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1. Study of the rare hyperon decay

Author

Daniel M. Kaplan, H. K. Park, E. C. Dukes, H. A. Rubin, N. Solomey, Y. Fu, M. J. Longo, P. Zyla, Christopher G. White, C. James, H. R. Gustafson, T. Holmstrom, Y. C. Chen, Juan C. Felix, Kam Biu Luk, A. Chakravorty, J. P. Perroud, S.L. White, C. Durandet, W. Luebke, R. A. Burnstein, K. Clark, D. Rajaram, W. S. Choong, L. C. Lu, J. Volk, G. Gidal, K. S. Nelson, M. Huang, O. Kamaev, T.D. Jones, and C. M. Jenkins

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Particle decay, Pion, Branching fraction, Hyperon, CP violation, Atomic physics, Omega baryon, Xi baryon, Dimensionless quantity
Abstract

We report a new measurement of the decay Ω − → Ξ − π + π − with 76 events and a first observation of the decay Ω ¯ + → Ξ ¯ + π + π − with 24 events, yielding a combined branching ratio ( 3.74 − 0.56 + 0.67 ) × 10 − 4 . This represents a factor 25 increase in statistics over the best previous measurement. No evidence is seen for CP violation, with B ( Ω − → Ξ − π + π − ) = 4.04 − 0.71 + 0.83 × 10 − 4 and B ( Ω ¯ + → Ξ ¯ + π + π − ) = 3.15 − 0.89 + 1.12 × 10 − 4 . Contrary to theoretical expectation, we see little evidence for the decays Ω − → Ξ 1530 ∗ 0 π − and Ω ¯ + → Ξ ¯ 1530 ∗ 0 π + and place a 90% C.L. upper limit on the combined branching ratio B ( Ω − ( Ω ¯ + ) → Ξ 1530 ∗ 0 ( Ξ ¯ 1530 ∗ 0 ) π ∓ ) 7.0 × 10 − 5 .

Published
2010

2. Observation of parity violation in the Ω−→ΛK− decay

Author

T. Holmstrom, H. K. Park, E. C. Dukes, H. R. Gustafson, D. Rajaram, C. Durandet, L. C. Lu, T.D. Jones, J. Volk, Daniel M. Kaplan, P. Zyla, A. Chakravorty, Juan C. Felix, K. S. Nelson, Kam-Biu Luk, M. Huang, M. J. Longo, K. Clark, G. Gidal, R. A. Burnstein, Y. Fu, H. A. Rubin, W. S. Choong, J. P. Perroud, S.L. White, C. M. Jenkins, Christopher G. White, Y. C. Chen, W. Luebke, and C. James

Subjects
Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Parity (physics), Fermilab
Abstract

The α decay parameter in the process Ω − → Λ K − has been measured from a sample of 4.50 million unpolarized Ω − decays recorded by the HyperCP (E871) experiment at Fermilab and found to be [ 1.78 ± 0.19 ( stat ) ± 0.16 ( syst ) ] × 10 −2 . This is the first unambiguous evidence for a nonzero α decay parameter, and hence parity violation, in the Ω − → Λ K − decay.

Published
2005

3. HyperCP: A high-rate spectrometer for the study of charged hyperon and kaon decays

Author

Michael J. Longo, W. Luebke, K. S. Nelson, S.L. White, Kam-Biu Luk, F. Lopez, M. Huang, N. Leros, Christopher G. White, T. Holmstrom, H.A. Rubin, C. Durandet, T.D. Jones, J. P. Perroud, C. James, G. Gidal, H. R. Gustafson, H. K. Park, Daniel M. Kaplan, C. Ho, E. C. Dukes, L.M. Lederman, A. Chan, B. Turko, R. A. Burnstein, P. K. Teng, Yi-Chun Chen, J. Volk, P. Zyla, K. Clark, R. Fuzesy, P. Gu, C. M. Jenkins, Juan C. Felix, W. S. Choong, L. C. Lu, D. Rajaram, and A. Chakravorty

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Calorimeter (particle physics), Spectrometer, Physics::Instrumentation and Detectors, Hadron, Hyperon, FOS: Physical sciences, High Energy Physics - Experiment, Momentum, Nuclear physics, High Energy Physics - Experiment (hep-ex), Magnet, CP violation, High Energy Physics::Experiment, Fermilab, Nuclear Experiment, Instrumentation
Abstract

The HyperCP experiment (Fermilab E871) was designed to search for rare phenomena in the decays of charged strange particles, in particular CP violation in $\Xi$ and $\Lambda$ hyperon decays with a sensitivity of $10^{-4}$. Intense charged secondary beams were produced by 800 GeV/c protons and momentum-selected by a magnetic channel. Decay products were detected in a large-acceptance, high-rate magnetic spectrometer using multiwire proportional chambers, trigger hodoscopes, a hadronic calorimeter, and a muon-detection system. Nearly identical acceptances and efficiencies for hyperons and antihyperons decaying within an evacuated volume were achieved by reversing the polarities of the channel and spectrometer magnets. A high-rate data-acquisition system enabled 231 billion events to be recorded in twelve months of data-taking., Comment: 107 pages, 45 Postscript figures, 14 tables, Elsevier LaTeX, submitted to Nucl. Instrum. Meth. A

Published
2005

4. Search for CP violation in hyperon decays

Author

Julián Félix, H. K. Park, S.L. White, B. Turko, T. Jones, Daniel M. Kaplan, N. Leros, W. Luebke, M. J. Longo, M. Jenkins, H. A. Rubin, K. Clark, K. S. Nelson, Kam-Biu Luk, Piotr Zyla, M. Huang, W. S. Choong, G. Gidal, N. Solomey, J. Volk, T. Holmstrom, P. Gu, A. Chakrovorty, L. C. Lu, Christopher G. White, C. Ho, Y. C. Chen, Aw Chan, H. R. Gustafson, F. Lopez, R. A. Burnstein, Yagmur Torun, E.C. Dukes, P. Zyla, J. P. Perroud, P. K. Teng, Leon M. Lederman, C. James, D. Rajaram, Y. Fu, and C. Durandet

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, media_common.quotation_subject, Hadron, Hyperon, Elementary particle, Rest frame, Lambda, Asymmetry, Atomic and Molecular Physics, and Optics, Nuclear physics, CP violation, Nucleon, media_common
Abstract

Direct CP violation in nonleptonic hyperon decays can be established by comparing the decays of hyperons and anti-hyperons. For Ξ decay to Λπ followed by Λ to pπ, the proton distribution in the rest frame of Lambda is governed by the product of the decay parameters αΞαΛ. The asymmetry ΛΞΛ, proportional to the difference of αΞαΛ of the hyperon and anti-hyperon decays, vanishes if CP is conserved. We report on an analysis of a fraction of 1997 and 1999 data collected by the HyperCP (E871) collaboration during the fixed-target runs at Fermilab. The preliminary measurement of the assymmetry is AΞΛ = [−7±12(stat)±6.2(sys)] × 10−4, an order of magnitude better than the present limit.

Published
2003

5. HyperCP (E871) experiment at Fermilab: search for direct CP violation in hyperon decays

Author

H. K. Park, E. C. Dukes, C. Durandet, R. A. Burnstein, Bojan T. Turko, M. Jenkins, P. Zyla, G. Gidal, K. S. Nelson, Kam Biu Luk, A. Chakravorty, L. C. Lu, M. Huang, J. P. Perroud, Julián Félix, P. K. Teng, T. Holmstrom, F. Lopez, Michael J. Longo, S.L. White, C. James, W. Luebke, D. Rajaram, G. Moreno, N. Leros, C. Ho, K. Clark, Aw Chan, J. Volk, T.D. Jones, H. R. Gustafson, H. A. Rubin, Christopher G. White, Y. C. Chen, Modesto Sosa, Daniel M. Kaplan, L.M. Lederman, and Woon-Seng Choong

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Particle physics, Pion, Antiproton, Hyperon, CP violation, Nucleon, Lambda baryon, Helicity, Atomic and Molecular Physics, and Optics, Xi baryon
Abstract

The Fermilab HyperCP experiment has accumulated the world's largest sample of Ξ− and Ξ + hyperon decays within two running periods in 1997 and 1999. The primary goal of the experiment is to search for direct CP violation in the decay sequences Ξ− → Λ π− → p π− π− and Ξ + → Λ π+ → p π+ π+. A violation of CP would manifest itself as a difference between the angular distribution of the proton and the antiproton in the Λ and Λ helicity frame. The amount of data is enough to reach a statistical sensitivity of 1.4 × 10−4 in the CP violating asymmetry A ΞΛ = (αΞ αΛ − α Ξ α Λ )/(αΞ αΛ + α Ξ α Λ ). We present an analysis method used to take into account the slight differences in the production of the Ξ− and Ξ + samples. A preliminary results on A ΞΛ at the level of a few 10−3 and based on a few percent of the 1997 data will be presented.

Published
2001

6. Search for direct CP violation in Λ and Ξ hyperon decays

Author

Kam Biu Luk, J. P. Perroud, C.S Yu, Bojan T. Turko, N. Leros, Z. Kou, M. Crisler, F. Lopez, K. S. Nelson, R. A. Burnstein, M. Huang, N. Saleh, Modesto Sosa, E. C. Dukes, Christopher G. White, Woon-Seng Choong, M. Carmack, Y. C. Chen, A. Chakravorty, J. Volk, Daniel M. Kaplan, S.L. White, M. J. Longo, W. Luebke, C. Durandet, L.M. Lederman, Z. Yu, Juan C. Felix, D. Rajaram, C. Ho, Aw Chan, H. A. Rubin, H. R. Gustafson, G. Gidal, T. Holmstrom, G. Lopez, C. James, J.P Sheng, K. Clark, J. Drapala, M. Jenkins, P. K. Teng, P. Zyla, and V. Papavassiliou

Subjects
Physics, Nuclear and High Energy Physics, Antiparticle, Particle physics, media_common.quotation_subject, Hyperon, Lambda baryon, Helicity, Asymmetry, Atomic and Molecular Physics, and Optics, Xi baryon, Nuclear physics, Particle decay, CP violation, High Energy Physics::Experiment, media_common
Abstract

A sensitive search for direct CP violation in Ξ− (Ξ+) and Λ (Λ) decays is underway at FNAL. Experiment E871 (HyperCP) intends to perform a precision measurement of the angular distribution of protons (anti-protons) with respect to the helicity axis in the rest frame of the Λ (Λ). The slopes of these distributions give the decay parameters αΞαΛ and αΞαΛ. An asymmetry parameter A in terms of these decay parameters has been defined for which a non-zero value would be unambiguous evidence for direct CP violation. Theoretical predictions for A range from no asymmetry up to ∼ 10−3. HyperCP expects to measure A with an uncertainty of ∼ 2 × 10−4.

Published
1999

7. Measurement of the Bottom-Quark Production Cross Section in 800 GeV/cProton-Gold Collisions

Author

C. N. Brown, R. Childers, T. A. Carey, L. D. Isenhower, R. S. Preston, Kam Biu Luk, D. W. Lane, M. H. Schub, Pei-Ming Ho, J. Sa, D. M. Jansen, M. E. Sadler, Josh Moss, P. K. Teng, R. Schnathorst, J. S. Kapustinsky, V. Tanikella, Yi-Chun Chen, W. E. Cooper, D. Pripstein, Leon M. Lederman, P. L. McGaughey, J. W. Lillberg, C. S. Mishra, Jen-Chieh Peng, R. G. Jeppesen, G. C. Kiang, M. S. Kowitt, G. Gidal, K. Gounder, W. Luebke, Daniel M. Kaplan, C. W. Darden, James R. Wilson, and M. J. Leitch

Subjects
Quantum chromodynamics, Mass number, Physics, Particle decay, Particle physics, Meson, Proton, General Physics and Astronomy, Production (computer science), Nucleon, Bottom quark
Abstract

Using a silicon-microstrip detector array to identify secondary vertices, we have observed {ital b}{r_arrow}{ital J}/{psi}{r_arrow}{mu}{sup +}{mu}{sup {minus}} decays in 800 GeV/{ital c} proton-gold interactions. The doubly differential cross section for {ital J}/{psi} mesons originating from {ital b}-quark decays, assuming linear dependence on nucleon number, is {ital d}{sup 2}{sigma}/{ital dx}{sub {ital Fdp}}{sup 2}{sub {ital T}}=107{plus_minus}28{plus_minus}19/nucleon at {ital x}{sub {ital F}}=0.05 and {ital p}{sub {ital T}}=1GeV/{ital c}. This measurement is compared to next-to-leading-order QCD predictions. The integrated {ital b}-quark production cross section, obtained by extrapolation over all {ital x}{sub {ital F}} and {ital p}{sub {ital T}}, is {sigma}({ital pN}{r_arrow}{ital bb}{ovr bar}+{ital X})=5.7{plus_minus}1.5{plus_minus}1.3 nb/nucleon.

Published
1995

8. Search for the decayD0→μ+μ−

Author

K. Gounder, P. L. McGaughey, J. W. Lillberg, Josh Moss, R. Schnathorst, W. E. Cooper, G. Gidal, M. S. Kowitt, T. A. Carey, Daniel M. Kaplan, V. M. Martin, M. J. Leitch, L. D. Isenhower, J. Sa, V. Tanikella, M. E. Sadler, Kam-Biu Luk, J. S. Kapustinsky, R. S. Preston, C. S. Mishra, D. W. Lane, Leon M. Lederman, C. N. Brown, M. H. Schub, P. K. Teng, R. Childers, C. W. Darden, R. E. Jeppesen, and Jen-Chieh Peng

Subjects
Physics, Particle physics
Published
1994

9. Production ofJ/ψ at largexFin 800 GeV/cp-copper andp-beryllium collisions

Author

James R. Wilson, R. S. Preston, V. M. Martin, J. Sa, M. H. Schub, W. E. Cooper, Daniel M. Kaplan, D. W. Lane, J. G. Boissevain, Kam Biu Luk, Pei-Ming Ho, R. Childers, J. S. Kapustinsky, H. Glass, M. S. Kowitt, M. J. Leitch, G. Gidal, T. A. Carey, C. W. Darden, Josh Moss, R. Schwindt, Leon M. Lederman, K. Gounder, P. K. Teng, W. Luebke, P. L. McGaughey, D. Pripstein, R. Schnathorst, J. W. Lillberg, D. M. Jansen, C. N. Brown, L. D. Isenhower, Yi-Chun Chen, Jen-Chieh Peng, C. S. Mishra, R. G. Jeppesen, G. C. Kiang, M. E. Sadler, and V. Tanikella

Subjects
Physics, Particle physics, General Physics and Astronomy, Duality (optimization), chemistry.chemical_element, Parton, Copper, law.invention, Cross section (geometry), Nuclear physics, chemistry, law, Production (computer science), Charm (quantum number), Beam dump, Beryllium
Abstract

The differential cross sections do/dxF for J/G produced inclusively in 800 GeV/c p-Cn and pBe collisions have been measured in the kinematic range 0.30 5 IF < 0.95 through the decay mode J/G + p+p-. They are compared with the predictions of the semilocal duality model for several sets of parton density functions. No evidence for a suggested intrinsic charm contribution to the cross section is observed. The ratio of the differential cross sections for Cu and Be targets confirms the suppression of J/$ production in heavy nuclei at large ZF.

Published
1994

10. Radiation damage effects on the silicon microstrip detector in E789 - A fixed target experiment at fermilab

Author

C. S. Mishra, R. G. Jeppesen, G. C. Kiang, D. Isenhower, R. Schwint, D. M. Jansen, G. Brown, C. W. Darden, V. M. Martin, H. Glass, Leon M. Lederman, K. Gounder, M. S. Kowitt, J. Sa, Josh Moss, M. E. Sadler, M. J. Leitch, G. Gidal, W. E. Cooper, W. Luebke, D. Pripstein, M. Apolinski, M. H. Schub, P. L. McGaughey, J.W. Wilson, J. W. Lillberg, Kam Biu Luk, Pei-Ming Ho, C. N. Brown, T. A. Carey, Daniel M. Kaplan, P. K. Teng, R. S. Preston, J. S. Kapustinsky, V.N. Tanikella, R. Schnathorst, Yi-Chun Chen, Jen-Chieh Peng, D. W. Lane, R. Childers, D. Snodgrass, and J. G. Boissevain

Subjects
Physics, Nuclear and High Energy Physics, Silicon, Spectrometer, Meson, Physics::Instrumentation and Detectors, chemistry.chemical_element, Atomic and Molecular Physics, and Optics, Charged particle, Ionizing radiation, Nuclear physics, chemistry, Radiation damage, High Energy Physics::Experiment, Fermilab, Silicon microstrip detectors
Abstract

A Silicon Microstrip Spectrometer has been installed and successfully operated in experiment E789 at Fermilab. The main physics goal of the experiment is to search for charged particle decays of B and D Mesons. Damage effects due to ionizing radiation exposure to the silicon during the experiment are reported.

Published
1993

11. Inclusive charged hadron and K0 production in two-photon interactions

Author

J. Boyer, Darien Wood, G. J. Feldman, K. Hayes, D. Herrup, J. A. Jaros, G. H. Trilling, G. S. Abrams, D. Karlen, P. C. Rowson, D. Cords, F. Butler, L. Gladney, N. S. Lockyer, G. Gidal, I. Juricic, M. S. Gold, J. Haggerty, A. M. Boyarski, M. L. Perl, R. A. Ong, K. Riles, Andrew Lankford, R. J. Hollebeek, D. Amidei, B. W. Leclaire, Michael Levi, V. Lüth, Mark E. Nelson, Gordon H. Hanson, J. A. Kadyk, J. M. Yelton, D. L. Burke, W. B. Schmidke, J. M. Dorfan, T. Schaad, H. Schellman, W. R. Innes, Patricia R. Burchat, G. Goldhaber, R. R. Larsen, A. Baden, and T. Barklow

Subjects
Quark, Nuclear physics, Physics, Nuclear and High Energy Physics, Particle physics, Pair production, Annihilation, Meson, Hadron, Elementary particle, Production (computer science), Fermion
Abstract

The analogous process to quark pair production in e{sup +} e{sup {minus}} annihilation is the hard-scattering quark exchange process in {gamma}{gamma} interactions. This hard-scattering process is expected to dominate the cross section at high transverse momenta of the produced quarks. Experimentally, one has looked for this process in two-jet as well as inclusive particle production and has found a relatively low PT onset of hard scattering in {gamma}{gamma} interactions. This report examines the issue in more detail (high statistics) for charged particle inclusive production and checks if the heavier flavors display a similar behavior in inclusive K{sup 0} production.

Published
1993

12. Measurement of the charged multiplicity of events containing bottom hadrons atEc.m.=91GeV

Author

B. A. Schumm, D. S. Koetke, C. E. Adolphsen, J. P. Alexander, D. Averill, B. C. Barish, T. Barklow, B. A. Barnett, D. Blockus, A. Boyarski, B. Brabson, A. Breakstone, F. Bulos, P. R. Burchat, D. L. Burke, R. J. Cence, J. Chapman, M. Chmeissani, D. Cords, D. P. Coupal, P. Dauncey, H. C. DeStaebler, J. M. Dorfan, P. S. Drell, D. C. Drewer, D. Durrett, R. Elia, G. J. Feldman, R. C. Field, W. T. Ford, C. Fordham, R. Frey, D. Fujino, K. K. Gan, E. Gero, G. Gidal, T. Glanzman, G. Goldhaber, J. J. Gomez Cadenas, G. Gratta, G. Hanson, R. Harr, B. Harral, F. A. Harris, K. Hayes, C. Hearty, C. A. Heusch, M. D. Hildreth, T. Himel, D. A. Hinshaw, S. J. Hong, D. Hutchinson, J. Hylen, W. R. Innes, R. G. Jacobsen, J. A. Jaros, C. K. Jung, J. A. Kadyk, C. Kenney, M. King, S. Komamiya, L. A. Kowalski, J. F. Kral, M. Kuhlen, L. Labarga, A. J. Lankford, F. Le Diberder, M. E. Levi, A. M. Litke, X. C. Lou, V. Lüth, J. A. McKenna, J. A. J. Matthews, T. Mattison, K. C. Moffeit, C. T. Munger, W. N. Murray, J. Nash, H. Ogren, K. F. O'Shaughnessy, S. I. Parker, C. Peck, M. L. Perl, M. Petradza, R. Pitthan, F. C. Porter, P. Rankin, F. R. Rouse, D. R. Rust, H. F. W. Sadrozinski, A. S. Schwarz, A. Seiden, J. G. Smith, A. Snyder, E. Soderstrom, D. P. Stoker, R. Stroynowski, M. Swartz, R. Thun, G. H. Trilling, M. Turala, R. Van Kooten, P. Weber, A. J. Weinstein, E. Wicklund, S. R. Wagner, M. Woods, M. Yurko, and C. Zaccardelli

Subjects
Nuclear physics, Physics, Quark, Particle decay, Particle physics, Electron–positron annihilation, Hadron, Quark model, High Energy Physics::Experiment, Elementary particle, Multiplicity (mathematics), Nuclear Experiment, Charged particle
Abstract

Using an impact-parameter tag to select an enriched sample of Z0bb» events, we have measured the difference between the average charged multiplicity of bb» and all hadronic Z0 decays to be 2.11.8(stat) 0.6(syst) tracks per event. The resulting total (nonleading) charged multiplicity for Z0 bb» events is 23.1(12.0)1.8 0.6 tracks. A comparison of this nonleading multiplicity to hadronic multiplicity data in the range of 10 to 60 GeV supports the hypothesis of flavor-independent hadronic fragmentation, and yields a measurement of the average energy fraction of bottom hadrons in Z0 decays of xEb=0.620.100.04. © 1992 The American Physical Society.

Published
1992

13. Search for the production of the final statesτ+τ−e+e−,τ+τ−μ+μ−, andτ+τ−π+π−ine+e−collisions at √s=29 GeV

Author

R. R. Larsen, Michael Levi, V. Lüth, S. R. Wagner, B. W. Leclaire, Darien Wood, A. M. Boyarski, J. A. Kadyk, P. D. Sheldon, G. H. Trilling, M. S. Gold, D. P. Stoker, K. Riles, N. S. Lockyer, Gordon H. Hanson, G. Gidal, G. J. Feldman, I. Juricic, G. Goldhaber, Patricia R. Burchat, J. M. Yelton, A. Snyder, D. Karlen, M. L. Perl, L. Golding, K. Hayes, W. R. Innes, Mark E. Nelson, A. Baden, D. Herrup, T. Barklow, R. A. Ong, L. Gladney, P. C. Rowson, H. Schellman, D. Amidei, G. S. Abrams, J. Haggerty, R. J. Hollebeek, F. Butler, M. Petradza, Burton Richter, Andrew Lankford, D. L. Burke, W. B. Schmidke, J. M. Dorfan, J. Boyer, T. Schaad, and J. A. Jaros

Subjects
Physics, Particle physics, Muon, Pion, Meson, Electron–positron annihilation, Hadron, General Physics and Astronomy, Elementary particle, Standard Model, Lepton
Abstract

We have searched for the reaction e+e-, where f is either an electron, muon, or charged pion, at s =29 GeV using the Mark II detector at the SLAC PEP storage ring. One candidate event is found while 2.3 events are expected from known processes. We would expect to see 11 events if the cross section for e+e- at s=29 GeV were enhanced by the factor of 4.7 which the ALEPH Collaboration reports for s=91 GeV. We also look for e+e- and e+e-, and for e+e-, using a similar analysis procedure, and see the number of events predicted by the standard model. © 1992 The American Physical Society.

Published
1992

14. Measurement of thebb¯fraction in hadronicZ0decays with precision vertex detectors

Author

R. G. Jacobsen, D. S. Koetke, C. E. Adolphsen, D. Fujino, B. A. Schumm, S. R. Wagner, J. P. Alexander, D. Averill, B. C. Barish, T. Barklow, B. A. Barnett, D. Blockus, A. Boyarski, B. Brabson, A. Breakstone, F. Bulos, P. R. Burchat, D. L. Burke, R. J. Cence, J. Chapman, M. Chmeissani, D. Cords, D. P. Coupal, P. Dauncey, H. C. DeStaebler, J. M. Dorfan, P. S. Drell, D. C. Drewer, D. Durrett, R. Elia, G. J. Feldman, R. C. Field, W. T. Ford, C. Fordham, R. Frey, K. K. Gan, E. Gero, G. Gidal, T. Glanzman, G. Goldhaber, J. J. Gomez Cadenas, G. Gratta, G. Hanson, R. Harr, B. Harral, F. A. Harris, K. Hayes, C. Hearty, C. A. Heusch, M. D. Hildreth, T. Himel, D. A. Hinshaw, S. J. Hong, D. Hutchinson, J. Hylen, W. R. Innes, J. A. Jaros, C. K. Jung, J. A. Kadyk, C. Kenney, M. King, S. Komamiya, L. A. Kowalski, J. F. Kral, M. Kuhlen, L. Labarga, A. J. Lankford, F. Le Diberder, M. E. Levi, A. M. Litke, X. C. Lou, V. Lüth, J. A. McKenna, J. A. J. Matthews, T. Mattison, K. C. Moffeit, C. T. Munger, W. N. Murray, J. Nash, H. Ogren, K. F. O’Shaughnessy, S. I. Parker, C. Peck, M. L. Perl, M. Petradza, R. Pitthan, F. C. Porter, P. Rankin, D. R. Rust, H. F. W. Sadrozinski, A. S. Schwarz, A. Seiden, J. G. Smith, A. Snyder, E. Soderstrom, D. P. Stoker, R. Stroynowski, M. Swartz, R. Thun, G. H. Trilling, M. Turala, R. Van Kooten, P. Weber, A. J. Weinstein, E. Wicklund, M. Woods, M. Yurko, and C. Zaccardelli

Subjects
Nuclear physics, Physics, Particle physics, Particle decay, Annihilation, Distribution function, Hadron, General Physics and Astronomy, Elementary particle, Particle identification, Bar (unit), Boson
Abstract

We have measured the fraction of {ital b{bar b}} events in hadronic {ital Z}{sup 0} decays, {ital R}{sub {ital b}{ital {bar b}}}, using the vertex detector system of the Mark II detector at the SLAC Linear Collider. We tag {ital b{bar b}} events by requiring the coincidence of three or more tracks with significant impact parameters. This tag is 50% efficient and results in a sample of 85% purity. We find {ital R}{sub {ital b}{ital {bar b}}}=0.251{plus minus}0.049{plus minus}0.030, in good agreement with other measurements and the standard model prediction.

Published
1991

15. Search for elastic nondiagonal lepton-pair production ine+e−annihilation at √s=29 GeV

Author

J. J. Gomez-Cadenas, C. A. Heusch, G. Abrams, C. E. Adolphsen, C. Akerlof, J. P. Alexander, M. Alvarez, D. Amidei, A. R. Baden, J. Ballam, B. C. Barish, T. Barklow, B. A. Barnett, J. Bartelt, D. Blockus, G. Bonvicini, A. Boyarski, J. Boyer, B. Brabson, A. Breakstone, J. M. Brom, F. Bulos, P. R. Burchat, D. L. Burke, F. Butler, F. Calvino, R. J. Cence, J. Chapman, D. Cords, D. P. Coupal, H. C. DeStaebler, D. E. Dorfan, J. M. Dorfan, P. S. Drell, G. J. Feldman, E. Fernandez, R. C. Field, W. T. Ford, C. Fordham, R. Frey, D. Fujino, K. K. Gan, G. Gidal, L. Gladney, T. Glanzman, M. S. Gold, G. Goldhaber, L. Golding, A. Green, P. Grosse-Wiesmann, J. Haggerty, G. Hanson, R. Harr, F. A. Harris, C. M. Hawkes, K. Hayes, D. Herrup, T. Himel, M. Hoenk, R. J. Hollebeek, D. Hutchinson, J. Hylen, W. R. Innes, M. Jaffre, J. A. Jaros, I. Juricic, J. A. Kadyk, D. Karlen, J. Kent, S. R. Klein, A. Koide, W. Koska, W. Kozanecki, A. J. Lankford, R. R. Larsen, B. W. LeClaire, M. E. Levi, Z. Li, A. M. Litke, N. S. Lockyer, V. Lüth, C. Matteuzzi, J. A. J. Matthews, D. I. Meyer, B. D. Milliken, K. C. Moffeit, L. Müller, J. Nash, M. E. Nelson, D. Nitz, H. Ogren, R. A. Ong, K. F. O’Shaughnessy, S. I. Parker, C. Peck, A. Petersen, M. Petradza, F. C. Porter, P. Rankin, B. Richter, K. Riles, P. C. Rowson, D. R. Rust, H. F. W. Sadrozinski, T. Schaad, T. L. Schalk, H. Schellman, W. B. Schmidke, A. S. Schwarz, A. Seiden, P. D. Sheldon, J. G. Smith, A. Snyder, E. Soderstrom, D. P. Stoker, R. Stroynowski, R. Thun, G. H. Trilling, R. Tschirhart, C. de la Vaissiere, R. Van Kooten, H. Veltman, P. Voruganti, S. R. Wagner, P. Weber, A. J. Weinstein, A. J. Weir, S. Weisz, S. L. White, E. Wicklund, D. R. Wood, D. Y. Wu, and J. M. Yelton

Subjects
Physics, Particle physics, Annihilation, Electron–positron annihilation, High Energy Physics::Phenomenology, General Physics and Astronomy, Elementary particle, Fermion, Nuclear physics, Pair production, High Energy Physics::Experiment, Production (computer science), Storage ring, Lepton
Abstract

We have searched for the annihilation of e+e- into the exclusive channels e and at s =29 GeV, using 226 and 133 pb-1, respectively, of data taken with the Mark II detector at the SLAC storage ring PEP. The resulting candidate sample is compatible with the expected background from pair production. Our analysis yields 95%-C.L. cross-section limits of e/

Published
1991

16. Measurement of the total hadronic cross section ine+e−annihilation ats=29GeV

Author

C. von Zanthier, W. de Boer, G. Grindhammer, J. Hylen, B. Harral, C. Hearty, L. Labarga, J. Matthews, M. Schaad, G. Abrams, C. E. Adolphsen, C. Akerlof, J. P. Alexander, M. Alvarez, A. R. Baden, J. Ballam, B. C. Barish, T. Barklow, B. A. Barnett, J. Bartelt, D. Blockus, G. Bonvicini, A. Boyarski, J. Boyer, B. Brabson, A. Breakstone, J. M. Brom, F. Bulos, P. R. Burchat, D. L. Burke, F. Butler, F. Calvino, R. J. Cence, J. Chapman, D. Cords, D. P. Coupal, H. C. DeStaebler, D. E. Dorfan, J. M. Dorfan, P. S. Drell, G. J. Feldman, E. Fernandez, R. C. Field, W. T. Ford, C. Fordham, R. Frey, D. Fujino, K. K. Gan, G. Gidal, T. Glanzman, G. Goldhaber, A. Green, P. Grosse-Wiesmann, J. Haggerty, G. Hanson, R. Harr, F. A. Harris, C. M. Hawkes, K. Hayes, D. Herrup, C. A. Heusch, T. Himel, M. Hoenk, D. Hutchinson, W. R. Innes, M. Jaffre, J. A. Jaros, I. Juricic, J. A. Kadyk, D. Karlen, J. Kent, S. R. Klein, W. Koska, W. Kozanecki, A. J. Lankford, R. R. Larsen, M. E. Levi, Z. Li, A. M. Litke, V. Lüth, D. I. Meyer, B. D. Milliken, K. C. Moffeit, L. Müller, J. Nash, M. E. Nelson, D. Nitz, H. Ogren, K. F. O'Shaughnessy, S. I. Parker, C. Peck, M. L. Perl, A. Petersen, M. Petradza, F. C. Porter, P. Rankin, K. Riles, D. R. Rust, H. F. W. Sadrozinski, T. L. Schalk, W. B. Schmidke, A. S. Schwarz, A. Seiden, J. G. Smith, A. Snyder, E. Soderstrom, D. P. Stoker, R. Stroynowski, R. Thun, G. H. Trilling, R. Tschirhart, R. Van Kooten, H. Veltman, P. Voruganti, S. R. Wagner, P. Weber, A. J. Weinstein, A. J. Weir, S. Weisz, S. L. White, E. Wicklund, D. R. Wood, and D. Y. Wu

Subjects
Physics, Elastic scattering, Cross section (physics), Particle physics, Luminosity (scattering theory), Pair production, Annihilation, Monte Carlo method, Radiative transfer, High Energy Physics::Experiment, Bhabha scattering
Abstract

A precise measurement of the ratio R of the total cross section e+e-hadrons to the pointlike cross section e+e-+- at a center-of-mass energy of 29.0 GeV is presented. The data were taken with the upgraded Mark II detector at the SLAC storage ring PEP. The result is R=3.920.050.09. The luminosity has been determined with three independent luminosity monitors measuring Bhabha scattering at different angular intervals. Recent calculations of higher-order QED radiative corrections are used to estimate the systematic error due to missing higher-order radiative corrections in the Monte Carlo event generators. © 1991 The American Physical Society.

Published
1991

17. Test of QED to fourth order by study of four-lepton final states ine+e−interactions at 29 GeV with the Mark II detector

Author

M. Petradza, R. Thun, G. Abrams, D. Amidei, A. R. Baden, T. Barklow, A. Boyarski, J. Boyer, P. R. Burchat, D. L. Burke, F. Butler, J. M. Dorfan, G. J. Feldman, G. Gidal, L. Gladney, M. S. Gold, G. Goldhaber, J. Haggerty, G. Hanson, K. Hayes, D. Herrup, T. Himel, R. J. Hollebeek, W. R. Innes, J. A. Jaros, J. A. Kadyk, D. Karlen, S. R. Klein, A. J. Lankford, R. R. Larsen, B. W. LeClaire, M. E. Levi, N. S. Lockyer, V. Lüth, M. E. Nelson, R. A. Ong, M. L. Perl, B. Richter, K. Riles, P. C. Rowson, T. Schaad, H. Schellman, W. B. Schmidke, P. D. Sheldon, G. H. Trilling, D. R. Wood, and J. M. Yelton

Subjects
Coupling constant, Physics, Particle physics, Fourth order, Annihilation, Muon, TheoryofComputation_ANALYSISOFALGORITHMSANDPROBLEMCOMPLEXITY, Elementary particle, Fermion, Lepton
Abstract

We have tested QED to fourth order in the coupling constant {alpha} in the large-{ital Q}{sup 2} region by studying four-lepton final states in {ital e}{sup +}{ital e}{sup {minus}} interactions with the Mark II detector at the SLAC storage ring PEP ({radical}{ital s} =29 GeV). All four final-state particles were detected at large angles with respect to the beam axis. For an integrated luminosity of 205 pb{sup {minus}1}, we observed ten {ital e}{sup +}{ital e}{sup {minus}}{ital e+}{ital e}{sup {minus}}, ten {ital e}{sup +}{ital e}{sup {minus}}{mu}{sup +}{mu}{sup {minus}}, and one {mu}{sup +}{mu}{sup {minus}}{mu}{sup +}{mu}{sup {minus}} events with opposite-charge pair masses greater than 1 GeV/{ital c}{sup 2}. These events show good agreement with the complete {alpha}{sup 4} QED calculation.

Published
1990

18. Searches for supersymmetric particles produced inZ-boson decay

Author

T. Barklow, G. S. Abrams, C. E. Adolphsen, D. Averill, J. Ballam, B. C. Barish, B. A. Barnett, J. Bartelt, S. Bethke, D. Blockus, G. Bonvicini, A. Boyarski, B. Brabson, A. Breakstone, F. Bulos, P. R. Burchat, D. L. Burke, R. J. Cence, J. Chapman, M. Chmeissani, D. Cords, D. P. Coupal, P. Dauncey, H. C. DeStaebler, D. E. Dorfan, J. M. Dorfan, D. C. Drewer, R. Elia, G. J. Feldman, D. Fernandes, R. C. Field, W. T. Ford, C. Fordham, R. Frey, D. Fujino, K. K. Gan, C. Gatto, E. Gero, G. Gidal, T. Glanzman, G. Goldhaber, J. J. Gomez Cadenas, G. Gratta, G. Grindhammer, P. Grosse-Wiesmann, G. Hanson, R. Harr, B. Harral, F. A. Harris, C. M. Hawkes, K. Hayes, C. Hearty, C. A. Heusch, M. D. Hildreth, T. Himel, D. A. Hinshaw, S. J. Hong, D. Hutchinson, J. Hylen, W. R. Innes, R. G. Jacobsen, J. A. Jaros, C. K. Jung, J. A. Kadyk, J. Kent, M. King, D. S. Koetke, S. Komamiya, W. Koska, L. A. Kowalski, W. Kozanecki, J. F. Kral, M. Kuhlen, L. Labarga, A. J. Lankford, R. R. Larsen, F. Le Diberder, M. E. Levi, A. M. Litke, X. C. Lou, V. Lüth, J. A. McKenna, J. A. J. Matthews, T. Mattison, B. D. Milliken, K. C. Moffeit, C. T. Munger, W. N. Murray, J. Nash, H. Ogren, K. F. O’Shaughnessy, S. I. Parker, C. Peck, M. L. Perl, M. Petradza, R. Pitthan, F. C. Porter, P. Rankin, K. Riles, F. R. Rouse, D. R. Rust, H. F. W. Sadrozinski, M. W. Schaad, B. A. Schumm, A. Seiden, J. G. Smith, A. Snyder, E. Soderstrom, D. P. Stoker, R. Stroynowski, M. Swartz, R. Thun, G. H. Trilling, R. Van Kooten, P. Voruganti, S. R. Wagner, S. Watson, P. Weber, A. J. Weinstein, A. J. Weir, E. Wicklund, M. Woods, D. Y. Wu, M. Yurko, C. Zaccardelli, and C. von Zanthier

Subjects
Physics, Particle physics, Annihilation, Electron–positron annihilation, Degenerate energy levels, General Physics and Astronomy, Elementary particle, Supersymmetry, Linear particle accelerator, law.invention, Nuclear physics, law, Collider, Boson
Abstract

We have searched for supersymmetric particles in 528 Z decays with the Mark II detector at the SLAC Linear Collider. We place 95%-confidence-level lower mass limits on degenerate squarks, nondegenerate up-type squarks, nondegenerate down-type squarks, charginos, pair-produced unstable neutralinos, and neutralinos from associated production. © 1990 The American Physical Society.

Published
1990

19. Radiativeτproduction and decay

Author

D. Y. Wu, K. Hayes, M. L. Perl, T. Barklow, A. Boyarski, P. R. Burchat, D. L. Burke, J. M. Dorfan, G. J. Feldman, L. Gladney, G. Hanson, R. J. Hollebeek, W. R. Innes, J. A. Jaros, D. Karlen, S. R. Klein, A. J. Lankford, R. R. Larsen, B. W. LeClaire, N. S. Lockyer, V. Lüth, R. A. Ong, B. Richter, K. Riles, J. M. Yelton, G. Abrams, D. Amidei, A. R. Baden, J. Boyer, F. Butler, G. Gidal, M. S. Gold, G. Goldhaber, L. Golding, J. Haggerty, D. Herrup, I. Juricic, J. A. Kadyk, M. E. Levi, M. E. Nelson, P. C. Rowson, H. Schellman, W. B. Schmidke, P. D. Sheldon, G. H. Trilling, D. R. Wood, and T. Schaad

Subjects
Nuclear physics, Physics, Antiparticle, Muon, Annihilation, Branching fraction, Electron–positron annihilation, Bremsstrahlung, Radiative transfer, High Energy Physics::Experiment, Lepton
Abstract

A study of the muon decay channel of the τ lepton with the presence of a photon has been carried out to verify theoretical predictions for the production rate of e + e - → τ + τ - γ and for the branching ratio of τ - → ν τ µ - ν µ γ. Included in this study is the first direct measurement of radiative tau decay. Using e + e - annihilation data taken at 29 GeV center-of-mass energy with the Mark II detector, we find the ratio of the measured τ - → ν τ µ - ν µ γ branching fraction to the expected value from QED to be 1.03 ± 0.42. The ratio of measured-to-predicted number of events from radiative T production, e + e - → τ + τ - γ, where one of the τ's decay to μνν is found to be 0.91 ± 0.20. We have not seen an indication of anomalous behavior in radiative tau events.

Published
1990

20. Measurements of charged-particle inclusive distributions in hadronic decays of theZboson

Author

G. S. Abrams, C. E. Adolphsen, D. Averill, J. Ballam, B. C. Barish, T. Barklow, B. A. Barnett, J. Bartelt, S. Bethke, D. Blockus, G. Bonvicini, A. Boyarski, B. Brabson, A. Breakstone, F. Bulos, P. R. Burchat, D. L. Burke, R. J. Cence, J. Chapman, M. Chmeissani, D. Cords, D. P. Coupal, P. Dauncey, H. C. DeStaebler, D. E. Dorfan, J. M. Dorfan, D. C. Drewer, R. Elia, G. J. Feldman, D. Fernandes, R. C. Field, W. T. Ford, C. Fordham, R. Frey, D. Fujino, K. K. Gan, E. Gero, G. Gidal, T. Glanzman, G. Goldhaber, J. J. Gomez Cadenas, G. Gratta, G. Grindhammer, P. Grosse-Wiesmann, G. Hanson, R. Harr, B. Harral, F. A. Harris, C. M. Hawkes, K. Hayes, C. Hearty, C. A. Heusch, M. D. Hildreth, T. Himel, D. A. Hinshaw, S. J. Hong, D. Hutchinson, J. Hylen, W. R. Innes, R. G. Jacobsen, J. A. Jaros, C. K. Jung, J. A. Kadyk, J. Kent, M. King, S. R. Klein, D. S. Koetke, S. Komamiya, W. Koska, L. A. Kowalski, W. Kozanecki, J. F. Kral, M. Kuhlen, L. Labarga, A. J. Lankford, R. R. Larsen, F. Le Diberder, M. E. Levi, A. M. Litke, X. C. Lou, V. Lüth, J. A. McKenna, J. A. J. Matthews, T. Mattison, B. D. Milliken, K. C. Moffeit, C. T. Munger, W. N. Murray, J. Nash, H. Ogren, K. F. O’Shaughnessy, S. I. Parker, C. Peck, M. L. Perl, F. Perrier, A. Petersen, M. Petradza, R. Pitthan, F. C. Porter, P. Rankin, K. Riles, F. R. Rouse, D. R. Rust, H. F. W. Sadrozinski, M. W. Schaad, B. A. Schumm, A. Seiden, J. G. Smith, A. Snyder, E. Soderstrom, D. P. Stoker, R. Stroynowski, M. Swartz, R. Thun, G. H. Trilling, R. Van Kooten, P. Voruganti, S. R. Wagner, S. Watson, P. Weber, A. Weigend, A. J. Weinstein, A. J. Weir, E. Wicklund, M. Woods, D. Y. Wu, M. Yurko, C. Zaccardelli, and C. von Zanthier

Subjects
Physics, Quantum chromodynamics, Particle physics, Annihilation, Computer Science::Information Retrieval, Electron–positron annihilation, Hadron, General Physics and Astronomy, Elementary particle, Charged particle, Nuclear physics, Particle decay, High Energy Physics::Experiment, Boson
Abstract

We have measured inclusive distributions for charged particles in hadronic decays of the {ital Z} boson. The variables chosen for study were charged-particle multiplicity, scaled momentum, and momenta transverse to the sphericity axes. The distributions have been corrected for detector effects and are compared with data from {ital e}{sup +}{ital e}{sup {minus}} annihilation at lower energies and with the predictions of several QCD-based models. The data are in reasonable agreement with expectations.

Published
1990

21. Measurement of thebb¯fraction in hadronicZdecays

Author

J. F. Kral, G. S. Abrams, C. E. Adolphsen, D. Averill, J. Ballam, B. C. Barish, T. Barklow, B. A. Barnett, J. Bartelt, S. Bethke, D. Blockus, G. Bonvicini, A. Boyarski, B. Brabson, A. Breakstone, F. Bulos, P. R. Burchat, D. L. Burke, R. J. Cence, J. Chapman, M. Chmeissani, D. Cords, D. P. Coupal, P. Dauncey, H. C. DeStaebler, D. E. Dorfan, J. M. Dorfan, D. C. Drewer, R. Elia, G. J. Feldman, D. Fernandes, R. C. Field, W. T. Ford, C. Fordham, R. Frey, D. Fujino, K. K. Gan, C. Gatto, E. Gero, G. Gidal, T. Glanzman, G. Goldhaber, J. J. Gomez Cadenas, G. Gratta, G. Grindhammer, P. Grosse-Wiesmann, G. Hanson, R. Harr, B. Harral, F. A. Harris, C. M. Hawkes, K. Hayes, C. Hearty, C. A. Heusch, M. D. Hildreth, T. Himel, D. A. Hinshaw, S. J. Hong, D. Hutchinson, J. Hylen, W. R. Innes, R. G. Jacobsen, J. A. Jaros, C. K. Jung, J. A. Kadyk, J. Kent, M. King, S. R. Klein, D. S. Koetke, S. Komamiya, W. Koska, L. A. Kowalski, W. Kozanecki, M. Kuhlen, L. Labarga, A. J. Lankford, R. R. Larsen, F. Le Diberder, M. E. Levi, A. M. Litke, X. C. Lou, V. Lüth, J. A. McKenna, J. A. J. Matthews, T. Mattison, B. D. Milliken, K. C. Moffeit, C. T. Munger, W. N. Murray, J. Nash, H. Ogren, K. F. O’Shaughnessy, S. I. Parker, C. Peck, M. L. Perl, M. Petradza, R. Pitthan, F. C. Porter, P. Rankin, K. Riles, F. R. Rouse, D. R. Rust, H. F. W. Sadrozinski, M. W. Schaad, B. A. Schumm, A. Seiden, J. G. Smith, A. Snyder, E. Soderstrom, D. P. Stoker, R. Stroynowski, M. Swartz, R. Thun, G. H. Trilling, R. Van Kooten, P. Voruganti, S. R. Wagner, S. Watson, P. Weber, A. J. Weinstein, A. J. Weir, E. Wicklund, M. Woods, D. Y. Wu, M. Yurko, C. Zaccardelli, and C. von Zanthier

Subjects
Nuclear physics, Physics, Particle physics, Particle decay, Annihilation, Electron–positron annihilation, Hadron, General Physics and Astronomy, Elementary particle, Fermion, Lepton, Standard Model
Abstract

Using isolated leptons reconstructed in the Mark II detector to tag bb events, we measure the fraction of bb events in hadronic Z0 decays to be 0.23-0.09+0.11, in good agreement with the standard-model prediction of 0.22. We find (Zbb)=0.43-0.17+0.21 GeV. © 1990 The American Physical Society.

Published
1990

22. Measurement of the Asymmetry in the DecayΩ¯+→Λ¯K+→p¯π+K+

Author

T. Holmstrom, H. R. Gustafson, H. K. Park, Y. Fu, C. Durandet, K. Clark, C. M. Jenkins, H. A. Rubin, E.C. Dukes, K. S. Nelson, Kam-Biu Luk, P. Zyla, R. A. Burnstein, M. Huang, Julián Félix, Christopher G. White, J. P. Perroud, M. J. Longo, D. Rajaram, S.L. White, C. James, G. Gidal, A. Chakravorty, Y. C. Chen, Woon-Seng Choong, J. Volk, Daniel M. Kaplan, T.D. Jones, W. Luebke, and L. C. Lu

Subjects
Physics, Particle physics, media_common.quotation_subject, High Energy Physics::Phenomenology, Hyperon, General Physics and Astronomy, Lambda, Omega, Asymmetry, Crystallography, Particle decay, Angular distribution, CP violation, High Energy Physics::Experiment, media_common, Bar (unit)
Abstract

The asymmetry in the {bar p} angular distribution in the sequential decay {bar {Omega}}{sup +} {yields} {bar {Lambda}}K{sup +} {yields} {bar p}{pi}{sup +}K{sup +} has been measured to be {bar {alpha}}{sub {Omega}}{bar {alpha}}{sub {Lambda}} = [+1.16{+-}0.18(stat){+-}0.17(syst)]x10{sup -2} using 1.89x10{sup 6} unpolarized {bar {Omega}}{sup +} decays recorded by the Hyper CP (E871) experiment at Fermilab. Using the known value of {alpha}{sub {Lambda}}, and assuming that {bar {alpha}}{sub {Lambda}} = -{alpha}{sub {Lambda}}, {bar {alpha}}{sub {Omega}} = [-1.81{+-}0.28(stat){+-}0.26(syst)]x10{sup -2}. A comparison between this measurement of {bar {alpha}}{sub {Omega}}{bar {alpha}}{sub {Lambda}} and recent measurements of {alpha}{sub {Omega}}{alpha}{sub {Lambda}} made by HyperCP shows no evidence of a violation of CP symmetry.

Published
2006

23. Measurement of the asymmetry in the decay Omega+--LamdaKappa+--rhopi+Kappa+

Author

L C, Lu, R A, Burnstein, A, Chakravorty, Y C, Chen, W-S, Choong, K, Clark, E C, Dukes, C, Durandet, J, Felix, Y, Fu, G, Gidal, H R, Gustafson, T, Holmstrom, M, Huang, C, James, C M, Jenkins, T D, Jones, D M, Kaplan, M J, Longo, W, Luebke, K-B, Luk, K S, Nelson, H K, Park, J-P, Perroud, D, Rajaram, H A, Rubin, J, Volk, C G, White, S L, White, and P, Zyla

Abstract

The asymmetry in the rho angular distribution in the sequential decay Omega+--LamdaKappa+--rhopi+Kappa+. has been measured to be alphaOmegaalphaLamda=[+1.16+/-0.18(stat)+/-0.17(syst)]x10(-2) using 1.89x10(6) unpolarized Omega+ decays recorded by the HyperCP (E871) experiment at Fermilab. Using the known value of alphaLamda, and assuming that alphaLamda=-alphaLamda, alphaOmega=[-1.81+/-0.28(stat)+/-0.26(syst)]x10(-2). A comparison between this measurement of alphaOmegaalphaLamda and recent measurements of alphaOmegaalphaLamda made by HyperCP shows no evidence of a violation of CP symmetry.

Published
2006

24. Measurement of theαasymmetry parameter for theΩ−→ΛK−Decay

Author

N. Leros, E.C. Dukes, S.L. White, H. K. Park, P. Gu, J. P. Perroud, M. J. Longo, R. A. Burnstein, D. Rajaram, Daniel M. Kaplan, J. Volk, Leon M. Lederman, C. James, A. Chakravorty, G. Gidal, K. Clark, T. Holmstrom, W. S. Choong, W. Luebke, P. K. Teng, L. C. Lu, Christopher G. White, P. Zyla, Y. C. Chen, F. Lopez, C. Durandet, K. S. Nelson, Kam-Biu Luk, M. Huang, Julián Félix, C. M. Jenkins, C. Ho, Aw Chan, H. R. Gustafson, and H. A. Rubin

Subjects
Physics, Combinatorics, Nuclear and High Energy Physics, Particle physics, media_common.quotation_subject, Lambda baryon, Omega, Asymmetry, media_common
Abstract

We have measured the $\ensuremath{\alpha}$ parameter of the ${\ensuremath{\Omega}}^{\ensuremath{-}}\ensuremath{\rightarrow}\ensuremath{\Lambda}{K}^{\ensuremath{-}}$ decay using data collected with the HyperCP spectrometer during the 1997 fixed-target run at Fermilab. Analyzing a sample of $0.96\ifmmode\times\else\texttimes\fi{}{10}^{6}$ ${\ensuremath{\Omega}}^{\ensuremath{-}}\ensuremath{\rightarrow}\ensuremath{\Lambda}{K}^{\ensuremath{-}}$, $\ensuremath{\Lambda}\ensuremath{\rightarrow}p{\ensuremath{\pi}}^{\ensuremath{-}}$ decays, we obtain ${\ensuremath{\alpha}}_{\ensuremath{\Omega}}{\ensuremath{\alpha}}_{\ensuremath{\Lambda}}=[1.33\ifmmode\pm\else\textpm\fi{}0.33(\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t})\ifmmode\pm\else\textpm\fi{}0.52(\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t})]\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2}$. With the accepted value of ${\ensuremath{\alpha}}_{\ensuremath{\Lambda}}$, ${\ensuremath{\alpha}}_{\ensuremath{\Omega}}$ is found to be $[2.07\ifmmode\pm\else\textpm\fi{}0.51(\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t})\ifmmode\pm\else\textpm\fi{}0.81(\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t})]\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}2}$.

Published
2005

25. Evidence for the DecayΣ+→pμ+μ−

Author

J. P. Perroud, R. A. Burnstein, N. Leros, Christopher G. White, T. Holmstrom, H. K. Park, A. Chakravorty, Y. C. Chen, Woon-Seng Choong, W. Luebke, Daniel M. Kaplan, J. Volk, Y. Fu, K. S. Nelson, Kam-Biu Luk, T. Jones, S.L. White, Leon M. Lederman, M. Huang, C. James, Julián Félix, G. Gidal, M. J. Longo, L. C. Lu, F. Lopez, H. R. Gustafson, C. Durandet, H. A. Rubin, C. M. Jenkins, E.C. Dukes, K. Clark, D. Rajaram, and P. Zyla

Subjects
Nuclear physics, Physics, Branching fraction, Hyperon, General Physics and Astronomy, Narrow range, Intermediate state, Fermilab, Sigma baryon
Abstract

We report the first evidence for the decay ∑+ → pμ+ μ- from data taken by the HyperCP (E871) experiment at Fermilab. Based on three observed events, the branching ratio is B(∑+ → pμ+ μ-) = [8.6 -5.4 +6.6(stat) ± 5.5(syst)] × 10 -8. The narrow range of dimuon masses may indicate that the decay proceeds via a neutral intermediate state, ∑+ rarr; pp0, p0 → μ+ μ- with a P0 mass of 214.3 ± 0.5 MeV/c 2 and branching ratio B(∑+ rarr; pp 0, p0 → μ+ μ-) = [3.1-1.9 -2.4(stat) ± 1.5(syst)] × 10 -8. © 2005 The American Physical Society.

Published
2005

26. Search forCPViolation in Charged-ΞandΛHyperon Decays

Author

C. Durandet, Daniel M. Kaplan, K. S. Nelson, Kam-Biu Luk, M. Huang, Julián Félix, G. Gidal, N. Leros, L. C. Lu, F. Lopez, C. James, R. A. Burnstein, Woon-Seng Choong, T. Holmstrom, Y. Fu, P. Gu, P. K. Teng, H. K. Park, S.L. White, T.D. Jones, Leon M. Lederman, D. Rajaram, W. Luebke, A. Chakravorty, C. Ho, H. A. Rubin, J. P. Perroud, J. Volk, Aw Chan, E.C. Dukes, K. Clark, P. Zyla, Christopher G. White, Y. C. Chen, M. J. Longo, H. R. Gustafson, and C. M. Jenkins

Subjects
Nuclear physics, Momentum, Physics, Particle physics, Angular distribution, Hyperon, General Physics and Astronomy, CP violation, High Energy Physics::Experiment, Fermilab, Lambda, Polarization (waves)
Abstract

The novel sources of CP violation observed in charged χ and λ hyperon decays were investigated. A comparison of the p and p angular distributions in the hyperon decays was made using a subset of the data from the HyperCP experiment (E871) at Fermilab. A possible source of bias was found to be a momentum-dependent differential loss of events due to interactions of the χ- and χ+ decay products. The obtained result was observed to be stable with respect to time, χ momentum, and secondary-beam intensity, The results show that differences between the χ- and χ+ production angles could cause a bias due to production polarization differences.

Published
2004

27. Search for the lepton-number-violating decay Xi(-)--pmu(-)mu(-)

Author

D, Rajaram, R A, Burnstein, A, Chakravorty, A, Chan, Y C, Chen, W S, Choong, K, Clark, E C, Dukes, C, Durandet, J, Felix, G, Gidal, P, Gu, H R, Gustafson, C, Ho, T, Holmstrom, M, Huang, C, James, C M, Jenkins, D M, Kaplan, L M, Lederman, N, Leros, M J, Longo, F, Lopez, L C, Lu, W, Luebke, K B, Luk, K S, Nelson, H K, Park, J-P, Perroud, H A, Rubin, P K, Teng, J, Volk, C G, White, S L, White, and P, Zyla

Abstract

A sensitive search for the lepton-number-violating decay Xi(-)--pmu(-)mu(-) has been performed using a sample of approximately 10(9) Xi(-) hyperons produced in 800 GeV/c p-Cu collisions. We obtain B(Xi(-)--pmu(-)mu(-))4.0x10(-8) at 90% confidence, improving on the best previous limit by 4 orders of magnitude.

Published
2004

28. High statistics search for theθ+(1.54)pentaquark state

Author

C. James, W. S. Choong, R. A. Burnstein, H. R. Gustafson, Y. Fu, K. Clark, N. Leros, F. Lopez, J. P. Perroud, A. Chakravorty, Leon M. Lederman, K. S. Nelson, Kam-Biu Luk, Daniel M. Kaplan, L. C. Lu, H. K. Park, G. Gidal, C. Durandet, T. Jones, J. Volk, M. Huang, C. M. Jenkins, H. A. Rubin, Julián Félix, E.C. Dukes, D. Rajaram, W. Luebke, Christopher G. White, Sebastian N. White, Y. C. Chen, T. Holmstrom, M. J. Longo, and P. Zyla

Subjects
Nuclear physics, Physics, Baryon, Nuclear and High Energy Physics, Particle physics, Mass distribution, State (functional analysis), Fermilab, Pentaquark
Abstract

We have searched for Theta+(1.54) -> K0,p decays using data from the 1999 run of the HyperCP experiment at Fermilab. We see no evidence for a narrow peak in the K0,p mass distribution near 1.54 GeV/c among 106,000 K0,p candidates, and obtain an upper limit for the fraction of Theta+(1.54) to K0,p candidates of

Published
2004

29. Search for DeltaS = 2 nonleptonic hyperon decays

Author

C G, White, R A, Burnstein, A, Chakravorty, A, Chan, Y C, Chen, W S, Choong, K, Clark, E C, Dukes, C, Durandet, J, Felix, G, Gidal, P, Gu, H R, Gustafson, C, Ho, T, Holmstrom, M, Huang, C, James, C M, Jenkins, D M, Kaplan, L M, Lederman, N, Leros, M J, Longo, F, Lopez, L C, Lu, W, Luebke, K B, Luk, K S, Nelson, H K, Park, J-P, Perroud, D, Rajaram, H A, Rubin, P K, Teng, J, Volk, S L, White, and P, Zyla

Abstract

A sensitive search for the rare decays Omega(-)--Lambdapi(-) and Xi(0)--ppi(-) has been performed using data from the 1997 run of the HyperCP (Fermilab E871) experiment. Limits on other such processes do not exclude the possibility of observable rates for |DeltaS| = 2 nonleptonic hyperon decays, provided the decays occur through parity-odd operators. We obtain the branching-fraction limits B(Omega(-)--Lambdapi(-))2.9 x 10(-6) and B(Xi(0)--ppi(-))8.2 x 10(-6), both at 90% confidence level.

Published
2004

30. Evidence for the decay sigma+ --pmu+ mu

Author

H K, Park, R A, Burnstein, A, Chakravorty, Y C, Chen, W S, Choong, K, Clark, E C, Dukes, C, Durandet, J, Felix, Y, Fu, G, Gidal, H R, Gustafson, T, Holmstrom, M, Huang, C, James, C M, Jenkins, T, Jones, D M, Kaplan, L M, Lederman, N, Leros, M J, Longo, F, Lopez, L C, Lu, W, Luebke, K B, Luk, K S, Nelson, J-P, Perroud, D, Rajaram, H A, Rubin, J, Volk, C G, White, S L, White, and P, Zyla

Abstract

We report the first evidence for the decay Sigma(+)--pmu(+)mu(-) from data taken by the HyperCP (E871) experiment at Fermilab. Based on three observed events, the branching ratio is B(Sigma(+)--pmu(+)mu(-))=[8.6(+6.6)(-5.4)(stat)+/-5.5(syst)]x10(-8). The narrow range of dimuon masses may indicate that the decay proceeds via a neutral intermediate state, Sigma(+)--pP(0),P0--mu(+)mu(-) with a P0 mass of 214.3+/-0.5 MeV/c(2) and branching ratio B(Sigma(+)--pP(0),P0--mu(+)mu(-))=[3.1(+2.4)(-1.9)(stat)+/-1.5(syst)]x10(-8).

Published
2004

31. Search for CP violation in charged-Xi and Lambda hyperon decays

Author

T, Holmstrom, N, Leros, R A, Burnstein, A, Chakravorty, A, Chan, Y C, Chen, W S, Choong, K, Clark, E C, Dukes, C, Durandet, J, Felix, Y, Fu, G, Gidal, P, Gu, H R, Gustafson, C, Ho, M, Huang, C, James, C M, Jenkins, T, Jones, D M, Kaplan, L M, Lederman, M J, Longo, F, Lopez, L C, Lu, W, Luebke, K B, Luk, K S, Nelson, H K, Park, J-P, Perroud, D, Rajaram, H A, Rubin, P K, Teng, J, Volk, C G, White, S L, White, and P, Zyla

Abstract

We have compared the p and p angular distributions in 117 x 10(6) Xi- --Lambdapi- --ppi-pi- and 41 x 10(6) Xi+ --Lambda pi+ --p pi+pi+ decays using a subset of the data from the HyperCP experiment (E871) at Fermilab. We find no evidence of CP violation, with the direct-CP-violating parameter AXiLambda identical with (alphaXialphaLambda-alpha Xialpha Lambda)/(alphaXialphaLambda+alphaXialphaLambda)=[0.0+/-5.1(stat)+/-4.4(syst)] x 10(-4).

Published
2004

32. New Measurement ofΞ−→Λπ−Decay Parameters

Author

C. Durandet, N. Leros, T.D. Jones, W. Luebke, A. Chakravorty, K. Clark, P. Zyla, G. Gidal, R. A. Burnstein, Leon M. Lederman, T. Holmstrom, E.C. Dukes, D. Rajaram, H. R. Gustafson, C. James, Woon-Seng Choong, M. J. Longo, J. Volk, Fred Lopez, L. C. Lu, J. P. Perroud, H. K. Park, C. M. Jenkins, K. S. Nelson, Kam-Biu Luk, M. Huang, Julián Félix, Daniel M. Kaplan, Christopher G. White, Sebastian N. White, Y. C. Chen, and H. A. Rubin

Subjects
Nuclear physics, Physics, Hyperon, General Physics and Astronomy, CP violation, Atomic physics, Polarization (waves)
Abstract

A study on the measurement of φ≡ using a sample of 144×106 ≡- →λπ- decays having an average polarization of 3.7% was presented. The polarized ≡-'s were produced by directing an 800 geV÷c proton beam onto a 2 mm ×2 mm× 60 mm cu target at angles of +3 and -3 mrad. The results were shown to be a 2.9× improvement over the best previous mesurements. It was shown that CP violation in charged ≡→λπ decays are not suppressed by a vanishing final phase shift difference.

Published
2004

33. Measurement of αΩ in Ω− → ΛΚ− Decays

Author

N. Leros, G. Gidal, Julián Félix, J. P. Perroud, D. M. Kaplan, N. Solomey, T. Jones, S.L. White, C. Ho, K. S. Nelson, Aw Chan, C. James, M. Huang, H. A. Rubin, L.M. Lederman, Y. Torun, W. Luebke, M. J. Longo, L. C. Lu, J. Volk, W. S. Choong, K. B. Luk, Y. Fu, R. A. Burnstein, P. K. Teng, C. Durandet, Y. C. Chen, D. Rajaram, A. Chakravorty, B. Turko, H. R. Gustafson, M. Jenkins, P. Zyla, F. Lopez, Christopher G. White, P. Gu, H. K. Park, E. C. Dukes, T. Holmstrom, and K. Clark

Subjects
Physics, Nuclear physics, Particle physics, Hyperon, CP violation, High Energy Physics::Experiment, Fermilab
Abstract

The HyperCP experiment (E871) at Fermilab has collected the largest sample of hyperon decays in the world. With a data set of over a million Ω− → ΛΚ− decays we have measured the product of αΩαΛ from which we have extracted αΩ. This preliminary result indicates that αΩ is small, but non‐zero. Prospects for a test of CP symmetry by comparing the α parameters in Ω− and Ω+ decays will be discussed.

Published
2003

34. A multichannel discriminator system for silicon strip detector readout

Author

Daniel M. Kaplan, Kam Biu Luk, G.J. Zizka, S. Mishra, J. Lillberg, G. Gidal, C.C. Brown, Bojan T. Turko, and P. McGaugley

Subjects
Nuclear and High Energy Physics, Signal processing, Engineering, Discriminator, Motherboard, business.industry, Preamplifier, Detector, Electrical engineering, Line driver, Nuclear Energy and Engineering, Nuclear electronics, Electrical and Electronic Engineering, business, Computer Automated Measurement and Control
Abstract

Up to 9216 fast discriminators are required for processing signals of the Fermilab silicon strip detector preamplifiers in experiment E789. Signals exceeding a preset discriminator threshold voltage are first stored in a clocked latch and then delayed by three 19-ns clock cycles with a shift resister. Discriminators are organized in 75 identical 128-channel subsystems. Each has four 32-channel PC boards housed in a signal routing motherboard. Eight 16-channel line driver boards transfer events from the motherboard through cables to the remote processing electronics. Three subsystems fit into the frame of a standard CAMAC crate. The authors describe the design considerations of the system and its performance, based on several months of testing the completed system. >

Published
2002

35. Observation of the DecayK−→π−μ+μ−and Measurements of the Branching Ratios forK±→π±μ+μ−

Author

J. P. Perroud, C. James, T. Holmstrom, C. Durandet, P. K. Teng, G. Gidal, R. A. Burnstein, A. Chakravorty, Michael J. Longo, L. C. Lu, W. Luebke, K. S. Nelson, Kam-Biu Luk, E.C. Dukes, M. Huang, N. Leros, H. R. Gustafson, P. Zyla, D. Rajaram, H. K. Park, Julián Félix, K. Clark, Leon M. Lederman, Woon-Seng Choong, H. A. Rubin, F. Lopez, C. Ho, Aw Chan, P. Gu, C. M. Jenkins, Christopher G. White, Sebastian N. White, Y. C. Chen, Daniel M. Kaplan, and J. Volk

Subjects
Physics, Nuclear magnetic resonance, Pi, Analytical chemistry, General Physics and Astronomy, Branching (polymer chemistry)
Abstract

Using data collected with the HyperCP (E871) spectrometer during the 1997 fixed-target run at Fermilab, we report the first observation of the decay K--->pi(-)mu(+)mu(-) and new measurements of the branching ratios for K+/--->pi(+/-)mu(+)mu(-). By combining the branching ratios for the decays K+-->pi(+)mu(+)mu(-) and K--->pi(-)mu(+)mu(-), we measure Gamma(K+/--->pi(+/-)mu(+)mu(-))/Gamma(K+/--->all) = (9.8+/-1.0+/-0.5)x10(-8). The CP asymmetry between the rates of the two decay modes is [Gamma(K+-->pi(+)mu(+)mu(-))-Gamma(K--->pi(-)mu(+)mu(-))]/[Gamma(K+-->pi(+)mu(+)mu(-))+Gamma(K--->pi(-)mu(+)mu(-))] = -0.02+/-0.11+/-0.04.

Published
2002

36. CP Violation in Hyperon and Charged Kaon Decays

Author

Leon M. Lederman, G. Gidal, R. Godang, J. Volk, Bojan T. Turko, Michael J. Longo, C. Durandet, T. Holmstrom, F. Lopez, P. K. Teng, K. S. Nelson, Kam-Biu Luk, David L. Kaplan, M. Huang, Julián Félix, M. Jenkins, P. Gu, H. A. Rubin, P. Zyla, C. James, C. Ho, K. Clark, Aw Chan, H. K. Park, M. J. Longo, N. Leros, J. P. Perroud, D. Rajaram, G. Moreno, Y. Fu, A. Chakravorty, R. A. Burnstein, Woon-Seng Choong, Christopher G. White, Sebastian N. White, Y. C. Chen, N. Solomey, Modesto Sosa, L. C. Lu, H. R. Gustafson, Yagmur Torun, C. Dukes, T.D. Jones, and W. Luebke

Subjects
Physics, Antiparticle, Particle physics, Meson, Nuclear Theory, Hyperon, Dalitz plot, Xi baryon, Nuclear physics, Particle decay, Pion, CP violation, High Energy Physics::Experiment, Nuclear Experiment
Abstract

The primary purpose of the HyperCP experiment at Fermilab is to test CP in hyperon decays by comparing the decay distributions for Ⅺ− (“cascade”) decays in the decay sequence: Ⅺ− → π− + Λ0, Λ0 → π− + p, with those for the antiparticle Ⅺ+. In addition, we can test CP in charged kaon decays by comparing the slopes of the Dalitz plot for Κ+ and Κ− decays. We are also looking at rare decay modes of charged kaons and hyperons, particularly those involving muons. In two runs in 1997 and 1999, we collected approx. 500 millon charged kaon decays, 2.5 billion Ⅺ− and Ⅺ+ decays, and 19 million Ω− and Ω+ decays. This is the largest sample of fully reconstructed particle decays ever collected.

Published
2002

37. Observation of the decay K- --pi(-)mu(+)mu(-) and measurements of the branching ratios for K+/- --pi(+/-)mu(+)mu(-)

Author

H K, Park, R A, Burnstein, A, Chakravorty, A, Chan, Y C, Chen, W S, Choong, K, Clark, E C, Dukes, C, Durandet, J, Felix, G, Gidal, P, Gu, H R, Gustafson, C, Ho, T, Holmstrom, M, Huang, C, James, C M, Jenkins, D M, Kaplan, L M, Lederman, N, Leros, M J, Longo, F, Lopez, L, Lu, W, Luebke, K B, Luk, K S, Nelson, J P, Perroud, D, Rajaram, H A, Rubin, P K, Teng, J, Volk, C, White, S, White, and P, Zyla

Abstract

Using data collected with the HyperCP (E871) spectrometer during the 1997 fixed-target run at Fermilab, we report the first observation of the decay K---pi(-)mu(+)mu(-) and new measurements of the branching ratios for K+/---pi(+/-)mu(+)mu(-). By combining the branching ratios for the decays K+--pi(+)mu(+)mu(-) and K---pi(-)mu(+)mu(-), we measure Gamma(K+/---pi(+/-)mu(+)mu(-))/Gamma(K+/---all) = (9.8+/-1.0+/-0.5)x10(-8). The CP asymmetry between the rates of the two decay modes is [Gamma(K+--pi(+)mu(+)mu(-))-Gamma(K---pi(-)mu(+)mu(-))]/[Gamma(K+--pi(+)mu(+)mu(-))+Gamma(K---pi(-)mu(+)mu(-))] = -0.02+/-0.11+/-0.04.

Published
2001

38. Search for flavor-changing neutral currents and lepton-family-number violation in two-body D0 decays

Author

R. Childers, D. M. Jansen, Daniel M. Kaplan, M. S. Kowitt, C. S. Mishra, R. G. Jeppesen, G. C. Kiang, Y. C. Chen, C. N. Brown, Jen-Chieh Peng, Pei-Ming Ho, P. K. Teng, V. Tanikella, C. W. Darden, J. Sa, Leon M. Lederman, K. Gounder, L. D. Isenhower, R. Schnathorst, W. E. Cooper, M. J. Leitch, G. Gidal, P. L. McGaughey, J. W. Lillberg, Kam-Biu Luk, Josh Moss, D. Pripstein, W. Luebke, J. S. Kapustinsky, R. S. Preston, James R. Wilson, M. E. Sadler, D. W. Lane, T. A. Carey, and M. H. Schub

Subjects
Physics, Nuclear and High Energy Physics, Particle physics, Particle decay, High Energy Physics - Experiment (hep-ex), Pair production, Branching fraction, FOS: Physical sciences, High Energy Physics::Experiment, Nuclear Experiment, Lepton, High Energy Physics - Experiment
Abstract

Results of a search for the three neutral charm decays, D0 -> mu e, D0 -> mu mu, and D0 -> e e, are presented. This study was based on data collected in Experiment 789 at the Fermi National Accelerator Laboratory using 800 GeV/c proton-Au and proton-Be interactions. No evidence is found for any of the decays. Upper limits on the branching ratios, at the 90% confidence level, are obtained., 28 pages, 18 figures. Submitted to Physical Review D

Published
1999

39. CP violation in strange baryon decays: A report from Fermilab experiment 871

Author

E.C. Dukes, Michael J. Longo, S.L. White, Leon M. Lederman, V. Papavassiliou, N. Leros, C. Durandet, G. Gidal, M. Jenkins, K. Clark, P. Zyla, Y. C. Chen, T. Holmstrom, Julián Félix, H. R. Gustafson, Modesto Sosa, J. P. Perroud, R. A. Burnstein, W. Luebke, D. Rajaram, G. Moreno, K. S. Nelson, M. Huang, A. Chakravorty, Bojan T. Turko, R. Fuzesy, C. James, K. B. Luk, P. K. Teng, H. A. Rubin, Christopher G. White, Daniel M. Kaplan, J. Volk, F. Lopez, C. Ho, Aw Chan, and Woon-Seng Choong

Subjects
Physics, Particle physics, media_common.quotation_subject, Hyperon, Lambda baryon, Asymmetry, Particle identification, Baryon, Nuclear physics, Particle decay, CP violation, High Energy Physics::Experiment, Fermilab, media_common
Abstract

Fermilab experiment 871, HyperCP, is a search for direct CP violation in Ⅺ and Λ hyperon decays. A non-zero value in the asymmetry parameter A, defined in terms of the decay parameter products αⅪαΛ and αⅪαΛ, would be unambiguous evidence for direct CP violation. The first data-taking run finished at the end of 1997 and accumulated over one billion Ⅺ− and Ⅺ+ decays. A sensitivity in A of ≈10−4 is expected. A review of CP violation in hyperon decays is given, the HyperCP detector is described, and the status of the data analysis is discussed.

Published
1999

40. Nuclear dependence of single-hadron and dihadron production in p-A interactions at sqrt s=38.8 GeV

Author

Daniel M. Kaplan, M. H. Schub, C. N. Brown, P. K. Teng, R. Childers, L. D. Isenhower, Josh Moss, W. E. Cooper, R. S. Preston, C. S. Mishra, M. E. Sadler, Jen-Chieh Peng, G. Gidal, P. L. McGaughey, M. J. Leitch, T. A. Carey, V. Tanikella, Kam-Biu Luk, Leon M. Lederman, M. S. Kowitt, and C. W. Darden

Subjects
Nuclear physics, Physics, Statistics::Theory, Nuclear and High Energy Physics, Particle physics, Pair production, Statistics::Applications, Scattering, Hadron, Transverse momentum, Parton, Nuclear Experiment
Abstract

We present a measurement of the W-to-Be per-nucleon cross-section ratio, ${\mathit{R}}_{\mathrm{W}/\mathrm{B}\mathrm{e}}$, for single hadrons and for opposite-sign hadron pairs produced in p-A collisions at \ensuremath{\surd}s=38.8 GeV. The data fill in regions of intermediate transverse momentum and dihadron mass that previously have revealed cross-section enhancements for scattering from nuclear targets. When combined with previous measurements, the new results help delineate the dependence of nuclear effects on the kinematic variables ${\mathit{p}}_{\mathit{t}}$, m, and \ensuremath{\surd}s. Both the single-hadron and hadron-pair enhancements in ${\mathit{R}}_{\mathrm{W}/\mathrm{B}\mathrm{e}}$ seen at intermediate values of ${\mathit{p}}_{\mathit{t}}$ and mass decrease with increasing \ensuremath{\surd}s, consistent with a multiple-scattering model of parton scattering. \textcopyright{} 1996 The American Physical Society.

Published
1996

41. Measurement of J/ psi and psi ' production in 800 GeV/c proton-gold collisions

Author

P. L. McGaughey, J. W. Lillberg, J. Sa, W. Luebke, Pei-Ming Ho, K. Gounder, L. D. Isenhower, C. N. Brown, Josh Moss, W. E. Cooper, D. Pripstein, D. M. Jansen, Jen-Chieh Peng, R. G. Jeppesen, G. C. Kiang, C. W. Darden, M. H. Schub, Y. C. Chen, Kam-Biu Luk, M. J. Leitch, Leon M. Lederman, J. S. Kapustinsky, R. S. Preston, M. S. Kowitt, G. Gidal, Daniel M. Kaplan, D. W. Lane, R. Schnathorst, R. Childers, James R. Wilson, C. S. Mishra, P. K. Teng, M. E. Sadler, V. Tanikella, and T. A. Carey

Subjects
Physics, Crystallography, Particle physics, TheoryofComputation_MATHEMATICALLOGICANDFORMALLANGUAGES, Proton, Computer Science::Information Retrieval, High Energy Physics::Experiment, Production (computer science), Rapidity, Nucleon
Abstract

With a data sample containing 1.1{times}10{sup 5} {ital J}/{psi}{r_arrow}{mu}{sup +}{mu}{sup {minus}} decays reconstructed with 16 MeV/{ital c}{sup 2} rms mass resolution, we have measured the differential cross sections versus Feynman-{ital x}, rapidity, and {ital p}{sub {ital T}} for the production of {ital J}/{psi} and {psi}{prime} in 800 GeV/{ital c} {ital p}-Au collisions. Our results are compared with leading-order QCD predictions and with previous measurements. While the shapes of the cross sections are in qualitative agreement with QCD predictions, the magnitudes disagree by factors of 7 ({ital J}/{psi}) and 25 ({psi}{prime}). Assuming an appropriate form for the differential cross sections in regions not measured we derive a total {ital J}/{psi} production cross section {sigma}({ital p}+{ital N}{r_arrow}{ital J}/{psi}+{ital X})=442{plus_minus}2{plus_minus}88 nb/nucleon and a (model-dependent) total {psi}{prime} cross secton {sigma}({ital p}+{ital N}{r_arrow}{psi}{prime}+{ital X})=75{plus_minus}5{plus_minus}22 nb/nucleon. For {ital J}/{psi} produced at central rapidity, {ital d}{sigma}({ital p}+{ital N}{r_arrow}{ital J}/{psi}+{ital X})/{ital dy}{vert_bar}{sub {ital y}=0}=230{plus_minus}5{plus_minus}46 nb/nucleon.

Published
1995

42. Nuclear dependence of neutral-D-meson production by 800 GeV/c protons

Author

V. M. Martin, J. Sa, P. L. McGaughey, J. W. Lillberg, Daniel M. Kaplan, W. Luebke, R. S. Preston, M. E. Sadler, Jen-Chieh Peng, W. E. Cooper, C. W. Darden, R. Schnathorst, Leon M. Lederman, D. M. Jansen, H. Glass, T. A. Carey, M. J. Leitch, J. G. Boissevain, Pei-Ming Ho, D. W. Lane, R. Childers, C. N. Brown, C. S. Mishra, Josh Moss, M. H. Schub, V. Tanikella, P. K. Teng, D. Pripstein, R. G. Jeppesen, G. C. Kiang, Y. C. Chen, L. D. Isenhower, J. S. Kapustinsky, James R. Wilson, K. Gounder, Kam-Biu Luk, M. S. Kowitt, and G. Gidal

Subjects
Nuclear reaction, Physics, Nuclear physics, Proton, Meson, D meson, Hadron, General Physics and Astronomy, Elementary particle, Neutron, Atomic physics, Nucleon
Abstract

The nuclear dependence for 800 GeV/[ital c] proton production of neutron [ital D] mesons has been measured near [ital x][sub [ital F]]=0 in Experiment 789 at Fermilab. [ital D] mesons from beryllium and gold targets were detected with a pair spectrometer and a silicon vertex detector via their decay [ital D][r arrow][ital K][pi]. No nuclear dependence is found, with a measured [alpha]=1.02[plus minus]0.03[plus minus]0.02. The measured differential cross section, [ital d][sigma]/[ital dx][sub [ital F]], for neutral-[ital D]-meson production at [l angle][ital x][sub [ital F]][r angle]=0.031 is 58[plus minus]3[plus minus]7 [mu]b/nucleon. The integrated cross section obtained by extrapolation of the measured cross section to all [ital x][sub [ital F]] is 17.7[plus minus]0.9[plus minus]3.4 [mu]b/nucleon and is consistent with previous measurements.

Published
1994

43. Preliminary results from Fermilab E789

Author

R. Schnathorst, D. Isenhower, V. M. Martin, R. S. Preston, H. Glass, M. H. Schub, J. Boissevain, J. S. Kapustinsky, C. S. Mishra, R. G. Jeppesen, G. Brown, J. Sa, G. C. Kiang, L. M. Lederman, M. S. Kowitt, D. Snodgrass, M.J. Leitch, D. W. Lane, P. L. McGaughey, J. W. Lillberg, W. E. Cooper, Pei-Ming Ho, K. Gounder, R. Schwindt, P. K. Teng, Kam-Biu Luk, T. A. Carey, V. Tanikella, Josh Moss, D. M. Jansen, G. Gidal, James R. Wilson, D. Pripstein, C. W. Darden, W. Luebke, D. M. Kaplan, Yi-Chun Chen, M. Apolinski, R. Childers, M.E. Sadler, Jen-Chieh Peng, and C. N. Brown

Subjects
Physics, Nuclear physics, Particle physics, Meson, Hadron, High Energy Physics::Experiment, B meson, Fermilab, Quarkonium
Abstract

Fermilab experiment 789 studies low‐multiplicity decays of neutral D and B mesons in a high‐rate fixed‐target environment. Preliminary results from the 1991 run are presented.

Published
1992

44. Direct search for pair production of heavy stable charged particles in Z decays

Author

E. Soderstrom, J. A. McKenna, G. S. Abrams, C. E. Adolphsen, D. Averill, J. Ballam, B. C. Barish, T. Barklow, B. A. Barnett, J. Bartelt, S. Bethke, D. Blockus, G. Bonvicini, A. Boyarski, B. Brabson, A. Breakstone, F. Bulos, P. R. Burchat, D. L. Burke, R. J. Cence, J. Chapman, M. Chmeissani, D. Cords, D. P. Coupal, P. Dauncey, H. C. DeStaebler, D. E. Dorfan, J. M. Dorfan, D. C. Drewer, R. Elia, G. J. Feldman, D. Fernandes, R. C. Field, W. T. Ford, C. Fordham, R. Frey, D. Fujino, K. K. Gan, E. Gero, G. Gidal, T. Glanzman, G. Goldhaber, J. J. Gomez Cadenas, G. Gratta, G. Grindhammer, P. Grosse-Wiesmann, G. Hanson, R. Harr, B. Harral, F. A. Harris, C. M. Hawkes, K. Hayes, C. Hearty, C. A. Heusch, M. D. Hildreth, T. Himel, D. A. Hinshaw, S. J. Hong, D. Hutchinson, J. Hylen, W. R. Innes, R. G. Jacobsen, J. A. Jaros, C. K. Jung, J. A. Kadyk, J. Kent, M. King, D. S. Koetke, S. Komamiya, W. Koska, L. A. Kowalski, W. Kozanecki, J. F. Kral, M. Kuhlen, L. Labarga, A. J. Lankford, R. R. Larsen, F. Le Diberder, M. E. Levi, A. M. Litke, X. C. Lou, V. Lüth, J. A. J. Matthews, T. Mattison, B. D. Milliken, K. C. Moffeit, C. T. Munger, W. N. Murray, J. Nash, H. Ogren, K. F. O’Shaughnessy, S. I. Parker, C. Peck, M. L. Perl, M. Petradza, R. Pitthan, F. C. Porter, P. Rankin, K. Riles, F. R. Rouse, D. R. Rust, H. F. W. Sadrozinski, M. W. Schaad, B. A. Schumm, A. Seiden, J. G. Smith, A. Snyder, D. P. Stoker, R. Stroynowski, M. Swartz, R. Thun, G. H. Trilling, R. Van Kooten, P. Voruganti, S. R. Wagner, S. Watson, P. Weber, A. J. Weinstein, A. J. Weir, E. Wicklund, M. Woods, D. Y. Wu, M. Yurko, C. Zaccardelli, and C. von Zanthie

Subjects
Physics, Particle physics, Annihilation, Muon, General Physics and Astronomy, Elementary particle, Fermion, Charged particle, law.invention, Nuclear physics, Pair production, law, High Energy Physics::Experiment, Collider, Lepton
Abstract

A search for pair production of stable charged particles from Z decay has been performed with the Mark II detector at the SLAC Linear Collider. Particle masses are determined from momentum, ionization energy loss, and time-of-flight measurements. A limit excluding pair production of stable fourth-generation charged leptons and stable mirror fermions with masses between the muon mass and 36.3 GeV/c2 is set at the 95% confidence level. Pair production of stable supersymmetric scalar leptons with masses between the muon mass and 32.6 GeV/c2 is also excluded. © 1990 The American Physical Society.

Published
1990

45. Search for nonminimal neutral Higgs bosons from Z-boson decays

Author

S. Komamiya, G. S. Abrams, C. E. Adolphsen, D. Averill, J. Ballam, B. C. Barish, T. Barklow, B. A. Barnett, J. Bartelt, S. Bethke, D. Blockus, G. Bonvicini, A. Boyarski, B. Brabson, A. Breakstone, F. Bulos, P. R. Burchat, D. L. Burke, R. J. Cence, J. Chapman, M. Chmeissani, D. Cords, D. P. Coupal, P. Dauncey, H. C. DeStaebler, D. E. Dorfan, J. M. Dorfan, D. C. Drewer, R. Elia, G. J. Feldman, D. Fernandes, R. C. Field, W. T. Ford, C. Fordham, R. Frey, D. Fujino, K. K. Gan, C. Gatto, E. Gero, G. Gidal, T. Glanzman, G. Goldhaber, J. J. Gomez Cadenas, G. Gratta, G. Grindhammer, P. Grosse-Wiesmann, G. Hanson, R. Harr, B. Harral, F. A. Harris, C. M. Hawkes, K. Hayes, C. Hearty, C. A. Heusch, M. D. Hildreth, T. Himel, D. A. Hinshaw, S. J. Hong, D. Hutchinson, J. Hylen, W. R. Innes, R. G. Jacobsen, J. A. Jaros, C. K. Jung, J. A. Kadyk, J. Kent, M. King, S. R. Klein, D. S. Koetke, W. Koska, L. A. Kowalski, W. Kozanecki, J. F. Kral, M. Kuhlen, L. Labarga, A. J. Lankford, R. R. Larsen, F. Le Diberder, M. E. Levi, A. M. Litke, X. C. Lou, V. Lüth, J. A. McKenna, J. A. J. Matthews, T. Mattison, B. D. Milliken, K. C. Moffeit, C. T. Munger, W. N. Murray, J. Nash, H. Ogren, K. F. O’Shaughnessy, S. I. Parker, C. Peck, M. L. Perl, F. Perrier, M. Petradza, R. Pitthan, F. C. Porter, P. Rankin, K. Riles, F. R. Rouse, D. R. Rust, H. F. W. Sadronzinski, M. W. Schaad, B. A. Schumm, A. Seiden, J. G. Smith, A. Snyder, E. Soderstrom, D. P. Stoker, R. Stroynowski, M. Swartz, R. Thun, G. H. Trilling, R. Van Kooten, P. Voruganti, S. R. Wagner, S. Watson, P. Weber, A. Weigend, A. J. Weinstein, A. J. Weir, E. Wicklund, M. Woods, D. Y. Wu, M. Yurko, C. Zaccardelli, and C. von Zanthier

Subjects
Physics, Particle physics, Annihilation, Computer Science::Information Retrieval, High Energy Physics::Phenomenology, General Physics and Astronomy, Elementary particle, Coupling (probability), Particle identification, law.invention, Particle decay, law, Higgs boson, High Energy Physics::Experiment, Collider, Boson
Abstract

Using the Mark II detector at the SLAC Linear Collider, we search for decays of the {ital Z} boson to a pair of nonminimal Higgs bosons ({ital Z}{r arrow}{ital H}{sub {ital s}}{sup 0}{ital H}{sub {ital p}}{sup 0}), where one of them is relatively light ({approx lt}10 GeV). We find no evidence for these decays and we obtain limits on the {ital ZH}{sub {ital s}}{sup 0}{ital H}{sub {ital p}}{sup 0} coupling as a function of the Higgs-boson masses.

Published
1990

46. Search for doubly charged Higgs scalars in Z decay

Author

M. Swartz, G. S. Abrams, C. E. Adolphsen, D. Averill, J. Ballam, B. C. Barish, T. Barklow, B. A. Barnett, J. Bartelt, S. Bethke, D. Blockus, G. Bonvicini, A. Boyarski, B. Brabson, A. Breakstone, F. Bulos, P. R. Burchat, D. L. Burke, R. J. Cence, J. Chapman, M. Chmeissani, D. Cords, D. P. Coupal, P. Dauncey, H. C. DeStaebler, D. E. Dorfan, J. M. Dorfan, D. C. Drewer, R. Elia, G. J. Feldman, D. Fernandes, R. C. Field, W. T. Ford, C. Fordham, R. Frey, D. Fujino, K. K. Gan, C. Gatto, E. Gero, G. Gidal, T. Glanzman, G. Goldhaber, J. J. Gomez Cadenas, G. Gratta, G. Grindhammer, P. Grosse-Wiesmann, G. Hanson, R. Harr, B. Harral, F. A. Harris, C. M. Hawkes, K. Hayes, C. Hearty, C. A. Heusch, M. D. Hildreth, T. Himel, D. A. Hinshaw, S. J. Hong, D. Hutchinson, J. Hylen, W. R. Innes, R. G. Jacobsen, J. A. Jaros, C. K. Jung, J. A. Kadyk, J. Kent, M. King, S. R. Klein, D. S. Koetke, S. Komamiya, W. Koska, L. A. Kowalski, W. Kozanecki, J. F. Kral, M. Kuhlen, L. Labarga, A. J. Lankford, R. R. Larsen, F. Le Diberder, M. E. Levi, A. M. Litke, X. C. Lou, V. Lüth, J. A. McKenna, J. A. J. Matthews, T. Mattison, B. D. Milliken, K. C. Moffeit, C. T. Munger, W. N. Murray, J. Nash, H. Ogren, K. F. O’Shaughnessy, S. I. Parker, C. Peck, M. L. Perl, F. Perrier, M. Petradza, R. Pitthan, F. C. Porter, P. Rankin, K. Riles, F. R. Rouse, D. R. Rust, H. F. W. Sadrozinski, M. W. Schaad, B. A. Schumm, A. Seiden, J. G. Smith, A. Snyder, E. Soderstrom, D. P. Stoker, R. Stroynowski, R. Thun, G. H. Trilling, R. Van Kooten, P. Voruganti, S. R. Wagner, S. Watson, P. Weber, A. Weigend, A. J. Weinstein, A. J. Weir, E. Wicklund, M. Woods, D. Y. Wu, M. Yurko, C. Zaccardelli, and C. von Zanthier

Subjects
Physics, Particle physics, Annihilation, Computer Science::Information Retrieval, High Energy Physics::Phenomenology, General Physics and Astronomy, Elementary particle, Coupling (probability), Particle identification, law.invention, Nuclear physics, Particle decay, law, Higgs boson, High Energy Physics::Experiment, Collider, Boson
Abstract

We describe a search for the decay of the {ital Z} boson into pairs of doubly charged Higgs bosons with the Mark II detector operating at the SLAC Linear Collider. Each Higgs boson is assumed to decay into a same-sign leptonic pair. No event candidates are found in a sample of 528 {ital Z} decays. At the 95% confidence level, this result excludes the region of leptonic coupling {ital g}{sub {ital l}{ital l}}{gt}3{times}10{sup {minus}7} and Higgs-boson mass 6.5{lt}{ital M}{sub {ital H}}{lt}36.5 GeV/{ital c}{sup 2} for isotriplet (left-handed) Higgs bosons. Isosinglet (right-handed) Higgs bosons are excluded in the same {ital g}{sub {ital l}{ital l}} interval and in the mass interval 7.3{lt}{ital M}{sub {ital H}}{lt}34.3 GeV/{ital c}{sup 2}.

Published
1990

47. Search for decays of the Z to unstable neutral leptons with mass between 2.5 and 22 GeV

Author

P. R. Burchat, M. King, G. S. Abrams, C. E. Adolphsen, D. Averill, J. Ballam, B. C. Barish, T. Barklow, B. A. Barnett, J. Bartelt, S. Bethke, D. Blockus, G. Bonvicini, A. Boyarski, B. Brabson, A. Breakstone, F. Bulos, D. L. Burke, R. J. Cence, J. Chapman, M. Chmeissani, D. Cords, D. P. Coupal, P. Dauncey, H. C. DeStaebler, D. E. Dorfan, J. M. Dorfan, D. C. Drewer, R. Elia, G. J. Feldman, D. Fernandes, R. C. Field, W. T. Ford, C. Fordham, R. Frey, D. Fujino, K. K. Gan, C. Gatto, E. Gero, G. Gidal, T. Glanzman, G. Goldhaber, J. J. Gomez Cadenas, G. Gratta, G. Grindhammer, P. Grosse-Wiesmann, G. Hanson, R. Harr, B. Harral, F. A. Harris, C. M. Hawkes, K. Hayes, C. Hearty, C. A. Heusch, M. D. Hildreth, T. Himel, D. A. Hinshaw, S. J. Hong, D. Hutchinson, J. Hylen, W. R. Innes, R. G. Jacobsen, J. A. Jaros, C. K. Jung, J. A. Kadyk, J. Kent, S. R. Klein, D. S. Koetke, S. Komamiya, W. Koska, L. A. Kowalski, W. Kozanecki, J. F. Kral, M. Kuhlen, L. Labarga, A. J. Lankford, R. R. Larsen, F. Le Diberder, M. E. Levi, A. M. Litke, X. C. Lou, V. Lüth, J. A. McKenna, J. A. J. Matthews, T. Mattison, B. D. Milliken, K. C. Moffeit, C. T. Munger, W. N. Murray, J. Nash, H. Ogren, K. F. O'Shaughnessy, S. I. Parker, C. Peck, M. L. Perl, F. Perrier, M. Petradza, R. Pitthan, F. C. Porter, P. Rankin, K. Riles, F. R. Rouse, D. R. Rust, H. F. W. Sadrozinski, M. W. Schaad, B. A. Schumm, A. Seiden, J. G. Smith, A. Snyder, E. Soderstrom, D. P. Stoker, R. Stroynowski, M. Swartz, R. Thun, G. H. Trilling, R. Van Kooten, P. Voruganti, S. R. Wagner, S. Watson, P. Weber, A. Weigend, A. J. Weinstein, A. J. Weir, E. Wicklund, M. Woods, D. Y. Wu, M. Yurko, C. Zaccardelli, and C. von Zanthier

Subjects
Physics, Particle physics, Electron–positron annihilation, Dirac (video compression format), Charged particle, law.invention, Nuclear physics, law, High Energy Physics::Experiment, Neutral vector, Neutrino, Collider, Lepton, Boson
Abstract

Using the sample of neutral vector bosons (Z's) produced at the SLAC Linear Collider and detected with the Mark II detector, we search for the decay of the Z to a pair of particles, one of which decays to two charged particles. The observed number of Z decays with this signature excludes, at a confidence level greater than 95%, the decay of the Z to a pair of fourth-generation Dirac neutrinos with mass between 2.5 and 22 GeV, a decay length less than about 1 cm, and coupling to any of the first three generations of charged leptons. This is the first time the existence of such a lepton coupling to the ± has been excluded by a direct search. © 1990 The American Physical Society.

Published
1990

48. Search for long-lived massive neutrinos in Z decays

Author

C. K. Jung, R. Van Kooten, G. S. Abrams, C. E. Adolphsen, D. Averill, J. Ballam, B. C. Barish, T. Barklow, B. A. Barnett, J. Bartelt, S. Bethke, D. Blockus, G. Bonvicini, A. Boyarski, B. Brabson, A. Breakstone, F. Bulos, P. R. Burchat, D. L. Burke, R. J. Cence, J. Chapman, M. Chmeissani, D. Cords, D. P. Coupal, P. Dauncey, H. C. DeStaebler, D. E. Dorfan, J. M. Dorfan, D. C. Drewer, R. Elia, G. J. Feldman, D. Fernandes, R. C. Field, W. T. Ford, C. Fordham, R. Frey, D. Fujino, K. K. Gan, C. Gatto, E. Gero, G. Gidal, T. Glanzman, G. Goldhaber, J. J. Gomez Cadenas, G. Gratta, G. Grindhammer, P. Grosse-Wiesmann, G. Hanson, R. Harr, B. Harral, F. A. Harris, C. M. Hawkes, K. Hayes, C. Hearty, C. A. Heusch, M. D. Hildreth, T. Himel, D. A. Hinshaw, S. J. Hong, D. Hutchinson, J. Hylen, W. R. Innes, R. G. Jacobsen, J. A. Jaros, J. A. Kadyk, J. Kent, M. King, S. R. Klein, D. S. Koetke, S. Komamiya, W. Koska, L. A. Kowalski, W. Kozanecki, J. F. Kral, M. Kuhlen, L. Labarga, A. J. Lankford, R. R. Larsen, F. Le Diberder, M. E. Levi, A. M. Litke, X. C. Lou, V. Lüth, J. A. McKenna, J. A. J. Matthews, T. Mattison, B. D. Milliken, K. C. Moffeit, C. T. Munger, W. N. Murray, J. Nash, H. Ogren, K. F. O’Shaughnessy, S. I. Parker, C. Peck, M. L. Perl, F. Perrier, M. Petradza, R. Pitthan, F. C. Porter, P. Rankin, K. Riles, F. R. Rouse, D. R. Rust, H. F. W. Sadrozinski, M. W. Schaad, B. A. Schumm, A. Seiden, J. G. Smith, A. Snyder, E. Soderstrom, D. P. Stoker, R. Stroynowski, M. Swartz, R. Thun, G. H. Trilling, P. Voruganti, S. R. Wagner, S. Watson, P. Weber, A. Weigend, A. J. Weinstein, A. J. Weir, E. Wicklund, M. Woods, D. Y. Wu, M. Yurko, C. Zaccardelli, and C. von Zanthier

Subjects
Nuclear physics, Physics, Massless particle, Particle physics, Annihilation, General Physics and Astronomy, High Energy Physics::Experiment, Elementary particle, Fermion, Neutrino, Particle identification, Boson, Lepton
Abstract

We search for events in the Mark II detector at SLAC Linear Collider with the topology of a {ital Z} boson decaying into a pair of long-lived massive particles. No events that are consistent with the search hypothesis are found. Interpreting the long-lived particle as a sequential Dirac neutrino {nu}{sub 4} of the fourth generation, we exclude at the 95% confidence level a significant range of mixing-matrix elements of {nu}{sub 4} to other-generation neutrinos for a {nu}{sub 4} mass from 10 to 43 GeV/{ital c}{sup 2}.

Published
1990

49. Erratum: Measurement ofJψandψ′production in 800 GeV/cproton-gold collisions

Author

D. W. Lane, R. G. Jeppesen, G. C. Kiang, R. Childers, K. Gounder, Kam-Biu Luk, Y. C. Chen, M. S. Kowitt, James R. Wilson, C. W. Darden, Jen-Chieh Peng, J. S. Kapustinsky, P. L. McGaughey, J. W. Lillberg, W. Luebke, M. J. Leitch, J. Sa, R. Schnathorst, M. E. Sadler, D. M. Jansen, C. S. Mishra, Leon M. Lederman, C. N. Brown, V. Tanikella, P. K. Teng, W. E. Cooper, Daniel M. Kaplan, G. Gidal, T. A. Carey, R. S. Preston, Josh Moss, D. Pripstein, M. H. Schub, Pei-Ming Ho, and L. D. Isenhower

Subjects
Physics, Nuclear physics, Nuclear and High Energy Physics, Proton
Published
1996

50. Experimental upper limits on branching fractions for unexpected decay modes of theτlepton

Author

M. E. Nelson, A. Blondel, William Carithers, G. S. Abrams, J. A. Kadyk, A. M. Boyarski, S. Cooper, T. Himel, W. Chinowsky, G. Goldhaber, J. Strait, D. L. Burke, Michael Levi, R. J. Hollebeek, E. N. Vella, J. F. Patrick, R. R. Larsen, L̈th, Kenneth G. Hayes, Burton Richter, A. Roussarie, J. Dorfan, G. Gidal, G. Hanson, J. Dorenbosch, G. J. Feldman, M. W. Coles, J. B. Dillon, Rafe Schindler, A. J. Lankford, R. E. Millikan, A. D. Johnson, W. E. Dieterle, Alam, J. A. Jaros, H. Taureg, M. E. B. Franklin, J. L. Siegrist, P. Jenni, I. Videau, H. Zaccone, M. L. Perl, G. H. Trilling, Walter R. Innes, Martin Breidenbach, R. A. Vidal, D. L. Scharre, M. W. Eaton, M. Tonutti, C. Y. Pang, J. M. Weiss, D. G. Hitlin, R. F. Schwitters, and CA Blocker

Subjects
Physics, Particle physics, Annihilation, Branching fraction, Electron–positron annihilation, High Energy Physics::Phenomenology, Hadron, Lepton number, Nuclear physics, Particle decay, Pair production, High Energy Physics::Experiment, Astrophysics::Earth and Planetary Astrophysics, Lepton
Abstract

Searches for 12 neutrinoless decay modes of the which violate lepton-number conservation have been made using the reaction e+e-+-. No evidence for lepton-number violation is observed, and we have set upper limits (90% C.L.) on the branching ratio for each decay mode. The branching-ratio limits on the radiative decays and e are 0.055 and 0.064%, respectively. For the charged lepton decays ee, eee, and, the branching ratio limits are 0.040, 0.033, 0.044, and 0.049%, respectively. Upper limits on the branching ratios for the following charged lepton + neutral hadron decays are 0 (0.037%), 0 (0.044%), eK0 (0.13%), K0 (0.10%), 0 (0.21%), and 0 (0.082%). We also use these data to search for the pair production in e+e- annihilation of some unconventional particles with masses less than about 3 GeV/c2. © 1982 The American Physical Society.

Published
1982

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