Title: s-wave scattering lengths for the ⁷$$\hbox{Be} +$$ p system from an R-matrix analysis

Abstract

The astrophysical $S$ factor for the radiative proton capture reaction on ${}_7\mathrm{Be}$ ( $S_{17}$) at low energies is affected by the $s$-wave scattering lengths. Herein, we report the measurement of elastic and inelastic scattering cross sections for the ${}_7\mathrm{Be}+p$ system in the center-of-mass energy range 0.474–2.740 MeV and center-of-mass angular range ${70}^{°}$– ${150}^{°}$. A radioactive ${}_7\mathrm{Be}$ beam produced at Oak Ridge National Laboratory's (ORNL) Holifield Radioactive Ion Beam Facility was accelerated and bombarded a thin polypropylene ${\left({\mathrm{CH}}_2\right)}_n$ target. Scattered ions were detected in the segmented Silicon Detector Array. Using an $R$-matrix analysis of ORNL and Louvain-la-Neuve cross-section data, the $s$-wave scattering lengths for channel spins 1 and 2 were determined to be $17.{34}_{–1.33}^{+1.11}$ and $–3.{18}_{–0.50}^{+0.55}$ fm, respectively. The uncertainty in the $s$-wave scattering lengths reported in this work is smaller by a factor of 5–8 compared to the previous measurement, which may reduce the overall uncertainty in $S_{17}$ at zero energy. The level structure of ${}_8\mathrm{B}$ is discussed based upon the results from this work. Evidence for the existence of $0^{+}$ and $2^{+}$ levels in ${}_8\mathrm{B}$ at 1.9 and 2.21 MeV, respectively, is observed.

Authors:

Paneru, S. N. ^[1]; Brune, C. R. ^[1]; Giri, R. ^[1]; Livesay, R. J. ^[2]; Greife, U. ^[2]; Blackmon, J. C. ^[3]; Bardayan, D. W. ^[4]; Chipps, Kelly  ^[5];

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Davids, B. ^[6]; Connolly, D. S. ^[7]; Chae, K. Y. ^[8]; Champagne, A. E. ^[8]; Deibel, C. ^[9]; Jones, K. L. ^[10]; Johnson, M. S. ^[11]; Kozub, R. L. ^[12]; Ma, Z. ^[13]; Nesaraja, Caroline D.  ^[5];

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Pain, Steven  ^[5];

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Sarazin, F. ^[2] more »; Shriner, Jr., J. F. ^[12]; Stracener, Dan  ^[5];

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Smith, Michael Scott  ^[5];

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• Search DOE PAGES for ORCID "0000-0002-4737-4099"

Thomas, J. S. ^[12]; Visser, D. W. ^[8]; Wrede, C. ^[12] « less

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+ Show Author Affiliations

1. Ohio Univ., Athens, OH (United States)
2. Colorado School of Mines, Golden, CO (United States)
3. Louisiana State Univ., Baton Rouge, LA (United States)
4. Univ. of Notre Dame, IN (United States)
5. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
6. Simon Fraser Univ., Burnaby, BC (Canada); Sungkyunkwan Univ., Suwon (Republic of Korea)
7. TRIUMF, Vancouver, BC (Canada)
8. Univ. of North Carolina, Chapel Hill, NC (United States)
9. Yale Univ., New Haven, CT (United States)
10. Univ. of Tennessee, Knoxville, TN (United States); Rutgers Univ., Piscataway, NJ (United States)
11. Rutgers Univ., Piscataway, NJ (United States)
12. Tennessee Technological Univ., Cookeville, TN (United States)
13. Univ. of Tennessee, Knoxville, TN (United States)

Publication Date:

Tue Apr 30 00:00:00 EDT 2019

Research Org.:

Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); University of North Carolina, Chapel Hill, NC (United States)

Sponsoring Org.:

USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Nuclear Physics (NP); National Science Foundation (NSF); Natural Sciences and Engineering Research Council of Canada (NSERC); National Research Foundation of Korea (NRF)

OSTI Identifier:

1566951

Alternate Identifier(s):

OSTI ID: 1509925; OSTI ID: 1659272

Grant/Contract Number:  

AC05-00OR22725; NA0002905; NA0003883; FG02-88ER40387; FG02-93ER40789; PHY-1713857; NRF-2016R1A5A1013277; NRF-2013M7A1A1075764; FG02-97ER41041

Resource Type:

Accepted Manuscript

Journal Name:

Physical Review C

Additional Journal Information:

Journal Volume: 99; Journal Issue: 4; Journal ID: ISSN 2469-9985

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

73 NUCLEAR PHYSICS AND RADIATION PHYSICS