Why our Universe was bone and how it developed into the present state?
Since its birth at the Big Bang, the Universe has experienced various drastic events.
Because the Universe is not a stable object, we have to understand and explain the present state as a consequence of dynamical processes the Universe has experienced.
Though many events in the History of the Universe have been clarified, many pieces are still missing to understand our Universe today.
Toward this goal, the center has established the following four research divisions:
- 2023/12/18 TCHoU Research Member Meeting / Activity and Achievement Reports
We have a research workshop to share achievements, exchanging activities and future projects for all members of TCHoU.
Details will be announced soon.
- Date: 27 June 2023 (mon) 9:00-17:00
- Venue: B114, Natural Science Bldg. B, Univ. Tsukuba
Contact: Prof. S. Esumi/p>
- 2023/11/29 HoU seminar
- Date: Nov. 29, 2023 (wed) 13:30-14:30
- Venue: B118, Natural Sci. Bldg. B, Univ. Tsukuba
- Speaker: Baltasar Vila-Vilaro (ALMA Observatory)
- Title1: "Properties of the ISM of Spiral Galaxies along the Hubble Sequence"
- The properties of the atomic and molecular ISM of normal spiral galaxies along the Hubble sequence will be reviewed. Special emphasis will be placed on trends of some specific tracers of the molecular ISM as a function of Hubble type, and their implications. Results of several recent single-dish surveys of the molecular ISM in nearby spiral galaxies will be presented.
Contact: Assi.Prof. T. Iida
- 2023/11/21 HoU seminar
- Date: Nov. 21, 2023 (tue) 16:00-17:00
- Venue: 1F201, Bldg. 1F of Area 1, Univ. Tsukuba
- Speaker: Prof. Dr. Qiye Shou (Fudan University)
- Title: "Recent activities of the ALICE Shanghai group"
- Joining the LHC-ALICE experiment since 2019, Fudan University (Shanghai group) is one of the four institutes in China. Our current physics interests are primarily on the study of exotic phenomena and matters. In this talk, first I'll generally introduce the group, and then summarize some of the research highlights we have achieved in recent years, including the charge dependent correlations, femtoscopic correlations, and the study of the hypertriton. The future plans to contribute to ALICE and promote collaborations with international colleagues will be discussed as well.
Qiye Shou is a tenured associate professor at Fudan University. He received his Doctor of Science degree in 2015 from the Shanghai Institute of Applied Physics (SINAP). After completing the postdoctoral research at CCNU and serving as an assistant professor at SINAP, he joined Fudan University in 2019. His primary research focuses on heavy-ion collisions, studying the properties of the Quark-Gluon Plasma (QGP), such as anomalous chiral effects, collectivity and exotic particles. He has previously worked on the RHIC-STAR experiment and currently works on the LHC-ALICE, serving as the (deputy) leader of the ALICE Shanghai group, the flow PAG coordinator and the contact person of the China T2 cluster.
Contact: Prof. S. Esumi
- 2023/11/17 HoU seminar
- Date: Nov. 17, 2023 (fri) 13:15-15:00
- Venue: B118, Natural Sci. Bldg. B, Univ. Tsukuba
- Speaker1: Katsuro Nakamura (KEK, Inst. Particle and Nuclear Studies)
- Title1: "Exploring New Physics at the Belle II experiment"
- One of the main goals of the Belle II experiment is to explore new physics beyond the Standard Model of particle physics. The Belle II experiment started full-scale data acquisition 2019 and has already collected 424fb^-1 of data, which have been used for the study of the decays of B mesons, D mesons, tau leptons and the search for the dark sector. This presentation will provide an overview of the Belle II experiment, covering the performance of the detectors and data acquisition, as well as presenting the latest analysis results.
- Speaker2: Takashi Mori (KEK, Accelerator Laboratory)
- Title2: "Challenges of unprecedented beam collision performance with SuperKEKB accelerator"
- SuperKEKB is a collider with a circumference of 3 km, located 11 meters below the ground level. Electrons and positrons are accelerated to the energies of 7 billion and 4 billion electron volts, respectively, in a linear accelerator and they are injected into two circular rings in opposite directions. A figure of merit for accelerator performance is described by “luminosity” (L), the collision frequency of particles. The KEKB accelerator, the accelerator that preceded SuperKEKB, reached the world record of L=2.11×1034cm-2s-1, and the target L of SuperKEKB is 6×1035cm-2s-1. To reach the target value, “nano-beam scheme” was adopted to SuperKEKB for the first time in the world in addition to the beam current increase in design, and extreme fine beam operation has been being performed. In this seminar, we will introduce the general features of SuperKEKB first, and then describe the individual accelerator components and challenges. Furthermore, we will talk about the prospects of the SuperKEKB upgrade.
- Number of participants:about 20

Contact: Assi.Prof. T. Iida
- 2023/11/4-5 Exibition at Campus Festival "Soho-Sai" of Univ. of Tsukuba
An exposition introducing the research activities of the Tomonaga Center was made at the Campus Festival "So-Ho Sai" of the Univ. of Tsukuba.
- Date: 4(Sun)-5(Mon) Nov 2023
- Venue: 3B401, Univ. Tsukuba
- Thema: "Clarification of the History of Universe"
- 2023/10/14 T. Omori received Student Presentation Award of the Physical Society of Japan
Master Course student Takumi Omori, supervised by Assi.Prof. T. Iida (Div. of Elementary Particles), received the Student Presentation Award of the Physical Society of Japan for his presentation at the 78th annual meeting of JPS at Sendai.
- "Double Beta Decay Search for Gd-160 by PIKACHU Experiment 5 - Development and performance evaluation of the high purity GAGG crystal for PIKACHU experiment -"
See also TSUKUBA JOURNAL of the Univ. Tsukuba.
- 2023/09/29 HoU seminar
- Date: Sept. 29, 2023 (fri) 13:45-15:15
- Venue: B114, Natural Sci. Bldg. B, Univ. Tsukuba
- Speaker: Sotaro Kanda (KEK)
- Title: "Precise measurements using muons: from spectroscopy to interferometry"
- The muon is a subatomic particle classified as a second-generation charged lepton, possessing the same charge, -e, and spin 1/2 as an electron. It is 200 times heavier than an electron and is an unstable particle decaying with an average lifetime of 2.2 microseconds. While it is applied as a local magnetic probe in materials and life science, its intrinsic properties are an intriguing subject of particle physics. In pursuing physics beyond the Standard Model, precise measurements and searches of rare processes involving muons have yielded important results. A significant factor behind this is the improvement in beam intensity due to advancements in accelerator technology. The pulsed muon beam at J-PARC MLF MUSE achieves the world's highest intensity, enabling numerous experiments previously deemed challenging. Precision measurements using a high-intensity pulsed beam require improvement in particle detectors and beam cooling techniques. This talk will discuss muon precision measurements using high-intensity beams, specifically the spectroscopy of atomic systems involving muons, a new measurement of the muon lifetime, and muonium interferometry with beam cooling.
- Number of participants:about 20

Contact: Assi.Prof. T. Iida
- 2023/09/28 Tomonaga Center Intanational Workshop "Origin and Evolution of the Universe, Matter and Life"
The international workshops was held as an event commemorating the 50th anniversary of University of Tsukuba. In addition to introducing the activities of the center, we invited people who are active in related fields in Japan and overseas to give lectures.
- Date: Sept. 28, 2023 (thu) 09:30-17:00
- Venue: International Conference Room, University Hall, University of Tsukuba
- URL: https://hep-www.px.tsukuba.ac.jp/TCHoU/symposium2023/
- Program: (Click on the title for presentation slides.)
- Number of participants: 47


Contact: Prof. N. Kuno
- 2023/09/20 Assi. Prof. Hashimoto made a press release on the most distant cluster of primordial galaxies
Assistant Professor Takuya Hashimoto (Division of the Antarctic Astronomy) held a press conference ”The Strongest Tag Team of the James Webb Space Telescope and ALMA Telescope Succeeded in Capturing the Most Distant Cluster of Primordial Galaxies” at the 2023 Fall Meeting of the Astronomical Society of Japan.
For more details, see the press release article and a web announcement of the Univ. of Tsukuba.
- 2023/08/08 N. Suzuki received Excellent Poster Award of SMART2023
Doctor Course student Naoki Suzuki, supervised by Assi.Prof. T. Iida (Div. of Elementary Particles), received the Excellent Poster Award at SMART2023, in which developments and applications of radiation detectors are discussed.
See also TSUKUBA JOURNAL of the Univ. Tsukuba.
- 2023/08/03 HoU seminar
- Date: Aug. 3, 2023 (thu) 15:15-16:30
- Venue: B114, Natural Sci. Bldg. B, Univ. Tsukuba
- Speaker: Masao YOSHINO (Tohoku Univ.)
- Title: "Radiation detectors and radiation imaging using single-crystal scintillators"
- Scintillators convert radiation into UV to visible light. They play an essential role as sensor heads in radiation detectors in underground particle experiments and in the field of high-energy physics. This talk focuses in particular on inorganic scintillator single crystals, such as oxides and halides, and describes the scintillation properties imparted by their crystal growth methods and growth processes. Furthermore, the latest trends in scintillation detectors in recent years will be discussed.
- Number of participants: about 20

Contact: Assi.Prof. T. Iida
- 2023/07/08 Tanabata Lecture of Astronomy
Lectures by astronomers will be held near Tanabata Day. The state-of-the-art research content will be explained in an easy-to-understand manner to the general public. (in Japanese)
Click on the poster for details.
- Date: 9 July 13:30-16:30
- Venue: Tsukuba International Congress Center EPOCHAL, Conference room 101
- Program:
13:30- | |
Toshiki Saito | (National Astronomical Observatory of Japan) |
All galaxies are a lion at home and a mouse abroad ~The true appearance of the galaxy revealed by large radio telescope~ |
15:00- | |
Hidenobu Yajima | (Univ. Tsukuba) |
Histroy of universe approaching with super computer |
16:30 | |
| End |
|
- Target: General public (junior high school students and above)
- Participation fee: Free (max. 130 people)
Contact: Prof. N. Kuno (TEL: 029-853-5080, e-mail: kuno.nario.gt [at] u.tsukuba.ac.jp)
- 2023/07/06 Assi.Prof. Iida received "2023 Japan Isotope Association Incentive Award"
As announced by our news of 2023/03/03, Takashi Iida, Assistant Professor at TCHoU, received the 2023 Japan Isotope Association Incentive Award on 6 July at the 60th meeting of the Japan Isotope Association for his contribution to the advancement of particle science through the development of detection methods for weak radiation.
Title: "Advancement of Detection System for the Study of Extremely Rare Decays of 48Ca"

See also TSUKUBA JOURNAL of the Univ. Tsukuba.
- 2023/06/27 TCHoU Research Member Meeting / Activity and Achievement Reports
We have a research workshop to share achievements, exchanging activities and future projects for all members of TCHoU.
- Date: 27 June 2023 (Tu) 9:30-17:30
- Venue: Natural Science Bldg. B114 (morning) / Sogo-B Bldg. B0110 (afternoon)
- Program: (presentations are given mostly in Japanese)
09:30-10:15 | |
KUNO, Nario | |
Report of activities of TCHoU |
Hereafter, presentations are open for public. |
10:30-11:00 | |
IIDA, Takashi | |
Double beta decay search for 160Gd by the PIKACHU experiment |
11:00-11:30 | |
AKIYAMA, Shinichiro | |
Critical endpoint of (3+1)-dimensional finite density Z3 gauge-Higgs model with tensor renormalization group |
11:30-12:00 | |
SHIBATA, Kazuki | |
Relationship between gas dynamics and star formation activity in barred spiral galaxies |
12:00-13:00 | |
| |
lunch |
13:00-13:30 | |
SUZUKI, Hisanori | |
TCAD simulation studies of radiation damage to the ATLAS SCT detector |
13:30-14:00 | |
ANDO, Yuji | |
Recent developments of string field theory |
14:00-14:30 | |
OKUBO, Kosuke | |
RHIC Beam Energy Scan and Vorticity |
14:30-15:00 | |
MAWATARI, Ken | |
Challenge to the Most Distant Evolved Galaxies: Hint on Star- Formation Activity during the First 500 Million Years of the Cosmic History |
15:00-15:20 | |
| |
break |
15:20-15:50 | |
GUERNANE, Rachid | (Grenoble) |
ALICE upgrades for LHC Run 4 and beyond |
15:50-16:20 | |
SATO, Koji | |
Recent Results from the ATLAS Experiment |
16:20-16:50 | |
OHNISHI, Tetsuya | (RIKEN) |
Current status of large scale experiments at RIBF towards nuclear synthesis |
16:50-17:20 | |
TSUNETOE, Yuh | (CCS) |
Investigating the Accretion Disk-Jet Structure around a Supermassive Black Hole through Polarization Images |
17:20-17:35 | |
UKEGAWA,Fumihiko | |
Closing remarks |
18:00- | |
| |
Banquet @ 1A cafeteria TSUKUBA TABLE |
- Click on the title for presentation slides.


- Number of participants: about 30
Contact: Prof. N. Kuno
- 2023/05/27 Open lecture "History of the Universe"
We explained the history of the universe of 13.8 billion years for high school students. We also introduced the research being conducted at the Tomonaga Center, University of Tsukuba.
- Date: 27, 28 May 2023
- Venue: 7A105, Kasuga campus, University of Tsukuba
- Program:
27 May (Sat) | |
| |
|
13:30-14:30 | |
Prof. K. Ohsuga | |
Evolution of universe and black hole |
14:45-15:45 | |
Prof. F. Ukegawa | |
Elementary particle mass and Higgs boson |
16:00-17:00 | |
Asso.Prof. Y. Takeuchi | |
Challenge to cosmic neutrinos |
28 May (Sun) | |
| |
|
13:30-14:30 | |
Prof. S. Esumi | |
QGP phase transition in the early universe |
14:45-15:45 | |
Prof. N. Kuno | |
Birth and evolution of stars and galaxies |
- Number of participants: 32

Contact: Prof. N. Kuno
- 2023/05/20 The member list was updated.
- 2023/05/12 HoU seminar
- Date: May 12, 2023 (fri) 13:45-15:00
- Venue: B118, Natural Sci. Bldg. B, Univ. Tsukuba
- Speaker: Takasumi MARUYAMA (KEK)
- Title: "Search for a new neutrino oscillation with a short baseline"
- Since the 1990s, the existence of neutrinos which cannot be explained by the Standard Model (sterile neutrinos) has been indicated. This indication originated from an experiment conducted in the United States called LSND, which claimed to have observed neutrino oscillations at short distances that cannot occur through standard neutrino oscillations. However, for these 20 years, no definitive results have been obtained regarding the existence of these neutrinos.
- Under these circumstances, the JSNS2 experiment being conducted at the J-PARC Materials and Life Science Experimental Facility in Ibaraki Prefecture aims to directly test LSND's observations without any excuses. The experiment has already collected data during the long-term physics runs in 2021 and 2022, and this presentation will report the progress of the data collection, calibration, and analysis. Additionally, the physics of neutrinos other than sterile neutrino searches and their analysis status will also be presented in this talk. Furthermore, as the next upgrade, a new far detector is being built at twice the distance of the current detector in the MLF outdoor area, and its progress will also be introduced.

- Number of participants: 24
Contact: Asso.Prof. Y. Takeuchi
- 2023/04/29-30 International Workshop on Highly Baryonic Matter at RHIC-BES and Future Facilities --- beyond the Critical Point towards Neutron Stars --- (WHBM 2023)
- Date: 29-30 Apr 2023
- Venue: Rooms 1D201, 1D204, Building 1D, Univ.Tsukuba
- URL: https://conference-indico.kek.jp/event/205/
- Contact: whbm2023-loc _AT_ ml.cc.tsukuba.ac.jp
- Workshop on Highly Baryonic Matter at RHIC-BES and Future Facilities --- beyond the Critical Point towards Neutron Stars --- (WHBM 2023) will take place in Univ. of Tsukuba at Tsukuba, Ibaraki as a satellite conference of ATHIC2023, focused specially on High Density Physics topics covering Critical Point, QCD Phase Diagram, Flow, Correlations, Fluctuations, Chirality, Vorticity, Hadron interactions, Hypernuclei, Equation of State and Neutron Stars.
Contact: Prof. S. Esumi
- 2023/04/24-27 The 9th Asian Triangle Heavy-Ion Conference (ATHIC 2023)
- Date: 24-27 Apr 2023
- Venue: JMS Aster Plaza, 4-17 Kakomachi, Naka-ku, Hiroshima, Japan
- URL: https://indico.cern.ch/event/1176274/
- Contact: athic23-loc _AT_ ml.hiroshima-u.ac.jp
- The 9th Asian Triangle Heavy-Ion Conference (ATHIC 2023) will be held in Hiroshima for high energy heavy-ion physics to investigate and discuss Quark Gluon Plasma, especially on Initial state and thermal equilibrium, Jets and medium response, Heavy quarks and quarkonia, Electromagnetic probes, Collective dynamics, Correlations and fluctuations, QCD phase diagram and extreme states, QGP in small systems, Intense field and vorticity, Hadron interactions and exotics.
- 2023/03/24 Ryota Ura received the Dean's Award of the Graduate School of Pure and Applied Sciences, Univ. of Tsukuba
A master student, Ryota Ura, supervised by Assistant Professor Takuya Hashimoto (Division of the Antarctic Astronomy), received the Dean's Award of the Graduate School of Pure and Applied Sciences at the degree conferment ceremony in 2022. His research results were published by Astrophysical Journal.
- 2023/03/17 Workshop on Photon and Particle Detectors
Workshop on Photon and Particle Detectors of AY2022, organized by the Photon and Particle Detectors Division of TCHoU, will be held. The workshop will be on-site (recommended) with a zoom connection available.
- Date: March 17 (Fri), 2023 13:00-16:00
- Venue: Room B118, Natural Sci. Bldg. B, Univ. Tsukuba
- Program:
- Number of participants: 32 (including 10 remote participants)

The symposium counted in total 32 participants (including 10 remote participants) and nine talks were presented from the nuclear experiment, astronomy and particle experiment groups. The discussions were active prolonging the scheduled symposium time by nearly one hour. For the participant from abroad, the presentations were conducted in English. Although the students had sometime difficulties in explanation, the symposium should have been a good experience for them, and the symposium itself was very fruitful.
Contact: Asso.Prof. K. Hara
- 2023/03/16 Workshop by the Division of Elementary Particles
TCHoU Workshop of AY 2022 on Particle Physics, organized by the Division of Elementary Particles, is held as follows. This workshop is free to access.
- Date: March 16 (Fri), 2023 13:30-16:00
- Venue: zoom online
- Program:
Contact: Asso.Prof. Y. Takeuchi
- 2023/03/13-15 2nd International Workshop on Forward Physics and Forward Calorimeter Upgrade in ALICE
Following topics will be discussed at the workshop:
- Forward physics at high energy in pp, p-A, AA, e-p, e-A collisions/li>
- Initial condition of high energy heavy ion collisions at LHC and RHIC
- Thermalization mechanism, strong fields
- Small-x physics, gluon PDF, saturation and Color Glass Condensate (CGC)
- Forward detector upgrade using Si-W calorimeter and hadron calorimeter at LHC
- related detector technologies and upgrade projects in other fields
- Date: March 13-15, 2023
- Venue: Univ. Tsukuba
- URL: https://indico.cern.ch/event/1235107/
- Program: https://indico.cern.ch/event/1235107/timetable/#all.detailed
- Invited speakers (in alphabetical order):
-
Ian Gardner Bearden (University of Copenhagen)
Christophe De La Taille (OMEGA)
Hirotsugu Fujii (University of Tokyo)
Takahiro Fusayasu (Saga University)
Yuji Goto (RIKEN)
Tetsufumi Hirano (Sophia University)
Kensuke Homma (Hiroshima University)
Motoi Inaba (Tsukuba University of Technology)
Tommaso Isidori (University of Kansas)
Peter Martin Jacobs (Lawrence Berkeley National Lab.)
Minho Kim (RIKEN)
Youngil Kwon (Yonsei University)
Artur Lobanov (Hamburg University)
Hiroaki Menjo (Nagoya University)
Sanjib Muhuri (Department of Atomic Energy)
Takafumi Niida (University of Tsukuba)
Yasunori Osana (University of the Ryukyus)
Hidetoshi Otono (Kyushu University)
Ken Oyama (Nagasaki Inst. of Applied Science)
Thomas Peitzmann (Utrecht University, University of Tsukuba)
Dieter Roehrich (University of Bergen)
Taikan Suehara (Kyushu University)
Daniel Tapia Takaki (University of Kansas)
Ton Van Den Brink (Nikhef)
Marco Van Leeuwen (Nikhef, CERN, University of Tsukuba)
Kazuhiro Watanabe (Seikei University)
Contact: Asso.Prof. T. Chujo (LOC)
- 2023/03/24 HoU seminar
- Date: Mar. 8, 2023 (wed) 13:30-15:00
- Venue: B118, Natural Sci. Bldg. B, Univ. Tsukuba
- Speaker: Osamu TAJIMA (Kyoto University)
- Title: "CMB++"
- Observing “decoupled” objects is an experimental approach for understanding the begin of the universe as well as the origin of the matters. Cosmic microwave background (CMB) is the oldest light which we can detect, and its precise observations have given us knowledge about origin of the universe and matters. Improved measurements of the CMB polarization are currently hot research topic. In particular, it is expected that spatial patterns of the CMB polarization provides us a smoking-gun evidence for the cosmic inflation as well as new knowledge about the neutrino mass. In this seminar, I present status and prospects of ground-based CMB experiments: Simons Observatory and GroundBIRD.
- Dark matter is another decoupling object while we have not established its detection method yet. We recently started a unique project to explore light, i.e., low mass (0.05-0.1 meV/c^2), dark matter by using the technologies established in the CMB experiments. I will also present its recent results and ambitious ideas in future.
- Number of participants: about 20
Contact: Prof. F. Ukegawa
- 2023/03/03 Assi.Prof. Iida received "2023 Japan Isotope Association Incentive Award"
Takashi Iida, Assistant Professor at TCHoU, has received the 2023 Japan Isotope Association Incentive Award for his contribution to the advancement of particle science through the development of detection methods for weak radiation.
Title of the research achievement: "Advancement of Detection System for the Study of Extremely Rare Decays of 48Ca"
The award will be given during the 60th meeting of the Japan Isotope Association in July 2023.
- 2023/03/01 Assi.Prof. Iida received "2022 Konica Minolta Imaging Science Encouragement Award"
Takashi Iida in TCHoU received the 2022 Konica Minolta Imaging Science Encouragement Award in recognition of his research on a new scintillation detector for particle identification using wavelength information.

- 2023/02/24 HoU seminar
- Date: Feb. 24, 2023 (fri) 13:45-15:00
- Venue: B118, Natural Sci. Bldg. B, Univ. Tsukuba
- Speaker: Yoshikazu NAGAI (ELTE Univ., Hungary)
- Title: "Hadron Production Measurements for Neutrino Experiments at NA61/SHINE"
- In current measurements of accelerator-based neutrino experiments, neutrino flux uncertainties represent a leading systematic uncertainty. Neutrino beams are created from the decays of secondary hadrons produced in hadron-nucleus interactions. The leading source of flux uncertainty is the primary and secondary hadron production processes for neutrino beams. Therefore, precise hadron production measurements are essential.The neutrino program of the NA61/SPS Heavy Ion and Neutrino Experiment (NA61/SHINE) at CERN’s Super Proton Synchrotron makes measurements of hadron production.
- This talk will first present recent hadron production measurements for precise neutrino flux predictions needed by T2K and Fermilab long-baseline neutrino experiments. The talk will then review the performance of the latest collected data with the upgraded NA61/SHINE facility. Lastly, the talk will discuss the prospects for near future hadron production measurements in NA61/SHINE, including the possibility to extend the physics program to lower beamline energies.
Contact: Assi.Prof. T. Iida
- 2023/02/08 Press Release "Identification of Radiation Particles Using Information on the Wavelength of Scintillation Light"
A press release was issued on the results of "Research on a new particle identification method using the information on the wavelength of scintillation light emitted by scintillators", in which Assistant Professor Takashi Iida of TCHoU serves as a representative.
See press release document (in Japanese) for details.
- Visit [Archive] for previous news and announcements.