Principal Investigators

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Primordial Universe

Josquin Errard

Josquin Errard

Researcher

I am a researcher at CNRS working in observational cosmology at Laboratoire Astroparticule & Cosmologie in France. I am interested in understanding what happened in the first fraction of the first second of our Universe, as well as trying to figure out what is the fundamental nature of dark energy. Over the past decade, I have been focusing on developing, testing and applying novel data analysis tools to the current and upcoming generation of Cosmic Microwave Background (CMB) Polarization experiments. In particular, I have looked into the characterization, modeling and exploitation of mitigation techniques for instrumental and astrophysical systematic effects which are among the major limitations in the search for primordial (perhaps inflationary) gravitational waves.

I have also looked at late Universe physics such as the reconstruction and removal of gravitational lensing effects from CMB observations as well as the cross-correlation of CMB data with optical or spectroscopic measurements. I am involved in several major observational projects: POLARBEAR, POLARBEAR-2, the Simons Array, the Simons Observatory, CMB-S4, LiteBIRD, as well as the Rubin Observatory. These collaborations involve a lot of international expertise and several countries around the world, among which Japan and France play key roles.

Tomotake Matsumura

Tomotake Matsumura

Associate Professor

I am an experimental cosmologist. My research interest is to study the physics of early universe. The measurements of cosmic microwave background (CMB) polarization, so called B-mode, can provide the tools to probe the cosmic inflation experimentally. My project involvement spans over various platforms, i.e. ground-based, balloon-borne, and space-borne telescopes. Currently, I am involved to LiteBIRD and POLARBEAR/SimonsArray. My current focus is to lead the various efforts in LiteBIRD. Since the great success of WMAP and Planck, there had been no funded CMB polarization satellite proposal until recently.

LiteBIRD is now selected as the second ISAS/JAXA large class mission and the prospective launch is in late 2020s. I am one of the first members to put the LiteBIRD concept together and drive this effort since 2008. Currently, I am in charge of leading the studies for calibration, polarization modulator development, and simulation/analysis preparation for LiteBIRD and more. In particular, one of the current focus includes the instrumental development of a half-wave plate that covers a broad range of technologies, including broadband anti-reflection coating, cryogenic rotational mechanism using applied superconducting technologies, millimeter-wave characterization, superconducting detector and more. For anyone who wants to join this endeavor through ILANCE please feel free to contact me at tomotake.matsumura@ipmu.jp.

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Neutrinos

Masato Shiosawa

Masato Shiosawa

Professor

Professor Shiozawa started as a student at the University of Tokyo Institute for Cosmic Ray Research in 1992 and received his doctorate in the year 2000. He became assistant professor in 1995, then associate professor in 2004, and has been advancing the Super-Kamiokande and T2K experiment as well as leading efforts towards the future experiment, Hyper-Kamiokande, as full professor since 2014. He has been awarded the 2015 Yoji Totsuka prize together with Professor Kobayashi Takashi of KEK and Professor Tsuyoshi Nakaya of Kyoto University for the discovery of the appearance of electron neutrinos in a beam of muon neutrinos

Michel Gonin

Michel Gonin

Professor

My research focuses on themes related to the primordial cosmology of the Universe. I took part in two major discoveries, the production of quark-gluon plasma in heavy ion collisions and the observation of the phenomenon of the appearance of electron neutrinos in flavor oscillation. In april 2021, he was appointed visiting professor at the University of Tokyo and director of the ILANCE Laboratory.

I began my research career working on the mechanism of incomplete nuclear fusion before studying during my postdoctoral years in USA the temperature limits of hot nuclei. In 1990, I participated in a new heavy ion collision program at Brookhaven to produce some very dense nuclear matter like that of neutron stars. In 1995, I joined CERN’s NA50 experiment to produce a deconfined phase of quarks and gluons present in our primordial universe. From 2000 to 2009, I engaged my group in the characterization of the primordial plasma with the PHENIX experiment at the RHIC. In 2006, I took part in the construction phase of the T2K near detectors and measured the first muon neutrino beams delivered at the end of 2009, followed in 2013 by the appearance of electron neutrinos that paves the way for CP violation measurements. More recently, I joined in 2016 with my group in France the Super-Kamiokande experiment for a original and ambitious cosmology program thanks to the addition of gadolinium in the water tank.

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The Dark Universe

Noaki Yasuda

Noaki Yasuda

Professor

As part of my study of the universe, I am observing type Ia supernovae (SNe Ia). An SNe Ia is thought to be the thermonuclear explosion of a white dwarf that has exceeded 1.4 solar masses as a result of accreting mass from its companion star in a binary system. SNe Ia have similar luminosity and spectrum characteristics, as well as a maximum luminosity comparable to that of an entire galaxy. Assuming that SNe Ia have a constant absolute luminosity, we can determine their distance up to 9 billion light-years, which gives us information about the expansion history of the universe and the content of its dark matter and dark energy. I have searched for distant SNe Ia using Hyper Suprime-cam on the NAOJ’s Subaru telescope and found this method to be more effective than the Hubble Space Telescope for detecting distant SNe Ia.

I graduated from the University of Tokyo in 1995. I became an assistant professor at National Observatory of Japan in 2000 and moved to the Institute for Cosmic Ray Research in 2003 as an associate professor. In 2009, I moved to Kavli Institute for the Physics and Mathematics of the Universe as a professor mainly to lead the Hyper Suprime-Cam survey project.

Nicolas Regnault

Nicolas Regnault

Researcher

I am a researcher in observational cosmology at Laboratoire de Physique Nucléraire et de Hautes-Energiesin Paris.   My research interests are linked to understanding the fundamental nature of Dark Energy, the mysterious component postulated to explain the acceleration of cosmic expansion.  I use type Ia supernovae as cosmological distance indicators to carry out precision measurements of the history of Cosmic Expansion, which in turn gives access to the Dark Energy equation of state. In the not-so-distant past, I have been involved in the Supernova Legacy Survey (SNLS), a very successful SN survey conducted by Canada, France and US teams. In SNLS, I have worked on precision photometry and on mitigating the impact of the main systematic uncertainties affecting SN distance measurements, notably photometric calibration uncertainties.

I am now working on two complementary projects, each targeting a specific redshift range of the Hubble diagram.  I am working with IPMU colleagues on a very high redshift supernova survey, targeting the z>0.8 window using the HyperSuprimeCam camera on the 8.2-m Subaru telescope.  This programme has delivered a unique sample of 300 very well observed supernovae in the critical redshift window where the transition from matter to dark-energy domination occurs.  I am also involved in the the Zwicky Transient Factory (ZTF) operating a 47 deg2 camera to survey the northern sky with a high cadence of observation. ZTF is currently gathering a sample of ~8000 very well measured nearby SNe Ia.  The combination of the ZTF and the Subaru/HSC samples, along with the existing statistics at intermediate redshifts will deliver the best pre-LSST constraints on the Dark Energy equation of state along with its possible variations.  Finally I am also a member of the LSST-DESC science collaboration where I am involved in the preparation of the SN science programme.

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Gravitational Waves

Masaki Ando

Masaki Ando

Asssociate Professor

Associate professor of Department of physics, the University of Tokyo. Gravitational-wave astrophysics has been my main research field. Currently I am working on KAGRA, a gravitational-wave antenna in Japan, and also future space mission B-DECIGO. I am also interested in laboratory-scale precision measurement experiments for fundamental physics, such as test of Relativity or macroscopic quantum physics, using laser interferometer and opt-mechanical techniques. One example is a development of sensitive gravity gradiometer for investigation of quantum opt-mechanics, Newtonian noise in gravitational-wave antenna, and earthquake early alert.

I began my research carrier as a graduate student at the University of Tokyo in 1994 and received my Ph.D in 1999. I became assistant professor in 1999. In 2009, I became a specific associate professor at Department of Physics, Kyoto University. After a position of associate professor of gravitational-wave project office at the National Astronomical Observatory Japan (NAOJ) in 2013, I moved to the current position in 2014.

Matteo Barsuglia

Matteo Barsuglia

Researcher

I’m research director at CNRS  at the Astroparticle and Cosmology Laboratory in Paris and currenty Virgo scientific responsible for France. After graduating in physics from the University of Pisa and receiving my PhD from the University of Paris Sud in 1999, I joined the CNRS in 2000 and since then I’m involved in research in the field of gravitational waves, and in particular in the development of the gravitational-wave interferometric detectors.

Among my past contributions, I’ve led the commissioning of the initial Virgo detector,  contributed to the design and construction of the Advanced Virgo detector, and participated to the first gravitational-wave detections by the LIGO-Virgo network. I’m actually involved in the development of the Advanced Virgo+ detector (an upgrade of Advanced Virgo) and of the Einstein Telescope project, a future detector and research infrastructure recently inserted in the European roadmap for large research facility (ESFRI).  I’m teaching gravitational-wave physics at the Université de Paris and École Polytechique.  I’m director of the « Paris Center for Cosmological Physics », a structure of the APC laboratory involved in numerous science outreach and education projects for middle and high school children and teachers.

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High Energy Astrophysics

Armand Fiasson

Armand Fiasson

Researcher

I am researcher at LAPP-Annecy since 2010 in the field of very high energy gamma-ray astronomy. I started searching for cosmic ray accelerator signatures in the analysis of the H.E.S.S. experiment data towards supernova remnant and molecular cloud associations. I joined the CTA (Cherenkov Telescope Array) project in 2013 and contributed in particular to the sub-project LST (Large Size Telescope), aiming at the design, construction and commisioning of the largest telescopes of the CTA array, and led by M. Teshima from the University of Tokyo. I have been leading the CTA group at LAPP from 2015 to 2021.

Since 2013, I am coordinating LAPP technical contributions to the LST project and contributing to various aspects of the first LST commissioning on La Palma island. In parallel I started studying gamma-ray burst physics, in the frame of the H.E.S.S. experiment and now within the first LST context. In this frame I am involved in and coordinating LST activities around transient event alert treatment, data acquisition towards these objects and their analysis, together in particular with colleagues from the University of Tokyo

Masahiro Teshima

Masahiro Teshima

Professor

Prof. Dr. Masahiro Teshima primarily investigates high-energy processes in the universe that take place in stellar explosions or in the vicinity of black holes, for example. His research field, astroparticle physics, combines the physics of the innermost constituent parts of matter with the investigation of how the universe formed. One of Prof. Dr. Teshima’s main collaborative projects is the observation of gamma radiation flashes with the aid of the MAGIC Cherenkov telescope. He and his research groups also make important contributions to the development of the successor project CTA. In addition, he is responsible for the CRESST,Cryogenic Rare Event Search with Superconducting Thermometers, in the Gran Sasso Massif in Italy.

Prof. Dr. Teshima was born in 1958 in Tottori/Japan, studied at Kyoto University and was awarded his doctorate there in 1986. In 1989, he became an associate professor at Tokyo University, where he remained until 2002. From 1992 to 1998, he was also a visiting researcher at the University of Utah in the USA, and from 1998 to 2002, director of the Akeno Observatory, ICRR, at Tokyo University. Since 2003, he has been Director at the Max Planck Institute for Physics. Since 2010, he has restarted to work as a professor in ICRR, the University Tokyo, to promote the CTA project in Japan in the framework of the cross-appointment.

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Particle Physics and Detectors

Tetiana Berger Hyrn'ova

Tetiana Berger Hyrn'ova

Researcher

Dr. Tetiana Berger-Hryn’ova is a particle physicist. She did her undergraduate studies at V. N. Karazin Kharkiv National University in Ukraine (1996-2006) and at the University of Liverpool in UK (1997-2000). Her doctorate thesis, obtained at Stanford University (USA) in 2006, was dedicated to studies of  baryonic B-meson decays and CsI(Tl) crystal radiation performance at the BaBar experiment at Stanford Linear Accelerator Center (SLAC). In 2006 she joined the ATLAS collaboration, first as a CERN fellow and since 2008 as a CNRS researcher at the Laboratoire d’Annecy de Physique des Particules in France. Dr. Tetiana Berger-Hryn’ova currently leads ATLAS LAPP group.

Her research is focused on searches and precision measurements, mostly in the final states with two leptons. The discoveries in the dilepton spectrum of the J/psi and Upsilon mesons and the Z boson were crucial steps in the establishment of the Standard model and detailed study of such processes at the Large Hadron Collider (LHC) will help to pave the way for a better understanding of physics processes beyond it. Dr. Tetiana Berger-Hryn’ova  also participates in the upgrade of the electronics of the ATLAS calorimeter for the High Luminosity LHC (HL-LHC, 2027+) and works on the ATLAS trigger system. She recently joined the Dark Matter Science Project within the ESCAPE project to better explore complementarity between astrophysics, particle physics and nuclear physics experiments searching for the dark matter.

Toshinori Mori

Toshinori Mori

Professor

Toshinori MORI is Full Professor at International Centre for Elementary Particle Physics (ICEPP), the University of Tokyo. As he completed a doctorate at University of Rochester, NY, USA, in 1989, he moved to Faculty of Science, the University of Tokyo, as Assistant Professor. From 1996 he was Associate Professor at ICEPP until he became Full Professor in 2003.

Professor Mori’s research interest ranges from electroweak physics, Higgs boson, charged lepton flavours, supersymmetry, to Grand Unified Theories (GUT). At the energy-frontier electron-positron collider, TRISTAN at KEK, that started operation in 1986, he dismissed existence of new quarks and discovered a slightly lighter Z0 mass than measured at the hadron collider through electroweak corrections. In the precision studies of Z0 boson at LEP, CERN, Professor Mori helped to establish experimentally the electroweak gauge theory to a per-mill precision. The studies determined the number of particle generations to be precisely three, predicted the top quark mass, and hinted at grand unification of three coupling constants at the GUT scale. In 1999 Professor Mori started international collaboration as Spokesperson to search for lepton flavour violating decays of muons at PSI, Switzerland. The MEG experiment excluded such decays down to a branching ratio of less than half a trillionth, thirty times more stringent than previous experiments. An upgraded experiment MEG II under his Spokespersonship is getting ready for another exploration with a tenfold sensitivity.

Professor Mori has also been playing an important role in promoting and leading the electron-positron International Linear Collider Project, ILC, as Chair of Committee for Japan’s Future High Energy Physics Projects and Chair of Japan High Energy Physics Committee, as well as ICFA member.