Direct Mass Measurements of Neutron-Rich Zinc and Gallium Isotopes: An Investigation of the Formation of the First r -Process Peak

Andrew Jacobs; Stylianos Nikas; John Ash; Behnam Ashrafkhani; Ivana Belosovic; Julian Bergmann; Callum Brown; Jaime Cardona; Eleanor Dunling; Timo Dickel; Luca Egoriti; Gabriella Gelinas; Zach Hockenbery; Sakshi Kakkar; Brian Kootte; Ali Mollaebrahimi; Eleni Marina Lykiardopoulou; Tobias Murböck; Stefan Paul; Wolfgang R. Plaß; William S. Porter; Moritz Pascal Reiter; Alex Ridley; Jon Ringuette; Christoph Scheidenberger; Rane Simpson; Coulter Walls; Yilin Wang; Jens Dilling; Ania Kwiatkowski

doi:10.1103/PhysRevLett.134.062701

Direct Mass Measurements of Neutron-Rich Zinc and Gallium Isotopes: An Investigation of the Formation of the First r -Process Peak

Andrew Jacobs
, Stylianos Nikas
, John Ash
, Behnam Ashrafkhani
, Ivana Belosovic
, Julian Bergmann
, Callum Brown
, Jaime Cardona
, Eleanor Dunling
, Timo Dickel
, Luca Egoriti
, Gabriella Gelinas
, Zach Hockenbery
, Sakshi Kakkar
, Brian Kootte
, Ali Mollaebrahimi
, Eleni Marina Lykiardopoulou
, Tobias Murböck
, Stefan Paul
, Wolfgang R. Plaß

William S. Porter, Moritz Pascal Reiter, Alex Ridley, Jon Ringuette, Christoph Scheidenberger, Rane Simpson, Coulter Walls, Yilin Wang, Jens Dilling, Ania Kwiatkowski

Neutron Sciences Directorate

Research output: Contribution to journal › Article › peer-review

2 Scopus citations

Abstract

The prediction of isotopic abundances resulting from the rapid neutron capture process (r process) requires high-precision mass measurements. Using TITAN's on-line time-of-flight spectrometer, first time mass measurements are performed for Zn83 and Ga86. These measurements reduced uncertainties, and are used to calculate isotopic abundances near the first r-process abundance peak using astrophysical conditions present during a binary neutron star (BNS) merger. Good agreement in abundance across a range of trajectories is found when comparing to several metal-poor stars while also strongly deviating from the solar r-process pattern. These findings point to a high degree of sensitivity to the electron fraction of a BNS merger on the final elemental abundance pattern for certain elements near the first r-process peak while others display universality. We find that small changes in electron fraction can produce distinct abundance patterns that match those of metal-poor stars with different classifications.

Original language	English
Article number	062701
Journal	Physical Review Letters
Volume	134
Issue number	6
DOIs	https://doi.org/10.1103/PhysRevLett.134.062701
State	Published - Feb 14 2025

Funding

We would like to thank the Targets and Ion Source group at TRIUMF. Particularly, we thank J. Lassen for the Zn laser development as well as A. Gottberg for the proton-to-neutron converter target development. Additionally, we would like to thank N. Vassh for fruitful discussion pertaining to our results. This work was supported by the Natural Sciences and Engineering Research Council (NSERC) of Canada under Grants No. SAPIN-2018-00027, No. RGPAS-2018-522453, and No. SAPPJ-2018-00028, the National Research Council (NRC) of Canada through TRIUMF, the Canada-UK Foundation, the UK Science and Technology Facilities Council (STFC) No. ST/V001051/1, German institutions DFG (Grants FR 601/3-1, Contract No. 422761894 and SFB 1245 and through PRISMA Cluster of Excellence), BMBF (Grants No. 05P21RGFN1 and No. 05P24RG4), and by the JLU and GSI under the JLU-GSI strategic Helmholtz partnership agreement.

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10.1103/PhysRevLett.134.062701

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Jacobs, A., Nikas, S., Ash, J., Ashrafkhani, B., Belosovic, I., Bergmann, J., Brown, C., Cardona, J., Dunling, E., Dickel, T., Egoriti, L., Gelinas, G., Hockenbery, Z., Kakkar, S., Kootte, B., Mollaebrahimi, A., Lykiardopoulou, E. M., Murböck, T., Paul, S., ... Kwiatkowski, A. (2025). Direct Mass Measurements of Neutron-Rich Zinc and Gallium Isotopes: An Investigation of the Formation of the First r -Process Peak. Physical Review Letters, 134(6), Article 062701. https://doi.org/10.1103/PhysRevLett.134.062701

@article{3a8931fafdc34ab2b9ed831a4a1db1dd,

title = "Direct Mass Measurements of Neutron-Rich Zinc and Gallium Isotopes: An Investigation of the Formation of the First r -Process Peak",

abstract = "The prediction of isotopic abundances resulting from the rapid neutron capture process (r process) requires high-precision mass measurements. Using TITAN's on-line time-of-flight spectrometer, first time mass measurements are performed for Zn83 and Ga86. These measurements reduced uncertainties, and are used to calculate isotopic abundances near the first r-process abundance peak using astrophysical conditions present during a binary neutron star (BNS) merger. Good agreement in abundance across a range of trajectories is found when comparing to several metal-poor stars while also strongly deviating from the solar r-process pattern. These findings point to a high degree of sensitivity to the electron fraction of a BNS merger on the final elemental abundance pattern for certain elements near the first r-process peak while others display universality. We find that small changes in electron fraction can produce distinct abundance patterns that match those of metal-poor stars with different classifications.",

author = "Andrew Jacobs and Stylianos Nikas and John Ash and Behnam Ashrafkhani and Ivana Belosovic and Julian Bergmann and Callum Brown and Jaime Cardona and Eleanor Dunling and Timo Dickel and Luca Egoriti and Gabriella Gelinas and Zach Hockenbery and Sakshi Kakkar and Brian Kootte and Ali Mollaebrahimi and Lykiardopoulou, \{Eleni Marina\} and Tobias Murb{\"o}ck and Stefan Paul and Pla{\ss}, \{Wolfgang R.\} and Porter, \{William S.\} and Reiter, \{Moritz Pascal\} and Alex Ridley and Jon Ringuette and Christoph Scheidenberger and Rane Simpson and Coulter Walls and Yilin Wang and Jens Dilling and Ania Kwiatkowski",

note = "Publisher Copyright: {\textcopyright} 2025 American Physical Society.",

year = "2025",

month = feb,

day = "14",

doi = "10.1103/PhysRevLett.134.062701",

language = "English",

volume = "134",

journal = "Physical Review Letters",

issn = "0031-9007",

publisher = "American Physical Society",

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Jacobs, A, Nikas, S, Ash, J, Ashrafkhani, B, Belosovic, I, Bergmann, J, Brown, C, Cardona, J, Dunling, E, Dickel, T, Egoriti, L, Gelinas, G, Hockenbery, Z, Kakkar, S, Kootte, B, Mollaebrahimi, A, Lykiardopoulou, EM, Murböck, T, Paul, S, Plaß, WR, Porter, WS, Reiter, MP, Ridley, A, Ringuette, J, Scheidenberger, C, Simpson, R, Walls, C, Wang, Y, Dilling, J & Kwiatkowski, A 2025, 'Direct Mass Measurements of Neutron-Rich Zinc and Gallium Isotopes: An Investigation of the Formation of the First r -Process Peak', Physical Review Letters, vol. 134, no. 6, 062701. https://doi.org/10.1103/PhysRevLett.134.062701

TY - JOUR

T1 - Direct Mass Measurements of Neutron-Rich Zinc and Gallium Isotopes

T2 - An Investigation of the Formation of the First r -Process Peak

AU - Jacobs, Andrew

AU - Nikas, Stylianos

AU - Ash, John

AU - Ashrafkhani, Behnam

AU - Belosovic, Ivana

AU - Bergmann, Julian

AU - Brown, Callum

AU - Cardona, Jaime

AU - Dunling, Eleanor

AU - Dickel, Timo

AU - Egoriti, Luca

AU - Gelinas, Gabriella

AU - Hockenbery, Zach

AU - Kakkar, Sakshi

AU - Kootte, Brian

AU - Mollaebrahimi, Ali

AU - Lykiardopoulou, Eleni Marina

AU - Murböck, Tobias

AU - Paul, Stefan

AU - Plaß, Wolfgang R.

AU - Porter, William S.

AU - Reiter, Moritz Pascal

AU - Ridley, Alex

AU - Ringuette, Jon

AU - Scheidenberger, Christoph

AU - Simpson, Rane

AU - Walls, Coulter

AU - Wang, Yilin

AU - Dilling, Jens

AU - Kwiatkowski, Ania

PY - 2025/2/14

Y1 - 2025/2/14

N2 - The prediction of isotopic abundances resulting from the rapid neutron capture process (r process) requires high-precision mass measurements. Using TITAN's on-line time-of-flight spectrometer, first time mass measurements are performed for Zn83 and Ga86. These measurements reduced uncertainties, and are used to calculate isotopic abundances near the first r-process abundance peak using astrophysical conditions present during a binary neutron star (BNS) merger. Good agreement in abundance across a range of trajectories is found when comparing to several metal-poor stars while also strongly deviating from the solar r-process pattern. These findings point to a high degree of sensitivity to the electron fraction of a BNS merger on the final elemental abundance pattern for certain elements near the first r-process peak while others display universality. We find that small changes in electron fraction can produce distinct abundance patterns that match those of metal-poor stars with different classifications.

AB - The prediction of isotopic abundances resulting from the rapid neutron capture process (r process) requires high-precision mass measurements. Using TITAN's on-line time-of-flight spectrometer, first time mass measurements are performed for Zn83 and Ga86. These measurements reduced uncertainties, and are used to calculate isotopic abundances near the first r-process abundance peak using astrophysical conditions present during a binary neutron star (BNS) merger. Good agreement in abundance across a range of trajectories is found when comparing to several metal-poor stars while also strongly deviating from the solar r-process pattern. These findings point to a high degree of sensitivity to the electron fraction of a BNS merger on the final elemental abundance pattern for certain elements near the first r-process peak while others display universality. We find that small changes in electron fraction can produce distinct abundance patterns that match those of metal-poor stars with different classifications.

UR - https://www.scopus.com/pages/publications/85217920388

U2 - 10.1103/PhysRevLett.134.062701

DO - 10.1103/PhysRevLett.134.062701

M3 - Article

C2 - 40021145

AN - SCOPUS:85217920388

SN - 0031-9007

VL - 134

JO - Physical Review Letters

JF - Physical Review Letters

IS - 6

M1 - 062701

ER -

Direct Mass Measurements of Neutron-Rich Zinc and Gallium Isotopes: An Investigation of the Formation of the First r -Process Peak

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