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Your search keyword '"Hamill, C.B."' showing total 6 results
Start Over Author "Hamill, C.B." Publication Year Range Last 50 years
6 results on '"Hamill, C.B."'

1. RIB induced reactions: Studying astrophysical reactions with low-energy RI beam at CRIB

Author

Yamaguchi H., Hayakawa S., Ma N.R., Shimizu H., Okawa K., Zhang Q., Yang L., Kahl D., La Cognata M., Lamia L., Abe K., Beliuskina O., Cha S.M., Chae K.Y., Cherubini S., Figuera P., Ge Z., Gulino M., Hu J., Inoue A., Iwasa N., Kim A., Kim D., Kiss G., Kubono S., La Commara M., Lattuada M., Lee E.J., Moon J.Y., Palmerini S., Parascandolo C., Park S.Y., Phong V.H., Pierroutsakou D., Pizzone R.G., Rapisarda G.G., Romano S., Spitaleri C., Tang X.D., Trippella O., Tumino A., Zhang N.T., Lam Y.H., Heger A., Jacobs A.M., Xu S.W., Ma S.B., Ru L.H., Liu E.Q., Liu T., Hamill C.B., Murphy A. St J., Su J., Fang X., Kwag M.S., Duy N.N., Uyen N.K., Kim D.H., Liang J., Psaltis A., Sferrazza M., Johnston Z., and Li Y.Y.

Subjects
Physics, QC1-999
Abstract

Astrophysical reactions involving radioactive isotopes (RI) often play an important role in high-temperature stellar environments. The experimental studies on the reaction rates for those are still limited mainly due to the technical difficulties in producing high-quality RI beams. A direct measurement of those reactions would be still challenging in many cases, however, we can make a reliable evaluation of the reaction rates by an indirect method or by studying the resonance prorerties. Here we ntroduce recent examples of experimental studies on such RI-involving astrophysical reactions, performed at Center for Nuclear Study, the University of Tokyo, using the low-energy RI beam separator CRIB. One is for the neutron-induced destruction reactions of 7Be in the Big-Bang nucleosynthesis, and the other is the study on the 22Mg(α, p) reaction relevant in X-ray bursts, which was performed with the resonant scattering method from the inverse reaction channel.

Published
2023
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2. First measurement of 25Al+p resonant scattering relevant to the astrophysical reaction 22Mg(α,p)25Al

Author

Hu J., Yamaguchi H., Lam Y.H., Heger A., Kahl D., Jacobs A.M., Johnston Z., Xu S.W., Zhang N.T., Ma S.B., Ru L.H., Liu E.Q., Liu T., Hayakawa S., Yang L., Shimizu H., Hamill C.B., Murphy A. StJ., Su J., Fang X., Chae K.Y., Kwag M.S., Cha S.M., Duy N.N., Uyen N.K., Kim D.H., Pizzone R.G., La Cognata M., Cherubini S., Romano S., Tumino A., Liang J., Psaltis A., Sferrazza M., Kim D., Li Y.Y., and Kubono S.

Subjects
Physics, QC1-999
Abstract

Type I X-ray bursts (XRBs) are the most frequently observed thermonuclear explosions in nature. The 22Mg(α,p)25Al reaction plays a critical role in XRB models. However, experimental information is insufficient to deduce a precise 22Mg(α,p)25Al reaction rate for the respective XRB temperature range. A new measurement of 25Al+p resonant scattring was performed up to the astrophysically interested energy region of 22Mg(α,p)25Al. Several resonances were observed in the excitation functions, and their level properties have been determined based on an R-matrix analysis. In particular, proton widths and spin-parities of four natural-parity resonances above the α threshold of 26Si, which can contribute the reaction rate of 22Mg(α,p)25Al, were first experimentally determined.

Published
2022
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3. Experimental studies on astrophysical reactions at the low-energy RI beam separator CRIB

Author

Yamaguchi H., Hayakawa S., Ma N.R., Shimizu H., Okawa K., Yang L., Kahl D., La Cognata M., Lamia L., Abe K., Beliuskina O., Cha S.M., Chae K.Y., Cherubini S., Figuera P., Ge Z., Gulino M., Hu J., Inoue A., Iwasa N., Kim A., Kim D., Kiss G., Kubono S., La Commara M., Lattuada M., Lee E.J., Moon J.Y., Palmerini S., Parascandolo C., Park S.Y., Phong V. H., Pierroutsakou D., Pizzone R.G., Rapisarda G.G., Romano S., Spitaleri C., Tang X.D., Trippella O., Tumino A., Zhang N.T., Lam Y.H., Heger A., Jacobs A.M., Xu S.W., Ma S.B., Ru L.H., Liu E.Q., Liu T., Hamill C.B., St J. Murphy A., Su J., Fang X., Kwag M.S., Duy N.N., Uyen N.K., Kim D.H., Liang J, Psaltis A., Sferrazza M., Johnston Z., and Li Y.Y.

Subjects
Physics, QC1-999
Abstract

Experimental studies on astrophysical reactions involving radioactive isotopes (RI) often accompany technical challenges. Studies on such nuclear reactions have been conducted at the low-energy RI beam separator CRIB, operated by Center for Nuclear Study, the University of Tokyo. We discuss two cases of astrophysical reaction studies at CRIB; one is for the 7Be+n reactions which may affect the primordial 7Li abundance in the Big-Bang nucleosynthesis, and the other is for the 22Mg(α, p) reaction relevantin X-raybursts.

Published
2022
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4. Advancement of Photospheric Radius Expansion and Clocked Type-I X-Ray Burst Models with the New Reaction Rate Determined at the Gamow Energy

Author

Hu, Jun, Yamaguchi, Hikaru, Lam, Y.H., Heger, Alexander, Kahl, Daid, Jacobs, A.M., Johnston, Zac, Xu, Shiwei S.W., Zhang, Ningtao N.T., Ma, Shaobo S.B., Ru, L.H., Liu, Enqiang E.Q., Liu, Tong, Hayakawa, Seiya, Yang, Lei, Shimizu, Hiroki, Hamill, C.B., Murphy, StJ A.S.J., Su, Jun, Fang, Xiao, Chae, K.Y., Kwag, Minsik M.S., Cha, Soomi S.M., Duy, Nguyen Ngoc, Uyen, Nguyen Kim, Kim, Dae-hwan, Pizzone, Rosario Gianluca, La Cognata, M., Cherubini, Silvio, Romano, Stefano, Tumino, Aurora, Liang, J., Psaltis, Athanasios, Sferrazza, Michele, Kim, Duhyun, Li, Yanyan Y.Y., Kubono, Shigeru, Hu, Jun, Yamaguchi, Hikaru, Lam, Y.H., Heger, Alexander, Kahl, Daid, Jacobs, A.M., Johnston, Zac, Xu, Shiwei S.W., Zhang, Ningtao N.T., Ma, Shaobo S.B., Ru, L.H., Liu, Enqiang E.Q., Liu, Tong, Hayakawa, Seiya, Yang, Lei, Shimizu, Hiroki, Hamill, C.B., Murphy, StJ A.S.J., Su, Jun, Fang, Xiao, Chae, K.Y., Kwag, Minsik M.S., Cha, Soomi S.M., Duy, Nguyen Ngoc, Uyen, Nguyen Kim, Kim, Dae-hwan, Pizzone, Rosario Gianluca, La Cognata, M., Cherubini, Silvio, Romano, Stefano, Tumino, Aurora, Liang, J., Psaltis, Athanasios, Sferrazza, Michele, Kim, Duhyun, Li, Yanyan Y.Y., and Kubono, Shigeru

Abstract

We report the first (in)elastic scattering measurement of with the capability to select and measure in a broad energy range the proton resonances in contributing to the reaction at type I x-ray burst energies. We measured spin-parities of four resonances above the threshold of that are found to strongly impact the rate. The new rate advances a state-of-the-art model to remarkably reproduce light curves of the GS clocked burster with mean deviation and permits us to discover a strong correlation between the He abundance in the accreting envelope of the photospheric radius expansion burster and the dominance of branch., SCOPUS: ar.j, info:eu-repo/semantics/published

Published
2021

5. First measurement of 25Al+p resonant scattering relevant to the astrophysical reaction 22Mg(α,p)25Al.

Author

Hu, J., Yamaguchi, H., Lam, Y.H., Heger, A., Kahl, D., Jacobs, A.M., Johnston, Z., Xu, S.W., Zhang, N.T., Ma, S.B., Ru, L.H., Liu, E.Q., Liu, T., Hayakawa, S., Yang, L., Shimizu, H., Hamill, C.B., Murphy, A. StJ., Su, J., and Fang, X.

Subjects
X-ray bursts, THERMONUCLEAR fuels, ASTROPHYSICS, RESONANCE, R-matrices
Abstract

Type I X-ray bursts (XRBs) are the most frequently observed thermonuclear explosions in nature. The 22Mg(α,p)25Al reaction plays a critical role in XRB models. However, experimental information is insufficient to deduce a precise 22Mg(α,p)25Al reaction rate for the respective XRB temperature range. A new measurement of 25Al+p resonant scattring was performed up to the astrophysically interested energy region of 22Mg(α,p)25Al. Several resonances were observed in the excitation functions, and their level properties have been determined based on an R-matrix analysis. In particular, proton widths and spin-parities of four natural-parity resonances above the α threshold of 26Si, which can contribute the reaction rate of 22Mg(α,p)25Al, were first experimentally determined. [ABSTRACT FROM AUTHOR]

Published
2022
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6. High-statistics measurement of the η→3π0 decay at the Mainz Microtron

Author

Prakhov, S., Abt, S., Achenbach, P., Adlarson, P., Afzal, F., Aguar-Bartolomé, P., Ahmed, Z., Ahrens, J., Annand, J.R.M., Arends, H.J., Bantawa, K., Bashkanov, M., Beck, R., Biroth, M., Borisov, N.S., Braghieri, A., Briscoe, W.J., Cherepnya, S., Cividini, F., Collicott, C., Constanza, S., Denig, A., Dieterle, M., Downie, E.J., Drexler, P., Ferretti Bondy, M.I., Fil'kov, L.V., Fix, A., Gardner, S., Garni, S., Glazier, D.I., Gorodnov, I., Gradl, W., Gurevich, G.M., Hamill, C.B., Heijkenskjöld, L., Horndige, D., Huber, G.M., Käser, A., Kashevarov, V.L., Kay, S., Keshelashvili, I., Kondratiev, R., Korolija, M., Krusche, B., Lazarev, A., Lisin, V., Livingston, K., Lutterer, S., MacGregor, I.J.D., Manley, D.M., Martel, P.P., McGeorge, J.C., Middleton, D.G., Miskimen, R., Mornacchi, E., Mushkarenkov, A., Neganov, A., Neiser, A., Oberle, M., Ostrick, M., Otte, P.B., Paudyal, D., Pedroni, P., Polonski, A., Ron, G., Rostomyan, T., Sarty, A., Sfienti, C., Sokhoyan, V., Spiekter, K., Steffen, O., Strakovsky, I.I., Strandberg, B., Strub, Th., Supek, I., Thiel, A., Thiel, M., Thomas, A., Unverzagt, M., Usov, Yu. A., Wagner, S., Walford, N.K., Watts, D.P., Werthmüller, D., Wettig, J., Witthauer, L., Wolfes, M., and Zana, L.A.

Subjects
tagged photon spectrometer, parameter alpha, dynamics, Physics, High Energy Physics::Experiment, Nuclear Experiment
Abstract

The largest, at the moment, statistics of 7×106η→3π0 decays, based on 6.2×107η mesons produced in the γp→ηp reaction, has been accumulated by the A2 Collaboration at the Mainz Microtron, MAMI. It allowed a detailed study of the η→3π0 dynamics beyond its conventional parametrization with just the quadratic slope parameter α and enabled, for the first time, a measurement of the second-order term and a better understanding of the cusp structure in the neutral decay. The present data are also compared to recent theoretical calculations that predict a nonlinear dependence along the quadratic distance from the Dalitz-plot center.

Published
2018

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