We present new experimental measurements of resonance strengths in the astrophysical $^{23}$Al(<math><mi>p</mi><mo>,</mo><mi>γ</mi></math>)$^{24}$Si reaction, constraining the pathway of nucleosynthesis beyond $^{22}$Mg in X-ray burster scenarios. Specifically, we have performed the first measurement of the (<math><mi>d</mi><mo>,</mo><mi>p</mi></math>) reaction using a radioactive beam of $^{23}$Ne to explore levels in $^{24}$Ne, the mirror analog of $^{24}$Si. Four strong single-particle states were observed and corresponding neutron spectroscopic factors were extracted with a precision of ∼20%. Using these spectroscopic factors, together with mirror state identifications, we have reduced uncertainties in the strength of the key ℓ = 0 resonance at <math><msub><mrow><mi>E</mi></mrow><mrow><mi>r</mi></mrow></msub></math> = 157 keV, in the astrophysical $^{23}$Al(<math><mi>p</mi><mo>,</mo><mi>γ</mi></math>) reaction, by a factor of 4. Our results show that the $^{22}$Mg(<math><mi>p</mi><mo>,</mo><mi>γ</mi></math>)$^{23}$Al(<math><mi>p</mi><mo>,</mo><mi>γ</mi></math>) pathway dominates over the competing $^{22}$Mg(<math><mi>α</mi><mo>,</mo><mi>p</mi></math>) reaction in all but the most energetic X-ray burster events (<math><mi>T</mi><mo>&gt;</mo><mn>0.85</mn></math> GK), significantly affecting energy production and the preservation of hydrogen fuel.

United Kingdom

G. Lotay

Canada

J. Henderson

W.N. Catford

Iraq

F.A. Ali

J. Berean

N. Bernier

S.S. Bhattacharjee

M. Bowry

R. Caballero-Folch

B. Davids

T.E. Drake

A.B. Garnsworthy

F. Ghazi Moradi

S.A. Gillespie

B. Greaves

G. Hackman

S. Hallam

D. Hymers

E. Kasanda

D. Levy

United States

B.K. Luna

A. Mathews

Z. Meisel

M. Moukaddam

D. Muecher

B. Olaizola

France

N.A. Orr

H.P. Patel

M.M. Rajabali

Y. Saito

J. Smallcombe

M. Spencer

C.E. Svensson

K. Whitmore

M. Williams

Single neutron transfer on Ne and its relevance for the pathway of nucleosynthesis in astrophysical X-ray bursts

The extremely neutron-deficient isotopes $^{177,179}$Au were studied by means of in-beam γ-ray spectroscopy. Specific tagging techniques, α-decay tagging in $^{177}$Au and isomer tagging in $^{179}$Au, were used for these studies. Feeding of positive-parity, nearly spherical states, which are associated with 2<math><msub><mrow><mi>d</mi></mrow><mrow><mn>3</mn><mo>/</mo><mn>2</mn></mrow></msub></math> and 3<math><msub><mrow><mi>s</mi></mrow><mrow><mn>1</mn><mo>/</mo><mn>2</mn></mrow></msub></math> proton-hole configurations, from the 1<math><msub><mrow><mi>i</mi></mrow><mrow><mn>13</mn><mo>/</mo><mn>2</mn></mrow></msub></math> proton-intruder configuration was observed in $^{177}$Au. Such a decay path has no precedent in odd-Au isotopes and it is explained by the effect of mixing of wave functions of the initial state.

Slovakia

M. Venhart

M. Balogh

A. Herzáň

J.L. Wood

D.T. Joss

Japan

A.N. Andreyev

Finland

K. Auranen

R.J. Carroll

M.C. Drummond

South Africa

J.L. Easton

P.T. Greenlees

T. Grahn

A. Gredley

U. Jakobsson

R. Julin

S. Juutinen

J. Konki

E.A. Lawrie

M. Leino

V. Matoušek

C.G. McPeake

D. O'Donnell

R.D. Page

J. Pakarinen

P. Papadakis

J. Partanen

P. Peura

P. Rahkila

P. Ruotsalainen

M. Sandzelius

J. Sarén

Türkiye

B. Saygı

M. Sedlák

C. Scholey

J. Sorri

S. Stolze

A. Thornthwaite

R. Urban

J. Uusitalo

Czechia

M. Veselský

F.P. Wearing

Population of a low-spin positive-parity band from high-spin intruder states in Au: The two-state mixing effect

Many-body nuclear theory utilizing microscopic or chiral potentials has developed to the point that collectivity might be studied within a microscopic or ab initio framework without the use of effective charges; for example with the proper evolution of the E2 operator, or alternatively, through the use of an appropriate and manageable subset of particle–hole excitations. We present a precise determination of E2 strength in 22Mg and its mirror 22Ne by Coulomb excitation, allowing for rigorous comparisons with theory. No-core symplectic shell-model calculations were performed and agree with the new <math><mi>B</mi><mo>(</mo><mi>E</mi><mn>2</mn><mo>)</mo></math> values while in-medium similarity-renormalization-group calculations consistently underpredict the absolute strength, with the missing strength found to have both isoscalar and isovector components. The discrepancy between two microscopic models demonstrates the sensitivity of E2 strength to the choice of many-body approximation employed.

S.R. Stroberg

K.D. Launey

J.D. Holt

M.A. Bentley

L.J. Evitts

R. Frederick

P.E. Garrett

B. Jigmeddorj

A.I. Kilic

J. Lassen

J. Measures

E. O'Sullivan

O. Paetkau

J. Park

R. Wadsworth

C.Y. Wu

Testing microscopically derived descriptions of nuclear collectivity: Coulomb excitation of Mg