Determining the meson-nucleus potential - on the way to mesic states

Metag, V.

doi:10.1007/s10751-015-1135-y

Cited by 15 publications

(17 citation statements)

References 28 publications

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“…In recent photoproduction experiments, we studied the ω-and η ′ -nucleus interaction and deduced information on the real [22][23][24][25] and imaginary part [21,26,27] of the optical potential. For the latter, values of ≈−70 MeV and ≈−10 MeV were extracted for the ω and η ′ meson, respectively, at saturation density and for average recoil momenta of ≈ 1G e V /c from transparency ratio measurements by studying the attenuation of the meson flux in the photoproduction off various nuclei.…”

Section: Introductionmentioning

confidence: 99%

Determination of the real part of theη′-Nb optical potential

Nanova¹,

Friedrich²,

Metag³

et al. 2016

Phys. Rev. C

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ReuseItems deposited in White Rose Research Online are protected by copyright, with all rights reserved unless indicated otherwise. They may be downloaded and/or printed for private study, or other acts as permitted by national copyright laws. The publisher or other rights holders may allow further reproduction and re-use of the full text version. This is indicated by the licence information on the White Rose Research Online record for the item. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request.PHYSICAL REVIEW C 94, 025205 (2016) Determination of the real part of the η ′ -Nb optical potential The excitation function and momentum distribution of η ′ mesons have been measured in photoproduction off 93 Nb in the energy range of 1.2-2.9 GeV. The experiment has been performed with the combined Crystal Barrel and MiniTAPS detector system, using tagged photon beams from the ELSA electron accelerator. Information on the sign and magnitude of the real part of the η ′ -Nb potential has been extracted from a comparison of the data with model calculations. An attractive potential of −(41 ± 10(stat) ± 15(syst)) MeV depth at normal nuclear matter density is deduced within model uncertainties. This value is consistent with the potential depth of −(37 ± 10(stat) ± 10(syst)) MeV obtained in an earlier measurement for a light nucleus (carbon). This relatively shallow η ′ -nucleus potential will make the search for η ′ -nucleus bound states more difficult.

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Section: Introductionmentioning

confidence: 99%

Determination of the real part of theη′-Nb optical potential

Nanova¹,

Friedrich²,

Metag³

et al. 2016

Phys. Rev. C

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“…The range of -ImU (0) values obtained for different fit functions reflects the systematic uncertainties. For the ω meson the modulus of the imaginary part of the meson nucleus potential near threshold is found to be (48 ± 12(stat)± 9(syst)) MeV comparable to the modulus of the real part of about 30 MeV, determined in [24,25,26]. For the η meson the extrapolation towards the production threshold yields an imaginary potential of (13 ± 3(stat)±3(syst)) MeV, corresponding to an imaginary part of the η scattering length Im(a η N ) = (0.16 ± 0.05) fm.…”

Section: Resultsmentioning

confidence: 49%

“…In this analysis the modification of the in-medium meson mass m * and momentum p * by the real part of the meson-nucleus potential is taken into account. In the calculations, potential depths V 0 at normal nuclear matter density of −30 and −40 MeV are used for the ω and η meson, respectively, as recently determined in [22,25,26]. The effect on the calculated transparency is, however, very small.…”

Section: Resultsmentioning

confidence: 99%

“…It is therefore important to study experimentally the relative strength of the real and imaginary part of the meson-nucleus interaction for the meson of interest. It has been shown in [18,19,20,21,22,23,24,25] that the real part of the mesonnucleus potential can be extracted from measurements of the excitation function and momentum distribution of the meson while the imaginary part can be deduced from measurements of the transparency ratio which compares the meson production cross section off a nucleus with the one off the free nucleon. When mesons are produced in a nuclear reaction in the 1-2 GeV energy range they exhibit -due to kinematics -a broad momentum distribution with a most probable value close to their mass.…”

Section: Introductionmentioning

confidence: 99%

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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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“…The data have been fitted and extrapolated towards the production threshold. For the ω meson the modulus of the imaginary part of the meson nucleus potential near threshold is found to be (48 ± 12(stat)± 9(syst)) MeV comparable to the modulus of the real part of about 30 MeV, determined in [20,22,27]. For the η meson the extrapolation towards the production threshold yields an imaginary potential of (13 ± 3(stat)±3(syst)) MeV, corresponding to an imaginary part of the η scattering length Im(a η N ) = (0.16 ± 0.05) fm.…”

Section: The Imaginary Part Of the ω-And η -Nucleus Optical Potentialmentioning

confidence: 52%

Determination of theω- andη′-nucleus optical potential

Nanova

Metag

2016

EPJ Web Conf.

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Abstract. The ω and η -nucleus interaction has been studied in photoproduction reactions off C and Nb targets, using the CBELSA/TAPS detector system. Transparency ratio measurements provide information on the inelastic cross section and in-medium width of mesons and thereby on the imaginary part of the meson-nucleus potential. The real part of the optical potential can be deduced from measurements of the excitation function and momentum distribution which are sensitive to the sign and depth of the potential. Data taken on a C and Nb target have been analysed to determine the real and the imaginary part of the ω-and η -nucleus optical potential. The momentum dependence of the imaginary part of both mesons is presented and discussed. The results are compared to previous experimental results and to model calculations assuming different scenarios. The data are consistent with a weakly attractive potential for both mesons. The relatively small in-medium width of the η meson encourages the search for η bound states.

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Determining the meson-nucleus potential - on the way to mesic states

Cited by 15 publications

References 28 publications

Determination of the real part of theη′-Nb optical potential

Determination of the real part of theη′-Nb optical potential

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

Determination of theω- andη′-nucleus optical potential

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