| 1. |
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| 2. |
- Aguar-Bartolome, P., et al.
(författare)
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New determination of the eta transition form factor in the Dalitz decay eta -> e(+) e(-) gamma with the Crystal Ball/TAPS detectors at the Mainz Microtron
- 2014
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 89:4
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Tidskriftsartikel (refereegranskat)abstract
- The Dalitz decay eta -> e(+) e(-) gamma has been measured in the gamma p -> eta p reaction with the Crystal Ball and TAPS multiphoton spectrometers, together with the photon-tagging facility at the Mainz Microtron MAMI. The experimental statistic used in this work is one order of magnitude greater than in any previous measurement of eta -> e(+) e(-) gamma. The value obtained for the slope parameter Lambda(-2) of the eta transition form factor, Lambda(-2) = (1.95 +/- 0.15(stat) +/- 0.10(syst)) GeV-2, is in good agreement with recent measurements conducted in eta -> e(+) e(-) gamma and eta -> mu(+) mu(-) gamma decays, as well as with recent form-factor calculations. The uncertainty obtained in the value of Lambda(-2) is lower compared to results from previous measurements of the eta -> e(+) e(-) gamma decay.
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| 3. |
- Aguar-Bartolome, P., et al.
(författare)
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Measurement of the gamma p -> K-0 Sigma(+) reaction with the Crystal Ball/TAPS detectors at the Mainz Microtron
- 2013
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 88:4
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Tidskriftsartikel (refereegranskat)abstract
- The gamma p -> K-0 Sigma(+) reaction has been measured from threshold to E-gamma = 1.45 GeV (W-CM = 1.9 GeV) using the Crystal Ball and TAPS multiphoton spectrometers together with the photon tagging facility at the Mainz Microtron MAMI. In the present experiment, this reaction was searched for in the 3 pi(0)p final state, by assuming K-S(0) -> pi(0)pi(0) and Sigma(+) -> pi(0)p. The experimental results include total and differential cross sections as well as the polarization of the recoil hyperon. The new data significantly improve empirical knowledge about the gamma p -> K-0 Sigma(+) reaction in the measured energy range. The results are compared to previous measurements and model predictions. It is demonstrated that adding the present gamma p -> K-0 Sigma(+) results to existing data allowed a better description of this reaction with various models.
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| 4. |
- Kashevarov, V. L., et al.
(författare)
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Experimental study of the gamma p -> pi (0)pi(0) p reaction with the Crystal Ball/TAPS detector system at the Mainz Microtron
- 2012
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 85:6
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Tidskriftsartikel (refereegranskat)abstract
- The gamma p -> pi(0)pi(0) p reaction has been measured from threshold to 1.4 GeV using the Crystal Ball and TAPS photon spectrometers together with the photon tagging facility at the Mainz Microtron. The experimental results include total and differential cross sections as well as specific angular distributions, which were used to extract partial-wave amplitudes. In particular, the energy region below the D-13(1520) resonance was studied.
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| 5. |
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| 6. |
- Strandberg, B., et al.
(författare)
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Near-threshold π-photoproduction on the deuteron
- 2020
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Ingår i: Physical Review C. - 2469-9985. ; 101:3
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Tidskriftsartikel (refereegranskat)abstract
- The first experimental investigation of the near-threshold cross section for incoherent π-photoproduction on the deuteron γd→π-pp is presented. The experimental technique involved detection of the ≈131 MeV γ ray resulting from the radiative capture of photoproduced π-in the target. The total cross section was measured using an unpolarized tagged-photon beam, a liquid-deuterium target, and three very large NaI(Tl) spectrometers. The data are compared to theoretical models that give insight into the elementary reaction γn→π-p and pion-nucleon and nucleon-nucleon final-state interactions.
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| 7. |
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| 8. |
- Strandberg, B., et al.
(författare)
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Compton scattering from the deuteron above pion-production threshold
- 2018
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Ingår i: Physical Review C. - 2469-9985. ; 98:1
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Tidskriftsartikel (refereegranskat)abstract
- The electromagnetic polarizabilities of the nucleon are fundamental nucleon-structure observables that characterize its response to external electromagnetic fields. The neutron polarizabilities can be accessed from Compton-scattering data on light nuclear targets. Recent measurements of the differential cross section for Compton scattering on the deuteron below the pion-production threshold have decreased the uncertainties in the neutron polarizabilities, yet the proton polarizabilities remain known substantially more accurately. As the sensitivity of the cross section to the polarizabilities increases with incident photon energy, measurements above the pion threshold may offer a way for an improved determination of the neutron polarizabilities. In this Rapid Communiciation, the first measurement of the cross section for coherent Compton scattering on the deuteron above the pion-production threshold is presented.
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| 9. |
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| 10. |
- Downie, J. R., et al.
(författare)
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Are there costs to extended larval transport in the Trinidadian stream frog, Mannophryne trinitatis (Dendrobatidae)?
- 2005
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Ingår i: Journal of Natural History. - : Taylor & Francis. - 0022-2933 .- 1464-5262. ; 39:22, s. 2023-2034
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Tidskriftsartikel (refereegranskat)abstract
- Previous work has shown that male Mannophryne trinitatis (Dendrobatidae) carry their larvae on their backs for up to 4 days in search of a predator-free pool in which to deposit them. The experiments reported here investigated whether costs to the larvae or to the adults limit transport duration. We simulated transport durations of 0, 4, 8, and 12 days for larvae, but found no deterioration in terms of ability to grow to metamorphosis; indeed, 12-day larvae grew better than all the others. After 8 days of simulated transport, larvae had used up all their yolk reserves and begun to lose dry weight. Larvae on wet substrates gained wet weight and length but on drier substrates merely maintained weight, suggesting that dehydration could be a problem on the male's back. In a trial of locomotor performance ( mean jump length; number of jumps to traverse a runway), females performed best with calling males not significantly different from transporting males, despite an average larval load equivalent to 15-20% of the frog's mass. Assessment of gut contents showed that females foraged more than males, but that transporting males foraged as much as did calling males. We found no differences between the three classes of adult frogs in fat body weight.
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