Flexible, low-cost silicon solar cell arrays

Silicon solar cell arrays are pressure-bonded to flexible backing and protected by fluorinated ethylene propylene cover in one mechanized operation. Arrays packaged by this method are flexible, lightweight, insulated, breakage resistant and less expensive

Method of making silicon solar cell array

A heat sealable transparent plastic film, such as a flourinated ethylene propylene copolymer, is used both as a cover material and as an adhesive for mounting a solar cell array to a flexible substrate

The core structure of presolar graphite onions

Of the ``presolar particles'' extracted from carbonaceous chondrite dissolution residues, i.e. of those particles which show isotopic evidence of solidification in the neighborhood of other stars prior to the origin of our solar system, one subset has an interesting concentric graphite-rim/graphene-core structure. We show here that single graphene sheet defects in the onion cores (e.g. cyclopentane loops) may be observable edge-on by HREM. This could allow a closer look at models for their formation, and in particular strengthen the possibility that growth of these assemblages proceeds atom-by-atom with the aid of such in-plane defects, under conditions of growth (e.g. radiation fluxes or grain temperature) which discourage the graphite layering that dominates subsequent formation of the rim.Comment: 4 pages, 7 figures, 11 refs, see also http://www.umsl.edu/~fraundor/isocore.htm

A large Hilbert space QRPA and RQRPA calculation of neutrinoless double beta decay

A large Hilbert space is used for the calculation of the nuclear matrix elements governing the light neutrino mass mediated mode of neutrinoless double beta decay of Ge76, Mo100, Cd116, Te128 and Xe136 within the proton-neutron quasiparticle random phase approximation (pn-QRPA) and the renormalized QRPA with proton-neutron pairing (full-RQRPA) methods. We have found that the nuclear matrix elements obtained with the standard pn-QRPA for several nuclear transitions are extremely sensitive to the renormalization of the particle-particle component of the residual interaction of the nuclear hamiltonian. Therefore the standard pn-QRPA does not guarantee the necessary accuracy to allow us to extract a reliable limit on the effective neutrino mass. This behaviour, already known from the calculation of the two-neutrino double beta decay matrix elements, manifests itself in the neutrinoless double-beta decay but only if a large model space is used. The full-RQRPA, which takes into account proton-neutron pairing and considers the Pauli principle in an approximate way, offers a stable solution in the physically acceptable region of the particle-particle strength. In this way more accurate values on the effective neutrino mass have been deduced from the experimental lower limits of the half-lifes of neutrinoless double beta decay.Comment: 19 pages, RevTex, 1 Postscript figur

Neutrinoless Double Beta Decay within QRPA with Proton-Neutron Pairing

We have investigated the role of proton-neutron pairing in the context of the Quasiparticle Random Phase approximation formalism. This way the neutrinoless double beta decay matrix elements of the experimentally interesting A= 48, 76, 82, 96, 100, 116, 128, 130 and 136 systems have been calculated. We have found that the inclusion of proton-neutron pairing influences the neutrinoless double beta decay rates significantly, in all cases allowing for larger values of the expectation value of light neutrino masses. Using the best presently available experimental limits on the half life-time of neutrinoless double beta decay we have extracted the limits on lepton number violating parameters.Comment: 16 RevTex page

A New Class of Majoron-Emitting Double-Beta Decays

Motivated by the excess events that have recently been found near the endpoints of the double beta decay spectra of several elements, we re-examine models in which double beta decay can proceed through the neutrinoless emission of massless Nambu-Goldstone bosons (majorons). Noting that models proposed to date for this process must fine-tune either a scalar mass or a VEV to be less than 10 keV, we introduce a new kind of majoron which avoids this difficulty by carrying lepton number $L=-2$. We analyze in detail the requirements that models of both the conventional and our new type must satisfy if they are to account for the observed excess events. We find: (1) the electron sum-energy spectrum can be used to distinguish the two classes of models from one another; (2) the decay rate for the new models depends on different nuclear matrix elements than for ordinary majorons; and (3) all models require a (pseudo) Dirac neutrino, having a mass of a several hundred MeV, which mixes with $\nu_e$.Comment: 43 pages, 10 figures (included), [figure captions are now included

Generalized Bounds on Majoron-neutrino couplings

We discuss limits on neutrino-Majoron couplings both from laboratory experiments as well as from astrophysics. They apply to the simplest class of Majoron models which covers a variety of possibilities where neutrinos acquire mass either via a seesaw-type scheme or via radiative corrections. By adopting a general framework including CP phases we generalize bounds obtained previously. The combination of complementary bounds enables us to obtain a highly non-trivial exclusion region in the parameter space. We find that the future double beta project GENIUS, together with constraints based on supernova energy release arguments, could restrict neutrino-Majoron couplings down to the 10^{-7} level.Comment: 17 pages, LateX, 7 figures, version to be published in Phys. Rev.

Pions in Nuclei and Manifestations of Supersymmetry in Neutrinoless Double Beta Decay

We examine the pion realization of the short ranged supersymmetric (SUSY) mechanism of neutrinoless double beta decay. It originates from the R-parity violating quark-lepton interactions of the SUSY extensions of the standard model of the electroweak interactions. We argue that pions are dominant SUSY mediators in neutrinoless double beta decay. The corresponding nuclear matrix elements for various isotopes are calculated within the proton-neutron renormalized quasiparticle random phase approximation. We define those isotopes which are most sensitive to the SUSY signal and outlook the present experimental situation with the double beta decay searches for the SUSY. Upper limits on the R-parity violating 1st generation Yukawa coupling are derived from various double beta decay experiments.Comment: 15 pages, Latex, 3 Postscript figure

Influence of the left-handed part of the neutrino mass matrix on the lepton number violating e-e- -> W-W- process

Influence of the neutrino mass submatrix $M_L$ on the e-e- -> W-W- process is discussed. Taking into account various possible CP signatures of heavy neutrinos it is shown that, in some cases, nonzero $M_L$ substantially changes predictions for maximum possible values of the e-e- -> W-W- cross section. A direct role of the $\omega^2$ parameter (coming from neutrinoless double beta decay) is clarified. The consequences of doubly charged Higgs particles $\delta^{--}$ with resonances even far away from energies of the future linear lepton collider ($\sqrt{s}=0.5-1$ TeV) are studied.Comment: revtex, epsfig, 5 figures, 9 pages. To appear in Phys.Rev.