Publications de Gaétan Charles Antoine Giriat

Bullet pressure-cell design for neutron scattering experiments with horizontal magnetic fields and dilution temperatures

Henrik Moodysson Rønnow, Richard Gaal, Luc Testa, Ellen Fogh, Gaétan Charles Antoine Giriat, Jana Pásztorová

The simultaneous application of high magnetic fields and high pressures for controlling magnetic ground states is important for testing our understanding of many-body quantum theory. However, the implementation for neutron scattering experiments presents a ...

2025

Spin Waves and Three Dimensionality in the High-Pressure Antiferromagnetic Phase of SrCu2 (BO3)2

Henrik Moodysson Rønnow, Frédéric Mila, Bruce Normand, Ellen Fogh, Jian Rui Soh, Gaétan Charles Antoine Giriat

Quantum magnetic materials can provide explicit realizations of paradigm models in quantum many-body physics. In this context, SrCu2(BO3)2 is a faithful realization of the Shastry-Sutherland model for ideally frustrated spin dimers, even displaying several ...

2024

Pressure-induced transformation of CH3NH3PbI3: the role of the noble-gas pressure transmitting media

László Forró, Endre Horvath, Andrzej Sienkiewicz, Alla Arakcheeva, Gaétan Charles Antoine Giriat, Bálint Náfrádi, Márton Kollár, Anastasiia Glushkova

The photovoltaic perovskite, methylammonium lead triiodide [CH3NH3PbI3 (MAPbI(3))], is one of the most efficient materials for solar energy conversion. Various kinds of chemical and physical modifications have been applied to MAPbI(3) towards better unders ...

International Union of Crystallography (IUCr)2019

Effect of Thermal Cycling on the Structural Evolution of Methylammonium Lead Iodide Monitored around the Phase Transition Temperatures

László Forró, Endre Horvath, Alla Arakcheeva, Gaétan Charles Antoine Giriat, Anastasiia Glushkova, Konstantins Mantulnikovs, Konstantin Semeniuk

Optoelectronic devices and solar cells based on organometallic hybrid perovskites have to operate over a broad temperature range, which may contain their structural phase transitions. For instance, the temperature of 330 K, associated with the tetragonal-c ...

2019

Search for a Light CP-odd Higgs Boson and Low-Mass Dark Matter at the Belle Experiment

Olivier Schneider, Yiming Li, Roberto Gargiani, Chao Wang, Mithilesh Nayak, Gaétan Charles Antoine Giriat, Tagir Aushev, Sun Hee Kim, Tara Nanut, Ke Huang

We report on the first Belle search for a light CP-odd Higgs boson, A(0), that decays into low mass dark matter, chi, in final states with a single photon and missing energy. We search for events produced via the dipion transition (sic)(2S) -> (sic)(1S)pi( ...

2019

Measurement of cos 2 beta in B-0 -> D((*))h(0) with D -> K-S(0)pi(+) pi(-) decays by a combined time-dependent Dalitz plot analysis of BABAR and Belle data

Olivier Schneider, Roberto Gargiani, Yiming Li, Mingkui Wang, Mithilesh Nayak, Chao Wang, Gaétan Charles Antoine Giriat, Tagir Aushev, Greig Alan Cowan, Sun Hee Kim

We report measurements of sin 2 beta and cos 2 beta using a time-dependent Dalitz plot analysis of B-0 -> D((*))h(0) with D -> K-S(0)pi(+)pi(-) decays, where the light unflavored and neutral hadron h(0) is a pi(0),eta, or omega meson. The analysis uses a c ...

American Physical Society2018

Search for the rare decay of B+ -> l(+)nu e gamma with improved hadronic tagging

Olivier Schneider, Roberto Gargiani, Yiming Li, Mingkui Wang, Mithilesh Nayak, Chao Wang, Gaétan Charles Antoine Giriat, Sun Hee Kim, Tagir Aushev, Seyed Sina Mirrazavi Salehian

We present the result of the search for the rare B meson decay of B+ -> l(+)nu e gamma with l = e, mu. For the search the full data set recorded by the Belle experiment of 711 fb(-1) integrated luminosity near the Upsilon(4S) resonance is used. Signal cand ...

American Physical Society2018

First Evidence for cos 2 beta > 0 and Resolution of the Cabibbo-Kobayashi-Maskawa Quark-Mixing Unitarity Triangle Ambiguity

Olivier Schneider, Roberto Gargiani, Yiming Li, Mingkui Wang, Mithilesh Nayak, Gaétan Charles Antoine Giriat, Chao Wang, Tagir Aushev, Greig Alan Cowan, Sun Hee Kim

We present first evidence that the cosine of the CP-violating weak phase 2 beta is positive, and hence exclude trigonometric multifold solutions of the Cabibbo-Kobayashi-Maskawa (CKM) Unitarity Triangle using a time-dependent Dalitz plot analysis of B-0 -> ...

2018

Measurement of the decays Lambda c -> Sigma pi pi at Belle

Olivier Schneider, Yiming Li, Roberto Gargiani, Mingkui Wang, Gaétan Charles Antoine Giriat, Sun Hee Kim, Chao Wang, Tagir Aushev, Tara Nanut, Seyed Sina Mirrazavi Salehian

We report measurements of the branching fractions of the decays Lambda(+)(c) -> Sigma(+)pi(-)pi(+), Lambda(+)(c) -> Sigma(0)pi(+)pi(0) and Lambda(+)(c) -> Sigma(+)pi(0)pi(0) relative to the reference channel Lambda(+)(c) -> pK(-)p(+). The analysis is based ...

American Physical Society2018

Observation of e(+) e(-) -> gamma chi(c1) and search for e(+) e(-) -> gamma chi(c0), gamma chi(c2), and gamma eta(c) at root s near 10.6 GeV at Belle

Olivier Schneider, Yiming Li, Roberto Gargiani, Mingkui Wang, Gaétan Charles Antoine Giriat, Chao Wang, Sun Hee Kim, Tagir Aushev, Timothy Chi Hin Liew, Chang-Hyun Park

Using data samples of 89.5 fb(-1), 711.0 fb(-1), and 121.4 fb(-1) collected with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider at center-of-mass energies 10.52, 10.58, and 10.867 GeV, respectively, we study the exclusive reactions e(+) ...

American Physical Society2018