Počet nalezených dokumentů: 216
Publikováno od do

First measurement of the O-18(p, alpha)N-15 cross section at astrophysical energies
La Cognata, M.; Spitaleri, C.; Mukhamedzhanov, A.; Tribble, R. E.; Al-Abdullah, T.; Banu, A.; Cherubini, S.; Coc, A.; Crucilla, V.; Goldberg, V.; Gulino, M.; Irgaziev, B.; Kiss, G. G.; Lamia, L.; Mrázek, Jaromír; Pizzone, R. G.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Tabacaru, G.; Trache, L.; Trzaska, W.; Tudisco, S.; Tumino, A.
2010 - anglický
The O-18(p, alpha)N-15 reaction rate has been deduced by means of the Trojan horse method. For the first time the contribution of the 20 keV resonance has been directly evaluated, giving a value about 35% larger than the one in the literature. Moreover, the present approach has allowed to improve the accuracy by a factor 8.5, as it is based on the measured strength instead of spectroscopic measurements. The contribution of the 90 keV resonance has been also determined, which turned out to be of negligible importance to astrophysics. Klíčová slova: spectroscoic measurements; astrophysics; resonance Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
First measurement of the O-18(p, alpha)N-15 cross section at astrophysical energies

The O-18(p, alpha)N-15 reaction rate has been deduced by means of the Trojan horse method. For the first time the contribution of the 20 keV resonance has been directly evaluated, giving a value about ...

La Cognata, M.; Spitaleri, C.; Mukhamedzhanov, A.; Tribble, R. E.; Al-Abdullah, T.; Banu, A.; Cherubini, S.; Coc, A.; Crucilla, V.; Goldberg, V.; Gulino, M.; Irgaziev, B.; Kiss, G. G.; Lamia, L.; Mrázek, Jaromír; Pizzone, R. G.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Tabacaru, G.; Trache, L.; Trzaska, W.; Tudisco, S.; Tumino, A.
Ústav jaderné fyziky, 2010

Neutral Kaon Photoproduction at LNS, Tohoku University
Kaneta, M.; Chiga, N.; Beckford, B.; Ejima, M.; Fujii, T.; Fujii, Y.; Fujibayashi, T.; Gogami, T.; Futatsukawa, K.; Hashimoto, O.; Hosomi, K.; Hirose, K.; Iguchi, A.; Kameoka, S.; Kanda, H.; Kawama, D.; Kawasaki, T.; Kimura, C.; Kiyokawa, S.; Koike, T.; Kon, T.; Ma, Y.; Maeda, K.; Maruyama, N.; Matsumura, A.; Miyagi, Y.; Miura, Y.; Miwa, K.; Nakamura, S. N.; Nomura, H.; Okuyama, A.; Ohtani, A.; Otani, T.; Sato, M.; Shichijo, A.; Shirotori, K.; Takahashi, T.; Tamura, H.; Taniya, N.; Tsubota, H.; Tsukada, K.; Terada, N.; Ukai, M.; Uchida, D.; Watanabe, T.; Yamamoto, T.; Yamauchi, H.; Yokota, K.; Ishikawa, T.; Kinoshita, T.; Miyahara, H.; Nakabayashi, T.; Shimizu, H.; Suzuki, K.; Tamae, T.; Terasawa, T.; Yamazaki, H.; Han, Y. C.; Wang, T. S.; Sasaki, A.; Konno, O.; Bydžovský, Petr; Sotona, Miloslav
2010 - anglický
The elementary photo-strangeness production process has been intensively studied based on the high-quality data of the charged kaon channel, gamma + p -> K+ + Lambda(Sigma(0)). However, there had been no reliable data for the neutral kaon channel gamma + n -> K-0 Lambda(Sigma(0)) and the theoretical investigations suffer seriously from the lack of the data. In order to have reliable data for the neutral kaon photo-production data, substantial effort has been made to measure the gamma + n -> K-0 + A process in the pi(+)pi(-) decay channel, using a liquid deuterium target and a tagged photon beam (E-gamma = 0.8-1.1 GeV) in the threshold region at the Laboratory of Nuclear Science (LNS), Tohoku University. We have taken exploratory data quite successfully with the use of Neutral Kaon Spectrometer (NKS) at LNS-Tohoku in 2003 and 2004. The data is compared to theoretical models and it indicates a hint that the K-0 differential cross section has a backward peak in the energy region. The second generation of the experiment, NKS2, is designed to extend the NKS experiment by considerably upgrading the original neutral kaon spectrometer, fully replacing the spectrometer magnet, tracking detectors and all the trigger counters. The new spectrometer NKS2 has significantly larger acceptance for neutral kaons compared with NKS, particularly covering forward angles and much better invariant mass resolution. The estimated acceptance of NKS2 is three (ten) times larger for K-S(0)(Lambda) than that of NKS. The spectrometer is newly constructed and installed at the Laboratory of Nuclear Science, Tohoku University in 2005. The deuterium target data was taken with tagged photon beam in 2006-2007. We will report recent results of NKS2 in this paper. Additionally, a status of the upgrade project that gives us larger acceptance and capability of K-0 + A coincidence measurement will be presented. Klíčová slova: strangeness; photoproduction Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Neutral Kaon Photoproduction at LNS, Tohoku University

The elementary photo-strangeness production process has been intensively studied based on the high-quality data of the charged kaon channel, gamma + p -> K+ + Lambda(Sigma(0)). However, there had been ...

Kaneta, M.; Chiga, N.; Beckford, B.; Ejima, M.; Fujii, T.; Fujii, Y.; Fujibayashi, T.; Gogami, T.; Futatsukawa, K.; Hashimoto, O.; Hosomi, K.; Hirose, K.; Iguchi, A.; Kameoka, S.; Kanda, H.; Kawama, D.; Kawasaki, T.; Kimura, C.; Kiyokawa, S.; Koike, T.; Kon, T.; Ma, Y.; Maeda, K.; Maruyama, N.; Matsumura, A.; Miyagi, Y.; Miura, Y.; Miwa, K.; Nakamura, S. N.; Nomura, H.; Okuyama, A.; Ohtani, A.; Otani, T.; Sato, M.; Shichijo, A.; Shirotori, K.; Takahashi, T.; Tamura, H.; Taniya, N.; Tsubota, H.; Tsukada, K.; Terada, N.; Ukai, M.; Uchida, D.; Watanabe, T.; Yamamoto, T.; Yamauchi, H.; Yokota, K.; Ishikawa, T.; Kinoshita, T.; Miyahara, H.; Nakabayashi, T.; Shimizu, H.; Suzuki, K.; Tamae, T.; Terasawa, T.; Yamazaki, H.; Han, Y. C.; Wang, T. S.; Sasaki, A.; Konno, O.; Bydžovský, Petr; Sotona, Miloslav
Ústav jaderné fyziky, 2010

High-resolution Hypernuclear Spectroscopy Electron Scattering at JLab, Hall A
Garibaldi, F.; Cisbani, E.; Cusanno, F.; Frullani, S.; Iodice, M.; Urciuoli, G.M.; De Leo, R.; Lagamba, L.; Marrone, S.; LeRose, J. J.; de Jager, C.W.; Feuerbach, R. J.; Higinbotham, D. W.; Reitz, B.; Acha, A.; Markowitz, P.; Bydžovský, Petr; Sotona, Miloslav; Chang, C. C.; Millener, J.
2010 - anglický
The characteristics of the Jefferson LAB electron beam, together with those of the experimental equipments, offer a unique opportunity to study hypernuclear spectroscopy via electromagnetic induced reactions. Experiment 94-107 started a systematic study on 1p-shell targets, C-12, Be-9 and O-16. We present the results from C-12, O-16 and very preliminary results from Be-9. For C-12 for the first time measurable strength in the core-excited part of the spectrum between the ground state and the p(Lambda) state was shown in B-12(Lambda) for the first time. A high-quality N-16(Lambda) spectrum was produced for the first time with sub-MeV Energy resolution. A very precise B-Lambda value for N-16(Lambda), calibrated against the elementary (e,e'K+) reaction on hydrogen, has also been obtained. Final data on Be-9 will be available soon. The missing energy resolution is the best ever obtained in hypernuclear production experiments. Klíčová slova: electromagneti production; Jefferson laboratory; stangeness Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
High-resolution Hypernuclear Spectroscopy Electron Scattering at JLab, Hall A

The characteristics of the Jefferson LAB electron beam, together with those of the experimental equipments, offer a unique opportunity to study hypernuclear spectroscopy via electromagnetic induced ...

Garibaldi, F.; Cisbani, E.; Cusanno, F.; Frullani, S.; Iodice, M.; Urciuoli, G.M.; De Leo, R.; Lagamba, L.; Marrone, S.; LeRose, J. J.; de Jager, C.W.; Feuerbach, R. J.; Higinbotham, D. W.; Reitz, B.; Acha, A.; Markowitz, P.; Bydžovský, Petr; Sotona, Miloslav; Chang, C. C.; Millener, J.
Ústav jaderné fyziky, 2010

QCD factorization at forward rapidities
Nemchik, J.; Šumbera, Michal
2010 - anglický
We analyze several reactions on nuclear targets at forward rapidities and different energies (at smallest experimentally accessible Bjorken x(2) in the target). Nuclear effects are then usually interpreted as a result of shadowing or the Color Glass Condensate. QCD factorization of soft and hard interactions requires the nucleus to be an universal filter for different Fock components of the projectile hadron. We demonstrate, however, that this is not the case in the vicinity of the kinematic limit, Feynman x(F) -> 1, where sharing of energy between the projectile constituents becomes an issue. The rise of suppression with x(F) is confirmed by the E772 and E886 data on the Drell-Yan and heavy quarkonium production. We show that this effect can be treated alternatively as an effective energy loss proportional to initial energy. This leads to a nuclear suppression at any energy, and predicts x(F) scaling of the suppression. We demonstrate also that the same kinematic limit can be approached in transverse momentum when the Cronin enhancement of particle production at medium-high p(T) switches to a suppression at larger p(T) violating thus QCD factorization. Such an unexpected effect seems to be confirmed by the RHIC data for pion production in d+A collisions, and even for direct photons in Au+Au collisions. Klíčová slova: suppression; collisions Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
QCD factorization at forward rapidities

We analyze several reactions on nuclear targets at forward rapidities and different energies (at smallest experimentally accessible Bjorken x(2) in the target). Nuclear effects are then usually ...

Nemchik, J.; Šumbera, Michal
Ústav jaderné fyziky, 2010

Spectral flux of the p-Li-7(C) Q-M neutron source measured by proton recoil telescope
Novák, Jan; Bém, Pavel; Fischer, U.; Götz, Miloslav; Honusek, Milan; Simakov, S. P.; Šimečková, Eva; Štefánik, Milan
2010 - anglický
The cyclotron-based fast neutron source at NPI produces mono-energetic neutron fields up to 35 MeV neutron energy using the p + 7Li(carbon backing) reactions. To be applied for activation cross-section measurements, not only the intensity of neutron peak, but also the contribution of low-energy continuum in the spectra must be well determined. Simulations of the spectral flux from present source at a position of irradiated samples were performed using CYRIC TOF-data validated in the present work against LA150h by calculations with the transport Monte Carlo code MCNPX. Klíčová slova: MCNPX; TOF; neutron source Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Spectral flux of the p-Li-7(C) Q-M neutron source measured by proton recoil telescope

The cyclotron-based fast neutron source at NPI produces mono-energetic neutron fields up to 35 MeV neutron energy using the p + 7Li(carbon backing) reactions. To be applied for activation ...

Novák, Jan; Bém, Pavel; Fischer, U.; Götz, Miloslav; Honusek, Milan; Simakov, S. P.; Šimečková, Eva; Štefánik, Milan
Ústav jaderné fyziky, 2010

Chiral model for (K)over-barN interactions and its pole content
Cieplý, Aleš; Smejkal, J.
2010 - anglický
We use chirally motivated effective meson-baryon potentials to describe the low energy (K) over barN data including the characteristics of kaonic hydrogen. Our results are examined in comparison with other approaches based on the unitarity and dispersion relation for the inverse of the T-matrix. We demonstrate that the movements of the poles generated by the model upon varying the model parameters can serve as a tool to get additional insights on the dynamics of the strongly coupled pi Sigma-(K) over barN system. Klíčová slova: chiral Lagrangians; coupled channels; meson-baryon interactions Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Chiral model for (K)over-barN interactions and its pole content

We use chirally motivated effective meson-baryon potentials to describe the low energy (K) over barN data including the characteristics of kaonic hydrogen. Our results are examined in comparison with ...

Cieplý, Aleš; Smejkal, J.
Ústav jaderné fyziky, 2010

Indirect measurement of O-17(p,alpha)N-14 cross section at ultra-low energies
Sergi, M. L.; Spitaleri, C.; Coc, A.; Mukhamedzhanov, A.; Burjan, Václav; Cherubini, S.; Crucilla, V.; Gulino, M.; Hammache, F.; Hons, Zdeněk; Irgaziev, B.; Kiss, G. G.; Kroha, Václav; La Cognata, M.; Lamia, L.; Pizzone, R. G.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; de Sereville, N.; Somorjai, E.; Tudisco, S.; Tumino, A.
2010 - anglický
The indirect measurement of O-17(p,alpha)N-14 cross section was performed by means of the Trojan Horse Method. This approach allowed to investigate the ultra-low energy range (E-c.m.= 0-300 keV) relevant for several astrophysics environments, where two resonant levels of F-18 at E-c.m.(R) = 65 keV and E-c.m.(R) = 183 keV play a significant role in the reaction rate determination. Klíčová slova: astrophysics; nuclear reaction; reaction rates Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Indirect measurement of O-17(p,alpha)N-14 cross section at ultra-low energies

The indirect measurement of O-17(p,alpha)N-14 cross section was performed by means of the Trojan Horse Method. This approach allowed to investigate the ultra-low energy range (E-c.m.= 0-300 keV) ...

Sergi, M. L.; Spitaleri, C.; Coc, A.; Mukhamedzhanov, A.; Burjan, Václav; Cherubini, S.; Crucilla, V.; Gulino, M.; Hammache, F.; Hons, Zdeněk; Irgaziev, B.; Kiss, G. G.; Kroha, Václav; La Cognata, M.; Lamia, L.; Pizzone, R. G.; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; de Sereville, N.; Somorjai, E.; Tudisco, S.; Tumino, A.
Ústav jaderné fyziky, 2010

Astrophysical Reaction Rates Obtained By Indirect Techniques
Tribble, R. E.; Al-Abdullah, T.; Alharbi, A.; Aysto, J.; Banu, A.; Burjan, Václav; Carstoiu, F.; Chen, X.; Clark, H. L.; Davidson, T.; Fu, C.; Gagliardi, C. A.; Hardy, J. C.; Iacob, V. E.; Jokinen, J.; Kroha, Václav; Lui, Y. W.; McCleskey, M.; Mukhamedzhanov, A.; Nica, N.; Park, H.; Roeder, B. T.; Saastamoinen, A.; Simmons, E.; Tabacaru, G.; Tokimoto, Y.; Trache, L.; Woods, P. J.; Zhai, Y.
2010 - anglický
ndirect techniques have been used to obtain information about reaction rates for several proton capture reactions that occur on short-lived nuclei. The techniques used to carry out the measurements are reviewed and the results obtained are presented. Also future prospects for further measurements with a new facility, T-REX, are discussed. Klíčová slova: nuclear astophysics; explosive nucleosynthesis; proton capture Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Astrophysical Reaction Rates Obtained By Indirect Techniques

ndirect techniques have been used to obtain information about reaction rates for several proton capture reactions that occur on short-lived nuclei. The techniques used to carry out the measurements ...

Tribble, R. E.; Al-Abdullah, T.; Alharbi, A.; Aysto, J.; Banu, A.; Burjan, Václav; Carstoiu, F.; Chen, X.; Clark, H. L.; Davidson, T.; Fu, C.; Gagliardi, C. A.; Hardy, J. C.; Iacob, V. E.; Jokinen, J.; Kroha, Václav; Lui, Y. W.; McCleskey, M.; Mukhamedzhanov, A.; Nica, N.; Park, H.; Roeder, B. T.; Saastamoinen, A.; Simmons, E.; Tabacaru, G.; Tokimoto, Y.; Trache, L.; Woods, P. J.; Zhai, Y.
Ústav jaderné fyziky, 2010

Indirect Approach To The H-2(d,p)H-3 Reaction Study
Sparta, R.; Pizzone, R. G.; Spitaleri, C.; Aliotta, M.; Burjan, Václav; Cherubini, S.; Crucilla, V.; Gulino, M.; Hons, Zdeněk; Kiss, G. G.; Kroha, Václav; La Cognata, M.; Lamia, L.; McCleskey, M.; Mrázek, Jaromír; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Trache, L.; Tumino, A.
2010 - anglický
In order to understand primordial and stellar nucleosynthesis, we have studied H-2(d,p)H-3 reaction at 0.4 MeV down to astrophysical energies. Knowledge of its S-factor is interesting also to plan reactions for fusion reactors to produce energy. The H-2(d,p)H-3 reaction has been studied through the Trojan Horse Method applied to the three-body reaction H-2(He-3,pt)H, at beam energy of 17 MeV. Once selection of protons and tritons detected in coincidence and the selection of quasi-free events, the obtained S-factor is compared with direct measurements. Such data are in agreement with the direct ones and a pole invariance test has been obtained comparing the present results with another H-2(d,p)H-3 THM measurements, where a different spectator particle was employed. Klíčová slova: nuclear astrohphysics; Trojan Horse; Big Bang nucleosynthesis Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Indirect Approach To The H-2(d,p)H-3 Reaction Study

In order to understand primordial and stellar nucleosynthesis, we have studied H-2(d,p)H-3 reaction at 0.4 MeV down to astrophysical energies. Knowledge of its S-factor is interesting also to plan ...

Sparta, R.; Pizzone, R. G.; Spitaleri, C.; Aliotta, M.; Burjan, Václav; Cherubini, S.; Crucilla, V.; Gulino, M.; Hons, Zdeněk; Kiss, G. G.; Kroha, Václav; La Cognata, M.; Lamia, L.; McCleskey, M.; Mrázek, Jaromír; Puglia, S. M. R.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Trache, L.; Tumino, A.
Ústav jaderné fyziky, 2010

Spectroscopy of Medium-mass Hypernuclear Production
Motoba, T.; Bydžovský, Petr; Sotona, Miloslav; Itonaga, K.; Ogawa, K.; Hashimoto, O.
2010 - anglický
Theoretical hypernuclear photoproduction spectra are demonstrated by choosing typical medium-heavy nuclear targets such as Si-28, Ca-40, and Cr-52. The predictions provide us with interesting opportunities of spectroscopic study beyond p-shell on the dynamical coupling between a hyperon and nuclear core excitations. Klíčová slova: hypernuclear photoproduction; DWIA; unnatural parity states Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR.
Spectroscopy of Medium-mass Hypernuclear Production

Theoretical hypernuclear photoproduction spectra are demonstrated by choosing typical medium-heavy nuclear targets such as Si-28, Ca-40, and Cr-52. The predictions provide us with interesting ...

Motoba, T.; Bydžovský, Petr; Sotona, Miloslav; Itonaga, K.; Ogawa, K.; Hashimoto, O.
Ústav jaderné fyziky, 2010

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