79 research outputs found
A Fast Universal Kinematic Fitting Code for Low-Energy Nuclear Physics: FUNKI_FIT
We present an open-source kinematic fitting routine designed for low-energy nuclear
physics applications. Although kinematic fitting is commonly used in high-energy particle physics,
it is rarely used in low-energy nuclear physics, despite its effectiveness. A FORTRAN and ROOT C++
version of the FUNKI_FIT kinematic fitting code have been developed and published open access.
The FUNKI_FIT code is universal in the sense that the constraint equations can be easily modified
to suit different experimental set-ups and reactions. Two case studies for the use of this code,
utilising experimental and Monte–Carlo data, are presented: (1) charged-particle spectroscopy using
silicon-strip detectors; (2) charged-particle spectroscopy using active target detectors. The kinematic
fitting routine provides an improvement in resolution in both cases, demonstrating, for the first time,
the applicability of kinematic fitting across a range of nuclear physics applications. The ROOT macro
has been developed in order to easily apply this technique in standard data analysis routines used by
the nuclear physics community
A Fast Universal Kinematic Fitting Code for Low-Energy Nuclear Physics: FUNKI_FIT
We present an open-source kinematic fitting routine designed for low-energy nuclear
physics applications. Although kinematic fitting is commonly used in high-energy particle physics,
it is rarely used in low-energy nuclear physics, despite its effectiveness. A FORTRAN and ROOT C++
version of the FUNKI_FIT kinematic fitting code have been developed and published open access.
The FUNKI_FIT code is universal in the sense that the constraint equations can be easily modified
to suit different experimental set-ups and reactions. Two case studies for the use of this code,
utilising experimental and Monte–Carlo data, are presented: (1) charged-particle spectroscopy using
silicon-strip detectors; (2) charged-particle spectroscopy using active target detectors. The kinematic
fitting routine provides an improvement in resolution in both cases, demonstrating, for the first time,
the applicability of kinematic fitting across a range of nuclear physics applications. The ROOT macro
has been developed in order to easily apply this technique in standard data analysis routines used by
the nuclear physics community
Structure of 10N in 9C+p resonance scattering
The structure of exotic nucleus 10N was studied using 9C+p resonance
scattering. Two L=0 resonances were found to be the lowest states in 10N. The
ground state of 10N is unbound with respect to proton decay by 2.2(2) or 1.9(2)
MeV depending on the 2- or 1- spin-parity assignment, and the first excited
state is unbound by 2.8(2) MeV.Comment: 6 pages, 4 figures, 1 table, submitted to Phys. Lett.
Nuclear structure beyond the neutron drip line: the lowest energy states in He via their T=5/2 isobaric analogs in Li
The level structure of the very neutron rich and unbound He nucleus has
been the subject of significant experimental and theoretical study. Many recent
works have claimed that the two lowest energy He states exist with spins
and and widths on the order of hundreds of keV.
These findings cannot be reconciled with our contemporary understanding of
nuclear structure. The present work is the first high-resolution study with low
statistical uncertainty of the relevant excitation energy range in the
He system, performed via a search for the T=5/2 isobaric analog states
in Li populated through He+p elastic scattering. The present data show
no indication of any narrow structures. Instead, we find evidence for a broad
state in He located approximately 3 MeV above the neutron
decay threshold
-cluster ANCs for nuclear astrophysics
Background. Many important -particle induced reactions for nuclear
astrophysics may only be measured using indirect techniques due to small cross
sections at the energy of interest. One of such indirect technique, is to
determine the Asymptotic Normalization Coefficients (ANC) for near threshold
resonances extracted from sub-Coulomb -transfer reactions. This
approach provides a very valuable tool for studies of astrophysically important
reaction rates since the results are practically model independent. However,
the validity of the method has not been directly verified.
Purpose. The aim of this letter is to verify the technique using the
O(Li,)Ne reaction as a benchmark. The Ne nucleus
has a well known state at excitation energy of 5.79 MeV with a width of
28 eV. Reproducing the known value with this technique is an ideal opportunity
to verify the method.
Method. The 1 state at 5.79 MeV is studied using the -transfer
reaction O(Li,)Ne at sub-Coulomb energies.
Results. The partial width for the state at excitation energy
of 5.79 MeV is extracted and compared with the known value, allowing the
accuracy of the method to be evaluated.
Conclusions. This study demonstrates that extracting the Asymptotic
Normalization Coefficients using sub-Coulomb -transfer reactions is a
powerful tool that can be used to determine the partial width of near
threshold states that may dominate astrophysically important nuclear reaction
rates. \end{description
Erratum: Measurement of d+ Be 7 cross sections for big-bang nucleosynthesis (Physical Review Letters (2019) 122 (182701) DOI: 10.1103/PhysRevLett.122.182701)
The cross sections of nuclear reactions between the radioisotope Be7 and deuterium, a possible mechanism of reducing the production of mass-7 nuclides in big-bang nucleosynthesis, were measured at center-of-mass energies between 0.2 and 1.5 MeV. The measured cross sections are dominated by the (d,a) reaction channel, towards which prior experiments were mostly insensitive. A new resonance at 0.36(5) MeV with a strength of ωγ=1.7(5) keV was observed inside the relevant Gamow window. Calculations of nucleosynthesis outcomes based on the experimental cross section show that the resonance reduces the predicted abundance of primordial Li7, but not sufficiently to solve the primordial lithium problem. (Figure Presented)
Measurement of Be cross sections for Big-Bang nucleosynthesis
The cross sections of nuclear reactions between the radioisotope Be and
deuterium, a possible mechanism of reducing the production of mass-7 nuclides
in Big-Bang nucleosynthesis, were measured at center-of-mass energies between
0.2 MeV and 1.5 MeV. The measured cross sections are dominated by the
reaction channel, towards which prior experiments were mostly
insensitive. A new resonance at 0.36(5)~MeV with a strength of =
1.7(5)~keV was observed inside the relevant Gamow window. Calculations of
nucleosynthesis outcomes based on the experimental cross section show that the
resonance reduces the predicted abundance of primordial Li, but not
sufficiently to solve the primordial lithium problem.Comment: 6 pages, 6 figure
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