| 1. |
- Schael, S., et al.
(författare)
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Electroweak measurements in electron positron collisions at W-boson-pair energies at LEP
- 2013
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Ingår i: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 532:4, s. 119-244
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Forskningsöversikt (refereegranskat)abstract
- Electroweak measurements performed with data taken at the electron positron collider LEP at CERN from 1995 to 2000 are reported. The combined data set considered in this report corresponds to a total luminosity of about 3 fb(-1) collected by the four LEP experiments ALEPH, DELPHI, 13 and OPAL, at centre-of-mass energies ranging from 130 GeV to 209 GeV. Combining the published results of the four LEP experiments, the measurements include total and differential cross-sections in photon-pair, fermion-pair and four-fermion production, the latter resulting from both double-resonant WW and ZZ production as well as singly resonant production. Total and differential cross-sections are measured precisely, providing a stringent test of the Standard Model at centre-of-mass energies never explored before in electron positron collisions. Final-state interaction effects in four-fermion production, such as those arising from colour reconnection and Bose Einstein correlations between the two W decay systems arising in WW production, are searched for and upper limits on the strength of possible effects are obtained. The data are used to determine fundamental properties of the W boson and the electroweak theory. Among others, the mass and width of the W boson, m(w) and Gamma(w), the branching fraction of W decays to hadrons, B(W -> had), and the trilinear gauge-boson self-couplings g(1)(Z), K-gamma and lambda(gamma), are determined to be: m(w) = 80.376 +/- 0.033 GeV Gamma(w) = 2.195 +/- 0.083 GeV B(W -> had) = 67.41 +/- 0.27% g(1)(Z) = 0.984(-0.020)(+0.018) K-gamma - 0.982 +/- 0.042 lambda(gamma) = 0.022 +/- 0.019. (C) 2013 Elsevier B.V. All rights reserved.
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| 2. |
- Schael, S, et al.
(författare)
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Precision electroweak measurements on the Z resonance
- 2006
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Ingår i: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 427:5-6, s. 257-454
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Forskningsöversikt (refereegranskat)abstract
- We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLID experiment using a polarised beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarised asymmetries. The mass and width of the Z boson, m(Z) and Gamma(Z), and its couplings to fermions, for example the p parameter and the effective electroweak mixing angle for leptons, are precisely measured: m(Z) = 91.1875 +/- 0.0021 GeV, Gamma(Z) = 2.4952 +/- 0.0023 GeV, rho(l) = 1.0050 +/- 0.0010, sin(2)theta(eff)(lept) = 0.23153 +/- 0.00016. The number of light neutrino species is determined to be 2.9840 +/- 0.0082, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model (SM). At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward-backward asymmetry in b-quark production shows the largest difference with respect to its SM expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, m(t) = 173(+10)(+13) GeV, and the mass of the W boson, m(W) = 80.363 +/- 0.032 GeV. These indirect constraints are compared to the direct measurements, providing a stringent test of the SM. Using in addition the direct measurements of m(t) and m(W), the mass of the as yet unobserved SM Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than 285 GeV at 95% confidence level. (c) 2006 Elsevier B.V. All rights reserved.
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| 3. |
- Walker, Anthony P, et al.
(författare)
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Horizon 2020 EuPRAXIA design study
- 2017
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Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 874:1
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Tidskriftsartikel (refereegranskat)abstract
- The Horizon 2020 Project EuPRAXIA ("European Plasma Research Accelerator with eXcellence In Applications") is preparing a conceptual design report of a highly compact and cost-effective European facility with multi-GeV electron beams using plasma as the acceleration medium. The accelerator facility will be based on a laser and/or a beam driven plasma acceleration approach and will be used for photon science, high-energy physics (HEP) detector tests, and other applications such as compact X-ray sources for medical imaging or material processing. EuPRAXIA started in November 2015 and will deliver the design report in October 2019. EuPRAXIA aims to be included on the ESFRI roadmap in 2020.
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| 4. |
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| 5. |
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| 6. |
- Adiels, Lars, 1952-, et al.
(författare)
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Test of CP violation with K0 and K‾0 at LEAR
- 1985
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Ingår i: Physics with antiprotons at LEAR in the ACOL era. - Gif sur Yvette : Editions Frontières. - 2863320351 ; , s. 467-482
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 7. |
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| 8. |
- Adiels, L., et al.
(författare)
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Experimental determination of the branching ratios {Mathematical expression}, and 2γ at rest
- 1987
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Ingår i: Zeitschrift für Physik C Particles and Fields. - : Springer. - 0170-9739 .- 1431-5858. ; 35:1, s. 15-19
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Tidskriftsartikel (refereegranskat)abstract
- The branching ratios of {Mathematical expression} annihilations into the neutral final states 2π 0, π 0γ, and 2γ are measured by stopping antiprotons in liquid hydrogen. They are {Mathematical expression}, {Mathematical expression}, and B γγ<1.7×10 -6 (95% c.l.).
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| 9. |
- Adiels, L., et al.
(författare)
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Experimental determination of the branching ratios proton-antiproton -> 2pi0, pi0γ and γγ at rest
- 1987
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Ingår i: Zeitschrift für Physik C Particles and Fields. - 0170-9739. ; 35:1, s. 15-19
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Tidskriftsartikel (refereegranskat)abstract
- The branching ratios of Mathematical expression annihilations into the neutral final states 2π0, π0γ, and 2γ are measured by stopping antiprotons in liquid hydrogen. They are Mathematical expression, Mathematical expression, and Bγγ<1.7×10-6 (95% c.l.). © 1987 Springer-Verlag.
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| 10. |
- Adiels, L., et al.
(författare)
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Experimental study of the inclusive η-spectrum from p {Mathematical expression} annihilations at rest in liquid hydrogen
- 1989
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Ingår i: Zeitschrift für Physik C Particles and Fields. - : Springer. - 0170-9739 .- 1431-5858. ; 42:1, s. 49-58
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Tidskriftsartikel (refereegranskat)abstract
- The inclusive η-momentum spectrum from {Mathematical expression} annihilations at rest in liquid hydrogen was measured at LEAR. Branching ratios were obtained for {Mathematical expression}, and ηη(8.1±3.1)×10 -5. An upper limit for {Mathematical expression} of 1.8×10 -4 at 95% CL was found. The ratio of the branching ratios is BR(ηρ{variant})/BR(ηω)=0.51 -0.06 +0.20. For the ratio of branching ratios into two pseudoscalar mesons, we have BR(ηπ 0)/BR(π 0π 0)=0.65±0.14, BR(ηη)/BR(π 0π 0), BR(ηη ′)/BR(π 0π 0) at 95% CL, and BR(ηη)/BR(ηπ 0). © 1989 Springer-Verlag.
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| 11. |
- Adiels, L., et al.
(författare)
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Investigations on baryonium and other rare pmacrp annihilation modes using high resolution pi0 spectrometers (PS 182)
- 1985
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Ingår i: Antiproton 1984. Proceedings of the VII European Symposium on Antiproton Interactions. - : Institution of Electrical Engineers (IEE). ; , s. 297-304
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Konferensbidrag (refereegranskat)abstract
- In the search for heavy, narrow exotic states such as baryonium or glueballs, carried out so far, various methods of high- and low-energy production, low-energy formation, and e+e- reactions were used. In particular, a search for baryonium states below threshold (mxlsimmppmacr) has shown some evidence [Richter et al., 1983, Brando et al., 1984] for a few states. However, the results of these measurements suffer from poor statistics. Among the possible methods which can be applied in the baryonium bound state research at LEAR, the authors consider the study of the reaction ppmacrrarrX+pi0 as the most promising. They have performed an experiment to study this reaction by means of an experimental set-up especially tailored for measuring monoenergetic pi0,s, allowing for both angular distribution measurements and high-resolution spectroscopy. They report on the preliminary results from our actual measurements of the inclusive pi0 and eta spectra following the antiproton annihilation at rest.
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| 12. |
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| 13. |
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| 14. |
- Adiels, L., et al.
(författare)
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Pi0 and eta spectra from proton-antiproton annihilations at rest
- 1984
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Ingår i: Zeitschrift für Physik. C, Particles and fields. - 0170-9739. ; 21:4, s. 315-319
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Tidskriftsartikel (refereegranskat)abstract
- The low-energy part of the Ï€0 spectrum associated with Mathematical expression annihilation at rest was measured in order to search for bound baryonium-like states. The upper limit for reaching such states via the emission of monochromatic Ï€0’s was found to be 8% per annihilation in the mass region of 1650 MeV. The low-energy part of the η spectrum from Mathematical expression annihilations at rest was also observed.
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| 15. |
- Adiels, L., et al.
(författare)
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Pi0 And Eta Spectroscopy At Lear
- 1986
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Ingår i: Tignes 1985, Proceedings, Physics With Antiprotons At Lear In The Acol Era. ; , s. 359-359
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Konferensbidrag (refereegranskat)
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| 16. |
- Adiels, L., et al.
(författare)
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Search for narrow exotic states in annihilations on 4He
- 1984
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 138:1-3, s. 235-240
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Tidskriftsartikel (refereegranskat)abstract
- After having found evidence for narrow exotic states in p annihilation, the production of such states on a nuclear target was studied with similar techniques. The γ spectrum associated with annihilation on 4He at rest was measured. The spectrum shows two peaks, at energies of 161.9 and 203.0 MeV, corresponding to intermediate narrow states of masses which seem to be related to states found in p annihilations. The confidence is better than 4 σ.
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| 17. |
- Adiels, L., et al.
(författare)
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Search for narrow signals in the [gamma]-spectrum from [Proton-antiproton] annihilation at rest
- 1986
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 182:3-4, s. 405-408
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Tidskriftsartikel (refereegranskat)abstract
- The [gamma]-spectrum originating from pp[combining macron] annihilations at rest in liquid hydrogen was measured with two BGO spectrometers. A total of 24 ï¿œ 106[gamma]’s were accumulated. No narrow peaks indicating exotic states such as baryonium were observed. The upper limit for the branching ratio with 1040 [less-than-or-equals, slant] mx [less-than-or-equals, slant] 1770 MeV/c2 and with [lambda]x [less-than-or-equals, slant] 25 MeV/c2 is less than 10-3 with more than 99.96% confidence.
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| 18. |
- Adiels, L., et al.
(författare)
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Search for narrow signals in the γ-spectrum from pp̄ annihilation at rest
- 1986
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Ingår i: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 182:3-4, s. 405-408
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Tidskriftsartikel (refereegranskat)abstract
- The γ-spectrum originating from pp̄ annihilations at rest in liquid hydrogen was measured with two BGO spectrometers. A total of 24 × 10 6 γ's were accumulated. No narrow peaks indicating exotic states such as baryonium were observed. The upper limit for the branching ratio p p ̄ → γ + X with 1040 ≤ m x ≤ 1770 MeV/c 2 and with λ x ≤ 25 MeV/c 2 is less than 10 -3 with more than 99.96% confidence. © 1986.
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| 19. |
- Adiels, L, et al.
(författare)
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Some results of experiment PS182 at LEAR
- 1986
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Ingår i: Antiproton 86. - Singspore : World Scientific Publishing. - 9971503131 ; , s. 199-204, s. 199-204
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 20. |
- Adiels, L, et al.
(författare)
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π0 and η spectroscopy at LEAR
- 1985
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Ingår i: Physics with antiprotons at LEAR in the ACOL era. - Gif sur Yvette : Editions Frontières. - 2863320351 ; , s. 359-360
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 21. |
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| 22. |
- Blüm, P., et al.
(författare)
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A modular NaI(Tl) detector for 20-1000 MeV photons
- 1983
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Ingår i: Nuclear Instruments and Methods in Physics Research. - : Elsevier BV. - 0167-5087. ; 213:2-3, s. 251-259
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Tidskriftsartikel (refereegranskat)abstract
- A detector consisting of 54 NaI (Tl) modules is described. The detector has been optimized for the detection of 20-1000 MeV photons. An energy resolution (fwhm) of 5.5% at 130 MeV could be attained, and the stability has been better than 1% over several months.
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| 23. |
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| 24. |
- Richter, B., et al.
(författare)
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New results in the search for narrow states in the p system below threshold
- 1983
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 126:3-4, s. 284-288
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Tidskriftsartikel (refereegranskat)abstract
- The γ-ray spectrum after p annihilation at rest was measured in two independent high-statistics runs. Both spectra show narrow peaks, corresponding to masses of 1210, 1638, 1694 and 1771 MeV.
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| 25. |
- Zioutas, K., et al.
(författare)
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Baryonium physics
- 1983
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Ingår i: Proceedings of the 1st Hellenic School on Elementary Particle Physics. - : Institution of Electrical Engineers (IEE). ; , s. 437-466
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Konferensbidrag (refereegranskat)abstract
- Various theoretical ideas on nuclear physics, quark models, and the dual topological unitarization lead to the expectation of massive mesons, called baryonium, coupled strongly to the ppmacr channel but weakly to mesons, thus resulting in a virtually high stability, particularly below the ppmacr threshold. Such states are relevant to nuclear physics owing to the fact that the badly explored short-range forces in the NN interactions are just the most relevant ones in the NNmacr systems. From the known NN potential, one is led to expect short-range attraction in NNmacr systems, and this should result in quasinuclear bound states in the vicinity of threshold.
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| 26. |
- Adiels, Lars, et al.
(författare)
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A π0 and η spectrometer of lead glass and BGO for momenta up to 1 GeV/c
- 1986
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 244:3, s. 380-390
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Tidskriftsartikel (refereegranskat)abstract
- A spectrometer consisting of two sets of bismuth germanium oxide (BGO) crystals and a lead-glass array has been used to measure the [pi]0 and [eta] momentum spectra produced from proton-antiproton annihilations at rest. We describe the test of the BGO sets in electron beams of energies from 50 to 450 MeV. We discuss the method of construction and calibration of the lead-glass array, as well as procedures to extract the energy and position resolutions for detected photons. A momentum resolution ([sigma]) for [pi]0’s and [eta]’s of 4% and 3%, respectively has been achieved at momenta below 1 GeV/c.
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| 27. |
- Adiels, Lars, et al.
(författare)
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Experimental study of the inclusive η-spectrum from proton-antiproton annihilations at rest in liquid hydrogen
- 1989
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Ingår i: Zeitschrift für Physik C Particles and Fields. - 0170-9739 .- 1431-5858. ; 42, s. 49-58
-
Tidskriftsartikel (refereegranskat)abstract
- The inclusive η-momentum spectrum from Mathematical expression annihilations at rest in liquid hydrogen was measured at LEAR. Branching ratios were obtained for Mathematical expression, and ηη(8.1±3.1)×10-5. An upper limit for Mathematical expression of 1.8×10-4 at 95% CL was found. The ratio of the branching ratios is BR(ηÏvariant)/BR(ηω)=0.51-0.06+0.20. For the ratio of branching ratios into two pseudoscalar mesons, we have BR(ηπ0)/BR(Ï€0Ï€0)=0.65±0.14, BR(ηη)/BR(Ï€0Ï€0), BR(ηη′)/BR(Ï€0Ï€0) at 95% CL, and BR(ηη)/BR(ηπ0). © 1989 Springer-Verlag.
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| 28. |
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| 29. |
- Guigas, R., et al.
(författare)
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Strong interaction effects in antiprotonic 6Li/7Li atoms
- 1984
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 137:56, s. 323-328
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Tidskriftsartikel (refereegranskat)abstract
- The effects of strong interaction on the 3 –> 2 X-ray transition in antiprotonic 6Li/7Li atoms have been measured at the low energy -beam at CERN. For the shifts and widths of the levels the values [epsilon]2p = (-230 ï¿œ 72) eV, [Gamma]2p = (443 ï¿œ 210) eV, and [Gamma]3d = (0.130 ï¿œ 0.045) eV for 6Li, and [epsilon]2p = (-336 ï¿œ 60) eV, [Gamma]2p = (456 ï¿œ 190) eV, and [Gamma]3d = (0.210 ï¿œ 0.062) eV for 7Li were found. The data are compared with optical model predictions.
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| 30. |
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| 31. |
- Köhler, Th., et al.
(författare)
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Precision measurement of strong interaction isotope effects in antiprotonic 16O, 17O, and 18O atoms
- 1986
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 176:3-4, s. 327-333
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Tidskriftsartikel (refereegranskat)abstract
- The strong-interaction effects in antiprotonic 16O, 17O, and 18O atoms were measured at the CERN antiproton facility, LEAR. The shifts ε{lunate} and the widths Γ of the 3d level were determined to be -112±20 eV (16O), -140±46 eV (17O), -195±20 eV (18O), and 495±45 eV (16O), 540±150 (17O), 640±40 eV (18O), respectively. © 1986.
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| 32. |
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| 41. |
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