Author
M. Meyer
Bio: M. Meyer is an academic researcher from Karlsruhe Institute of Technology. The author has contributed to research in topics: Detector. The author has an hindex of 2, co-authored 2 publications receiving 54 citations.
Topics: Detector
Papers
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TL;DR: In this article, the high-energy part of the spectrum was used to deduce branching ratios for the so far unobserved annihilation channels: R(p p →π 0 ω) = (2.38 ± 0.65)%, R( p p → π 0 η ) = (0.82 ± 0.04)% and an upper limit for the π0η′ channel was deduced.
48 citations
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TL;DR: In this article, a detector consisting of 54 NaI (Tl) modules is described for the detection of 20-1000 MeV photons, with an energy resolution of 5.5% at 130 MeV.
8 citations
Cited by
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TL;DR: In this paper, the general properties of antiproton-proton annihilation at rest are presented, with special focus on the two-meson final states, and the data exhibit remarkable dynamical selection rules: some allowed annihilation modes are suppressed by one order of magnitude with respect to modes of comparable phase-space.
97 citations
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TL;DR: In this article, the authors studied the possibility of producing a new kind of nuclear system that in addition to ordinary nucleons contains a few antibaryons (B{sup -}=p{sup-},{lambda}{sup -}, etc.).
Abstract: We study the possibility of producing a new kind of nuclear system that in addition to ordinary nucleons contains a few antibaryons (B{sup -}=p{sup -},{lambda}{sup -}, etc.). The properties of such systems are described within the relativistic mean-field model by employing G-parity transformed interactions for antibaryons. Calculations are first done for infinite systems and then for finite nuclei from {sup 4}He to {sup 208}Pb. It is demonstrated that the presence of a real antibaryon leads to a strong rearrangement of a target nucleus, resulting in a significant increase of its binding energy and local compression. Noticeable effects remain even after the antibaryon coupling constants are reduced by a factor of 3-4 compared to G-parity motivated values. We have performed detailed calculations of the antibaryon annihilation rates in the nuclear environment by applying a kinetic approach. It is shown that owing to significant reduction of the reaction Q values, the in-medium annihilation rates should be strongly suppressed, leading to relatively long-lived antibaryon-nucleus systems. Multinucleon annihilation channels are analyzed too. We have also estimated formation probabilities of bound B{sup -}+A systems in p{sup -}A reactions and have found that their observation will be feasible at the future GSI antiproton facility. Several observablemore » signatures are proposed. The possibility of producing cold multi-quark-antiquark clusters is discussed.« less
63 citations
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TL;DR: In this article, the high-energy part of the spectrum was used to deduce branching ratios for the so far unobserved annihilation channels: R(p p →π 0 ω) = (2.38 ± 0.65)%, R( p p → π 0 η ) = (0.82 ± 0.04)% and an upper limit for the π0η′ channel was deduced.
48 citations
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University of Zurich1, University of California, Berkeley2, Karlsruhe Institute of Technology3, Rutherford Appleton Laboratory4, University of Mainz5, Ludwig Maximilian University of Munich6, Queen Mary University of London7, CERN8, University of California, Los Angeles9, University of Hamburg10, Hungarian Academy of Sciences11
TL;DR: In this article, the branching ratio of two meson final states at rest in liquid hydrogen has been investigated and the first measurements of branching ratios were made for different η and η′ decays.
Abstract: We report measurements of branching ratios for production of a series of two meson final states in
$$\bar p$$
p annihilations at rest in liquid hydrogen. We find:
$$\begin{gathered} BR(\bar pp \to \pi ^ + \pi ^ - ) = (3.07 \pm 0.13) \cdot 10^{ - 3} \hfill \\ BR(\bar pp \to K^ + K^ - ) = (0.99 \pm 0.05) \cdot 10^{ - 3} \hfill \\ BR(\bar pp \to \pi ^0 \pi ^0 ) = (6.93 \pm 0.43) \cdot 10^{ - 4} \hfill \\ BR(\bar pp \to \pi ^0 \eta ) = (2.12 \pm 0.12) \cdot 10^{ - 4} \hfill \\ BR(\bar pp \to \pi ^0 \omega ) = (5.73 \pm 0.47) \cdot 10^{ - 3} \hfill \\ BR(\bar pp \to \pi ^0 \eta ') = (1.23 \pm 0.13) \cdot 10^{ - 4} \hfill \\ BR(\bar pp \to \eta \eta ) = (1.64 \pm 0.10) \cdot 10^{ - 4} \hfill \\ BR(\bar pp \to \eta \omega ) = (1.51 \pm 0.12) \cdot 10^{ - 2} \hfill \\ BR(\bar pp \to \eta \eta ') = (2.16 \pm 0.25) \cdot 10^{ - 4} \hfill \\ BR(\bar pp \to \omega \omega ) = (3.32 \pm 0.34) \cdot 10^{ - 2} \hfill \\ BR(\bar pp \to \omega \eta ') = (0.78 \pm 0.08) \cdot 10^{ - 2} \hfill \\ \end{gathered}$$
These are the first measurements of the channels ηη′ and ωη′ and in almost all the other channels are more precise than previous results. We also obtain, in a more precise fashion, the following ratios of branching ratios:K
+
K
−/π+π−=0.323±0.013, π0η′/π0η=0.548±0.056, ηη′/ηη=0.31±0.15, ωη′/ωη=0.515±0.040, π0η/π0π0=0.303±0.010, ηη/π0π0=0.232±0.011 and π0ω/ηω=0.377±0.12. The measurements are made for different η and η′ decays, and we thus obtain Γη→3π
0/Γη→γγ=0.841±0.034, and
$$\Gamma _{\eta ' \to \gamma \gamma } /\Gamma _{\eta ' \to \pi ^0 \pi ^0 \eta } = 0.091 \pm 0.009$$
.
42 citations
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TL;DR: In this article, a review of developments in the field of low energy antinucleon physics since 1983, the year in which the Low Energy Antiproton Ring opened in CERN, is presented.
36 citations