk might be expected to behave immediately after a large-scale, steady jet has been removed from the system in the form of a sudden ejection. I simulate the ejection's effect on the disk by allowing the strength of turbulence (modeled by the alpha parameter of Shakura and Sunyaev) to increase rapidly in time, and I show how this change can lead to an outburst in an otherwise-steady disk. The motivation for treating the jet removal in this way is the fact that many models for jets involve large-scale magnetic fields that should inhibit the magnetorotational instability believed to drive turbulence; this should naturally lead to a rapid increase in turbulence when the magnetic field is ejected from the system or otherwise destroyed during the ejection event. I show how the timescale and luminosity of the outburst can be controlled by the manner in which alpha is allowed to change, and I briefly discuss ways in which these simulations can be compared to observations of X-ray binaries, in particular GRS 1915+105, which shows the most complex and variable behavior of any black hole system in outburst.Comment: 10 pages, 6 figures; accepted for publication in the proceedings of VI Microquasar Workshop: Microquasars and Beyond, Sept 18-22 2006, Como, Italy, ed: T. Belloni (2006), PoS(MQW6)03

A Precision Model Independent Determination of |Vub| from B -> pi e nu

A precision method for determining |Vub| using the full range in q^2 of B-> pi \ell nu data is presented. At large q^2 the form factor is taken from unquenched lattice QCD, at q^2=0 we impose a model independent constraint obtained from B-> pi pi using the soft-collinear effective theory, and the shape is constrained using QCD dispersion relations. We find |Vub| =(3.54\pm 0.17\pm 0.44) x 10^{-3}. With 5% experimental error and 12% theory error, this is competitive with inclusive methods. Theory error is dominated by the input points, with negligible uncertainty from the dispersion relations.Comment: 4 pages, 3 figure

Stability of Neutrinos in the Singlet Majoron Model

We show that there is no one-loop enhancement of the rate for a light neutrino to decay into a lighter neutrino plus a majoron, contrary to a recent claim. Thus the light neutrinos must satisfy the cosmological bound of having masses less than 35 eV in the singlet majoron model, or else violate the constraint imposed by galaxy formation. In the latter case, $\nu_\tau$ could have a mass between 40 and 500 keV, while satisfying all other cosmological constraints.Comment: 11 pp., latex, UMN-TH-1218-93. Correct nucleosynthesis bound of 500 keV on nu_tau mass is incorporated; one-loop electroweak contribution to neutrino mass is correcte

Energy Expectation Values and the Integral Hellmann–Feynman Theorem: H2+ Molecule

It is by now well known that the integral Hellmann–Feynman (IHF) theorem has little quantitative utility for chemically interesting problems, although the formalism potentially affords a ready physical interpretation of changes in molecular conformation. In this paper, the IHF theorem is applied to variational and simple LCAO wavefunctions for the H2+ ground state, which range in quality from crude to essentially exact. The IHF results improve quite dramatically with the quality of the wavefunctions. This suggests that errors in the IHF formula may be of the same order as those in the wavefunction. (In contrast, errors in variationally determined energies are of second order.) Our results suggest a convenient test which can be applied to any revised IHF formalism developed in the future.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70096/2/JCPSA6-49-3-1284-1.pd