The πρ cloud contribution to the ω width in nuclear matter

Cabrera, D.; Rapp, Ralf

doi:10.1016/j.physletb.2013.12.056

Cited by 8 publications

(17 citation statements)

References 43 publications

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“…They differ in the partitioning into the π and ρ modifications and obtain differences in the 3-momentum dependence of the ω width. While Cabrera and Rapp [27] find a moderate momentum dependence, Ramos et al [28] get an almost linear increase of the width with momentum. Alternatively, Klingl et al [29], Lutz et al [30] and Mühlich et al [31] consider the coupling of the ω meson to nucleon resonances as the main effect driving the in-medium broadening of the ω meson.…”

Section: Resultsmentioning

confidence: 93%

“…4). The solid curves correspond to calculations by Ramos et al [28], the short dashed curves to calculations by Cabrera and Rapp [27] for different model assumptions (see text). The brown dashed-dotted curve shows the momentum dependence of the ω in-medium width calculated in a coupled-channel resonance model [31].…”

Section: Resultsmentioning

confidence: 94%

“…A further motivation for the present work were recent theoretical studies of the ω width in cold nuclear matter as a function of momentum and nuclear density by Cabrera and Rapp [27] and by Ramos et al [28]. Both groups calculated the in-medium ω width in a hadronic many-body approach, focusing on a detailed treatment of the in-medium modifications of intermediate πρ states.…”

Section: Introductionmentioning

confidence: 99%

“…At normal nuclear matter density, they found an in-medium ω width of the order of 100-200 MeV, however, with differences in the 3-momentum dependence. The calculations were confined to the momentum ranges below 1000 MeV/c in [27] and 600 MeV/c in [28]. Earlier calculations investigated the direct coupling of the ω meson to nucleon resonances.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Momentum dependence of the imaginary part of the $ \omega$ - and $ \eta^{\prime}$ -nucleus optical potential

Friedrich¹,

Nanova²,

Metag³

et al. 2016

Eur. Phys. J. A

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Abstract. The photoproduction of ω and η mesons off carbon and niobium nuclei has been measured as a function of the meson momentum for incident photon energies of 1.2-2.9 GeV at the electron accelerator ELSA. The mesons have been identified via the ω → π 0 γ → 3γ and η → π 0 π 0 η → 6γ decays, respectively, registered with the CBELSA/TAPS detector system. From the measured meson momentum distributions the momentum dependence of the transparency ratio has been determined for both mesons. Within a Glauber analysis the in-medium ω and η widths and the corresponding absorption cross sections have been deduced as a function of the meson momentum. The results are compared to recent theoretical predictions for the in-medium ω width and η -N absorption cross sections. The energy dependence of the imaginary part of the ω-and η -nucleus optical potential has been extracted. The finer binning of the present data compared to the existing data allows a more reliable extrapolation towards the production threshold. The modulus of the imaginary part of the η nucleus potential is found to be about three times smaller than recently determined values of the real part of the η -nucleus potential, which makes the η meson a suitable candidate for the search for meson-nucleus bound states. For the ω meson, the modulus of the imaginary part near threshold is comparable to the modulus of the real part of the potential. As a consequence, only broad structures can be expected which makes the observation of ω mesic states very difficult experimentally.

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Section: Resultsmentioning

confidence: 93%

Section: Resultsmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Momentum dependence of the imaginary part of the $ \omega$ - and $ \eta^{\prime}$ -nucleus optical potential

Friedrich¹,

Nanova²,

Metag³

et al. 2016

Eur. Phys. J. A

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show abstract

“…[18] ≈ 0 MeV/c 2 ≈ 60 MeV χ unitary [19] 100-200 MeV many-body [20] 150-200 MeV e.g. for a meson at rest in infinitely extended nuclear matter with constant density, a scenario far from reality.…”

Section: Introductionmentioning

confidence: 99%

In-medium properties of mesons

2017

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Abstract. In the project B.4, the modification of meson properties (mass, width) in a nuclear medium has been studied in photoproduction of mesons off nuclear targets. This work has been motivated by theoretical expectations of in-medium modifications of hadrons based on the conjecture of a partial restoration of chiral symmetry in a strongly interacting medium. It has been shown that these in-medium changes can be discussed in a compact form in terms of an optical potential describing the meson-nucleus interaction. Experimental approaches to determine the real and imaginary part of the meson-nucleus potential have been developed. The experiments have been performed with the Crystal Barrel/TAPS detector at the electron accelerator ELSA (Bonn) and the Crystal Ball/TAPS detector at MAMI (Mainz). Measuring the excitation function and momentum distribution for photo production of ω and η mesons, the real parts of the ω and η -nucleus potential, given by the in-medium mass shift, have been determined. For the η meson a lowering of the mass at normal nuclear matter density by -(39±7(stat)±15(syst)) MeV is observed, while for the ω meson a slightly smaller mass shift is found, however, with much larger uncertainties, not excluding a zero mass shift. The imaginary part of the potentials has been extracted from the measurement of the transparency ratio which compares the meson production cross section per nucleon within a nucleus to the production cross section off the free proton. For the η meson the imaginary part of the potential is found to be smaller than the real part. In case of the ω meson the opposite is observed. This makes the η meson a good candidate for the search for meson-nucleus bound states while no resolved ω mesic states can be expected. The results are compared with theoretical predictions. An outlook on future experiments is given.

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Meson–nucleus potentials and the search for meson–nucleus bound states

Metag

Nanova

Paryev

2017

Progress in Particle and Nuclear Physics

103

102

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Recent experiments studying the meson-nucleus interaction to extract meson-nucleus potentials are reviewed. The real part of the potentials quantifies whether the interaction is attractive or repulsive while the imaginary part describes the meson absorption in nuclei. The review is focused on mesons which are sufficiently long-lived to potentially form meson-nucleus quasi-bound states. The presentation is confined to meson production off nuclei in photon-, pion-, proton-, and lightion induced reactions and heavy-ion collisions at energies near the production threshold. Tools to extract the potential parameters are presented. In most cases, the real part of the potential is determined by comparing measured meson momentum distributions or excitation functions with collision model or transport model calculations. The imaginary part is extracted from transparency ratio measurements. Results on K + , K 0 , K − , η, η , ω, and φ mesons are presented and compared with theoretical predictions. The interaction of K + and K 0 mesons with nuclei is found to be weakly repulsive, while the K − , η, η , ω and φ meson-nucleus potentials are attractive, however, with widely different strengths. Because of meson absorption in the nuclear medium the imaginary parts of the meson-nucleus potentials are all negative, again with a large spread. An outlook on planned experiments in the charm sector is given. In view of the determined potential parameters, the criteria and chances for experimentally observing meson-nucleus quasi-bound states are discussed. The most promising candidates appear to be the η and η mesons.

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The πρ cloud contribution to the ω width in nuclear matter

Cited by 8 publications

References 43 publications

Momentum dependence of the imaginary part of the $ \omega$ - and $ \eta^{\prime}$ -nucleus optical potential

Momentum dependence of the imaginary part of the $ \omega$ - and $ \eta^{\prime}$ -nucleus optical potential

In-medium properties of mesons

Meson–nucleus potentials and the search for meson–nucleus bound states

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