Colóquios Agendados

Creation of Matter in the Nucleus of the Atom: neutrinoless double-beta decay and the nature of the neutrino | Colóquio IFUSP

Data de Início: 
Thursday, 17 September, 2026 - 16:00
Palestrante: 
Ubirajara van Kolck - ECT*, CNRS e University of Arizona
Local: 
Auditório Abrahão de Moraes
 

Sobre o evento:

At the highest experimental resolution achieved so far, matter consists of quarks (from which the constituents of the atomic nucleus, protons and neutrons, are made) and leptons (such as the electrons of the atom and the elusive neutrinos). Creation of matter has only been seen together with an equivalent amount of antimatter, for example in (single) beta decay where a neutron decays into a proton, an electron, and an antineutrino. Yet the universe seems to be made of much more matter than antimatter. Can matter be created without antimatter?

I will present the effective-field theoretical arguments that suggest the answer is yes, thanks to the rare process of neutrinoless double-beta decay, when two neutrons inside a heavy nucleus transform into two prótons and two electrons, without any antineutrinos. The interaction that gives rise to this process also endows neutrinos with a type of mass first proposed by Majorana 90 years ago. I will discuss the progress and remaining steps needed to reach the tremendously challenging goal of calculating the frequency of this decay and extracting neutrino properties once it is observed.

 

Minibiografia do palestrante: 

Ubirajara van Kolck is Director of the European Centre for Theoretical Studies in Nuclear Physics and Related Areas (ECT*), Directeur de recherche at Centre National de la Recherche Scientifique (CNRS), and Professor of Physics at the University of Arizona. Fellow of the American Physical Society, chair of the APS Group on Few-Body Physics, and member of Academia Europaea, among other honorary titles. Awarded with: Prix Paul Langevin de la Société Française de Physique (2015), Henry and Phyllis Koffler Prize in Research, Scholarship and Creative Activity of the University of Arizona (2019), Herman Feshbach Prize in Theoretical Nuclear Physics of the American Physical Society (2020).


Acessos:

  • Auditório Abrahão de Moraes
  • Transmissão pública: acompanhe pelo YouTube do IFUSP.

 

Multi-neutron clusters in neutron-rich nuclei | Colóquio IFUSP

Data de Início: 
Thursday, 24 September, 2026 - 16:00
Palestrante: 
Takashi Nakamura - Institute of Science (Tokyo)
Local: 
Auditório Abrahão de Moraes
 

Sobre o evento:

How do extremely neutron-rich nuclei behave at the limit of nuclear binding? The seminar addresses fundamental questions concerning nuclear structure, nuclear interactions, and multi-neutron correlations at and beyond the neutron drip line. The talk will focus on multi-neutron clustering, which is expected to become increasingly important in nuclei near the neutron drip line. After discussing some common features of cluster formation across different scales, from hadrons and nuclei to atoms and molecules [1], I will focus on neutron-rich nuclei. I will first discuss dineutron (2n) correlations [2], in which two neutrons develop a strong spatial correlation in the low-density surface region of a nucleus. I will show how such correlations can be probed through Coulomb breakup, illustrated by recent studies of 19B [3] and 22C. I will then present recent Coulomb-breakup results for 8He [4], where correlations among the four valence neutrons may play an important role in the nuclear surface. I will also discuss the observation of 28O [5], a candidate for a doubly magic nucleus, and possible four-neutron correlations in this extremely neutron-rich system. All the experimental results presented here were obtained using the large-acceptance, multi-purpose spectrometer SAMURAI at the RI-Beam factory (RIBF), RIKEN, Japan. Finally, I will introduce the recent development of a new-generation neutron detector array, NEOLITH, designed to explore multi-neutron correlations and clustering near and beyond the neutron drip line.

References:
[1] T. Nakamura et al., Eur. Phys. J. A 61:273 (2025).
[2] T. Nakamura, K. Hagino, Y.Kondo, Eur. Phys. J. A 62:144 (2026).
[3] K.J. Cook et al., Phys. Rev. Lett. 124, 212503 (2020).
[4] C. Lehr et al., Phys. Rev. Lett. 136, 172501 (2026).
[5] Y. Kondo et al., Nature 620, 965-970 (2023).

 

Minibiografia do palestrante: 

Takashi Nakamura received his Doctor of Science degree from the University of Tokyo in 1996. Following research appointments at RIKEN, the University of Tokyo, and Michigan State University, he joined the Department of Physics at Tokyo Institute of Technology as an Associate Professor and was promoted to Full Professor in 2008. In 2024, Tokyo Institute of Technology merged with Tokyo Medical and Dental University to form Institute of Science Tokyo. His research expertise lies in experimental nuclear physics, with a particular focus on the structure of extremely neutron-rich nuclei near and beyond the neutron drip line. He played a central leadership role in the SAMURAI collaboration at RIBF, serving as Chair of the SAMURAI Collaboration Board from 2012 to 2023. His current research interests include the development of NEOLITH, a next-generation neutron detector array aimed at exploring multi-neutron systems beyond the neutron drip line.


Acessos:

  • Auditório Abrahão de Moraes
  • Transmissão pública: acompanhe pelo YouTube do IFUSP.

 

Desenvolvido por IFUSP