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136 results on '"W. Schmidt-Parzefall"'

1. Alignment methods for the OPERA drift tube detector

Author

A. Hollnagel, C. Göllnitz, Torben Ferber, J. Ebert, Björn Wonsak, J. Lenkeit, W. Schmidt-Parzefall, B. Büttner, I. Rostovtseva, Yu. Zaitsev, D. Goloubkov, M. Hierholzer, and Caren Hagner

Subjects
Physics, Nuclear and High Energy Physics, Muon, Spectrometer, Physics::Instrumentation and Detectors, Detector, Nuclear physics, High Energy Physics::Experiment, Muon neutrino, Neutrino, Neutrino oscillation, Instrumentation, Beam (structure), Theodolite
Abstract

The goal of the OPERA experiment is to give the first direct evidence for neutrino oscillations in the channel ν μ → ν τ . The OPERA detector is designed to observe the appearance of tau neutrinos in the originally pure muon neutrino CNGS beam. An important part of the magnetic spectrometer is the Precision Tracker (PT), a drift tube detector consisting of 9504 drift tubes. Its main task is the determination of the muon charge and momentum. The alignment strategy for the PT consists of two parts: the hardware measurement by theodolite and the software alignment using long muon tracks. In this paper, the hardware and the software alignment are described, and the track-based alignment methods are explained in detail. Results of the software alignment are presented with a focus on the analysis of cosmic particles.

Published
2014

2. The gas system of the drift tube detector of the neutrino experiment OPERA

Author

J. Lenkeit, D. Bick, Björn Wonsak, R. Zimmermann, J. Ebert, Torben Ferber, Caren Hagner, B. Janutta, M. Hierholzer, W. Schmidt-Parzefall, and C. Göllnitz

Subjects
Physics, Nuclear and High Energy Physics, Argon, Radioactive source, Detector, Analytical chemistry, chemistry.chemical_element, Oxygen, law.invention, Nuclear physics, Pressure measurement, chemistry, Neutrino detector, law, Gas detector, Neutrino, Instrumentation
Abstract

The gas system of the drift tube detector of the neutrino experiment OPERA is presented. The drift tube detector, called precision tracker (PT), consists of 10 000 thinwalled aluminum tubes of 38 mm diameter and 8 m length filled with an 80% Ar 20% CO 2 gas mixture. The total gas volume amounts to 80 m 3 . During stable operation the gas is exchanged once per 80 h and not recycled. Thus about 1 m3 per hour is consumed. Argon and CO 2 are stored and supplied in liquid form. Subsequently they are mixed and the composition ratio is regulated with a precision better than 1% per component. Inside the drift tubes the gas is kept at a constant absolute pressure within ± 0.5 % . Since the experiment is operated in the low activity environment of the Gran Sasso underground laboratory, monitoring of the gas quality with a radioactive source is prohibited. Instead the oxygen content of the used gas is measured. We report on the first experience with the performance of the gas system.

Published
2008

3. The precision tracker of the OPERA detector

Author

J. Ebert, V. Saveliev, J. Sewing, W. Schmidt-Parzefall, R. Zimmermann, B. Koppitz, Caren Hagner, and Yu. Zaitsev

Subjects
Physics, Nuclear and High Energy Physics, Muon, Argon, Comparator, Physics::Instrumentation and Detectors, business.industry, Amplifier, Detector, chemistry.chemical_element, Signal, Optics, chemistry, Muon spectrometer, business, Instrumentation, Ultrashort pulse
Abstract

The Precision Tracker of the muon spectrometer of the OPERA detector consists of ∼ 10000 aluminum drift tubes of 8 m length. They have an outer diameter of 38 mm and a wall thickness of 0.85 mm. The challenge of the detector design originates from the 8 m length of the drift tubes, a detector length, which has not been used before. Tight mechanical tolerances for positioning and alignment of the signal wires are required in order to make a significant measurement of the sign of the muon charge. The detector is manufactured in modules, which are 50 cm wide, each consisting of four adjacent drift tube planes. This guarantees high efficiency and complete rejection of the left–right ambiguity. The details of the novel mechanical design are described in this paper. For safety reasons, the drift tubes are operated with an Argon / CO 2 gas mixture. The gas volume of the drift tubes is entirely sealed with O-rings, in order to avoid ageing problems. The total gas volume amounts to about 80 m 3 . The front end electronics of the drift tubes consist of a bootstrap amplifier followed by a commercial ultrafast comparator. Thus only digital LVDS signals are transmitted over large distances. We report on the development and performance of the first two prototype modules of the precision tracker including test measurements of the resolution and efficiency obtained.

Published
2005

4. A search for the electric dipole moment of the τ-lepton

Author

H. Albrecht, T. Hamacher, R.P. Hofmann, T. Kirchhoff, R. Mankel, A. Nau, S. Nowak, D. Reßing, H. Schröder, H.D. Schulz, M. Walter, R. Wurth, C. Hast, H. Kapitza, H. Kolanoski, A. Kosche, A. Lange, A. Lindner, M. Schieber, T. Siegmund, H. Thurn, D. Töpfer, D. Wegener, C. Frankl, J. Graf, M. Schmidtler, M. Schramm, K.R. Schubert, R. Schwierz, B. Spaan, R. Waldi, K. Reim, H. Wegener, R. Eckmann, H. Kuipers, O. Mai, R. Mundt, T. Oest, R. Reiner, A. Rohde, W. Schmidt-Parzefall, J. Stiewe, S. Werner, K. Ehret, W. Hofmann, A. Hüpper, K.T. Knöpfle, J. Spengler, P. Krieger, D.B. MacFarlane, J.D. Prentice, P.R.B. Saull, K. Tzamariudaki, R.G. Van de Water, T.-S. Yoon, M. Schneider, S. Weseler, M. Bračko, G. Kernel, P. Križan, E. Križnič, G. Medin, T. Podobnik, T. Živko, V. Balagura, S. Barsuk, I. Belyaev, R. Chistov, M. Danilov, V. Eiges, L. Gershtein, Yu. Gershtein, A. Golutvin, O. Igonkina, I. Korolko, G. Kostina, D. Litvintsev, P. Pakhlov, S. Semenov, A. Snizhko, I. Tichomirov, and Yu. Zaitsev

Subjects
Systematic error, Physics, Nuclear and High Energy Physics, Particle physics, Argus, 010308 nuclear & particles physics, FOS: Physical sciences, Observable, 01 natural sciences, High Energy Physics - Experiment, High Energy Physics - Experiment (hep-ex), Dipole, Electric dipole moment, 0103 physical sciences, CP violation, 010306 general physics, computer, Storage ring, Lepton, computer.programming_language
Abstract

Using the ARGUS detector at the e+e- storage ring DORIS II, we have searched for the real and imaginary part of the electric dipole formfactor d_tau of the tau lepton in the production of tau pairs at q^2=100 GeV^2. This is the first direct measurement of this CP violating formfactor. We applied the method of optimised observables which takes into account all available information on the observed tau decay products. No evidence for CP violation was found, and we derive the following results: Re(d_tau)=(1.6+-.9)*10^(-16) ecm and Im(d_tau)=(-0.2+-0.8)*10^(-16) ecm, where statistical and systematic errors have been combined., 8 pages, 5 figures (10 subfigures)

Published
2000

5. Application of liquid-core fibres for a radiation-hard vertex detector

Author

K. Hoepfner and W. Schmidt-Parzefall

Subjects
Vertex (graph theory), Physics, Nuclear and High Energy Physics, business.industry, Detector, Resolution (electron density), Radiation, Optics, High Energy Physics::Experiment, Vertex detector, Particle beam, business, Instrumentation, Radiation resistance, Mixing (physics)
Abstract

We propose a novel vertex detector based on liquid-core fibers which can reach and exceed the performance of the current HERA-B vertex detector, while offering even greater resistance to aging due to radiation effects. This radiation resistance would provide an improved vertex resolution by allowing one to place the detector elements closer to the particle beam, and thus provide an improvement in the measurement of B s , mixing while extending the accessible region of x s .

Published
2000

6. Tests of a multianode PMT for the HERA-B RICH

Author

C. Oehser, R. Pestotnik, P. Križan, W. Schmidt-Parzefall, M. Starič, Aleš Stanovnik, A. S. Schwarz, Samo Korpar, D. Broemmelsiek, J. Pyrlik, E. Michel, and T. Hamacher

Subjects
Physics, Nuclear and High Energy Physics, Photomultiplier, Argon, Perfluorobutane, Physics::Instrumentation and Detectors, business.industry, chemistry.chemical_element, chemistry.chemical_compound, Optics, chemistry, business, Instrumentation, Photon detection, Cherenkov radiation, HERA-B
Abstract

A new multianode photomultiplier tube, type H6568 manufactured by Hamamatsu company, has been tested in view of using it for measuring Cherenkov rings in the HERA-B experiment. The results of measurements of single-photoelectron pulse-height distributions, uniformity of response, cross-talk, photon detection efficiency, rate dependence of the gain and ageing will be presented and discussed. In addition, the response of the PMT to scintillations of perfluorobutane (C 4 F 10 ), argon and air has been measured.

Published
1997

7. Evidence for Λc(2593)+ production

Author

D. O. Litvintsev, R. Mundt, C. Frankl, B. Spaan, H. Thurn, Ruslan Chistov, P. Pakhlov, V. Eiges, R. Waldi, R. P. Hofmann, P. R.B. Saull, D. B. MacFarlane, Sebastian Nowak, D. Wegener, J. Spengler, T. Siegmund, A. Snizhko, W. Schmidt-Parzefall, T. Oest, M. Schramm, H. Kapitza, H. Kuipers, A. Nau, I. Korolko, Michael Schneider, Holger Schulz, Peter Krieger, Sergey Semenov, M. Bracko, G. Kernel, Hermann Kolanoski, H. Wegener, S. Weseler, T. Živko, H. Schröder, T. S. Yoon, R. Schwierz, T. Podobnik, G. Medin, O. Igonkina, Klaus R. Schubert, K. T. Knöpfle, Ivan Belyaev, L. Gershtein, Sergey Barsuk, J.D. Prentice, A. Lindner, M. Schieber, C. Hast, Thomas Hamacher, S. Werner, J. Graf, K. Tzamariudaki, D. Töpfer, A. Lange, M. Walter, R. G. Van de Water, O. Mai, A. Rohde, R. Eckmann, Yu. Zaitsev, K. Reim, H. Albrecht, R. Mankel, R. Wurth, T. Kirchhoff, E. Križnič, P. Križan, A. Golutvin, Yu. Gershtein, J. Stiewe, D. Reßing, I. Tichomirov, M. Schmidtler, A. Hüpper, Vladislav Balagura, Mikhail Danilov, A. Kosche, Werner Hofmann, K. Ehret, G. Kostina, and R. Reiner

Subjects
Baryon, Physics, Nuclear and High Energy Physics, Argus, Electron–positron annihilation, Excited state, DESY, Atomic physics, computer, computer.programming_language
Abstract

Using the ARGUS detector at the e+e− storage ring DORIS II at DESY, we have found evidence for the production of the excited charmed baryon state Λc(2593)+ in the channel Λc+π+π−. Its mass was determined to be (2594.6±0.9±0.4) MeV/c2, and the natural width measured to be Γ = (2.9−2.1−1.4+2.9+1.8) MeV. The production cross section times the branching ratios of σ(e+e− → Λc(2593)+X) × Br(Λc(2593)+ → Λc+π+π−) × Br(Λc+ → pK−π+) was measured to be (0.25−0.13+0.24 ±0.13) pb. The fractions of Λc(2593)+ decays proceeding through the Σc0π+ and Σc++π− channels were determined to be 0.29±0.10±0.11 and 0.37±0.12±0.13, respectively.

Published
1997

8. Photon detectors for the HERA-B RICH

Author

T. Hamacher, P. Weyers, Peter Krizan, M. Cindro, C. Oehser, Samo Korpar, D. Skrk, W. Schmidt-Parzefall, D. Broemmelsiek, R. Pestotnik, J. Pyrlik, Aleš Stanovnik, A. Bulla, E. Michel, and M. Starič

Subjects
Physics, Nuclear and High Energy Physics, Photomultiplier, Physics::Instrumentation and Detectors, Photon detector, Detector, Anode, Nuclear physics, Radiation damage, High Energy Physics::Experiment, Quantum efficiency, Instrumentation, Photon detection, HERA-B
Abstract

Results of tests of different position-sensitive photon detectors for the HERA-B RICH are given. It is observed, that the CsI-MWPC cannot be routinely produced and maintained with sufficiently high quantum efficiency and that the TMAE detector loses anode wire gain too quickly. The third candidate, the H-6568 Hamamatsu multianode PMT, seems to meet all the requirements necessary for photon detection in the HERA-B RICH.

Published
1997

9. Two measurements of mixing using kaon tagging

Author

H. Wegener, R. Schwierz, R. G. Van de Water, T. Podobnik, H. Albrecht, J. Spengler, A. Hüpper, T. S. Yoon, R. Mankel, Klaus R. Schubert, R. Waldi, W. Schmidt-Parzefall, R. Wurth, R. Mundt, O. Igonkina, R. P. Hofmann, H. Kuipers, Yu. Gershtein, J. Stiewe, C. Frankl, Ivan Belyaev, A. Nau, S. Werner, C. Hast, Michael Schneider, D. Reßing, Sergey Semenov, G. Kernel, Hermann Kolanoski, M. Walter, H. Thurn, J. D. Prentice, T. Oest, R. Chistov, I. Tichomirov, A. Lange, Sebastian Nowak, J. Graf, K. Ehret, L. Gershtein, D. Wegener, D. Töpfer, P. Eckstein, O. Mai, I. Korolko, D. O. Litvintsev, M. Schramm, Vladislav Balagura, T. Kirchhoff, V. Eiges, B. Spaan, P. Krieger, M. Schieber, H. Kapitza, P. Pakhlov, G. Kostina, Thomas Hamacher, Axel Lindner, K. Reim, M. Schmidtler, R. Reiner, H. Schröder, Mikhail Danilov, R. Eckmann, Yu. Zaitsev, Holger Schulz, A. Kosche, K. T. Knöpfle, E. Križnič, T. Živko, Werner Hofmann, S. Weseler, D. B. Macfarlane, P. R. B. Saull, P. Križan, A. Golutvin, T. Siegmund, K. Tzamariudaki, and A. Snizhko

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Argus, Branching fraction, Electron–positron annihilation, DESY, Multiplicity (mathematics), computer, Mixing (physics), computer.programming_language
Abstract

Using the ARGUS detector at the e+e− storage ring DORIS II at DESY, we have made two measurements of the mixing parameter χd using kaons as flavour tags. Using D∗+ K± correlations we found χd = 0.20 ± 0.13 ± 0.12 and from the study of (D∗+l−) K± correlations we obtained χd = 0.19 ± 0.07 ± 0.09. The branching ratio for B → D∗+ X has been updated: Br(B → D∗+ X) = (19.6 ± 1.9)%. We have also determined the average multiplicity of charged kaons in B0 decays to be 0.78 ± 0.08.

Published
1996

10. Two-photon production of ω pairs

Author

Sebastian Nowak, D. Wegener, Mikhail Danilov, J. Spengler, T. Siegmund, M. Schramm, A. Kosche, R. Mundt, Axel Lindner, K. Ehret, C. Frankl, G. Kernel, R. Chistov, G. Kostina, Ivan Belyaev, R. Reiner, Werner Hofmann, A. Lange, I. Korolko, I. Tichomirov, H. Thurn, T. Oest, W. Schmidt-Parzefall, J. Stiewe, O. Mai, T. S. Yoon, O. Igonkina, D. Reßing, K. T. Knöpfle, J. Graf, V. Eiges, Klaus R. Schubert, H. Kuipers, D. Töpfer, Holger Schulz, P. R. B. Saull, A. Hüpper, H. Wegener, M. Schieber, T. Živko, R. P. Hofmann, T. Podobnik, H. Kapitza, K. Reim, Yu. Gershtein, P. Pakhlov, M. Schmidtler, R. Waldi, S. Weseler, R. G. Van de Water, C. Hast, Michael Schneider, A. Nau, Sergey Semenov, Hermann Kolanoski, Vladislav Balagura, L. Gershtein, Thomas Hamacher, P. Eckstein, R. Schwierz, D. O. Litvintsev, B. Spaan, H. Schröder, M. Walter, S. Werner, Sergey Barsuk, H. Albrecht, R. Mankel, R. Wurth, J. D. Prentice, P. Krieger, T. Kirchhoff, R. Eckmann, Yu. Zaitsev, K. Tzamariudaki, A. Snizhko, E. Križnič, D. B. Macfarlane, P. Križan, and A. Golutvin

Subjects
Physics, Nuclear and High Energy Physics, Cross section (physics), Argus, Two-photon excitation microscopy, Value (computer science), Production (computer science), Maximum likelihood analysis, Atomic physics, computer, Omega, computer.programming_language
Abstract

A maximum likelihood analysis of ARGUS data on two-photon production of π+π+π0π0π−π− is presented. A small fraction of events is due to the production of omega pairs. The γγ → ωω cross section has its maximum value close to threshold.

Published
1996

11. Measurement of the semileptonic branching fractions of the D0 meson

Author

I. Korolko, A. Snizhko, R. G. Van de Water, S. Weseler, Yu. Gershtein, J. Stiewe, R. Waldi, P. R. B. Saull, D. Reßing, M. Schieber, Ivan Belyaev, T. Oest, Klaus R. Schubert, A. Lindner, R. Mundt, M. Walter, J. Graf, D. Töpfer, R. Schwierz, C. Frankl, Mikhail Danilov, Michael Schneider, H. Kapitza, Olga Igonkina, M. Schmidtler, H. Wegener, J. Spengler, T. Siegmund, T. Podobnik, D. O. Litvintsev, H. Thurn, Sebastian Nowak, A. Kosche, T. S. Yoon, B. Spaan, G. Kernel, R. Chistov, P. Pakhlov, D. Wegener, V. Eiges, W. Schmidt-Parzefall, Werner Hofmann, I. Tichomirov, Vladislav Balagura, M. Schramm, L. Gershtein, P. Eckstein, Thomas Hamacher, K. Tzamariudaki, H. Kuipers, A. Nau, Sergey Semenov, Holger Schulz, Hermann Kolanoski, K. T. Knöpfle, H. Schröder, K. Reim, T. Živko, A. Hüpper, R. P. Hofmann, R. Eckmann, Yu. Zaitsev, T. Kirchhoff, S. Werner, H. Albrecht, R. Mankel, R. Wurth, Sergey Barsuk, C. Hast, A. Lange, O. Mai, E. Križnič, P. Krieger, J. D. Prentice, D. B. Macfarlane, P. Križan, A. Golutvin, K. Ehret, G. Kostina, and R. Reiner

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Argus, Annihilation, Meson, Branching fraction, Hadron, Analytical chemistry, Branching (polymer chemistry), computer, Particle Physics - Experiment, computer.programming_language
Abstract

Using the ARGUS detector at the e + e − storage ring DORIS II, we have measured the semileptonic branching ratios of the D 0 meson to be Br ( D 0 → e + ν e X ) = (6.9 ± 0.3 ± 0.5) % and Br ( D 0 → μ + ν μ X ) = (6.0 ± 0.7 ± 1.2) %, and the semileptonic branching ratio of the charmed hadron mixture from e + e − annihilation around 10 GeV to be Br ( c → e + ν e X ) = (9.6 ± 0.4 ± 1.1) %.

Published
1996

12. The RICH detector for HERA-B

Author

D. Skrk, A. Bulla, R. F. Schwitters, P. Kriẑan, T. Hamacher, Griša Močnik, M. Zavrtanik, E. Michel, M. Cindro, Samo Korpar, W. Schmidt-Parzefall, P. Weyers, Aleš Stanovnik, and M. Starič

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Physics::Instrumentation and Detectors, Cherenkov detector, Astrophysics::High Energy Astrophysical Phenomena, Detector, Astrophysics::Instrumentation and Methods for Astrophysics, Ring (chemistry), law.invention, law, High Energy Physics::Experiment, Instrumentation, Cherenkov radiation, HERA-B
Abstract

The expected performance of the Ring Imaging Cherenkov (RICH) detector to be used in the HERA-B experiment is discussed.

Published
1996

13. A TMAE based photon detector for the HERA-B RICH

Author

P. Križan, T. Hamacher, P. Weyers, W. Schmidt-Parzefall, E. Michel, Samo Korpar, and M. Starič

Subjects
Physics, Nuclear and High Energy Physics, business.industry, Detector, Photon detector, Condensation, DESY, HERA, Optics, Test beam, Absorption (electromagnetic radiation), business, Instrumentation, HERA-B
Abstract

In the framework of the recently approved HERA-B experiment at DESY, a photon detector based on TMAE is investigated for a possible later use in the HERA-B RICH detector. To avoid condensation of TMAE, the partial pressure of TMAE is kept as low as possible. The lower absorption is compensated by a longer absorption path in the chamber. The chamber is made up of rectangular cells, 10 cm long with a 0.8 × 0.8 cm 2 base. The results are presented of test beam studies that have been carried out since spring 1994 with a 32 × 32 channel prototype chamber in a setup at the DESY test beam facility.

Published
1996

14. Tests of photon detectors for the HERA-B RICH

Author

M. Starič, M. Zavrtanik, P. Križan, D. Skrk, P. Weyers, Samo Korpar, M. Cindro, W. Schmidt-Parzefall, Aleš Stanovnik, E. Michel, and T. Hamacher

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Wire chamber, Pion, Physics::Instrumentation and Detectors, Photon detector, High Energy Physics::Experiment, DESY, Instrumentation, Cherenkov radiation, Photocathode, HERA-B
Abstract

A multiwire proportional chamber with CsI photocathode pads and a TMAE based photon detector have been tested in order to evaluate their potential as candidates for a fast ring imaging Cherenkov counter, to be used for separation of pions from kaons in the HERA-B experiment proposed at DESY. Results of the tests are presented.

Published
1995

15. Tests of rich photon detectors for the HERA-B experiment

Author

T. Hamacher, E. Michel, Peter Krizan, M. Zavrtanik, Aleš Stanovnik, Samo Korpar, P. Weyers, D. Skrk, M. Cindro, M. Starič, and W. Schmidt-Parzefall

Subjects
Physics, Nuclear and High Energy Physics, Wire chamber, Photon, Physics::Instrumentation and Detectors, Cherenkov detector, DESY, Atomic and Molecular Physics, and Optics, Photocathode, law.invention, Nuclear physics, Pion, law, High Energy Physics::Experiment, Cherenkov radiation, HERA-B
Abstract

A multiwire proportional chamber with CsI photocathode pads and a TMAE based photon detector have been tested in order to evaluate their potential as candidates for a fast ring imaging Cherenkov counter, to be used for separation of pions from kaons in the HERA-B experiment proposed at DESY. Results of the tests are presented and the following parameters are discussed: the number of photons detected per ring, resolution of the Cherenkov angle, photoelectron drift time distribution, fraction of clusters and avalanche photon feedback.

Published
1995

16. The first measurement of the Michel parameter η in τ decays

Author

Mikhail Danilov, Ivan Belyaev, G. Kostina, Klaus R. Schubert, T. S. Yoon, R. Schwierz, S. Weseler, A. Nau, Sergey Semenov, D. O. Litvintsev, R. Reiner, A. Kosche, Yuri Gershtein, B. Spaan, Hermann Kolanoski, D. Töpfer, I. Korolko, P. Pakhlov, P. Eckstein, H. Schröder, R. P. Hofmann, P. R.B. Saull, V. Lubimov, T. Siegmund, Werner Hofmann, Sebastian Nowak, D. Wegener, M. Schmidtler, R. G. Van de Water, I. Tichomirov, J. Stiewe, H. Wegener, K. T. Knöpfle, S. Chechelnitsky, R. Mundt, D. Reßing, P. Krieger, K. Ehret, A. Snizhko, C. Hast, H. Thurn, T. Podobnik, J. Spengler, Michael Schneider, E. Križnič, H. Kapitza, A. Hüpper, D. B. MacFarlane, Holger Schulz, K. Reim, J. D. Prentice, R. Waldi, Axel Lindner, T. Živko, A. Droutskoy, G. Kernel, A. Lange, C. Frankl, M. Walter, T. Oest, O. Mai, M. Schieber, R. Eckmann, Thomas Hamacher, Yu. Zaitsev, S. Werner, K. Tzamariudaki, P. Križan, A. Golutvin, W. Schmidt-Parzefall, Vladislav Balagura, H. Kuipers, T. Kirchhoff, H. Albrecht, R. Mankel, and R. Wurth

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Argus, Electron–positron annihilation, Hadron, DESY, Spectral line, Vertex (geometry), Nuclear physics, High Energy Physics::Experiment, computer, Storage ring, computer.programming_language, Lepton
Abstract

Using the ARGUS detector at the e+e - storage ring DORIS II at DESY, we have studied lepton energy spectra in ~- decays. We present a "pseudo-rest-frame" technique in which the second r in the event, decaying into a heavy hadronic system, is used as reference. This method allows for the first measurement of the Michel Parameter 7/in ~- decays. We also determine the Michel Parameter p in 7" --~ e~u decays with a precision comparable to the present world average. The measured values of the parameters p = 0.735 4- 0.036 4- 0.020 and r 1 = 0.03 4- 0.18 4- 0.12 are in good agreement with standard V-A coupling at the ~--~,-W vertex.

Published
1995

17. Evidence for W-exchange in charmed baryon decays

Author

S. Werner, D. O. Litvintsev, H. Schröder, Vladislav Balagura, B. Spaan, M. Walter, H. Wegener, Klaus R. Schubert, P. Krieger, T. Podobnik, I. Tichomirov, V. Lubimov, R. Waldi, M. Schieber, R. Mundt, I. Korolko, G. Kostina, H. Albrecht, R. Mankel, R. Wurth, P. R. B. Saull, Sebastian Nowak, D. Wegener, P. Križan, A. Golutvin, P. Eckstein, H. Thurn, Axel Lindner, Thomas Hamacher, S. Weseler, R. Schwierz, R. Reiner, Sally Seidel, H. Kapitza, A. Hüpper, T. Oest, Ivan Belyaev, Holger Schulz, J. D. Prentice, E. Križnič, A. Nau, Sergey Semenov, J. Stiewe, W. Schmidt-Parzefall, A. Snizhko, C. Frankl, R. P. Hofmann, S. Chechelnitsky, Hermann Kolanoski, K. Ehret, M. Schmidtler, H. Kuipers, C. E. K. Charlesworth, D. Töpfer, K. T. Knöpfle, T. Živko, T. Kirchhoff, D. B. Macfarlane, Mikhail Danilov, U. Becker, A. Droutskoy, D. Reßing, P. Pakhlov, T. Siegmund, J. Spengler, A. Kosche, A. Lange, G. Kernel, P. Eckmanm, K. Reim, O. Mai, Werner Hofmann, C. Hast, Michael Schneider, Yu. Zaitsev, Yu. Gershtein, T. S. Yoon, R. G. Van de Water, and K. Tzamariudaki

Subjects
Nuclear physics, Physics, Baryon, Nuclear and High Energy Physics, Argus, Particle physics, Branching fraction, Electron–positron annihilation, Mass spectrum, DESY, computer, computer.programming_language
Abstract

Using the detector ARGUS at the e+e− storage ring DORIS II at DESY, we have observed the decays Λc+ → Ξ−K+π+ and Λc+ → Ξ∗0K+ and obtained evidence for the decay Ξc0 → ΛKs0. All three of these decays are of interest as they provide information about W-exchange processes. The products of cross sections and branching ratios for Λc+ → Ξ−K+π+ and Λc+ → Ξ∗0K+ are (1.7±0.3±0.3) pb and (0.6±0.2±0.1) pb, respectively, which implies that (35±17) % of the Ξ−K+π+ final state is generated through a two-body decay via intermediate W-exchange. The product of production cross section and branching ratio for Ξc0 → Λ Ks0 is (2.1 ± 1.0 ± 0.6) pb.

Published
1995

18. Measurement of the polarization in the decay

Author

A. Snizhko, Holger Schulz, W. Schmidt-Parzefall, H. Kapitza, T. Živko, Ivan Belyaev, K. Tzamariudaki, H. Kuipers, R. Mundt, D. Töpfer, Yu. Gershtein, S. Weseler, R. G. Van de Water, Mikhail Danilov, L. Gershtein, H. Thurn, J. Stiewe, M. Schieber, Sebastian Nowak, T. Siegmund, R. Waldi, A. Droutskoy, D. Wegener, I. Korolko, E. Križnič, A. Kosche, G. Kostina, P. Pakhlov, M. Schramm, A. Lange, T. Kirchhoff, D. B. Macfarlane, Werner Hofmann, A. Hüpper, K. Reim, H. Wegener, T. Podobnik, R. Reiner, O. Mai, Vladislav Balagura, T. S. Yoon, K. T. Knöpfle, Axel Lindner, S. Barsuk, C. Hast, Michael Schneider, R. Chistov, I. Tichomirov, Klaus R. Schubert, D. Reβing, A. Nau, Sergey Semenov, H. Albrecht, R. Mankel, Hermann Kolanoski, J. Spengler, R. Wurth, T. Oest, P. R. B. Saull, P. Križan, A. Golutvin, M. Schmidtler, G. Kernel, Thomas Hamacher, K. Ehret, R. Schwierz, D. O. Litvintsev, B. Spaan, P. Eckstein, H. Schröder, M. Walter, R. P. Hofmann, P. Krieger, J. D. Prentice, C. Frankl, S. Werner, R. Eckmann, and Yu. Zaitsev

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Argus, Particle physics, Electron–positron annihilation, CP violation, Polarization (waves), computer, Storage ring, computer.programming_language
Abstract

Polarization in the exclusive decay B → J/ψK ∗ was measured using the ARGUS detector at the e+e− storage ring DORIS II. The ratio of the transverse to the total decay width was found to be ΓT/Γ = 0.03±0.16±0.15. This measurement demonstrates that the B 0 → J/ψK ∗0 decay channel can be effectively used for CP violation studies.

Published
1994

19. Measurement of the absolute branching fractions for D0 decays into

Author

Sebastian Nowak, D. Wegener, M. Walter, R. Schwierz, V. Lubimov, E. Gershtein, M. Schieber, M. Schmidtler, T. Oest, W. Schmidt-Parzefall, I. Korolko, G. Kernel, Klaus R. Schubert, R. Eckmann, Yu. Zaitsev, H. Schröder, H. Kuipers, H. Wegener, C. Hast, S. Werner, T. Kirchhoff, R. G. Van de Water, T. Podobnik, A. Lange, S. Barsuk, G. Kostina, A. Lindner, R. Waldi, T. Siegmund, D. O. Litvintsev, O. Mai, Michael Schneider, Vladislav Balagura, Mikhail Danilov, John D. Spengler, T. S. Yoon, B. Spaan, Thomas Hamacher, H. Albrecht, R. Reiner, R. Mankel, R. Wurth, P. Pakhlov, K. T. Knöpfle, P. R. B. Saull, H. Kapitza, P. Eckstein, K. Ehret, R. P. Hofmann, M. Schram, Ivan Belyaev, A. Kosche, D. Töpfer, A. Droutskoy, Werner Hofmann, I. Tichomirov, Holger Schulz, A. Nau, Sergey Semenov, Hermann Kolanoski, A. Hüpper, T. Živko, K. Tzamariudaki, R. Mundt, A. Snizhko, H. Thurn, J. Stiewe, D. Reβing, K. Reim, Yu. Gershtein, S. Weseler, P. Krieger, J. D. Prentice, C. Frankl, E. Križnič, D. B. Macfarlane, P. Križan, and A. Golutvin

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Argus, Crystallography, Angular distribution, Meson, Electron–positron annihilation, Branching (polymer chemistry), computer, computer.programming_language
Abstract

Using the ARGUS detector at the e+ e− storage ring DORIS II we have measured the absolute branching ratios of the D0 meson, Br(D0→K− π+)=(3.41±0.12±0.28)%, Br(D0→K− π+ π+ π−)=(6.80± 0.27±0.57)%, and Br (D 0 → K 0 π + π − )=(5.03±0.39±0.49)% .

Published
1994

20. Determination of the structure of τ decays in the reaction and a precision measurement of the τ-neutrino helicity

Author

I. Tichomirov, A. Lange, Ivan Belyaev, T. Oest, O. Mai, E. Križnič, Vladislav Balagura, S. Weseler, T. Kirchhoff, R. Mundt, Sebastian Nowak, D. Wegener, D. O. Litvintsev, A. Snizhko, H. Thurn, Mikhail Danilov, D. Töpfer, T. S. Yoon, B. Spaan, I. Korolko, J. D. Prentice, Axel Lindner, V. Lubimov, A. Kosche, Yuri Gershtein, J. Stiewe, M. Schramm, S. Werner, P. Pakhlov, H. Wegener, W. Schmidt-Parzefall, M. Schmidtler, D. Reßing, C. Hast, Michael Schneider, D. B. MacFarlane, R. Waldi, T. Podobnik, R. P. Hofmann, P. R.B. Saull, Werner Hofmann, A. Hüpper, Thomas Hamacher, H. Kapitza, M. Walter, P. Krieger, H. Albrecht, R. Mankel, A. Droutskoy, P. Križan, A. Golutvin, R. Wurth, Holger Schulz, C. Frankl, R. Eckmann, Yu. Zaitsev, P. Eckstein, T. Živko, H. Kuipers, R. Schwierz, H. Schröder, T. Siegmund, K. Reim, A. Nau, Sergey Semenov, Hermann Kolanoski, S. Chechelnitsky, K. Ehret, G. Kostina, R. Reiner, M. Schieber, K. Tzamariudaki, R. G. Van de Water, K. R. Schubert, J. Spengler, G. Kernel, and K. T. Knöpfle

Subjects
Physics, Pseudoscalar, Nuclear and High Energy Physics, Particle physics, Absolute value, Neutrino, Helicity, Pseudovector, Standard Model, Spin-½, Lepton
Abstract

Using the ARGUS detector at the DORIS II storage ring we have investigated the Lorentz structure of the electroweak interaction in semi-hadronic τ decays. Spin correlations in the process e + e − → τ + τ − → v τ π + π 0 v τ π − π 0 are exploited for a measurement of the normalized product of the vector ( g V ) and axial vector ( g A ) couplings of the τ lepton, γin AV = 2 Re {g A g V ∗ } (|g V | 2 ) . The correlations are sensitive to the product of the couplings in both τ decays: γ AV 2 = γ AV (τ − → ν τ W − ) AV = −h(v τ )h( v τ ) . The measured value, γ AV 2 = 1.044±0.057±0.060, determines the relative sign of the neutrino helicities. Assuming CP invariance, the absolute value | γ AV | = 1.022±0.028±0.030 was found to be incellent agreement with the Standard Model. The contribution of scalar ( g s ) or pseudoscalar ( g P ) couplings was also investigated. No evidence for a scalar-like coupling was found.

Published
1994

21. Determination of the radiative decay width of the η meson

Author

I. Korolko, Klaus R. Schubert, K. Reim, Sebastian Nowak, Mikhail Danilov, A. Hüpper, D. Wegener, A. Kosche, J. Spengler, Werner Hofmann, G. Kostina, R. Mundt, A. Nau, Sergey Semenov, T. Oest, K. Tzamariudaki, H. Albrecht, Thomas Hamacher, Hermann Kolanoski, R. Mankel, R. Wurth, Yu. Gershtein, M. Schramm, S. Werner, R. Reiner, T. S. Yoon, H. Thurn, P. Kržan, A. Snizhko, P. Eckstein, H. Kapitza, H. Wegener, V. Lubimov, S. Weseler, P. Pakhlov, M. Walter, D. O. Litvintsev, D. Reβing, P. Krieger, Ivan Belyaev, T. Podobnik, G. Kernel, B. Spaan, J. Stiewe, J. D. Prentice, R. G. Van de Water, C. Frankl, D. Töpfer, Axel Lindner, Holger Schulz, R. P. Hofmann, C. Hast, Michael Schneider, T. Kirchhoff, S. Chechelnitsky, R. Schwierz, M. Schmidtler, T. Živko, R. Waldi, M. Schieber, K. Ehret, A. Droutskoy, H. Schröder, R. Eckmann, Yu. Zaitsev, K. T. Knöpfle, A. Golutvin, E. Križnič, D. B. Macfarlane, Vladislav Balagura, A. Lange, O. Mai, W. Schmidt-Parzefall, H. Kuipers, P. R. B. Saull, T. Siegmund, and I. Tichomirov

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Argus, Meson, Branching fraction, Radiative decay, Mass spectrum, Value (computer science), Atomic physics, computer, computer.programming_language
Abstract

An analysis of the reaction yy ~ r/c was l~erformed in five different decay channels of the r/c: /~sK+~r ~, K+K-Tr+~ "- , 27r+21r -, ~b~b and 2K+2K -. A value Fry(r/c) = ( 11.3 + 4.2) keV was obtained for the radiative decay width by combining the results from the first four channels. Using our result on the two-photon width we also determined the branching ratio for the decay r/c --~ 2K+2K -.

Published
1994

22. Reconstruction of the decay B− → D10(2414) π−

Author

M. Walter, Holger Schulz, S. Chechelnitsky, H. Wegener, T. Podobnik, Michael Schneider, J. Stiewe, K. T. Knöpfle, K. Ehret, I. Tichomirov, Klaus R. Schubert, M. Schieber, T. Živko, T. Oest, R. Schwierz, G. Kostina, John D. Spengler, V. Lubimov, A. Lindner, H. Albrecht, R. Mankel, Sebastian Nowak, I. Korolko, Mikhail Danilov, R. Mundt, R. P. Hofmann, R. Wurth, D. Wegener, H. Schröder, G. Kernel, K. Reim, A. Kosche, P. Križan, A. Golutvin, H. Thurn, P. R. B. Saull, T. Kirchhoff, Vladislav Balagura, W. Schmidt-Parzefall, Werner Hofmann, A. Hüpper, P. Pakhlov, C. Hast, A. Droutskoy, Yu. Gershtein, T. Siegmund, T. S. Yoon, S. Weseler, K. Tzamariudaki, H. Kuipers, A. Nau, Sergey Semenov, A. Lange, R. Eckmann, Hermann Kolanoski, Yu. Zaitsev, A. Snizhko, D. Reβing, P. Eckstein, D. O. Litvintsev, R. G. Van de Water, B. Spaan, M. Schmidtler, S. Werner, Ivan Belyaev, E. Križnič, D. B. Macfarlane, D. Töpfer, R. Waldi, O. Mai, H. Kapitza, Thomas Hamacher, J. D. Prentice, C. Frankl, R. Reiner, and P. Krieger

Subjects
Physics, Nuclear and High Energy Physics, Argus, Meson, Excited state, Analytical chemistry, Atomic physics, computer, computer.programming_language
Abstract

We present the results of a partial reconstruction of the decay channel B − → D j (∗) π − performed using the ARGUS detector operating at the e+e− storage-ring DORIS II. In the context of this paper, D j (∗)0 is an L = 1 excited charm meson decaying to D ∗+ π − . The measured product of branching ratios is Br(B − → D 1 0 (2414)π − ) · Br Br(D 1 0 → D ∗+ π − ) = (0.17 ± 0.05 ± 0.04)% where the first error is statistical and statistical and the second systematic. No evidence for the decay B − → D 2 ∗0 (2459) π − ) · Br(D 2 ∗0 → D ∗+ π − ) at the 90% confidence level.

Published
1994

23. Observation of γγ → φϱ0 and γγ → φω

Author

H. Wegener, T. Podobnik, V. Lubimov, Sebastian Nowak, I. Korolko, D. Wegener, T. Oest, D. O. Litvintsev, T. Siegmund, C. E.K. Charlesworth, M. Schieber, A. Hüpper, M. Walter, John D. Spengler, D. B. MacFarlane, K. Reim, S. Chechelnitsky, K. Tzamariudaki, Michael Schneider, P. Krieger, B. Spaan, P. Pakhlov, K. Ehret, H. Kapitza, E. Križan, H. Albrecht, R. Mankel, A. Droutskoy, R. Wurth, W. Schmidt-Parzefall, G. Kernel, A. Nau, C. Franki, C. Hast, R. Mundt, Sergey Semenov, Vladislav Balagura, M. Seeger, R. Eckmann, K. W. Edwards, R. Schwierz, A. Lange, H. Schröder, Yu. Zaitsev, S. Werner, T. Kirchhoff, Klaus R. Schubert, Hermann Kolanoski, R. P. Hofmann, P. R.B. Saull, G. Kostina, Thomas Hamacher, H. Thurn, Manfred Paulini, Dave Britton, I. Tichomirov, R. Reiner, P.M. Patel, R. Waldi, R. G. Van de Water, Holger Schulz, S. Khan, T. S. Yoon, E. R.F. Hyatt, A. Lindner, T. Živko, P. Eckstein, Ivan Belyaev, Mikhail Danilov, D. Töpfer, A. Kosche, Yuri Gershtein, A. Snizhko, Werner Hofmann, K. T. Knöpfle, J. D. Prentice, M. Schmidtler, J. Stiewe, D. Reßing, S. Weseler, H. Ehrlichmann, P. Križan, and A. Golutvin

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Argus, Hadron, DESY, computer, Storage ring, computer.programming_language
Abstract

Two-photon production of the hadronic final states K + K − π + π − and K + K − π + π 0 π − has been studied using the ARGUS detector at the e + e − storage ring DORIS II at DESY. The cross sections of the reactions γγ → oϱ 0 and γγ → oω have been measured for the first time. In addition, angular distrubutions have been determined for the reaction γγ → oϱ 0 → K + K − π + π − .

Published
1994

24. A study of mixing using partial reconstruction

Author

R. Mundt, R. Waldi, H. Thurn, D. B. MacFarlane, C. Hast, M. Seeger, A. Droutskoy, K. Reim, A. Lange, Rainer Mankel, Manfred Paulini, M. Schmidtler, R. P. Hofmann, P. R.B. Saull, S. Werner, K. R. Schubert, S. Chechelnitsky, D. O. Litvintsev, P. Pakhlov, A. Hüpper, B. Spaan, A. Nau, Sergey Semenov, V. Lubimov, T. Siegmund, T. Kirchhoff, Hermann Kolanoski, I. Korolko, Sebastian Nowak, Holger Schulz, S. Weseler, D. Wegener, K. Ehret, T. Živko, T. S. Yoon, K. T. Knöpfle, W. Schmidt-Parzefall, I. Tichomirov, H. Ehrlichmann, A. Snizhko, G. Kostina, J. D. Prentice, Ivan Belyaev, Thomas Hamacher, P. Krieger, Mikhail Danilov, J. Stiewe, R. Reiner, A. Kosche, J. Spengler, D. Töpfer, Yuri Gershtein, D. Reßing, Werner Hofmann, Vladislav Balagura, H. Albrecht, C. E.K. Charlesworth, G. Kernel, R. Wurth, R. Eckmann, Yu. Zaitsev, K. W. Edwards, H. Wegener, M. Schieber, K. Tzamariudaki, P. M. Patel, M. Walter, H. Kapitza, E. Križnič, T. Podobnik, H. Schröder, M. Schnieder, T. Oest, P. Križan, A. Golutvin, R. G. Van de Water, S. Khan, E. R.F. Hyatt, P. Eckstein, Dave Britton, and A. Lindner

Subjects
Physics, Nuclear and High Energy Physics, Meson, Branching fraction, Electron–positron annihilation, Analytical chemistry, B meson, Atomic physics, Lepton
Abstract

Using the ARGUS detector at the e + e − storage ring DORIS II at DESY, we have studied the decay B 0 → D ∗+ l − v by exploiting a partial D ∗+ reconstruction technique. The branching ratio for this mode was thereby determined to be (4.5 ± 0.3 ± 0.4)%. Using the corresponding sample of tagged B 0 mesons, we measured the B 0 B 0 mixing parameter to be r d = 0.194 ± 0.062 ± 0.054, a result only weakly dependent upon the ratio of semileptonic widths for and production rates of B 0 and B + mesons. We have also determined the branching ratio Br ( B 0 → X l − v to be (9.3 ± 1.1 ± 1.5)%. By comparing the results for full and partial D ∗+ reconstuction we found the absolute branching ratios for D 0 → K − π + and D 0 → K − π + π + π − to be (4.5 ± 0.6 ± 0.4)% and (7.9 ± 1.5 ± 0.9)%, respectively.

Published
1994

25. Observation of a new charmed baryon

Author

P. Krieger, J. D. Prentice, R. Waldi, K. W. Edwards, K. T. Knöpfle, Ivan Belyaev, A. Hüpper, I. Korolko, E. Križnič, P. R. B. Saull, K. Tzamariudaki, K. Strahl, R. Mundt, Vladislav Balagura, V. Lubimov, B. Spaan, J. Stiewe, H. Thurn, K. R. Schubert, A. Snizhko, T. Siegmund, S. Chechelnitsky, Sebastian Nowak, H. Schröder, S. Werner, D. Wegener, D. Töpfer, D. B. Macfarlane, Dmitry Litvintsev, M. Bittner, K. Reim, Thomas Hamacher, H. Wegener, G. Kernel, Dave Britton, K. Ehret, T. Podobnik, H. Kapitza, Holger Schulz, E.R.F. Hyatt, I. Tichomirov, M. Schieber, W. Schmidt-Parzefall, M. Walter, A. Nau, Rainer Mankel, Sergey Semenov, Manfred Paulini, P. M. Patel, Hermann Kolanoski, S. Weseler, C. Hast, C. E. K. Charlesworth, T. Živko, P. Križan, A. Golutvin, R. Eckmann, Yu. Zaitsev, M. Seeger, R. P. Hofmann, H. Ehrlichmann, A. Lange, G. Kostina, T. Kirchhoff, P. Pakhlov, John D. Spengler, M. Schmidtler, R. Reiner, Yu. Gershtein, A. Lindner, Mikhail Danilov, Michael Schneider, H. Albrecht, R. Wurth, A. Droutskoy, A. Kosche, D. Reβing, Werner Hofmann, T. Oest, P. Eckstein, T. S. Yoon, R. G. Van de Water, and S. Khan

Subjects
Nuclear physics, Physics, Baryon, Nuclear and High Energy Physics, Argus, Branching fraction, Electron–positron annihilation, Elementary particle, Charge (physics), DESY, computer, Storage ring, computer.programming_language
Abstract

Using the ARGUS detector at the e+e− storage ring DORIS II at DESY, we have observed a new charmed baryon state in the channel Λc+π+π−. (All references to a specific charged state also imply the charge conjugate state.) The mass of this state was measured to be (2626.6 ± 0.5 ± 1.5) MeV/c2. The product of the production cross section and branching ratio for this channel was determined to be (11.5 ± 2.5 ± 3.0) pb, and the natural width estimated to be smaller than 3.2 MeV/c2 at 90% CL.

Published
1993

26. A determination of two Michel parameters in purely leptonic tau decays

Author

D. Reβing, Yu. Gershtein, V. Lubimov, A. Nau, Sergey Semenov, Hermann Kolanoski, K. Reim, Rainer Mankel, K. T. Knöpfle, H. Schröder, S. Weseler, Dave Britton, T. S. Yoon, J. D. Prentice, K. Strahl, Vladislav Balagura, H. Ehrlichmann, C. Hast, H. Kapitza, M. Seeger, A. Lange, M. Schmidtler, A. Lindner, Michael Schneider, M. Schieber, P. Krieger, E.R.F. Hyatt, M. Walter, Andreas Kirchhoff, Ivan Belyaev, R. Waldi, A. Droutskoy, R. Mundt, P. Eckstein, D. O. Litvintsev, D. Töpfer, B. Spaan, W. Funk, H. Thurn, R. G. Van de Water, Holger Schulz, S. Khan, G. Kernel, P. R. B. Saull, T. Živko, Thomas Hamacher, V. Soloshenko, T. Siegmund, P. Pakhlov, R. P. Hofmann, K. R. Schubert, Manfred Paulini, S. Chechelnitsky, K. Tzamariudaki, K. Ehret, W. Schmidt-Parzefall, G. Kostina, C. E. K. Charlesworth, R. Reiner, H. Wegener, P. M. Patel, I. Tichomirov, R. Eckmann, Yu. Zaitsev, T. Podobnik, S. Werner, M. Bittner, A. Hüpper, Fedor Ratnikov, T. Oest, Mikhail Danilov, A. Kosche, Werner Hofmann, A. Snizhko, John D. Spengler, H. Albrecht, R. Wurth, Sebastian Nowak, D. Wegener, E. Križnič, D. B. Macfarlane, P. Križan, A. Golutvin, K. W. Edwards, and J. Stiewe

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Argus, Muon, Electron–positron annihilation, Elementary particle, Electron, Spectral line, Nuclear physics, Momentum, Michel parameters, computer, computer.programming_language
Abstract

Using the ARGUS detector at the e+e− storage ring DORIS II, we have determined the Michel parameters ϱ and ξ of τ → μν ν and τ → eν ν decays. From a data sample with 333 events/pb around s = 10 GeV , we select 3230 events e + e − → τ + τ − → (μ ± μ μ )( e ǂv v ) and determine ϱ from the e and μ momentum spectra and ξ from the correlations between e and μ momenta. For ϱ we obtain ϱτ→e = 0.79 ± 0.08 ± 0.06 and ϱτ→μ = 0.76 ± 0.08 in accordance with the V - A structure of the decays. The momentum correlations are only sensitive to the product ξτ→eξτ→μ. Setting ξτ→e = ξτ→μ, we obtain |ξτ| = 0.90 ± 0.15 ± 0.10 also in accordance with V - A. The updated decay fractions are B(τ → e v v ) = (17.5 ± 0.3 ± 0.5)% and B(τ → μv v ) = (17.4 ± 0.3 ± 0.5)% .

Published
1993

27. A partial wave analysis of the decay D0 → KS0π+π−

Author

R. Mundt, J. Stiewe, D. Reßing, H. Thurn, G. Kostina, K. Reim, V. Shibaev, A. Hüpper, V. Lubimov, Rainer Mankel, R. Reiner, A. Nau, Sergey Semenov, Hermann Kolanoski, Holger Schulz, M. Schmidtler, J. Tamminga, A. Walther, D. B. MacFarlane, Fedor Ratnikov, C. Hast, T. Kirchhoff, W. Schmidt-Parzefall, K. R. Schubert, A. Lange, T. Živko, K. T. Knöpfle, A. Droutskoy, R. G. Van de Water, S. Weseler, I. V. Gorelov, I. Tichomirov, S. Khan, K. Ehret, H. Ehrlichmann, P. Pakhlov, Sebastian Nowak, R. P. Hofmann, D. Wegener, T. S. Yoon, E.R.F. Hyatt, Peter Krieger, Mikhail Danilov, K. W. Edwards, John D. Spengler, Ivan Belyaev, H. Albrecht, Werner Hofmann, R. Wurth, K. Strahl, P. R. B. Saull, Vladislav Balagura, C. E. K. Charlesworth, D. Töpfer, Michael Schneider, T. Siegmund, M. Schieber, Manfred Paulini, H. Kapitza, P. M. Patel, A. Lindner, G. Kernel, H. Wegener, Thomas Hamacher, V. Soloshenko, T. Podobnik, M. Walter, T. Oest, H. Schröder, B. Spaan, W. Funk, R. D. Appuhn, K. Tzamariudaki, P. Križan, A. Golutvin, Dave Britton, E. Križnič, P. Murat, R. Waldi, J. D. Prentice, S. Werner, and Yu. Zaitsev

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle decay, Pion, Pair production, Meson, Branching fraction, Partial wave analysis, Excited state, Analytical chemistry, Dalitz plot
Abstract

Using the ARGUS detector at the DORIS-II electron-positron storage ring at DESY, we have investigated the exclusive decay D ∗+ → D 0 π + , D 0 → K S 0 π + π − . From a partial wave analysis of the KS0π+π− system we find that (71.8± 4.2 ± 3.0)% are D 0 → K ∗− π + and (22.7 ± 3.2 ± 0.9)% are D 0 → K 0 ϱ 0 with a relative phase of (−137 ± 7 ± 3)° between the channels. The remaining fraction can be described by several channels involving excited resonances, but not by a three-body phase space decay, thus giving first evidence for D0 decays into K 0 ∗ (1430) − π + , K 0 f 0 (1975), K 0 f 2 (1270) , and K 0 f 0 (1400) .

Published
1993

28. Observation of semileptonic decay

Author

P. Murat, Sally Seidel, R. Waldi, S. Weseler, John D. Spengler, A. Lindner, M. Walter, Holger Schulz, H. Albrecht, J. Stiewe, R. Wurth, H. Ehrlichmann, H. I. Cronström, T. Živko, M. Schieber, B. Spaan, W. Funk, A. Nau, Sergey Semenov, T. Kirchhoff, Hermann Kolanoski, R. Mundt, K. T. Knöpfle, Thomas Hamacher, V. Soloshenko, S. Werner, K. Reim, Mikhail Danilov, P. Krieger, H. Thurn, P. Križan, A. Golutvin, P. R. B. Saull, J. D. Prentice, V. Shibaev, A. Hölscher, R. D. Appuhn, Rainer Mankel, R. P. Hofmann, W. Schmidt-Parzefall, M. Schmidtler, C. Hast, E. Križnič, Manfred Paulini, C. E. K. Charlesworth, H. Schröder, D. Reβing, P. Pakhlov, K. W. Edwards, A. Lange, K. R. Schubert, Werner Hofmann, A. Hüpper, D. B. Macfarlane, Dave Britton, T. Siegmund, I. V. Gorelov, Fedor Ratnikov, M. Reidenbach, A. Walther, K. Ehret, P. M. Patel, G. Kernel, I. Tichomirov, G. Kostina, Yu. Zaitsev, R. Reiner, Michael Schneider, K. Strahl, Vladislav Balagura, V. Lubimov, Ivan Belyaev, D. Töpfer, H. Kapitza, Leif J. Jönsson, A. Droutskoy, T. Oest, E.R.F. Hyatt, H. Wegener, T. Podobnik, Sebastian Nowak, D. Wegener, R. G. Van de Water, S. Khan, K. Tzamariudaki, and T. S. Yoon

Subjects
Semileptonic decay, Physics, Nuclear and High Energy Physics, Argus, Physics::Instrumentation and Detectors, Branching fraction, High Energy Physics::Phenomenology, DESY, Nuclear physics, Baryon, High Energy Physics::Experiment, computer, Storage ring, computer.programming_language
Abstract

Observation of the semileptonic decay of the charmed baryon in the decay channel has been made using the ARGUS detector at the e + e − storage ring DORIS II at DESY. The cross section times branching ratio was found to be .

Published
1993

29. Observation of the decay

Author

H. Schröder, P. R. B. Saull, M. Schieber, J. D. Prentice, K. Strahl, Vladislav Balagura, S. Werner, A. Droutskoy, Ivan Belyaev, P. Pakhlov, Mikhail Danilov, T. S. Yoon, G. Kostina, Manfred Paulini, R. P. Hofmann, I. Tichomirov, A. Walther, A. Linder, R. Reiner, V. Shibaev, K. R. Schubert, C. Hast, M. Walter, R. G. Van de Water, K. Reim, Werner Hofmann, K. W. Edwards, T. Siegmund, Dave Britton, H. Wegener, H. I. Cronström, A. Hüpper, A. Lange, D. Töpfer, P. Krieger, S. Khan, Michael Schneider, K. Ehret, Fedor Ratnikov, T. Podobnik, Holger Schulz, P. Murat, E. Križnič, Rainer Mankel, B. Spaan, W. Funk, T. Kirchhoff, M. Schmidtler, Sebastian Nowak, K. Tzamariudaki, W. Schmidt-Parzefall, R. Waldi, D. Wegener, K. T. Knöpfle, T. Živko, H. Kapitza, C. E. K. Charlesworth, I. V. Gorelov, D. B. Macfarlane, R. D. Appuhn, V. Lubinov, R. Mundt, John D. Spengler, G. Kernel, Leif J. Jönsson, P. Križan, A. Golutvin, H. Albrecht, D. Reβing, H. Thurn, P. M. Patel, J. Stiewe, T. Oest, S. Weseler, R. Wurth, E.R.F. Hyatt, Yu. Zaitsev, H. Ehrlichmann, A. Nau, Sergey Semenov, Hermann Kolanoski, Thomas Hamacher, and V. Soloshenko

Subjects
Physics, Nuclear and High Energy Physics, Argus, Meson, Electron–positron annihilation, Analytical chemistry, Value (computer science), DESY, Excited state, Mass spectrum, Atomic physics, computer, Storage ring, computer.programming_language
Abstract

Using the ARGUS detector at the e + e - storage ring using DORIS II at DESY, we have observed a new decay channel for the excited charm-strange meson D s1 (2536) + →D∗ O K + . The production cross section for the D s 1 (2536) + decaying via this channel is measured to be σ ( D s1 (2536) + )· BR (D sl (2536) + →D∗ 0 K + )= 18±4±3 pb at E CM = 10.4 GeV. The mass of the D s 1 (2536) + is found to be 2535.2 ± 0.5±1.5 MeV/ c 2 in agreement with the value obtained from an analysis of the D s1 (2536) + →D∗ + K 0 s decay channel. The natural width is determined to be less than 3.9 MeV/ c 2 at 90%CL.

Published
1992

30. A measurement of the tau mass

Author

G. Kernel, M. Schieber, V. Shibaev, S. Semenov, Leif J. Jönsson, V. Lubimov, H. Schröder, D. Wegener, D. Reβing, R. Wurth, C. Hast, J. Stiewe, T. Oest, P. Križan, G. Kostina, K. Reim, A. Lange, T. Kirchhoff, S. Werner, Michael Schneider, A. Droutskoy, H. Albrecht, H. Wegener, E. Križnič, W. Funk, R. P. Hofmann, M. Schmidtler, T. Podobnik, H.D. Schulz, R. Reiner, J. D. Prentice, Sebastian Nowak, A. Walther, M. Danilov, K. Strahl, Vladislav Balagura, Ivan Belyaev, W. Schmidt-Parzefall, R. Mankel, K. T. Knöpfle, K. R. Schubert, C. E. K. Charlesworth, S. Weseler, I. Tichomirov, P. Murat, D. Töpfer, R. Mundt, R. Waldi, K. W. Edwards, R. D. Appuhn, H. Ehrlichmann, H. Thurn, K. Ehret, P. Krieger, R. G. Van de Water, E.R.F. Hyatt, A. Nau, P. M. Patel, A. Golutvin, H. Kapitza, Hermann Kolanoski, S. Khan, Dave Britton, P. Pakhlov, Yu. Zaitsev, J. Spengler, T. S. Yoon, M. Walter, H. I. Cronström, I. Gorelov, T. Živko, Werner Hofmann, A. Hüpper, K. Tzamariudaki, P. R. B. Saull, F. Ratnikov, A. Lindner, T. Siegmund, Manfred Paulini, B. Spaan, Thomas Hamacher, and V. Soloshenko

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Argus, Particle physics, Electron–positron annihilation, Mass spectrum, computer, Storage ring, Lepton, computer.programming_language
Abstract

Using the ARGUS detector at the DORIS II storage ring, a new measurement of the mass of the τ lepton has been obtained. An analysis of the tau pseudomass spectrum for decays of the type τ− → π−π−π+ντ finds mτ = 1776.3±2.4±1.4 MeV/c2. This result also leads to an improvement of the upper limit on the ντ mass to mντ < 31 MeV/c2 at the 95% confidence level.

Published
1992

31. Evidence for the production of the charmed, doubly strange baryon Ωc in e+e− annihilation

Author

Sebastian Nowak, T. Kirchhoff, C. Hast, S. Kahn, D. Wegener, R. P. Hofmann, A. Lange, M. Walter, R. G. Van de Water, T. Siegmund, V. Lubimov, H. I. Cronström, T. S. Yoon, I. Tichomirov, H. Schröder, I. V. Gorelov, V. Shibaev, W. Schmidt-Parzefall, E. Križnič, J. Stiewe, S. Weseler, John D. Spengler, P. M. Patel, D. Reßing, P. R. B. Saull, H. Wegener, C. E. K. Charlesworth, H. Albrecht, K. W. Edwards, D. B. Macfarlane, K. Strahl, Vladislav Balagura, Manfred Paulini, T. Podobnik, R. Wurth, K. Tzamariudaki, H. Ehrlichmann, Thomas Hamacher, K. T. Knöpfle, V. Soloshenko, A. Lindner, J. D. Prentice, Yu. Zaitsev, P. Križan, A. Golutvin, U. Becker, G. Kernel, A. Hölscher, Leif J. Jönsson, A. Droutskoy, A. Walther, M. Schmidtler, M. Schieber, T. Oest, S. Werner, E.R.F. Hyatt, K. Reim, Ivan Belyaev, Rainer Mankel, Mikhail Danilov, D. Töpfer, P. Murat, A. Nau, R. Waldi, H. Kapitza, Sergey Semenov, Hermann Kolanoski, P. Krieger, Werner Hofmann, A. Hüpper, Fedor Ratnikov, M. Reidenbach, Michael Schneider, P. Pakhlov, Sally Seidel, Holger Schulz, T. Živko, R. Mundt, H. Thurn, R. D. Appuhn, G. Kostina, B. Spaan, W. Funk, Dave Britton, R. Reiner, K. R. Schubert, and K. Ehret

Subjects
Physics, Nuclear and High Energy Physics, Argus, Particle physics, Annihilation, Branching fraction, Electron–positron annihilation, DESY, lcsh:QC1-999, Baryon, Nuclear physics, Production (computer science), computer, lcsh:Physics, Storage ring, computer.programming_language
Abstract

Using the detector ARGUS at the storage ring DORIS II of DESY, we have found evidence for the production of the charmed and doubly strange baryon Ω c through its decay channel Ξ − K − π + π + . Its mass has been determined to be ((2719.0±7.0±2.5)MeV/ c 2 , and the product of production cross section and branching ratio the above channel to be (2.41±0.90±0.30) pb.

Published
1992

32. A measurement of the inclusive semileptonic decay fraction of charmed hadrons

Author

V. Lubimov, A. Walther, R. D. Appuhn, M. Danilov, H. Wegener, R. Waldi, M. Schäfer, H.D. Schulz, C. W. Darden, A. Semenov, T. Podobnik, J. C. Gabriel, P. Krieger, K. R. Schubert, S. Werner, J. D. Prentice, P. M. Patel, T. Siegmund, S. Ball, Leif J. Jönsson, J. Spengler, V. Shevchenko, I. Tichomirov, T. S. Yoon, D. Wegener, C. Geyer, C. Hast, T. Oest, R. Mankel, K. Strahl, Vladislav Balagura, K. W. Edwards, M. Schieber, A. Lange, C. E. K. Charlesworth, U. Volland, B. Holzer, D. Töpfer, R. Childers, G. Herrera, A. Golutvin, R. S. Orr, A. Droutskoy, Manfred Paulini, Yu. Zaitsev, A. Krüger, R. G. Van de Water, Dave Britton, B. Spaan, K. Tzamariudaki, R. Wurth, F. Sefkow, S. Khan, B. Boštjančič, F. Ratnikov, H. Ehrlichmann, A. Lindner, Thomas Hamacher, V. Soloshenko, A. Rostovtsev, Stefan Schael, I. Gorelov, H. I. Cronström, H. Kapitza, E. Križnič, W. Funk, A. Nippe, D. B. Macfarlane, G. Kernel, Robert K. Kutschke, P. Križan, A. Hölscher, J. Stiewe, D. Reßing, S. Semenov, H. Schröder, H. Albrecht, M. Reidenbach, B. Fominykh, Werner Hofmann, Michael Schneider, R. Mundt, H. Thurn, Sally Seidel, T. Živko, S. Weseler, K. Reim, M. Schmidtler, W. Schmidt-Parzefall, A. Nau, G. Tsipolitis, Hermann Kolanoski, and K. T. Knöpfle

Subjects
Semileptonic decay, Physics, Nuclear and High Energy Physics, Argus, Particle physics, Branching fraction, Hadron, Detector, DESY, Fraction (chemistry), Nuclear physics, computer, Storage ring, computer.programming_language
Abstract

Using the ARGUS detector at the DORIS-II storage ring at DESY, we have measured the inclusive semileptonic branching ratio of charmed hadrons produced in e+e− annihilition at =10 GeV to be BR(c→eveX)=(9.8±0.9±0.5 0.6)% and BR(c→μvμX)=(8.6±1.7±0.70.8)%.

Published
1992

33. First evidence of χc production in B meson decays

Author

K. T. Knöpfle, K. Strahl, P. Pakhlov, Vladislav Balagura, T. Siegmund, John D. Spengler, S. Ball, D.I. Britton, U. Volland, Leif J. Jönsson, H. Albrecht, D. Reβing, D. Wegener, S.C. Seidel, T. Oest, R. Wurth, J. Stiewe, V. Lubimov, B. Spaan, W. Funk, H. Wegener, R. Kutschke, A. Nau, Sergey Semenov, W. Schmidt-Parzefall, Manfred Paulini, D. B. Macfarlane, T. Podobnik, G. Tsipolitis, Hermann Kolanoski, G. Kernel, H.O. Cronström, V. Shevchenko, I. Tichomirov, A. Droutskoy, H. Schröder, Fedor Ratnikov, P. Krieger, G. Herrera, K. R. Schubert, C.E.K. Charlesworth, A. Lindner, R. D. Appuhn, M. Schieber, E. Križnič, M. Reidenbach, C. W. Darden, A. Walther, Stefan Schael, Holger Schulz, M. Schäfer, K. W. Edwards, Mikhail Danilov, S. Werner, A. Nippe, T. Živko, B. Fominykh, H. Kapitza, I. V. Gorelov, B. Boštjančič, P. Križan, A. Golutvin, D. Töpfer, P. M. Patel, R. Mundt, A. Hölscher, Werner Hofmann, J. D. Prentice, R. S. Orr, Thomas Hamacher, V. Soloshenko, F. Sefkow, A. Rostovtsev, H. Thurn, B. Holzer, Yu. Zaitsev, K. Reim, Rainer Mankel, S. Weseler, H. Ehrlichmann, R. Childers, C. Geyer, C. Hast, A. Lange, A. Semenov, J. C. Gabriel, R. Waldi, K. Tzamariudaki, T. S. Yoon, A. Krüger, R. G. Van de Water, and S. Khan

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Argus, Meson, Branching fraction, Electron–positron annihilation, DESY, B meson, computer, computer.programming_language
Abstract

Using the ARGUS detector at the e + e − storage ring DORIS II at DESY, we have obtained the first evidence for B meson decays into χ c mesons. The inclusive branching ratio for the decay B → χ c X was measured to the (1.05±0.35±0.25)% assuming no χ c2 production. In addition, four candidates for the exclusive decay B ± → χ c1 K ± have been observed, corresponding to a branching ratio of (0.19 ± 0.13 ± 0.06)%.

Published
1992

34. Measurement of the decay

Author

A. Lindner, Thomas Hamacher, V. Lubimov, V. Soloshenko, W. Schmidt-Parzefall, C. E. K. Charlesworth, Sebastian Nowak, P. Krieger, D. Wegener, John D. Spengler, H. Schröder, J. D. Prentice, H. Albrecht, A. Semenov, K. Strahl, Vladislav Balagura, R. Wurth, H. Wegener, M. Schmidtler, T. Siegmund, T. Podobnik, M. Schneider, M. Schieber, K. W. Edwards, Ivan Belyaev, I. Tichomirov, S. Werner, P. Murat, Mikhail Danilov, Leif J. Jönsson, R. Waldi, P. Križan, A. Golutvin, B. Fominykh, T. Oest, A. Hölscher, C. Hast, D. Töpfer, G. Kernel, A. Walther, A. Lange, H. I. Cronström, E. Križnič, A. Rostovtsev, Manfred Paulini, Werner Hofmann, P. Pakhlov, A. Hüpper, K. R. Schubert, P. M. Patel, M. Walter, A. Nippe, D. B. Macfarlane, A. Nau, Sergey Semenov, Fedor Ratnikov, S. Weseler, Hermann Kolanoski, Yu. Zaitsev, A. Droutskoy, M. Reidenbach, K. T. Knöpfle, K. Ehret, D. Reβing, R. Mundt, J. Stiewe, G. Kostina, H. Thurn, Sally Seidel, H. Ehrlichmann, Holger Schulz, I. V. Gorelov, T. Živko, Dave Britton, K. Reim, Rainer Mankel, R. D. Appuhn, M. Schäfer, B. Spaan, W. Funk, A. Krüger, R. G. Van de Water, S. Khan, T. S. Yoon, H. Kapitza, G. Herrera, and K. Tzamariudaki

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Argus, Meson, Branching fraction, Electron–positron annihilation, Analytical chemistry, B meson, DESY, computer, computer.programming_language
Abstract

Using the ARGUS detector at the e + e − storage ring DORIS II at DESY we have studied the decay B − → D ∗0 l − λ , where l − = e − or μ − , using the D 0 γ and D 0 π 0 decay modes of the D ∗0 meson. B mesons were produced in 209 000 decays of γ (4S). Assuming electron-muon universality, we obtain a value for the branching ratio of BR ( B − → D ∗0 l − λ )= (5.8 ± 1.4 ± 1.3)% .

Published
1992

35. A measurement of asymmetry in the decay Λc+ → Λπ+

Author

H. Albrecht, H. Ehrlichmann, T. Hamacher, A. Krüger, A. Nau, A. Nippe, M. Reidenbach, M. Schäfer, H. Schröder, H.D. Schulz, F. Sefkow, R. Wurth, R.D. Appuhn, C. Hast, G. Herrera, H. Kolanoski, A. Lange, A. Lindner, R. Mankel, M. Schieber, T. Siegmund, B. Spaan, H. Thurn, D. Töpfer, A. Walther, D. Wegener, M. Paulini, K. Reim, U. Volland, H. Wegener, R. Mundt, W. Schmidt-Parzefall, W. Funk, J. Stiewe, S. Werner, S. Ball, J.C. Gabriel, C. Geyer, A. Hölscher, W. Hofmann, B. Holzer, S. Khan, K.T. Knöpfle, J. Spengler, D.I. Britton, C.E.K. Charlesworth, K.W. Edwards, H. Kapitza, P. Krieger, R. Kutschke, D.B. MacFarlane, R.S. Orr, P.M. Patel, J.D. Prentice, S.C. Seidel, G. Tsipolitis, K. Tzamariudaki, R.G. Van de Water, T.-S. Yoon, D. Reßing, S. Schael, K.R. Schubert, K. Strahl, R. Waldi, S. Weseler, B. Boštjančič, G. Kernel, P. Križan, E. Križnič, T. Podobnik, T. Živko, H.I. Cronström, L. Jönsson, V. Balagura, M. Danilov, A. Droutskoy, B. Fominykh, A. Golutvin, I. Gorelov, F. Ratnikov, V. Lubinov, P. Pakhlov, A. Rostovtsev, A. Semenov, S. Semenov, V. Shevchenko, V. Soloshenko, I. Tichomirov, Yu. Zaitsev, R. Childers, and C.W. Darden

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Argus, media_common.quotation_subject, Electron–positron annihilation, DESY, Parity (mathematics), Asymmetry, computer, Storage ring, media_common, computer.programming_language
Abstract

Using the ARGUS detector at the e + e − storage ring DORIS II at DESY, we have observed parity violation in the decay Λ ± c → Λπ ± . We measure the coefficient of parity violation, α Λ c , to be −0.96±0.42. In addition, we measure σ BR ( Λ + c → Λπ + and σ BR ( Λ + c → Σ 0 π + ) to be, respectively, (2.2±0.3±0.4) pb and (2.0±0.7±0.4) pb.

Published
1992

36. Observations of Λc+ semileptonic decay

Author

U. Volland, H. Schröder, G. Herrera, A. Droutskoy, Leif J. Jönsson, K. Tzamariudaki, T. Oest, S. Werner, R. Waldi, C. Geyer, C. Hast, T. S. Yoon, J. Stiewe, V. Shevchenko, B. Boštjančič, Mikhail Danilov, A. Lange, I. Tichomirov, Sally Seidel, R. S. Orr, B. Fominykh, A. Linder, G. Kernel, H. Wegener, D. Wegener, D. Töpfer, S. Weseler, P. Krieger, T. Siegmund, T. Podobnik, Holger Schulz, A. Semenov, K. W. Edwards, A. Nau, Sergey Semenov, J. C. Gabriel, K. R. Schubert, Werner Hofmann, G. Tsipolitis, J. D. Prentice, Stefan Schael, Hermann Kolanoski, H. I. Cronström, Dave Britton, H. Kapitza, H. Ehrlichmann, F. Sefkow, Fedor Ratnikov, T. Živko, V. Balagura, V. Soloshenkp, K. T. Knöpfle, W. Schmidt-Parzefall, A. Rostovtsev, A. Krüger, M. Reidenbach, R. G. Van de Water, R. D. Appuhn, C. E. K. Charlesworth, A. Walther, M. Schieber, M. Schäfer, K. Reim, S. Khan, B. Spaan, W. Funk, P. M. Patel, Robert K. Kutschke, Yu. Zaitsev, Rainer Mankel, John D. Spengler, P. Križan, A. Golutvin, H. Albrecht, B. Holzer, R. Wurth, A. Hölscher, R. Childers, E. Križnič, I. V. Gorelov, A. Nippe, D. B. Macfarlane, R. Mundt, H. Thurn, Manfred Paulini, V. Lubimov, C. W. Darden, S. Ball, D. Ressing, Thomas Hamacher, Anton Babaev, and K. Strahl

Subjects
Semileptonic decay, Nuclear physics, Physics, Nuclear and High Energy Physics, Argus, Muon, Branching fraction, Electron–positron annihilation, Analytical chemistry, Wave function, computer, Lepton, computer.programming_language
Abstract

Direct observations of the semileptonic decay of Λc+ in the decay channels Λc+→Λe+X and Λc+→Λμ+X have been made using the ARGUS detector at the DORIS II e+e− storage ring. The cross section times branching ratio were found to be σ(e+e−→Λc+X)·BR(Λc+→Λe+X)=4.20±1.28±0.71 pb and σ(e+e−→Λc+X)·BR(Λc+→Λμ+X)=3.91±2.02±0.90 pb.

Published
1991

37. A spin-parity analysis of γγ→ϱ+ϱ−

Author

K. W. Edwards, A. Semenov, J. C. Gabriel, S. Werner, V. Lubimov, M. Schieber, G. Schweda, R. Childers, John D. Spengler, C. W. Darden, U. Volland, Fedor Ratnikov, S. Weseler, M. Reidenbach, Leif J. Jönsson, C. Geyer, K. T. Knöpfle, G. Herrera, H. Albrecht, A. Rostovtsev, C. Hast, H. Ehrlichmann, Robert K. Kutschke, R. Wurth, A. Lange, P. Križan, P. M. Patel, A. Golutvin, T. Oest, Sally Seidel, R. S. Orr, K. Tzamariudaki, W. Schmidt-Parzefall, Holger Schulz, Thomas Hamacher, V. Soloshenko, K. Reim, A. Hölscher, J. D. Prentice, C. E. K. Charlesworth, I. V. Gorelov, Yu. Zaitsev, K. Strahl, P. Križnič, T. Živko, Mikhail Danilov, Rainer Mankel, A. Droutskoy, H. Wegener, B. Fominykh, R. Mundt, T. Siegmund, A. Nippe, K. R. Schubert, D. B. Macfarlane, Werner Hofmann, A. Nau, A. Walther, H. Thurn, Sergey Semenov, G. Tsipolitis, Hermann Kolanoski, G. Kernel, Stefan Schael, B. Boštjančič, H. Kapitza, V. Shevchenko, I. Tichomirov, P. Krieger, D. Ressing, R. Waldi, B. Holzer, Anton Babaev, B. Spaan, W. Funk, T. S. Yoon, R. D. Appuhn, M. Schäfer, A. Lindner, D. Wegener, Dave Britton, F. Sefkow, H. I. Cronström, H. Schröder, S. Ball, V. Balagura, Manfred Paulini, A. Krüger, R. G. Van de Water, S. Khan, and J. Stiewe

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Argus, Amplitude, Parity (physics), DESY, computer, computer.programming_language
Abstract

A spin-parity analysis of the ϱ + ϱ − system in the reaction γγ→ϱ + ϱ − →Π + Π − Π 0 Π 0 has been performed using the ARGUS detector at the e + e − storage ring DORIS II at DESY. The cross section is found to be dominated by the amplitudes J P = 0 + and J P = 2 + ( J z = 2).

Published
1991

38. Search for b→sX+X− in exclusive decays of B mesons

Author

S. Khan, T. Ruf, A. Drescher, H. Scheck, U. Volland, John D. Spengler, M. Reidenbach, A. Semenov, J. C. Gabriel, B. Holzer, G. Schweda, Robert K. Kutschke, T. S. Yoon, H. Albrecht, R. Wurth, P. M. Patel, J. Stiewe, Mikhail Danilov, P. Križan, A. Golutvin, H. Schröder, D. Wegener, A. Linder, A.W. Nilsson, K. W. Edwards, H. Wegener, B. Fominykh, A. Hölscher, R. Gläser, V. Soloshenko, Werner Hofmann, C. Geyer, C. Hast, Yu. Zaitsev, S. Werner, Stefan Schael, A. Lange, J. A. Parsons, H. Kapitza, R. S. Orr, R. Waldi, F. Sefkow, R. Childers, V. Shevchenko, B. Boštjančič, A. Walther, R. Davis, Manfred Paulini, E. Križnič, I. Tichomirov, A. Krüger, William R. Frisken, A. Rostovtsev, A. Nippe, D. B. Macfarlane, S. Weseler, B. Spaan, W. Funk, Sergey Semenov, G. Kernel, G. Tsipolitis, Hermann Kolanoski, Sally Seidel, Anton Babaev, G. Harder, V. Tchistilin, C. E. K. Charlesworth, Leif J. Jönsson, P. Krieger, Holger Schulz, I. V. Gorelov, S. Ball, T. Oest, J. D. Prentice, G. Herrera, K. Reim, Rainer Mankel, V. Lubimov, W. Schmidt-Parzefall, C. W. Darden, K. R. Schubert, M. Pleško, R. D. Appuhn, K. W. McLean, K. Strahl, J. D. Swain, M. Schäfer, and H. I. Cronström

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Argus, High Energy Physics::Lattice, Electron–positron annihilation, High Energy Physics::Phenomenology, DESY, Standard Model, Nuclear physics, Higgs boson, High Energy Physics::Experiment, B meson, computer, Storage ring, computer.programming_language
Abstract

Using the ARGUS detector at the e + e − storage ring DORIS II at DESY, penguin decays of B mesons involving b→sX + X − have been searched for, where X is one of e, μ , π , or K. No evidence for these decays was found and upoer limits are quoted. These numbers represent important constraints of flavour-changing neutral currents in B meson decays and probe the heavy-quark and Higgs sectors of the standard model.

Published
1991

39. Observation of the decay τ → ϱππντ

Author

K. W. Edwards, U. Volland, Sally Seidel, D. Wegener, M. Schieber, Dave Britton, Holger Schulz, A. Nau, F. Sefkow, V. Lubimov, J. D. Prentice, C. Geyer, C. Hast, D. Ressing, Anton Babaev, Sergey Semenov, G. Tsipolitis, Hermann Kolanoski, A. Lange, T. Živko, R. Childers, A. Droutskoy, I. V. Gorelov, S. Weseler, R. S. Orr, A. Walter, J. Stiewe, A. Lindner, C. W. Darden, R. D. Appuhn, H. Ehrlichmann, Thomas Hamacher, V. Soloshenko, A. Semenov, W. Hoffmann, J. C. Gabriel, H. I. Cronström, H. Schröder, Mikhail Danilov, M. Schäfer, I. Tichomirov, R. Waldi, B. Fominykh, B. Holzer, B. Spaan, W. Funk, R. Mundt, Stefan Schael, K. Strahl, J. A. Parsons, H. Kapitza, G. Kernel, John D. Spengler, V. Shevchencko, K. T. Knöpfle, H. Thurn, K. Reim, H. Albrecht, P. Krieger, R. Wurth, Rainer Mankel, B. Boštjančič, K. R. Schubert, Fedor Ratnikov, M. Reidenbach, S. Ball, T. S. Yoon, W. Schmidt-Parzefall, C. E. K. Charlesworth, H. Wegener, G. Schweda, V. Balagura, Manfred Paulini, A. Krüger, T. Siegmund, R. G. Van de Water, S. Khan, G. Herrera, K. Tzamariudaki, Leif J. Jönsson, T. Oest, S. Werner, E. Križnič, A. Rostovtsev, P. M. Patel, A. Nippe, D. B. Macfarlane, Yu. Zaitsev, Robert K. Kutschke, P. Križan, A. Golutvin, and A. Hölscher

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Argus, Pion, Meson, Electron–positron annihilation, computer, computer.programming_language
Abstract

An analysis of the decay τ− → π−π−π+π0ντ has been performed with the ARGUS detector at the DORIS II storage ring. From a study of the two pion subsystems we have found first evidence for the decays τ− → ϱ0π−π0ντ, τ− → ϱ −π+π−ντ, and τ− → ϱ+π−π−ντ with relative contributions to the decay τ− → π−π−π+π0ντ of 0.30 ± 0.04, 0.26 ± 0.05, and 0.10 ± 0.03, respectively. The fraction of the subchannel τ− → ωπ−ντ has been determined to be 0.33 ± 0.05. The production of ϱ mesons is enhanced by a factor of 1.9 ± 0.3 over that of ω mesons. We conclude that in more than 81% (95% CL) of all τ− → π−π−π+π0ντ decays either a ϱ or ω meson is produced.

Published
1991

40. Observation of the decays Ds−→φe− and D−→K∗0e−

Author

D. Wegener, S. Weseler, R. Mundt, H. Ehrlichmann, T. Siegmund, Mikhail Danilov, H. Thurn, G. Schweda, R. Waldi, A. Rostovtsev, S. Ball, C. Geyer, C. Hast, V. Lubimov, J. D. Prentice, K. Reim, Rainer Mankel, H. Albrecht, Leif J. Jönsson, A. Lange, M. Schieber, B. Fominykh, R. Wurth, Manfred Paulini, G. Herrera, R. S. Orr, W. Schmidt-Parzefall, T. Oest, Thomas Hamacher, V. Soloshenko, C. E. K. Charlesworth, C. W. Darden, Sally Seidel, K. Tzamariudaki, Holger Schulz, B. Spaan, W. Funk, P. Krieger, A. Nau, A. Semenov, H. Schröder, J. C. Gabriel, Sergey Semenov, Werner Hofmann, Stefan Schael, J. Spengler, H. Kapitza, G. Tsipolitis, H. Wegener, Hermann Kolanoski, T. Živko, G. Kernel, K. Strahl, Vladislav Balagura, R. D. Appuhn, K. W. Edwards, V. Shevchenko, A. Nippe, Fedor Ratnikov, D. B. Macfarlane, M. Schäfer, M. Reidenbach, I. Tichomirov, Dave Britton, K. T. Knöpfle, K. R. Schubert, H. I. Cronström, Robert K. Kutschke, F. Sefkow, P. Križan, A. Golutvin, R. Childers, A. Droutskoy, B. Boštjančič, A. Walther, A. Hölscher, B. Holzer, U. Volland, I. V. Gorelov, A. Lindner, J. Stiewe, D. Ressing, Anton Babaev, P. M. Patel, Yu. Zaitsev, S. Werner, T. S. Yoon, A. Krüger, R. G. Van de Water, and S. Khan

Subjects
Physics, Nuclear and High Energy Physics, Argus, Meson, Branching fraction, Electron–positron annihilation, Continuum (design consultancy), DESY, Electron, Atomic physics, computer, computer.programming_language
Abstract

Using the ARGUS detector at the e + e − storage ring DORIS II at DESY, we have studied semileptonic charmed meson decays through ф- and K ∗0 -electron correlations in continuum production. Evidence for the decay D − s →фe − v has been observed, with a branching ratio relative to the channel D − s →фπ − determined to be 0.57±0.15±0.15. The decay D − →K ∗0 e − v was also seen, with a value of 0.55±0.08±0.10 extracted for the branching ratio relative to the channel D − →K + π − π − . The ratio of the two measurements, after application of SU(3) corrections, implies a branching ratio for D − s →фπ − of (2.4±1.0)%.

Published
1991

41. Reconstruction of semileptonic b→u decays

Author

V. Lubimov, H. Schröder, C. E. K. Charlesworth, W. Schmidt-Parzefall, E. Križnič, T. Ruf, C. W. Darden, Manfred Paulini, J. Stiewe, G. Harder, A. Nippe, D. B. Macfarlane, Sally Seidel, Holger Schulz, T. Živko, S. Khan, P. Krieger, Robert K. Kutschke, J. D. Swain, P. Križan, A. Golutvin, A. Krüger, V. Soloshenko, K. Reim, A. Hölscher, G. Schweda, Rainer Mankel, M. Reidenbach, K. W. Edwards, K. W. McLean, Mikhail Danilov, K. Strahl, B. Holzer, G. Herrera, B. Fominykh, K. Tzamariudaki, D. Wegener, H. Scheck, Werner Hofmann, John D. Spengler, Anton Babaev, H. Albrecht, P. M. Patel, R. Wurth, F. Sefkow, S. Ball, Leif J. Jönsson, S. Weseler, A. Lindner, A. Nau, Sergey Semenov, R. D. Appuhn, G. Tsipolitis, T. S. Yoon, Hermann Kolanoski, A. Walther, R. Gläser, B. Boštjančič, H. Ehrlichmann, T. Oest, M. Schäfer, C. Geyer, C. Hast, R. Childers, Yu. Zaitsev, A. Lange, R. Waldi, R. S. Orr, H. Wegener, B. Spaan, W. Funk, A. Drescher, J. D. Prentice, A. W. Nilsson, U. Volland, V. Shevchenko, I. V. Gorelov, I. Tichomirov, H. I. Cronström, A. Semenov, J. C. Gabriel, Stefan Schael, J. A. Parsons, H. Kapitza, S. Werner, A. Rostovtsev, G. Kernel, V. Tchistilin, and K. R. Schubert

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Argus, Meson, Electron–positron annihilation, B meson, DESY, computer, Storage ring, computer.programming_language
Abstract

Using the ARGUS detector at the e+ e− storage ring DORIS II at DESY we have updated our result on charmless semileptonic B decays and searched for direct evidence for b→u transitions through reconstruction of complete events. This approach has successfully identified two ϒ (4S) events which contain B meson decays to a non-charm final state. In one case, a B0 meson is found in the channel π + μ − ν , while in the other a decay B+→ωμ+ν is seen. These events show that the previously observed signal of charmless semileptonic B decays is due to b→u transitions from which we obtain | V ub V cb | = 0.11±0.012 using the model of Altarelli et al.

Published
1991

42. Search for b→s.gluon in B meson decays

Author

A.W. Nilsson, V. Lubimov, A. Semenov, J. C. Gabriel, J. Stiewe, E. Križnič, W. Schmidt-Parzefall, Sergey Semenov, William R. Frisken, R. Childers, Anton Babaev, G. Tsipolitis, C. W. Darden, Hermann Kolanoski, A. Nippe, D. B. Macfarlane, B. Boštjančič, H. I. Cronström, K. W. Edwards, C. Geyer, C. Hast, T. S. Yoon, D. Wegener, U. Volland, A. Lange, J. D. Swain, K. W. McLean, R. S. Orr, C. E. K. Charlesworth, G. Kernel, K. Strahl, A. Lindner, V. Tchistilin, Robert K. Kutschke, T. Ruf, H. Schröder, R. Gläser, P. Križan, A. Golutvin, K. R. Schubert, I. V. Gorelov, S. Ball, A. Hölscher, S. Khan, V. Shevchenko, A. Drescher, V. Soloshenko, I. Tichomirov, M. Pleško, Manfred Paulini, B. Holzer, G. Schweda, R. Waldi, Stefan Schael, G. Herrera, J. A. Parsons, H. Kapitza, R. D. Appuhn, A. Walther, R. Davis, Mikhail Danilov, A. Krüger, B. Fominykh, Werner Hofmann, Leif J. Jönsson, M. Reidenbach, M. Schäfer, S. Werner, T. Oest, J. D. Prentice, H. Scheck, H. Wegener, John D. Spengler, H. Albrecht, R. Wurth, F. Sefkow, A. Rostovtsev, B. Spaan, W. Funk, G. Harder, P. M. Patel, P. Krieger, Yu. Zaitsev, Sally Seidel, Holger Schulz, K. Reim, Rainer Mankel, and S. Weseler

Subjects
Physics, Nuclear and High Energy Physics, Argus, Particle physics, Physics::Instrumentation and Detectors, High Energy Physics::Lattice, Electron–positron annihilation, High Energy Physics::Phenomenology, DESY, Gluon, Nuclear physics, High Energy Physics::Experiment, B meson, computer, Storage ring, computer.programming_language
Abstract

Using the ARGUS detector at the e + e − storage ring DORIS II at DESY, a search for penguin decays of B mesons involving b→s gluon has been performed. No evidence for the penguin mechanism was found and a number of upper limits are quoted.

Published
1991

43. Determination of the tau-neutrino helicity

Author

V. Lubimov, E. Križnič, Leif J. Jönsson, C. Geyer, C. Hast, W. Schmidt-Parzefall, C. W. Darden, T. Oest, J. Stiewe, A. Lange, R. S. Orr, A. Nippe, D. B. Macfarlane, H. Schröder, J. D. Prentice, A. W. Nilsson, H. Scheck, John D. Spengler, S. Ball, Fedor Ratnikov, A. Drescher, H. Albrecht, A. Semenov, J. C. Gabriel, R. Wurth, K. W. McLean, M. Reidenbach, K. Strahl, A. Walther, Stefan Schael, G. Schweda, D. Wegener, A. Lindner, J. A. Parsons, V. Shevchenko, H. Kapitza, I. V. Gorelov, H. Wegener, Mikhail Danilov, I. Tichomirov, S. Werner, U. Volland, K. W. Edwards, G. Herrera, B. Fominykh, R. D. Appuhn, Manfred Paulini, Robert K. Kutschke, P. Križan, K. Tzamariudaki, A. Golutvin, G. Harder, A. Hölscher, A. Rostovtsev, Werner Hofmann, Anton Babaev, P. Krieger, M. Schäfer, V. Soloshenko, P. M. Patel, T. Ruf, H. I. Cronström, Yu. Zaitsev, C. E. K. Charlesworth, B. Boštjančič, B. Holzer, A. Krüger, B. Spaan, W. Funk, R. Waldi, Dave Britton, F. Sefkow, K. R. Schubert, G. Kernel, V. Tchistilin, Sally Seidel, Holger Schulz, M. Schieber, M. Spahn, T. Živko, A. Nau, Sergey Semenov, A. Droutskoy, G. Tsipolitis, Hermann Kolanoski, S. Weseler, H. Ehrlichmann, R. Childers, K. Reim, Rainer Mankel, T. S. Yoon, and S. Khan

Subjects
Physics, Coupling constant, Nuclear and High Energy Physics, Argus, Particle physics, Electron–positron annihilation, media_common.quotation_subject, Helicity, Asymmetry, Nuclear physics, Pion, Tau neutrino, High Energy Physics::Experiment, Neutrino, computer, computer.programming_language, media_common
Abstract

Using the ARGUS detector at the DORIS II e + e − storage ring we measured for the first time the τ neutrino helicity from a parity violating asymmetry in the τ decay into three charged pions. From the measured asymmetry we derived the normalized product of the axial and vector coupling constant 2 g A g v / ( g A 2 + g V 2 ) = 1.14±0.34 −0.17 0.34 , which is in good agreement with the standard model prediction.

Published
1990

44. Study of inclusive semileptonic B meson decays

Author

Sally Seidel, U. Volland, Holger Schulz, G. Schweda, Mikhail Danilov, M. Spahn, T. Živko, B. Fominykh, Leif J. Jönsson, T. Oest, A. Droutskoy, V. Lubimov, H. I. Cronström, Werner Hofmann, H. Wegener, W. Schmidt-Parzefall, E. Križnič, P. M. Patel, C. W. Darden, J. D. Prentice, A. W. Nilsson, A. Semenov, K. W. Edwards, Fedor Ratnikov, B. Holzer, Yu. Zaitsev, S. Werner, Stefan Schael, J. A. Parsons, J. C. Gabriel, Dave Britton, G. Herrera, M. Reidenbach, H. Kapitza, K. Reim, Rainer Mankel, H. Schröder, K. W. McLean, K. Tzamariudaki, T. Ruf, F. Sefkow, A. Nippe, D. B. Macfarlane, J. D. Swain, K. Strahl, A. Rostovtsev, C. E. K. Charlesworth, G. Harder, C. Geyer, C. Hast, T. S. Yoon, P. Krieger, I. V. Gorelov, A. Lange, J. Stiewe, R. Childers, R. S. Orr, A. Nau, Sergey Semenov, G. Tsipolitis, Hermann Kolanoski, R. D. Appuhn, S. Weseler, K. R. Schubert, A. Walther, R. Waldi, H. Scheck, M. Schäfer, John D. Spengler, H. Ehrlichmann, A. Krüger, H. Albrecht, B. Spaan, W. Funk, R. Wurth, V. Shevchenko, I. Tichomirov, A. Drescher, S. Khan, Anton Babaev, Manfred Paulini, A. Lindner, S. Ball, R. Gläser, D. Wegener, V. Soloshenko, B. Boštjančič, Robert K. Kutschke, P. Križan, A. Golutvin, A. Hölscher, G. Kernel, V. Tchistilin, and M. Schieber

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Argus, Muon, Electron–positron annihilation, Resonance, Electron, Baryon, Nuclear physics, B meson, computer, computer.programming_language, Lepton
Abstract

Using the ARGUS detector at the e + e − storage ring DORIS-II, we have measured the inclusive semileptonic decays of B-mesons into electrons and muons. The data originate from 220.5 events/pb on the ϒ(4S) resonance. We find BR (B→e + v e X = (10.3 ± 0.6 ± 0.2)% and BR (B→ μ + v μ X) = (10.0 ± 0.6 ± 0.2)% using the model of Altarelli et al. for extrapolating over all lepton momenta, and BR (B→e + v e X) = (9.9±0.6)%, BR(B→ μ + v μ X) = (9.7±0.6)% using the model of Grinstein et al. For semileptonic decays into baryons, we obtain an upper limit of BR ( B → p e + v X ) CL ) .

Published
1990

45. Measurement of Ξc production in e+e− annihilation at 10.5 GeV center-of-mass energy

Author

A. Lindner, A. Rostovtsev, C. Geyer, C. Hast, H. Scheck, S. Werner, D. Wegener, P. M. Patel, B. Spaan, Anton Babaev, W. Funk, A. Walther, A. Lange, T. S. Yoon, Yu. Zaitsev, R. S. Orr, H. Albrecht, R. Childers, K. W. McLean, Fedor Ratnikov, K. Strahl, R. Wurth, M. Reidenbach, Stefan Schael, A. Droutskoy, J. A. Parsons, H. Wegener, I. Tichomirov, A. Semenov, H. Kapitza, U. Volland, H. Schröder, J. C. Gabriel, K. W. Edwards, K. Reim, A. Drescher, G. Harder, R. D. Appuhn, V. Soloshenko, V. Lubimov, K. R. Schubert, P. Krieger, Mikhail Danilov, Leif J. Jönsson, M. Schäfer, W. Schmidt-Parzefall, Rainer Mankel, A. Krüger, B. Fominykh, T. Oest, T. Ruf, S. Weseler, V. Shevchenko, S. Khan, Werner Hofmann, C. W. Darden, R. Waldi, Dave Britton, H. Ehrlichmann, C. E. K. Charlesworth, J. D. Prentice, B. Holzer, A. W. Nilsson, F. Sefkow, H. I. Cronström, Manfred Paulini, J. Spengler, B. Boštjančič, G. Kernel, V. Tchistilin, M. Schieber, S. Ball, J. Stiewe, Robert K. Kutschke, P. Križan, A. Golutvin, A. Hölscher, I. V. Gorelov, E. Križnič, A. Nau, Sergey Semenov, G. Tsipolitis, Hermann Kolanoski, A. Nippe, F. Heintz, D. B. Macfarlane, Sally Seidel, Holger Schulz, T. Živko, G. Herrera, K. Tzamariudaki, and G. Schweda

Subjects
Physics, Nuclear and High Energy Physics, Argus, Annihilation, Branching fraction, Electron–positron annihilation, DESY, Baryon, Nuclear physics, Isospin, Atomic physics, computer, Storage ring, computer.programming_language
Abstract

Using the ARGUS detector at the e+e− storage ring DORIS II at DESY, we have observed production of the charmed-strange baryon Ξc+ and its neutral isospin partner, the Ξc0. The Ξc+ was reconstructed in the final state Ξ−π+π+, while the Ξc0 was seen in decay to Ξ−π+ and Ξ−π+π+π−. The average Ξc fragmentation spectrum has been determined, as well as the production cross section times branching ratio for each decay mode. The charged and neutral masses were measured to be 2465.1 ± 3.6 ± 1.9 MeV/c2 and 2472.1 ± 2.7 ± 1.6 MeV/c2 respectively, corresponding to a mass-splitting, M(Ξc+) − M(Ξc0), of −7.0±4.5±2.2 MeV/c2.

Published
1990

46. Determination of the Michel parameter in tau decay

Author

J. Spengler, A. Golutvin, Dave Britton, F. Sefkow, S. Semenov, R. D. Appuhn, M. Schäfer, B. Holzer, M. Danilov, R. Waldi, A. Nau, K. Reim, H. Schröder, M. Schieber, V. Shevchenko, H. Wegener, I. Tichomirov, G. Tsipolitis, Robert K. Kutschke, B. Boštjančič, P. Križan, Hermann Kolanoski, A. Krüger, G. Harder, T. Ruf, I. Gorelov, R. Mankel, H. Scheck, A. Hölscher, M. Reidenbach, P. Krieger, S. Weseler, V. Soloshenko, E. Križnič, A. Walther, W. Funk, C. E. K. Charlesworth, K. W. McLean, R. Wurth, A. Nippe, D. B. Macfarlane, H. I. Cronström, J. D. Prentice, Leif J. Jönsson, A. W. Nilsson, K. Strahl, Sally Seidel, H. Albrecht, K. W. Edwards, B. Fominykh, T. Oest, K. R. Schubert, V. Lubimov, G. Schweda, U. Volland, T. Živko, C. W. Darden, Stefan Schael, J. A. Parsons, G. Kernel, H. Kapitza, G. Herrera, V. Tchistilin, S. Werner, K. Tzamariudaki, W. Schmidt-Parzefall, R. Childers, Werner Hofmann, H.D. Schulz, A. Droutskoy, J. Stiewe, A. Semenov, J. C. Gabriel, H. Ehrlichmann, D. Wegener, C. Geyer, C. Hast, A. Rostovtsev, A. Lange, R. S. Orr, P. M. Patel, Yu. Zaitsev, Anton Babaev, F. Ratnikov, A. Lindner, S. Ball, Manfred Paulini, B. Spaan, A. Drescher, T. S. Yoon, and S. Khan

Subjects
Coupling constant, Physics, Nuclear and High Energy Physics, Argus, Particle physics, Muon, Electron–positron annihilation, Electron, Nuclear physics, Goldstone boson, High Energy Physics::Experiment, computer, computer.programming_language, Boson, Lepton
Abstract

Using the ARGUS detector at the DORIS II e+e− storage ring we have studied the electron and muon energy spectra in τ − → e − ν ν and τ − →μ − ν ν decays. The measured value of the Michel parameter, ρ=0.742±0.035±0.020, is in good agreement with a standard V-A coupling at the τ-ντ-W vertex. Pure V, A and V + A couplings are completely excluded by this measurement. Upper limits have been obtained for two-body tau decays, including final states with a Goldstone boson.

Published
1990

47. Observation of the decay Ds+ → η'π+

Author

G. Harder, P. Krieger, A. Rostovtsev, A. Krüger, D. Wegener, P. M. Patel, B. Holzer, Holger Schulz, S. Khan, R. Waldi, Yu. Zaitsev, U. Volland, S. Werner, J. D. Prentice, A. W. Nilsson, Mikhail Danilov, T. Živko, C. E. K. Charlesworth, C. Geyer, C. Hast, A. Drescher, A. Lange, H. Wegener, S. Ball, V. Soloshenko, R. S. Orr, B. Fominykh, V. Shevchenko, E. Križnič, A. Nau, Sergey Semenov, G. Tsipolitis, A. Lindner, T. S. Yoon, Hermann Kolanoski, H. Scheck, A. Semenov, J. C. Gabriel, K. W. McLean, A. Nippe, R. Gläser, Werner Hofmann, H. Albrecht, K. Strahl, Stefan Schael, Robert K. Kutschke, G. Schweda, J. A. Parsons, H. Kapitza, P. Križan, A. Golutvin, R. Wurth, Leif J. Jönsson, A. Hölscher, A. Walther, V. Lubimov, B. Boštjančič, M. Reidenbach, T. Oest, K. W. Edwards, Manfred Paulini, I. Tichomirov, G. Herrera, Dave Britton, F. Sefkow, W. Schmidt-Parzefall, Anton Babaev, K. R. Schubert, K. Tzamariudaki, J. D. Swain, T. Ruf, R. D. Appuhn, M. Schäfer, C. W. Darden, B. Spaan, W. Funk, K. Reim, Rainer Mankel, S. Weseler, M. Schieber, H. Ehrlichmann, H. Schröder, D.G. MacFarlane, J. Spengler, J. Stiewe, G. Kernel, V. Tchistilin, R. Childers, H. I. Cronström, I. V. Gorelov, and Sally Seidel

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Crystallography, Argus, Electron–positron annihilation, DESY, computer, computer.programming_language
Abstract

Using the ARGUS detector at the e + e - storage ring DORIS II at DESY, we have observed the decay D s + → η'π + in two decay modes of the η'. We measure the ratio of branching ratios BR(D s + → η'π + )/BR(D s + → Oπ + ) to be 2.5±0.5±0.3.

Published
1990

48. Search for hadronic b→u decays

Author

M. Danilo, Manfred Paulini, B. Spaan, J. Stiewe, C. Geyer, J. D. Swain, C. Hast, F. Sefkow, A. Lange, U. Volland, J. D. Prentice, R. D. Appuhn, Sally Seidel, K. R. Schubert, S. Werner, A. W. Nilsson, M. Schäfer, K. W. Edwards, R. S. Orr, K. W. McLean, H. Wegener, Holger Schulz, D. Wegener, G. Kernel, H. Schröder, S. Ball, V. Tchistilin, Stefan Schael, K. Strahl, J. A. Parsons, H. Kapitza, A. Semenov, J. C. Gabriel, G. Schweda, H. Scheck, G. Harder, B. Holzer, Sergey Semenov, B. Fominykh, G. Tsipolitis, Leif J. Jönsson, P. Krieger, G. Herrera, A. Walther, John D. Spengler, Hermann Kolanoski, K. Tzamariudaki, C. E. K. Charlesworth, T. Oest, Werner Hofmann, V. Lubimov, H. Albrecht, A. Krüger, T. Ruf, Robert K. Kutschke, I. V. Gorelov, Anton Babaev, R. Wurth, P. Križan, A. Golutvin, M. Reidenbach, W. Schmidt-Parzefall, R. Waldi, A. Lindner, A. Hölscher, V. Soloshenko, D. B. Macfarlene, E. Križnič, R. Gläser, C. W. Darden, H. I. Cronström, Wolfgang Funk, William R. Frisken, V. Shevchenko, A. Nippe, I. Tichomirov, R. Childers, B. Boštjančič, K. Reim, Rainer Mankel, S. Weseler, A. Rostovtsev, P. M. Patel, Yu. Zaitsev, A. Drescher, T. S. Yoon, and S. Khan

Subjects
Physics, Nuclear and High Energy Physics, Argus, Particle physics, Electron–positron annihilation, Nuclear Theory, Hadron, DESY, Nuclear physics, Pion, High Energy Physics::Experiment, B meson, Nuclear Experiment, computer, Storage ring, computer.programming_language
Abstract

Using the ARGUS detector at the e+e− storage ring DORIS II at DESY, we searched for b→u transitions in exclusive hadronic B meson decays. A systematic analysis of B decays into pions has been performed for decay modes with 2–7 pions in the final state. In none of the decays a positive signal was observed. The upper limits obtained on various branching ratios are consistent with the current model predictions.

Published
1990

49. Study of antideuteron production in e+ e− annihilation at 10 GeV centre-of-mass energy

Author

A.W. Nilsson, B. Spaan, W. Funk, G. Herrera, Mikhail Danilov, E. Križnič, R. Childers, B. Fominykh, P. M. Patel, Yu. Zaitsev, B. Holzer, Manfred Paulini, William R. Frisken, J. D. Swain, A. Nippe, A. Krüger, Leif J. Jönsson, S. Weseler, U. Volland, D. B. Macfarlane, K. W. McLean, A. Lindner, A. Semenov, Werner Hofmann, K. W. Edwards, S. Khan, G. Schweda, K. Strahl, V. Shevchenko, K. R. Schubert, T. Oest, C. E. K. Charlesworth, R. Gläser, J. C. Gabriel, I. Tichomirov, J. Spengler, Stefan Schael, H. I. Cronström, J. A. Parsons, V. Lubimov, H. Kapitza, T. S. Yoon, A. Rostovtsev, T. Ruf, H. Wegener, K. Reim, V. Soloshenko, W. Schmidt-Parzefall, S. Ball, G. Kernel, Sally Seidel, Anton Babaev, C. W. Darden, Sergey Semenov, G. Tsipolitis, C. Geyer, C. Hast, H. Schröder, V. Tchistilin, Holger Schulz, A. Drescher, Rainer Mankel, Hermann Kolanoski, A. Lange, M. Reidenbach, F. Sefkow, A. Walther, R. Davis, R. S. Orr, M. Pleško, B. Boštjančič, Robert K. Kutschke, P. Križan, A. Golutvin, R. D. Appuhn, A. Hölscher, M. Schäfer, H. Scheck, I. V. Gorelov, H. Albrecht, J. Stiewe, R. Wurth, G. Harder, P. Krieger, R. Waldi, J. D. Prentice, D. Wegener, and S. Werner

Subjects
Physics, Nuclear and High Energy Physics, Argus, Particle physics, Annihilation, Electron–positron annihilation, Hadron, Elementary particle, Nuclear physics, Antiproton, computer, Storage ring, computer.programming_language, Production rate
Abstract

We report a measurement of the production of antideuterons d in e+e− annihilation at centre-of-mass energies around 10 GeV using the ARGUS detector at the DORIS II storage ring. We observe an enhancement of d production in direct hadronic ϒ(1S) and ϒ(2S) resonance decays. From 21 events width a d candidate the inclusive cross section 1σdirhad · dσdp and the production rate of antideuterons are determined. A production rate of (6.0±2.0±0.6) × 10-5d per direct hadronic ϒ decay and a 90% CL upper limit of 1.7 × 10−5d per e+e−→qq continuum event are obtained. These results are related to antiproton production through a simple model.

Published
1990

50. Observation of semileptonic charmless B meson decays

Author

K. W. Edwards, U. Volland, Robert K. Kutschke, P. Križan, A. Golutvin, T. S. Yoon, A. Hölscher, J. D. Swain, I. V. Gorelov, V. Shevchenko, I. Tichomirov, Mikhail Danilov, S. Werner, J. Stiewe, V. Lubimov, A. Krüger, T. Ruf, B. Fominykh, H. Albrect, W. Schmidt-Parzefall, A. Semenov, C. W. Darden, Leif J. Jönsson, J. C. Gabriel, A. Rostovtsev, Werner Hofmann, Anton Babaev, T. Oest, H. Scheck, G. Herrera, Sally Seidel, D. Wegener, John D. Spengler, S. Khan, R. Wurth, M. Reidenbach, A. Walther, R. Davis, K. W. McLean, A. Lindner, Holger Schulz, C. E. K. Charlesworth, K. Strahl, H. Wegener, R. Gläser, V. Soloshenko, P. M. Patel, E. Križnič, Manfred Paulini, A. Drescher, Yu. Zaitsev, G. Schweda, Stefan Schael, J. A. Parsons, William R. Frisken, H. Kapitza, B. Boštjančič, S. Ball, A. Nippe, D. B. Macfarlane, Sergey Semenov, G. Tsipolitis, Hermann Kolanoski, E. Tzamariudaki, B. Holzer, K. R. Schubert, R. Waldi, G. Harder, P. Krieger, J. D. Prentice, A. W. Nilsson, R. D. Appuhn, M. Schäfer, B. Spaan, W. Funk, C. Geyer, C. Hast, A. Lange, F. Sefkow, R. S. Orr, G. Kernel, V. Tchistilin, K. Reim, Rainer Mankel, R. Childers, S. Weseler, H. I. Cronström, and H. Schröder

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Argus, Electron–positron annihilation, DESY, Nuclear physics, Momentum, Matrix (mathematics), B meson, computer, Storage ring, Lepton, computer.programming_language
Abstract

A detailed study of the lepton momentum spectrum in υ(4S) decays has been made using the ARGUS detector at the DORIS II e+e− storage ring at DESY. In the region from 2.3 to 2.6 GeV/c, which is above the endpoint for contributions from B decays via b→c transitions, we observe 41±10 events in excess of known backgrounds. These events are interpreted as a signal for b→u transitions. A model dependent value of 0.10±0.01 is obtained for the ratio of Cabibbo-Kobayashi-Maskawa matrix elements |Vub|/|Vcv|, using the Altarelli et al. model.

Published
1990

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