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Proposed vacuum ultraviolet laser in nitric oxide

(1989) 112-113

Authors:

SM Hooker, CE Webb

Abstract:

An optically pumped laser that operates in the VUV region of the spectrum with pulse energies in the millijoule range is proposed. The laser is expected to oscillate on ten to 13 new laser lines between 158 and 250 n. The transmission of the F2 pump laser output was measured as a function of NO pressure to deduce the absorption cross section. The absorption was also modeled using spectral rate equations. The model reproduces the observed transmission very well and predicts that the broadening of the absorption line is due to rapid quenching of the upper level. The measurements are not consistent with the results reported by T.J. McKee The predicted upper level population is of the order of 8 × 1014 cm-3 for an NO pressure of 800 mbar, which would give a small signal gain of ≈ 1 cm-1 for the strongest line. On the basis of this it appears to be possible to realize the proposed laser.

Study of intermittency in electron-positron annihilation into hadrons

Physics Letters B 231:4 (1989) 548-556

Authors:

W Braunschweig, R Gerhards, FJ Kirschfink, HU Martyn, HM Fischer, H Hartmann, J Hartmann, E Hilger, A Jocksch, R Wedemeyer, B Foster, AJ Martin, E Bernardi, J Chwastowski, A Eskreys, K Genser, H Hultschig, P Joos, H Kowalski, A Ladage, B Löhr, D Lüke, D Notz, JM Pawlak, KU Pösnecker, E Ros, D Trines, R Walczak, G Wolf, H Kolanoski, T Kracht, J Krüger, E Lohrmann, G Poelz, W Zeuner, D Binnie, J Hassard, J Shulman, D Su, I Tomalin, F Barreiro, A Leites, J Del Peso, PN Burrows, GP Heath, ME Veitch, JC Hart, DH Saxon, S Brandt, M Holder, Y Eisenberg, U Karshon, G Mikenberg, A Montag, D Revel, E Ronat, A Shapira, N Wainer, G Yekutieli, A Caldwell, D Muller, S Ritz, M Takashima, S Lan Wu, G Zobernig

Abstract:

Intermittency effects have been studied directly for the first time in e+e- annihilation, using 37 509 hadronic events at an average CM energy of 〈√s〉=35 GeV. The factorial moments F2, F3 and F4 are given for the rapidity distribution and for the two-dimensional distributions in rapidity and azimuthal angle. The effects of cuts in sphericity and particle momentum are large. Comparison with several fragmentation models are made; some models like the Lund model with O(αs2) matrix element give a qualitative description of the phenomena. The importance of detector effects is demonstrated. The results are discussed in terms of various suggested interpretations of this effect. © 1989.
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A measurement of muon pair production in e+e- annihilation at centre of mass energies {Mathematical expression} GeV

Zeitschrift für Physik C Particles and Fields 42:2 (1989) 348

Authors:

W Braunschweig, R Gerhards, FJ Kirschfink, HU Martyn, B Bock, HM Fischer, H Hartmann, J Hartmann, E Hilger, A Jocksch, R Wedemeyer, B Foster, AJ Martin, AJ Sephton, E Bernardi, J Chwastowski, A Eskreys, K Gather, K Genser, H Hultschig, P Joos, H Kowalski, A Ladage, B Löhr, D Lüke, P Mättig, D Notz, JM Pawlak, KU Pösnecker, E Ros, D Trines, R Walczak, G Wolf, H Kolanoski, T Kracht, J Krüger, E Lohrmann, G Poelz, W Zeuner, J Hassard, J Shulman, D Su, F Barreiro, L Hervas, A Leites, J del Peso, M Traseira, C Balkwill, MG Bowler, PN Burrows, RJ Cashmore, CM Hawkes, GP Heath, PN Ratoff, IM Silvester, IR Tomalin, ME Veitch, GE Forden, JC Hart, DH Saxon, S Brandt, M Holder, L Labarga, E Duchovni, Y Eisenberg, U Karshon, G Mikenberg, A Montag, D Revel, E Ronat, AN Wainer, G Yekutieli, D Muller, S Ritz, D Strom, M Takashima, SL Wu, G Zobernig
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Strange baryon production in e+e- annihilation

Zeitschrift für Physik C Particles and Fields 45:2 (1989) 209-222

Authors:

W Braunschweig, R Gerhards, FJ Kirschfink, HU Martyn, B Bock, HM Fischer, H Hartmann, J Hartmann, E Hilger, A Jocksch, R Wedemeyer, B Foster, AJ Martin, AJ Sephton, E Bernardi, J Chwastowski, A Eskreys, K Gather, K Genser, H Hultschig, P Joos, H Kowalski, A Ladage, B Löhr, D Lüke, P Mattig, D Notz, JM Pawlak, KU Posnecker, E Ros, W Schütte, D Trines, R Walczak, G Wolf, H Kolanoski, T Kracht, J Krüger, E Lohrmann, G Poelz, W Zeuner, DM Binnie, J Hassard, J Shulman, D Su, F Barreiro, A Leites, L Hervas, J del Peso, M Traseira, C Balkwill, MG Bowler, PN Burrows, RJ Cashmore, GP Heath, PN Ratoff, IM Silvester, IR Tomalin, ME Veitch, JM Yelton, SL Lloyd, GE Forden, JC Hart, DH Saxon, S Brandt, M Holder, L Labarga, Y Eisenberg, U Karshon, G Mikenberg, A Montag, D Revel, E Ronat, A Shapira, N Wainer, G Yekutieli, D Muller, S Ritz, D Strom, M Takashima, SL Wu, G Zobernig

Abstract:

The production of strange baryons in e+e- annihilation has been studied at centre of mass energies of 34.8 GeV and 42.1 GeV, using the TASSO detector at DESY. Inclusive cross-sections have been obtained for Λ0 and Ξ- production and an upper limit has been placed upon the production rate of Σ*±(1385). We measure the Λ0 multiplicity per event to be {Mathematical expression} and {Mathematical expression} at {Mathematical expression} and 42.1 GeV respectively. The Ξ- multiplicity per event is found to be {Mathematical expression} at {Mathematical expression}. An investigation has been made of the extent to which Λ0 are produced in pairs. The Λ0 cross-section has been studied as a function of event sphericity. © 1989 Springer-Verlag.
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Experimental study of jet masses in e+e- annihilation at c.m. energies between 12 and 43.5 GeV

Zeitschrift für Physik C Particles and Fields 45:1 (1989) 11-23

Authors:

W Braunschweig, R Gerhards, FJ Kirschfink, HU Martyn, HM Fischer, H Hartmann, J Hartmann, E Hilger, A Jocksch, R Wedemeyer, B Foster, AJ Martin, F Barreiro, E Bernardi, J Chwastowski, K Genser, H Kowalski, B Löhr, D Lüke, D Notz, JM Pawlak, KU Pösnecker, E Ros, R Walczak, G Wolf, H Kolanoski, T Kracht, J Krüger, E Lohrmann, G Poelz, W Zeuner, A Hassard, J Shulman, D Su, I Tomalin, A Leites, J del Peso, L Hervas, M Traseira, MG Bowler, PN Burrows, RJ Cashmore, GP Heath, ME Veitch, JC Hart, DH Saxon, S Brandt, M Holder, L Labarga, Y Eisenberg, U Karshon, G Mikenberg, A Montag, D Revel, E Ronat, AN Wainer, G Yekutieli, D Muller, S Ritz, M Takashima, SL Wu, G Zobernig, A Caldwell

Abstract:

Data on jet masses, resulting from the decomposition of e+e- hadronic final states into two hemispheres, are presented at centre of mass energies between 12 and 43.5 GeV. Comparisons are made with bare O(αs2) QCD predictions as well as with QCD based fragmentation models. Values for αs and {Mathematical expression} are determined, both with and without hadronization effects included. Upper and lower limits for {Mathematical expression} independent of fragmentation models have been determined to be 0.480±0.025 GeV and 0.047±0.007 GeV respectively. © 1989 Springer-Verlag.
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