arXiv subjects

M. DeNudt

Publications and source records attributed to M. DeNudt.

4 recordsLinked to original sources

arXiv2026

Spectroscopy of $^{11}$Be from the $^{10}$Be($d,p$) reaction measured in inverse kinematics by the AT-TPC in SOLARIS

The spectroscopy of $^{11}$Be is explored using the $^{10}$Be$(d,p)$$^{11}$Be transfer reaction performed in inverse kinematics at $9.6\,\MeV/u$ using the Active Target Time Projection Chamber (AT-TPC) inside the SOLARIS solenoid. This experiment is the first attempt at coupling the AT-TPC with SOLARIS to perform a high luminosity transfer reaction measurement without compromising excitation energy and scattering angle resolutions. The angular momentum transfer for states up to $3.40\,\MeV$ are determined from distorted-wave Born approximation analysis of the measured angular distributions, from which the corresponding spectroscopic factors are deduced. These factors are compared with those from various shell model interactions, and those for the $3.40\,\MeV$ state are consistent with a positive parity assignment. Recent \textit{ab initio} no-core configuration interaction (NCCI) calculations with various nucleon-nucleon interactions are presented for the low-lying positive parity states of $^{11}$Be. The excitation energies produced using the Daejeon16 interaction are in good agreement with those found from both this experiment and the literature, thus supporting a positive parity assignment. The $3.40\,\MeV$ state, if assigned a tentative $J^\pi=3/2^+$, would then correspond to the second excited state of the $K^P=1/2^+$ one-neutron halo ground state rotational band also predicted from such NCCI calculations.

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arXiv2025

Near-threshold dipole strength in {^{10}}Be with isoscalar character

Isoscalar dipole transitions are a distinctive fingerprint of cluster structures. A {1^-} resonance at 7.27(10) MeV, located just below the {\alpha}-emission threshold, has been observed in the deuteron inelastic scattering reactions off 10Be. The deformation lengths of the excited states in 10Be below 9 MeV have been inferred from the differential cross sections using coupled channel calculations. This observed {1^-} resonance has isoscalar characteristics and exhausts approximately 5{\%}-15{\%} of the isoscalar dipole energy-weighted sum rule, providing evidence for pronounced {\alpha} cluster structure in 10Be. The Gamow coupled channel approach supports this interpretation and suggests the near-threshold effect might be playing an important role in this excitation energy domain. The {\alpha}+{\alpha}+n+n four-body calculation reproduces the observed enhanced dipole strength, implying that the four-body cluster structure is essential to describe the {1^-} states in 10Be.

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arXiv2022

Simulations and analysis tools for charge-exchange $(d,{}^{2}\text{He})$ reactions in inverse kinematics with the AT-TPC

Charge-exchange $(d,{}^{2}\text{He})$ reactions in inverse kinematics at intermediate energies are a very promising method to investigate the Gamow-Teller transition strength in unstable nuclei. A simulation and analysis software based on the $\rm{\scriptsize ATTPCROOT}$ package was developed to study these type of reactions with the active-target time projection chamber (AT-TPC). The simulation routines provide a realistic detector response that can be used to understand and benchmark experimental data. Analysis tools and correction routines can be developed and tested from simulations in $\rm{\scriptsize ATTPCROOT}$, because they are processed in the same way as the real data. In particular, we study the feasibility of using coincidences with beam-like particles to unambiguously identify the $(d,{}^{2}\text{He})$ reaction channel, and to develop a kinematic fitting routine for future applications. More technically, the impact of space-charge effects in the track reconstruction, and a possible correction method are investigated in detail. This analysis and simulation package constitutes an essential part of the software development for the fast-beams program with the AT-TPC.

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arXiv2022

$β^{+}$ Gamow-Teller strengths from unstable $^{14}$O via the $(d,{}^2\text{He})$ reaction in inverse kinematics

For the first time, the $(d,{}^2\text{He})$ reaction was successfully used in inverse kinematics to extract the Gamow-Teller transition strength in the $β^{+}$ direction from an unstable nucleus. The nucleus studied was $^{14}$O, and the Gamow-Teller transition strength to $^{14}$N was extracted up to an excitation energy of 22 MeV. The measurement of the $(d,{}^2\text{He})$ reaction in inverse kinematics was made possible by the combination of an active target time projection chamber and a magnetic spectrometer. The data were used to test shell-model and state-of-the-art coupled cluster calculations. Shell-model calculations reproduce the measured Gamow-Teller strength distribution up to about 15 MeV reasonably well, after the application of a phenomenological quenching factor. Coupled-cluster calculation reproduces the full strength distribution well without such quenching, owing to the large model space, the inclusion of strong correlations, and the coupling of the weak interaction to two nucleons through two-body currents. This indicates that such calculations provide a very promising path for answering long-standing questions about the observed quenching of Gamow-Teller strengths in nuclei.

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