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Recent results on open and hidden charm production in e/sup +/e/sup -/ annihilation at 29 GeV

Description: Inclusive )psi) production in e/sup +/e/sup )minus/) annihilation at 29 GeV has been measured with the Mark II detector. The )psi) cross section is found to be 1.1 )+-) 0.5 )+-) 0.4 pb. An upper limit of 0.02 sigma/sub ..mu mu../ is obtained for other sources of )psi) production. )eta) production has also been investigated, using the ..gamma gamma.. decay mode. The )eta) fragmentation function has been measured and found to be in good agreement with the Lund model prediction. )eta)' production … more
Date: March 1, 1988
Creator: Wormser, G.
Partner: UNT Libraries Government Documents Department
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Search for tau decays to the eta meson

Description: Using a sample of 530,000 tau leptons collected by the Crystal Ball experiment at the e/sup +/e/sup -/ storage ring DORIS II, we have searched for tau decays to the eta meson. No eta signal is found in the inclusive analysis, tau ..-->.. eta X, of 1-prong decays, leading to the upper limits, BR(tau/sup -/ ..-->.. nu ..pi../sup -/eta) <0.3%, BR(tau/sup -/ ..-->.. ..pi../sup -/..pi../sup 0/eta) <0.9%, BR(tau/sup -/ ..-->.. nu ..pi../sup -/..pi../sup 0/..pi../sup 0/eta) <3.1%, BR(tau/sup -/ ..-->.… more
Date: December 1, 1987
Creator: Skwarnicki, T.
Partner: UNT Libraries Government Documents Department
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W and Z candidates observed in the 1987 CDF run

Description: This is a report on W and Z candidate events seen in the data taken by CDF in the 1987 run at the Tevatron Collider at Fermilab. These results are preliminary in that acceptances have not been properly calculated and backgrounds have not been appropriately determined. Data corresponding to an integrated luminosity of 35 mg/sup -1/ were collected during the run. Peak luminosities were of the order of 1 x 10/sup 29/ cm/sup -2/ sec/sup -1/. There is some 20% uncertainty in the value of the luminos… more
Date: January 1, 1987
Creator: Holloway, L.
Partner: UNT Libraries Government Documents Department
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Adiabatic supernova expansion into the circumstellar medium

Description: We perform one dimensional numerical simulations with a Lagrangian hydrodynamics code of the adiabatic expansion of a supernova into the surrounding medium. The early expansion follows Chevalier's analytic self-similar solution until the reverse shock reaches the ejecta core. We follow the expansion as it evolves towards the adiabatic blast wave phase. Some memory of the earlier phases of expansion is retained in the interior even when the outer regions expand as a blast wave. We find the resul… more
Date: June 8, 1987
Creator: Band, D.L. & Liang, E.P.
Partner: UNT Libraries Government Documents Department
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APT radionuclide production experiment

Description: Tritium ({sup 3}H, a heavy isotope of hydrogen) is produced by low energy neutron-induced reactions on various elements. One such reaction is n+{sup 3}He {yields}>{sup 3}H+{sup 1}H in which {sup 3}He is transmuted to tritium. Another reaction, which has been used in reactor production of tritium, is the n+{sup 6}Li {yields}> {sup 3}H+{sup 4}He reaction. Accelerator Production of Tritium relies on a high-energy proton beam to produce these neutrons using the spallation reaction, in which high-en… more
Date: July 2, 1994
Creator: Ullmann, J. L.; Gavron, A. & King, J. D.
Partner: UNT Libraries Government Documents Department
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Fusion-fission in light nuclear systems

Description: The fission process, which has been largely ignored for reactions involving light nuclear systems, will be shown to play a significant role in the /sup 32/S + /sup 24/Mg reaction at energies greater than about 1 1/2 times the Coulomb barrier energy. The magnitude of the fusion-fission cross section ant its fragment mass dependence are found to be consistent with newer estimates of the fission barriers in lighter systems. The presence of the fission mechanism has significance for understanding t… more
Date: January 1, 1988
Creator: Sanders, S. J.
Partner: UNT Libraries Government Documents Department
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Spontaneous fission properties and lifetime systematics

Description: Half-lives for spontaneous fission of nuclides with even and odd numbers of particles are compared with recent theoretical calculations. A summary of odd particle hindrance factors is given. The most recent measurements of kinetic-energy and mass distributions and neutron emission for spontaneous fission of the heaviest nuclides are summarized and discussed. 51 refs., 9 figs.
Date: March 1, 1989
Creator: Hoffman, D.C.
Partner: UNT Libraries Government Documents Department
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Search for D/sup *//sup 0/. -->. D/sup +/. pi. /sup -/

Description: We report on a search for the decay mode D/sup *//sup 0/(2007) ..-->.. D/sup +/..pi../sup -/ using the High Resolution Spectrometer at PEP. Although this decay is kinematically forbidden for the central mass value, it can occur through the natural width of the D/sup *//sup 0/. The D/sup +/ was reconstructed in the K/sup -/..pi../sup +/..pi../sup +/ decay mode. The mass difference distribution (K/sup -/..pi../sup +/..pi../sup +/..pi../sup +/) - (K/sup -/..pi../sup +/..pi../sup -/), which shows n… more
Date: January 1, 1987
Creator: Abachi, S.; Akerlof, C.; Baringer, P.; Blockus, D.; Brabson, B.; Brom, J.M. et al.
Partner: UNT Libraries Government Documents Department
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Dynamical evolution of cosmic strings

Description: The author have studied by means of numerical simulations the dynamical evolution of a network of cosmic strings, both in the radiation and matter era. Our basic conclusion is that a scaling solution exists, i.e., the string energy density evolves as t/sup -2/. This means that the process by which long strings dump their energy into closed loops (which can gravitationally radiate away) is efficient enough to prevent the string domination over other forms of energy. This conclusion does not depe… more
Date: May 11, 1988
Creator: Bouchet, F. R.
Partner: UNT Libraries Government Documents Department
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Status and first results of BNL experiment 777: A search for K/sup +/. -->. pi. /sup +/. mu. /sup +/e/sup -/ and a study of K/sup +/. -->. mu. /sup +/e/sup +/e/sup -/

Description: Results of our search for short lived neutral particles emitted in K/sup +/ decay are given. We also seek to make an accurate measurement of the branching ratio for ..pi../sup 0/ ..-->.. e/sup +/e/sup -/ by looking for the decay chain K/sup +/ ..-->.. ..pi../sup +/..pi../sup 0/, ..pi../sup 0/ ..-->.. e/sup +/e/sup -/. The world average branching ratio for this decay is (1.8 +- 0.7) x 10/sup -7/ based on about 30 events from two experiments. Theory predicts that this branching ratio should be of… more
Date: October 1, 1987
Creator: Baker, N. J.; Gordon, H. A.; Lazarus, D. M.; Polychronakos, V. A.; Rehak, P.; Tannenbaum, M. J. et al.
Partner: UNT Libraries Government Documents Department
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Measurements of f/sub 1/(1285). -->. pi. /sup +/. pi. /sup /minus//. pi. /sup +/. pi. /sup /minus//, /eta//sub c/. -->. /rho//sup 0//rho//sup 0/ and /eta//sub c/. -->. f/sub 2/(1270)f/sub 2/(1270) in radiative J//psi/ decays

Description: A measurement of J//psi/ ..-->.. ..gamma pi../sup +/..pi../sup /minus//..pi../sup +/..pi../sup /minus// is presented. The f/sub 1/(1285) is observed and its spin and parity are investigated. The /eta//sub c/ is observed to decay to /rho//sup 0//rho//sup 0/, and that first observation of /eta//sub c/ decays to f/sub 2/(1270)f/sub 2/(1270) is presented. 1 ref., 3 figs.
Date: August 1, 1988
Creator: Adler, J.; Becker, J. J.; Blaylock, G. T.; Bolton, T.; Brient, J. C.; Brown, J. S. et al.
Partner: UNT Libraries Government Documents Department
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Experimental studies of quasi-fission reactions

Description: A large body of experimental data on these fission-like processes have become available in recent years using a number of different target-projectile combinations. None of these experimental studies are specifically addressing the question of entrance channel effects. These effects are expected to play an important role if the dynamics in the approach phase of the reaction is responsible for the occurrence of quasi-fission. An alternate interpretation in terms of the disappearance of the fissio… more
Date: January 1, 1988
Creator: Back, B. B.; Glagola, B. G.; Henderson, D.; Kaufman, S. B.; Keller, J. G.; Sanders, S. J. et al.
Partner: UNT Libraries Government Documents Department
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Detecting the Heavy Higgs Boson at the SSC

Description: Detection of a heavy Higgs boson (2M/sub z/ < M/sub H/ < 1 TeV) is considered. The production mechanisms and backgrounds are discussed. Their implementation in the PYTHIA and ISAJET Monte Carlo programs are checked. The decay modes H ..-->.. ZZ ..-->.. llll and H ..-->.. ZZ ..-->.. llvv are discussed in detail. The signal/background is evaluated and some relevant detector parameters are specified. Some remarks are also made concerning the requirements imposed on detectors by the decay mode H ..… more
Date: December 18, 1987
Creator: Cahn, R. N.; Chanowitz, M.; Golden, M.; Herrero, M. J.; Hinchliffe, I.; Wang, E. M. et al.
Partner: UNT Libraries Government Documents Department
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University of Maryland Nuclear Chemistry annual progress report, (January 1991--January 1992)

Description: This report discusses: mass and charge distributions in Cl-induced heavy-ion reactions; comparison of mass and charge distributions to model predictions in deep inelastic reactions; the decay of hot nuclei formed in La-induced reactions at intermediate energies; and the Maryland very forward array.
Date: January 1, 1992
Creator: Mignerey, A.C.
Partner: UNT Libraries Government Documents Department
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Fragmentation and flow in central collisions

Description: Investigation of the fragmentation mechanism requires the measurement of complicated observables. To identify what part of the reacting system gives rise to the fragments, it would be useful to tag them as participants or spectators. A large acceptance for all the reaction products and an event-by-event measurement of the fragment multiplicity is required to distinguish fragment formation via sequential emission from a large equilibrated system and multifragmentation. In order to address whethe… more
Date: January 1, 1987
Creator: Jacak, B. V.; Doss, K. G. R.; Gustafsson, H. A.; Gutbrod, H.; Harris, J. W.; Kampert, K. H. et al.
Partner: UNT Libraries Government Documents Department
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Complex fragments from excited actinide nuclei: A new test of the finite range model

Description: Complex fragments ranging in charge from 7less than or equal toZless than or equal to45 have been detected in binary coincidence following the reaction of 8.4 MeV/u/sup 232/Th+/sup 12/C, and are shown to arise from the binary decay of a /sup 244/Cm compound nucleus. This work confirms earlier radiochemical observations of very light fragments in the fission fragment mass distribution, establishes their binary character, and interprets their yield in terms of finite range potential energy barrie… more
Date: May 1, 1988
Creator: Sarantities, D. G.; Bowman, D. R.; Wozniak, G. J.; Charity, R. J.; Liu, Z. H.; McDonald, R. J. et al.
Partner: UNT Libraries Government Documents Department
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Experimental review of J/psi decays

Description: This is a review of J/psi physics from e/sup +/e/sup -/ colliders presented at the Charm Workshop in Beijing, China. The review includes a brief historical summary of J/psi physics, a general discussion of theoretical models and detailed results on radiative and hadronic J/psi decays from the Mark III, DM2, Crystal Ball and MARK II groups. 119 refs., 13 figs., 10 tabs.
Date: September 1, 1987
Creator: Toki, W.H.
Partner: UNT Libraries Government Documents Department
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Measurement of the inclusive K/sub S//sup 0/ branching fraction in tau decay

Description: A data sample corresponding to an integrated luminosity of 300 pb/sup -1/ of e/sup +/e/sup -/ annihilations at 29 GeV was used to measure the inclusive branching fraction tau/sup -/ ..-->.. K/sub S//sup 0/X/sup -/nu/sub tau/. The experiment was performed using the High Resolution Spectrometer at the PEP storage ring. The measured branching fraction is (0.64 +- 0.15)%. The data are consistent with all K/sub S//sup 0/ coming from the Cabibbo-suppressed decay tau ..-->.. K*/sup -/(890)nu/sub tau/ … more
Date: January 1, 1987
Creator: Tschirhart, R.; Abachi, S.; Akerlof, C.; Baringer, P.; Blockus, D.; Brabson, B. et al.
Partner: UNT Libraries Government Documents Department
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Evidence for bimodal fission in the heaviest elements

Description: We have measured the mass and kinetic-energy partitioning in the spontaneous fission of five heavy nuclides: /sup 258/Fm, /sup 259/Md, /sup 260/Md /sup 258/No, and /sup 260/(104). Each was produced by heavy-ion reactions with either /sup 248/Cm, /sup 249/Bk, or /sup 254/Es targets. Energies of correlated fragments from the isotopes with millisecond half lives, /sup 258/No and /sup 260/(104), were measured on-line by a special rotating-wheel instrument, while the others were determined off-line … more
Date: August 1, 1987
Creator: Hulet, E. K.; Wild, J. F.; Lougheed, R. W.; Dougan, R. J.; Landrum, J. H.; Dougan, A. D. et al.
Partner: UNT Libraries Government Documents Department
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Improved calculation of the prompt fission neutron spectrum from the spontaneous fission of /sup 252/Cf

Description: An improved calculation is presented for the prompt fission neutron spectrum N(E) from the spontaneous fission of /sup 252/Cf. In this calculation the fission-spectrum model of Madland and Nix is used, but with several improvements leading to a physically more accurate representation of the spectrum. Specifically, the contributions to N(E) from the entire fission-fragment mass and charge distributions will be calculated instead of calculating on the basis of a seven-point approximation to the p… more
Date: January 1, 1988
Creator: Madland, D. G.
Partner: UNT Libraries Government Documents Department
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(p,n) systematics and the cosmological connection

Description: Inclusive measurements of (p,n) reactions at intermediate energies of 50 to 1000 MeV have yielded new information in recent years on the energy and target mass dependence for direct interactions in (p,n) reactions. Furthermore, central collision processes can add appreciably to the inelastic cross-section at intermediate energy producing intermediate mass fragments (IMF) in substantial yields at energies above 200 MeV. These systematics are of much value for interpreting cosmic-ray exposure tim… more
Date: January 1, 1987
Creator: Ward, T.E.; Breeden, J. & Porter, R.
Partner: UNT Libraries Government Documents Department
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Experimental studies of quasi-fission reactions

Description: A large number of recent experimental studies have shown that a substantial fraction of the total reaction cross section in heavy-ion reactions is found in fission-like processes, which do not result from the fission decay of a completely fused system. Following the suggestion of Swiatecki such processes, which represents a complete relaxation of the relative kinetic energy and a substantial amount of net mass transfer between the two fragments, are denoted quasi-fission reactions. They are dis… more
Date: January 1, 1988
Creator: Back, B.B.
Partner: UNT Libraries Government Documents Department
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