40Ca(alpha, gamma)44Ti reaction in the energy regime of supernova nucleosynthesis.
The 44Ti(t1/2=59 yr) nuclide, an important signature of supernova nucleosynthesis, has recently been observed as live radioactivity by gamma-ray astronomy from the Cas A remnant. We investigate in the laboratory the major 44Ti production reaction 40Ca(alpha, gamma)44Ti (Ec.m. approximately 0.6-1.2 MeV/u by direct off-line counting of 44Ti nuclei. The yield, significantly higher than inferred from previous experiments, is analyzed in terms of a statistical model using microscopic nuclear inputs. The associated stellar rate has important astrophysical consequences, increasing the calculated supernova 44Ti yield by a factor approximately 2 over previous estimates and bringing it closer to Cas A observations.
Racah Institute of Physics, Hebrew University, 91904 Jerusalem, Israel.
H
H
Nassar
M
M
Paul
I
I
Ahmad
Y
Y
Ben-Dov
J
J
Caggiano
S
S
Ghelberg
S
S
Goriely
J P
JP
Greene
M
M
Hass
A
A
Heger
A
A
Heinz
D J
DJ
Henderson
R V F
RV
Janssens
C L
CL
Jiang
Y
Y
Kashiv
B S
BS
Nara Singh
A
A
Ofan
R C
RC
Pardo
T
T
Pennington
K E
KE
Rehm
G
G
Savard
R
R
Scott
R
R
Vondrasek