4,074 research outputs found

    Detecting Gluino-Containing Hadrons

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    When SUSY breaking produces only dimension-2 operators, gluino and photino masses are of order 1 GeV or less. The gluon-gluino bound state has mass 1.3-2.2 GeV and lifetime > 10^{-5} - 10^{-10} s. This range of mass and lifetime is largely unconstrained because missing energy and beam dump techniques are ineffective. With only small modifications, upcoming K^0 decay experiments can study most of the interesting range. The lightest gluino-containing baryon (uds-gluino) is long-lived or stable; experiments to find it and the uud-gluino are also discussed.Comment: 13 pp, 1 figure (uuencoded). Descendant of hep-ph/9504295, hep-ph/9508291, and hep-ph/9508292, focused on experimental search techniques. To be published in Phys Rev Let

    Flammability screening tests of resins

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    Selected flammability characteristics of glass cloth laminates of thermosetting resins are evaluated. A protocol for the evaluation of the flammability hazards presented by glass cloth laminates of thermosetting resins and the usefulness of that protocol with two laminates are presented. The glass laminates of an epoxy resin, M-751 are evaluated for: (1) determination of smoke generation from the laminates; (2) analysis of products of oxidative degradation of the laminates; (3) determination of minimum oxygen necessary to maintain flaming oxidation; (4) evaluation of toxicological hazards

    Radiative Decay of Vector Quarkonium: Constraints on Glueballs and Light Gluinos

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    Given a resonance of known mass, width, and J^{PC}, we can determine its gluonic branching fraction, b(R->gg), from data on its production in radiative vector quarkonium decay, V -> gamma+R. For most resonances b(R->gg) is found to be O(10%), consistent with being q-qbar states, but we find that both pseudoscalars observed in the 1440 MeV region have b(R->gg) ~ 1/2 - 1, and b(f_0^{++}->gg) ~ 1/2. As data improves, b(R->gg) should be a useful discriminator between q-qbar and gluonic states and may permit quantitative determination of the extent to which a particular resonance is a mixture of glueball and q-qbar. We also examine the regime of validity of pQCD for predicting the rate of V -> gamma+eta_gluino, the ``extra'' pseudoscalar bound state which would exist if there were light gluinos. From the CUSB limit on peaks in Upsilon -> gamma X, the mass range 3 GeV < m(eta_gluino) < 7 GeV can be excluded. An experiment must be significantly more sensitive to exclude an eta_gluino lighter than this.Comment: 36pp (inc figs),RU-94-04. (Replaces original which didn't latex correctly and didn't have figures.

    Experiments to Find or Exclude a Long-Lived, Light Gluino

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    Gluinos in the mass range ~1 1/2 - 3 1/2 GeV are absolutely excluded. Lighter gluinos are allowed, except for certain ranges of lifetime. Only small parts of the mass-lifetime parameter space are excluded for larger masses unless the lifetime is shorter than ~ 2 10^{-11} (m_{gluino}/ GeV) sec. Refined mass and lifetime estimates for R-hadrons are given, present direct and indirect experimental constraints are reviewed, and experiments to find or definitively exclude these possibilities are suggested.Comment: 27 pp, latex with 1 uufiled figure, RU-94-35. New version amplifies discussion of some points and corresponds to version for Phys. Rev.

    A Study in the Metabolism of the Adult Honey Bee

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    The study of metabolism in the higher forms of life has been carried on for many year and much has been found out that has been of great importance in understanding the way things live and grow. It has been only in the last few years that attention has been given to this phase of the work in insects. The extensive work that has been carried on concerning metabolism in men and animals is the basis for the more recent researches on the lower forms including the microorganisms. Before this work could be carried out on the small forms it was first necessary to develop special technique and instruments which would accurately measure their respiration. The basis of metabolism is the chemical break down of food material by the body and the use of the food in carrying on body activity. Most organisms have adjusted their mode of living to the extent that their diet is confined to a rather restricted food range. Such is the case in the animals concerned in this paper. In the selection of honey bees as subject for metabolism studies, the selection was made in light of their economic importance and not because of the fact that bees would be good material on which to work. Actually, bees, due to their gregarious instincts, are unusually difficult to handle in the manner called for in this type of research. Since this work is some of the first along this line, the results and conclusions can not be taken as at all conclusive but rather as a basis for future study as better technique is developed. The greater part of this study has been carried on in a micro-respirometer modified after Thunberg 1905 and Trendlenburg 1909. The apparatus was designed for the study of tissue respiration and can be equally adapted for work with small organisms. The instrument is volumetric in nature and consists of two small respiratory chambers of equal capacity connected together thru stop-cocks by a fine capillary tube. In the capillary is placed a drop of oil and any change in the capacity of either chamber is read on a scale along the length of the capillary tube by observing the movement of the oil drop. In metabolism studies we are interested in the use of food and the elimination of body wastes. These wastes are carbon dioxide, water and nitrogenous products. In the study of the bees, we need consider only the carbon dioxide and water because the honey bee subsists as a diet almost exclusively of honey. Honey is a mixture of the simple sugars of the formula C6H12O5. One gram molecule of this sugar requires 6 molecules of oxygen for its combustion and in metabolism gives off 6 molecules of carbon dioxide and 6 parts of water. Since a molecule of one gas is equivalent to a molecule of any other gas, both taken at the same temperature and pressure, in the burning of honey equal volumes of oxygen and of carbon dioxide are involved. In the light of this chemically established fact, a metabolic relationship has been established between the oxygen intake and the carbon dioxide outgo. This relationship is the value of carbon dioxide, divided by the value for oxygen, the resulting ratio being called the respiratory quotient or R.Q. Theoretically this can be calculated for the metabolism of carbohydrates, fats and proteins. The R.Q. of carbohydrates should be (1), protein (0.8), and fats (0.7). These ratios have been borne out in experiments on men and animals and have established the fact that nothing is gained or lost in the body without a compensating force of energy to balance. The measurement of oxygen consumption was done by absorbing the CO2 ­in KOH and recording the loss in volume. Carbon dioxide is measured by using sulphuric acid in the chambers and observing the difference between oxygen used and carbon dioxide given off. For good readings with the volumetric apparatus a water bath was constructed which held constant temperature thruout [sic] the experiments. The instruments required about one hour to adjust for temperature; therefore, all readings were begun at the end of one hour. Bees differ from other insects in that they do not hibernate during cold weather but instead form a cluster within their hive. The temperature of this cluster never falls below 14° C, any time during the year. Sufficient host is generated within the cluster to maintain this temperature by the consumption of honey and by body activity. In view of this fact several temperatures for experiments were selected that would correspond with known hive temperatures. The following temperatures were used, 0° C; 14° C cluster temperatures; 21° C room temperature; 25° C; 34° C breed rearing temperature

    An ecological approach to problems of Dark Energy, Dark Matter, MOND and Neutrinos

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    Modern astronomical data on galaxy and cosmological scales have revealed powerfully the existence of certain dark sectors of fundamental physics, i.e., existence of particles and fields outside the standard models and inaccessible by current experiments. Various approaches are taken to modify/extend the standard models. Generic theories introduce multiple de-coupled fields A, B, C, each responsible for the effects of DM (cold supersymmetric particles), DE (Dark Energy) effect, and MG (Modified Gravity) effect respectively. Some theories use adopt vanilla combinations like AB, BC, or CA, and assume A, B, C belong to decoupled sectors of physics. MOND-like MG and Cold DM are often taken as opposite frameworks, e.g. in the debate around the Bullet Cluster. Here we argue that these ad hoc divisions of sectors miss important clues from the data. The data actually suggest that the physics of all dark sectors is likely linked together by a self-interacting oscillating field, which governs a chameleon-like dark fluid, appearing as DM, DE and MG in different settings. It is timely to consider an interdisciplinary approach across all semantic boundaries of dark sectors, treating the dark stress as one identity, hence accounts for several "coincidences" naturally.Comment: 12p, Proceedings to the 6-th Int. Conf. of Gravitation and Cosmology. Neutrino section expande

    Possible manifestation of heavy stable colored particles in cosmology and cosmic rays

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    We discuss the cosmological implications as well as possible observability of massive, stable, colored particles which often appear in the discussion of physics beyond the standard model. We argue that if their masses are more than a few hundred GeV and if they saturate the halo density and/or occur with closure density of the universe, they are ruled out by the present WIMP search experiments as well as the searches for anomalous heavy isotopes of ordinary nuclei. We then comment on the possibility that these particles as well as the monopoles could be responsible for the ultra high energy cosmic rays with energy 1020\geq 10^{20} eV and point out that their low inelasticity argues against this.Comment: 9 pages; UMD-PP-98-1

    Recalculation of Proton Compton Scattering in Perturbative QCD

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    At very high energy and wide angles, Compton scattering on the proton (gamma p -> gamma p) is described by perturbative QCD. The perturbative QCD calculation has been performed several times previously, at leading twist and at leading order in alpha_s, with mutually inconsistent results, even when the same light-cone distribution amplitudes have been employed. We have recalculated the helicity amplitudes for this process, using contour deformations to evaluate the singular integrals over the light-cone momentum fractions. We do not obtain complete agreement with any previous result. Our results are closest to those of the most recent previous computation, differing significantly for just one of the three independent helicity amplitudes, and only for backward scattering angles. We present results for the unpolarized cross section, and for three different polarization asymmetries. We compare the perturbative QCD predictions for these observables with those of the handbag and diquark models. In order to reduce uncertainties associated with alpha_s and the three-quark wave function normalization, we have normalized the Compton cross section using the proton elastic form factor. The theoretical predictions for this ratio are about an order of magnitude below existing experimental data.Comment: Latex, 23 pages, 13 figures. Checked numerical integration one more way; added results for one more proton distribution amplitude; a few other minor changes. Version to appear in Phys. Rev.

    Electroproduction and Hadroproduction of Light Gluinos

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    In a class of supergravity models, the gluino and photino are massless at tree level and receive small masses through radiative corrections. In such models, one expects a gluino-gluon bound state, the R0R_0, to have a mass of between 1.0 and 2.2 GeV and a lifetime between 101010^{-10} and 10610^{-6} seconds. Applying peturbative QCD methods (whose validity we discuss), we calculate the production cross sections of R0R_0's in epe-p, πp\pi-p, KpK-p, pp\overline{p}-p and ppp-p collisions. Signatures are also discussed.Comment: 10 pages, latex, 6 figures uuencoded, figures also available via anonymous ftp to ftp://physics.wm.edu/pub/gluinofig.p

    Thermal Phase Mixing During First Order Phase Transitions

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    The dynamics of first order phase transitions are studied in the context of (3+1)-dimensional scalar field theories. Particular attention is paid to the question of quantifying the strength of the transition, and how `weak' and `strong' transitions have different dynamics. We propose a model with two available low temperature phases separated by an energy barrier so that one of them becomes metastable below the critical temperature TcT_c. The system is initially prepared in this phase and is coupled to a thermal bath. Investigating the system at its critical temperature, we find that `strong' transitions are characterized by the system remaining localized within its initial phase, while `weak' transitions are characterized by considerable phase mixing. Always at TcT_c, we argue that the two regimes are themselves separated by a (second order) phase transition, with an order parameter given by the fractional population difference between the two phases and a control parameter given by the strength of the scalar field's quartic self-coupling constant. We obtain a Ginzburg-like criterion to distinguish between `weak' and `strong' transitions, in agreement with previous results in (2+1)-dimensions.Comment: 28 pages RevTeX, 9 postscript figures, IMPERIAL/TP/93-94/58, DART-HEP-94/0
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