Direct reactions with the AT-TPC

Yassid Ayyad ^1* Daniel Bazin ^2,3 Francesca Bonaiti ^2,4 Jie Chen ⁵ Xiaobin Li ⁵ Tan Ahn ⁶ Adam Anthony ⁷ Melina Avila ⁸ Saul Beceiro ⁹ Khushi Bhatt ⁸ Cristina Cabo ¹ Tatsuya Furuno ¹⁰ Valdir Guimaraes ¹¹ Alex Hall-Smith ⁸ Curtis Hunt ² Heshani Jayatissa ⁸ Takahiro Kawabata ¹⁰ Harriet Kumi ⁹ Jose Manuel López-González ¹ Juan Lois-Fuentes ² Augusto Macchiavelli ⁴ Gordon Mccann ² Claus MÜller-Gatermann ⁸ Alicia MuÑoz-Ramos ¹ Wolfgang Mittig ^2,3 Bruno Olaizola ¹² Zarif Rahman ^2,3 Daniel Regueira ¹ Javier Rufino ⁶ Soki Sakajo ¹⁰ Clementine Santamaria ² Michael Z Serikow ^2,3 Tianxudong Tang ^2,3 Ivan Tolstukhin ⁸ Nathan Turi ^2,3 Nathan Watwood ⁸ Juan Zamora ²

• ¹ University of Santiago de Compostela, Santiago de Compostela, Spain
• ² Facility for Rare Isotope Beams, Michigan State University, East Lansing, Michigan, United States
• ³ Michigan State University, East Lansing, Michigan, United States
• ⁴ Physics Division, Oak Ridge National Laboratory (DOE), Oak Ridge, Tennessee, United States
• ⁵ Southern University of Science and Technology, Shenzhen, Guangdong Province, China
• ⁶ University of Notre Dame, Notre Dame, Indiana, United States
• ⁷ High Point University, High Point, North Carolina, United States
• ⁸ Argonne National Laboratory (DOE), Lemont, Illinois, United States
• ⁹ University of A Coruña, A Coruña, Spain
• ¹⁰ Osaka University, Suita, Ōsaka, Japan
• ¹¹ Instituto de Física, Universidade de São Paulo, Sao Paulo, Brazil
• ¹² Consejo Superior de Investigaciones Científicas, Madrid, Spain

Direct reactions are crucial tools for accessing properties of the atomic nucleus. Fundamental and exotic phenomena such as collective modes, pairing, weak-binding effects and evolution of single-particles energies can be investigated in peripheral collisions between a heavy nucleus and a light target. The necessity of using inverse kinematics to reveal how these structural properties change with isospin imbalance renders direct reactions a challenging technique when using 1 Y. Ayyad et al.the missing mass method. In this scenario, Active Target Time Projection Chambers (AT-TPC) have demonstrated an outstanding performance in enabling these types of reactions even under conditions of very low beam intensities.The AT-TPC of the Facility for Rare Isotope Beams (FRIB) is a next-generation multipurpose Active Target. When operated inside a solenoidal magnet, direct reactions benefit from the measurement of the magnetic rigidity that enables particle identification and the determination of the excitation energy with high resolution without the need of auxiliary detectors. Additionally, the AT-TPC can be coupled to a magnetic spectrometer improving even further its spectroscopic investigation capability. In this contribution, we discuss inelastic scattering and transfer reaction data obtained via the AT-TPC and compare them to theory. In particular, we present the results for the 14 C(p,p') and 12 Be(p,d) 11 Be reactions. For 14 C, we compare the experimental excitation energy of the first 1 -excited state with coupled-cluster calculations based on nuclear interactions from chiral effective field theory and with available shell-model predictions. For 12 Be, we determine the theoretical spectroscopic factors of the 12 Be(p,d) 11 Be transfer reaction in the shell model and compare them to the experimental excitation spectrum from a qualitative standpoint.