「ニュートリノで拓く素粒子と宇宙」研究会２０２０
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Japan
Virtual
Virtual
Description
新学術領域「ニュートリノで拓く素粒子と宇宙」では、ニュートリノを基軸に、 素粒子、原子核、宇宙線、宇宙にわたる様々な未解明の現象に迫ることで 21世紀の「新しい素粒子・宇宙像」を確立することを目指しています。
本領域では、以下の日程でオンライン研究会を開催いたします。
新学術領域「ニュートリノで拓く素粒子と宇宙」
研究会 日程：
１２月２１日（月） ０９：００ー１８：００
１２月２２日（火） ０９：００ー１８：００
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11:00 AM
Coffee break
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公募研究#1
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6
Exploring the GUT and generation structure via neutrinosWe study the grand unified theory (GUT) and the generation structure of elementary particles, using neutrinos as a probe. We primarily focus on the possibility that the suppression of "dimension-5 proton decays" (proton decays via colored Higgsino exchange, which are too fast if supersymmetric particles are at TeV scale) in supersymmetric SO(10) GUT is realized with a unique flavor structure of the Yukawa couplings and such a structure yields a prediction on the neutrino flavor mixings. We aim to reveal the correlation between the extent of the suppression of dimension-5 decays and neutrino oscillation parameters, in particular the Dirac CP phase. Additionally, we investigate the connection between the ratio of the widths of different dimension-5 proton decay modes and types of GUT models. We aim to discriminate different GUT models by measuring multiple dimension-5 proton decay modes. The relation between the width ratios and neutrino flavor mixings is also discussed.Speaker: Prof. Naoyuki Haba (Shimane university)
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7
Gravitational waves from a phase transition of an extra U(1) in SO(10) GUTThe breaking of the U(1) symmetry is a source of stochastic gravitational wave (GW) background. We show a successful ultraviolet completion of a U(1) extended SM by an SO(10) grand unified model through an intermediate step of SU(5)×U(1) unification.Speaker: Osamu Seto (Hokkaido University)
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8
CMB Lensing Measurement of Distant Galaxy Clusters and Galaxies Detected by the Subaru Hyper Suprime-CamThe large-scale structure of the Universe, such as the abundance of galaxy clusters and the matter correlation function, is sensitive to the total neutrino mass, and thus serve as the independent probe from CMB fluctuations. As a first step, we measure dark matter distributions of distant objects detected by the Subaru Hyper Suprime-Cam (HSC); the one is galaxy clusters at z~1, and the other is galaxies at z~4. To measure the dark matter distributions of such high-redshift objects, we use a phenomena called CMB lensing which is the coherent distortion in CMB maps caused by foreground massive objects. We then discuss cosmological constraints enabled by these measurements as well as future prospects of these measurements in the upcoming optical and CMB surveys.Speaker: Dr Hironao Miyatake (Nagoya University)
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6
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12:25 PM
Lunch break
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若手セッション: Lightning talks
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12
Analysis status of one water target Emulsion Cloud Chamber for NINJA experiment 4
4
Virtual
NINJA実験は原子核乾板を用いたニュートリノ-原子核反応の精密測定実験であり、物理ランでは2019年末から2020年始にかけて75kg水標的検出器に対し0.48×10^21POTのニュートリノ照射を行った。 本実験で用いている検出器である水ECCは、2mmの水と原子核乾板を用いたトラッキングプレートを積層した構造をしている。 その高い位置分解能、高サンプリングレートを生かして、低速陽子の検出が可能であることが大きな特徴である(陽子検出閾値>200MeV/c)。 物理ランでは9個のECCを作成し、ニュートリノ照射を行ったが、今回は1個のECCでの解析状況について報告する。Speaker: yosuke suzuki (Nagoya Univ.) -
13
Baryon, Lepton, and Fermion Number Symmetries as parts of SU(16) GUT Gauge Symmetry 8
8
Virtual
Grand unification is one of the most attractive ideas for constructing unified theories beyond the standard model (SM). As is well-known in SO(10) and E(6) GUTs, the SM quarks and leptons are embedded into one unified multiple. So, a part of baryon (B) and lepton (L) numbers, i.e., B-L, is a part of the GUT gauge group. The B and L symmetries play a crucial role of understanding low-energy phenomena such as proton decay and neutrinoless double beta decay, One may wonder whether B and L number symmetries can be embedded into a GUT gauge symmetry or not. In this talk, I would like to show SU(16) GUT gauge group contains baryon, lepton, and fermion number symmetries if SU(16) is broken to not only regular subgroups, but also special subgroups.Speaker: Naoki Yamatsu (Kyushu University) -
14
Cosmic Amorphous Dust Model: To Improve the Accuracy of the CMB Component Separation 9
9
Virtual
Observation of the Cosmic Microwave Background radiation (CMB) B-mode polarization aims at measuring the neutrino mass and detecting primordial gravitational waves. Since the CMB B-mode signals are embedded in emission from interstellar dust in the Milky Way, the dust emission must be removed from the CMB data. To improve the accuracy of component separation between the CMB and the dust emission, we constructed a dust emission spectrum model based on the physics of amorphous materials that compose most of the interstellar dust. We name our dust model as the cosmic amorphous dust model, abbreviated to CAD. The CAD can explain the dust intensity and polarization spectra from far-infrared to millimeter wave, including the anomalous microwave emission (AME) whose radiation mechanism is unresolved, without assuming additional dust components. We introduce the detail of the CAD and show verification results comparing the CAD with astronomical observation.Speaker: Dr Masashi Nashimoto (NAOJ) -
15
DAQ development for Super FGD in the T2K experiment 10
10
Virtual
Super FGD is a part of the near detector (ND280) upgrade of the T2K experiment. This upgrade is to reduce the systematic uncertainty for the measurement of the neutrino oscillation parameters. The Super FGD consists of about two million scintillator cubes read out along three orthogonal directions by wavelength shifting fibers, to realize large acceptance and fine granularity. We develop the DAQ system with a software framework, called MIDAS, to integrate the new detectors to the current ND280. This poster shows the current status of the DAQ development.Speaker: Mr Soichiro Kuribayashi (Kyoto University) -
16
Detector performance of AXEL prototype high pressure Xe gas TPC for 0nbb search 5
5
Virtual
ニュートリノがマヨラナ粒子であるか否かを検証すべく, ニュートリノを伴わない二重ベータ崩壊($0\nu\beta\beta$)の探索が世界中で行われている. 稀事象である$0\nu\beta\beta$を高感度で探索するためには, 大量の崩壊核・高いエネルギー分解能・背景事象の除去, の3点を全て達成することが重要であり, 我々はこの要件を全て満たす検出器として, 高圧キセノンガスタイムプロジェクションチェンバーであるAXELを開発している. $^{136}$Xeの$0\nu\beta\beta$におけるQ値2458 keVでのエネルギー分解能や飛跡再構成能力などの検出器性能を実証するため, 我々は現在容積180 Lの試作機を開発し, ガンマ線源を用いた性能評価を行なっている. 本講演では, 性能評価に至るまでの開発の試行錯誤と, この測定および得られたデータの解析について詳細に解説し, 今後の大型化の計画について述べる.Speaker: Mr Masashi Yoshida (Kyoto University) -
17
Development of blackbody absorber by using a 3D-printed mold for millimeter-wave measurements 1
1
Virtual
In millimeter-wave measurements, recent super-conducting detectors achieve high sensitive detection of the millimeter-wave. In order to achieve further sensitivity in the millimeter waves, the reduction of stray light becomes essential. For instance, in the cosmic microwave background (CMB) observation, we need to suppress the radiation noise coming from the outside of the telescope like ground radiation. To suppress such a radiation noise, the installation of the millimeter-wave absorber onto the inside of the telescope is effective. We have developed a new production method of the millimeter-wave absorber by using a pyramidal mold made by a 3D printer. In this production method, a radio-wave absorptive material is filled into the pyramidal mold. Now, we are evaluating various materials to be filled and optimizing the filling material to achieve a higher absorption performance. In this poster, I will show the development status of the 3D-printed mold absorber.Speaker: Dr Shunsuke Adachi (Kyoto University) -
18
Development of high voltage modules for Hyper-Kamiokande 2
2
Virtual
Hyper-Kamiokande is a next generation water Cherenkov detector and will start operation in 2027. Cherenkov light emitted from charged particles produced from proton decay and neutrino interactions are detected by photo multiplier tubes (PMT). High voltage (HV) is necessary device for PMT to accelerate electrons between the dynodes. With the current plan, HV will be set in water proof case with the other electronics and put in water. I will present the status of the development of HV system for Hyper-Kamiokande.Speaker: Takuto Suganuma (Tokyo University of Science) -
19
Development of the evaluation methods and the test-bed for TES bolometers for CMB polarization measurements 11
11
Virtual
To study the initial conditions and evolution of the universe, we measure Cosmic Microwave Background (CMB) polarization. The telescopes for the CMB observation have over 10,000 Transition Edge Sensor (TES) detectors, which can detect faint signals sensitively. We aim to evaluate the thermal and optical performance of many TES detectors simultaneously, which are developed for the next-generation experiments such as Simons Observatory (SO). I reported the progress of the establishment of the measurement environment and the performance evaluation for that purpose.Speaker: Ms Yume Nishinomiya (University of Tokyo) -
20
Droop correction database for D-Egg modules 3
3
Virtual
The IceCube Neutrino Observatory, located at the geographic South Pole, will deploy 300 next-generation optical modules, known as D-Eggs, for the detector upgrade. Each one of these D-Egg modules contains two photomultiplier tubes (PMTs) as their primary sensors. Each PMT receives power through a high voltage (HV) base, which contains a high voltage transformer toroid used as a highpass filter. One feature of this filter is the distortion of the PMT signal output, in the form of a drooped response and an undershoot of the baseline. Current generation IceCube calibration corrects for this effect by restoring the true shape of the PMT signal. Following the example of IceCube Gen1, we extend these techniques for the next generation HV board and PMT system. This consists of measuring the droop and undershoot for each board, which enables the detection of defective HV boards. This presentation will encompass the correction performance analyzed in terms of a function generated signal for ~300 HV boards, and later on, the correction is analyzed with different PMT signals. The proper correction conditions of this effect are a vital part of the wider IceCube Collaboration calibration program, to ensure accurate energy and direction reconstruction of astrophysical neutrinos.Speaker: Ms Stephany Elizabeth Vargas Piedra (Chiba University) -
21
Machine Learning based ring reconstruction for water Cherenkov detectors 6
6
Virtual
We present initial developments of machine learning based ring event reconstruction for water Cherenkov detectors, in particular the Intermediate Water Cherenkov Detector proposed as near detector for the HyperK experiment. By exploiting PMT hit correlations due to shower- or scattering-induced variations in the Cherenkov profile, as well as additional spatial and directional information from higher granularity PMTs, we expect to improve on the existing reconstruction performance and enable new measurements that are very challenging in conventional maximum-likelihood fitters. Several ongoing works are presented both on particle identification and kinematic reconstruction, using both conventional and newly proposed CNN architectures, as well as various implementations of topology and geometry of cylindrical detectors. We also explore methods to deal with variations of scales and units of the regression variables in constructing combined loss functions.Speaker: Mr Lukas Berns (Tokyo Inst. of Tech, Hyper Kamiokande collaboration) -
22
Search for dark photon cold dark matter using technologies for CMB anisotropy 7
7
Virtual
We report on new ideas of an experiment to search for dark-photon cold dark matter (DP-CDM) in the mass region of 10^-4 eV, applying the method used to measure the CMB anisotropy. Photons from the conversion from DPs on a metal plate, in the millimeter wave range (10-18 GHz), will be searched with three antennas in order to make this measurement sensitive to the polarization and velocity distribution in the milky-way galaxy.Speaker: Toshi Sumida (Kyoto University) -
23
Boltzmann-radiatioin-hydrodynamics simulations of the core collapse of rapidly rotating stars 3
3
Virtual
大質量星の死である重力崩壊型超新星はニュートリノ加熱によって爆発すると考えられている。そこではニュートリノ輸送が重要な役割を果たすため、我々はボルツマン方程式を直接解くニュートリノ輻射流体コードを開発した。本講演では、これを用いて高速回転する親星の重力崩壊をシミュレーションした結果を概説し、放射されるニュートリノの性質について議論する。Speaker: Dr Akira Harada (ICRR) -
24
Current progress of large angle electron beam test of water-ECC and Iron-ECC at ELPH 11
11
Virtual
This test beam experiment is designed to study detection and momentum measurements of electron which optimised for NINJA water-ECC and Iron-ECC. Water-ECC, iron-ECC and stacked nuclear emulsion plates were irradiated by an electron beam with 150, 300, 500 and 800 MeV/c of energy at angle from 0 to 79degree in GeV-gamma room in ELPH in Tohoku University. We will give an overview of the experiment and the current progress in this poster.Speaker: Mr Tomokazu Matsuo (Nagoya University) -
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Development of a cryogenic half-wave plate rotator and its contactless monitoring system for Simons Observatory experiment 8
8
Virtual
For polarization measurements of the cosmic microwave background that probe the physics of the inflationary period, it is important to reduce low-frequency noise and systematic contamination by polarization modulation. For the Simons Observatory experiment, we are developing a large aperture cryogenic continuously rotating half-wave plate (HWP) that is magnetically levitated on a superconducting magnetic bearing. In this talk, I will introduce the status of the development of a HWP system and a new contactless monitoring system of temperature and position of levitating and rotating HWP, that operates under cryogenic conditions.Speaker: Kyohei Yamada (The university of Tokyo) -
26
Development of a multiplexing readout system for superconducting detectors combining commercially available digital and analog boards 5
5
Virtual
Superconducting detectors have been widely applied to scientific instruments, including CMB polarimeters, X-ray telescopes, and dark matter detectors. Multiplexing readout is a key for those applications to operate more detectors while suppressing heat transfer to the superconducting device from warmer stages. RF multiplexing uses superconducting resonators to map detectors in frequency space, allowing reading $\cal{O}(10^3)$ detectors with a single pair of coaxial cables. We built a room-temperature electronics for RF multiplexing readout combining commercially available digital and analog boards. High-speed data converters in the analog board enable 1 GHz bandwidth, which is five times wider than the system previously developed by us. The digital board receives data from the analog board, transforms the time-stream data to the frequency domain, and sends compressed data to a host computer. In this poster, we show the feature of our system, describe the working principle of the digital board firmware, and present test results of the whole system using a superconducting resonator array.Speaker: Dr Junya Suzuki (Kyoto University) -
27
Development of characterization system for superconducting devices MKID. 10
10
Virtual
Superconducting devices are getting adopted in CMB and dark matter search experiments. MKID has intrinsically breakthrough potential to realize frequency domain multiplexing over 1000 pixels. However, there are a few places where we can characterize the MKID because superconducting detectors are typically operated at O(10-100) mK. We have developed the characterization system for the MKID. This poster reports the MKID characterization system developed in Kyoto and several unique performance evaluation methods using the test MKID device.Speaker: Mr Yoshinori SUENO (Kyoto University) -
28
Development of WLS fiber test system without light shielding for a new near detector Super-FGD in T2K experiment 9
9
Virtual
We are developing a new near detector SuperFGD in T2K experiment. This detector is constructed from about 2 million scintillator cubes and their scintillation light are led by inserted WLS fibers. It is necessary to check the fibers are not damaged by pressure of cubes. We are developing a fiber test system which does not require light shielding, and evaluating the precision.Speaker: Masaki Kawaue (Kyoto University) -
29
Improvement of low energy reconstruction in Super-Kamiokande 7
7
Virtual
Position dependence of the energy scale is one of the major systematic error sources in the solar neutrino analysis in Super-Kamiokande. In the low energy analysis, the energy of a charged particle is reconstructed with the number of hit PMTs after some corrections. In the latest study, we succeeded in suppressing the position dependence of the energy reconstruction by the modification of the corrections for the PMT response and water transparency. I will present the detail of this study.Speaker: Masataka Shinoki (Tokyo University of Science) -
30
Performance test for next-generation optical module “mEgg” in the IceCube Gen2 6
6
Virtual
現在千葉大学では、IceCube Upgrade計画におけるニュートリノ観測および南極氷河光伝搬較正のための光検出器「D-Egg」の実機300台の製作を行っており、2022年末に南極氷河に埋設される予定である。さらに10,000台規模での新型光検出器の埋設を目指すIceCube Gen2計画に向け、このD-Eggを高エネルギーニュートリノ点源観測に向けて最適化した次世代光検出器「mEgg」のデザイン研究が進行している。本ポスターでは、Geant4を基盤としたモンテカルロシミュレーションを用いて、実際の南極環境におけるmEggの検出効率を見積もり、その結果と現D-Eggとの比較についてを報告する。Speaker: Mariko Suzuki (Chiba Univ.) -
31
Search for ultra-light-mass dark matter using a K-band cryogenic receiver - study for mitigating thermal radiation noise 1
1
Virtual
“Dark photon'' is one of the candidates of cold dark matter. There are models which predict tiny conversion from the dark photons to the standard model photons at the surface of the metal plate. DOSUE-RR (Dark-photon Observing System at Un-Explored Radio-Range) is an experiment to search for the conversion photon in the K-band millimeter-wave range (20~30 GHz). The corresponding mass range for the dark photon is approximately 10^-4 eV. The power of conversion photons is expected to be low (< 10^-17 W). Therefore, thermal radiation is the major noise in this experiment. Operating the system in cryogenic condition (~4 K) is the best strategy for mitigating the thermal radiation. In this poster, we present an optimization study for mitigating the thermal radiation. We also estimate our sensitivity based on the optimized design.Speaker: Mr Shumpai Kotaka (Kyoto Univ.) -
32
Study of muon monitor using CT in the T2K experiment 4
4
Virtual
T2K実験ではミューオンモニターによりスピルごとにビームの方向を測定している。ミューオンモニターに設置する新しい検出器の候補の一つとしてCTが検討されている。CTは通過する正負の荷電粒子数の差に比例した信号が得られるため、正負の荷電粒子の和に比例した信号が得られるSi検出器の測定と合わせることにより、ミューオンビームの方向だけでなく、正負の荷電粒子数の比率にも感度を持つ。本講演では、測定精度をビームシミュレーションにより評価した結果を報告する。Speaker: Hina Nakamura (TUS) -
33
The Simons Observatory - status and roles of the Japanese group 2
2
Virtual
The Simons Observatory will precisely observe cosmic microwave background (CMB) using the world’s largest CMB telescope arrays. Our science goals are the most precise measurements of cosmological parameters obtained from polarization patterns in CMB, such as tensor-to-scalar ratio, a sum of neutrino mass, and so on. Towards the first light in FY2021, constructions are going on. The Japanese group is in charge of developing “cold optics tubes” for all telescopes which are optimized for the tensor-to-scalar ratio measurement. We are also in charge of two calibration hardware, polarization modulation hardware, anti-reflection coating, detector testing, and software developments for the data analysis. In this poster, we will present the status of the project and the roles of the Japanese group.Speaker: Dr Yuki Sakurai (Kavli IPMU) -
34
Atmospheric Gamma-ray Observation on GRAINE 2018 Balloon Experiment and Comparison with HKKM Model 2
2
Virtual
We started up a precise gamma-ray observation project, Gamma-Ray Astro-Imager with Nuclear Emulsion (GRAINE), using balloon-borne emulsion gamma-ray telescopes to enable high angular resolution, polarization-sensitive, and large-aperture observations in the 0.01–100 GeV energy region. In 2018, we conducted the balloon experiment (GRAINE 2018) and succeeded in the first detection of a celestial gamma-ray object, Vela pulsar. In the next experiment (scheduled in 2022), we aim to expand the detector area and start scientific observation. Our main background is atmospheric gamma rays, and its understanding is important. The observation data can also be used to estimate the amount of π0 mesons produced at balloon altitude. In this presentation, we report the results of the atmospheric gamma-ray measurement on GRAINE 2018. In addition, the results are compared with predictions calculated by the HKKM model.Speaker: Dr Hiroki Rokujo (Nagoya University) -
35
Development of sparse wire grid calibrator for Simons Observatory experiment 9
9
Virtual
We will report the development of the sparse wire grid calibrator for the Simons Observatory(SO) experiment. In the SO experiment, we aim to detect a B-mode polarized signal of the cosmic microwave background. The B-mode polarized signal contains the signature of the primordial gravitational wave generated at the inflation era. To measure the B-mode polarized signal with σ(r)=0.003 accuracy, we have to calibrate the polarization angle with ΔΘ=0.1°. We develop a sparse wire grid calibrator that generates a polarized signal. This polarized signal comes from sparse parallel metal wires (sparse wire grid). By measuring the rotation angle of the sparse wire grid, we identify the angle of the polarized signal. We will present the design and the performance evaluation of the sparse wire grid calibrator we have developed.Speaker: Mr Masaaki Murata (The University of Tokyo) -
36
Electric-field dependence of dark noise in a photomultiplier tube 10
10
Virtual
In neutrino experiments, photomultiplier tubes (PMTs) in water or liquid scintillators are frequently used to measure a signal of light. Dark pulses of the PMTs are an important background which affects low energy measurements. It is known that the dark pulse rate depends on temperature and magnitude of the electric-field around the photo cathode. To find optimal settings in the actual environment, I measure these dependences and represent the dark rate with a theoretical model.Speaker: Mr Yuto Maekawa (Keio Univ.) -
37
Evaluation of event reconstruction with 100 ton to 1,000 ton scale water Cherenkov detectors 5
5
Virtual
The Hyper-Kamiokande experiment is planned to start in 2027 aiming for precise measurement of neutrino oscillation using J-PARC neutrino beam including the search for CP violation. Intermediate Water Cherenkov Detector (IWCD) based on detection principle as Hyper-Kamiokande is proposed to reduce the systematic uncertainty in the long baseline measurement. Water Cherenkov Test Experiment (WCTE) is currently under preparation to evaluate the performance of IWCD. In this poster, I will report the performance of event reconstruction with these small water Cherenkov detectors using the simulation.Speaker: Koki Yamauchi (Tokyo University of Science) -
38
Investigation of collective beam instability in the J-PARC main ring 1
1
Virtual
The transverse impedance, known to cause betatron tune shift and beam instability, has a significant impact on the beam operation at the J-PARC main ring (MR). Its estimations and countermeasures are indispensable for higher beam intensity from current intensity of 3.3\times 10^{13} ppb (protons per bunch) \times 8 bunches to future intensity of 4.4\times 10^{13} ppb \times 8 bunches. Beam instability is suppressed by the intra-bunch feedback system, but it may not be suppressed or adjusted in high-intensity operation. In this study, in order to understand the behavior of the beam, we aim to model the resistive wall effect, which is considered to be the main impedance source. A beam test was conducted in the vertical direction, where the contribution of other impedances such as kickers is considered to be small, and the growth rate of instability was investigated. After modeling, we aim to predict the behavior of the beam and improve the instability control system.Speaker: Dr Aine Kobayashi (KEK) -
39
Measurement of LED Intensity and Angular Distribution for IceCube D-Egg Calibration Modules 7
7
Virtual
南極氷河で宇宙から飛来するニュートリノを観測するIceCube実験では、ニュートリノ観測の高精度化を目指しIceCube-Upgrade計画が進行中である。本計画で新たに埋設される新型光検出器D-Egg約300台の内部に設置されている12個の較正用LED及びその高速パルス駆動回路を用いることで、南極氷河の光伝搬特性をより詳細に理解する。光伝搬特性を詳細に調べるためにはこのD-Egg内部のLEDシステムの性能理解が必須であり、そのための光度及び指向特性の計測システムを開発した。本講演ではこの計測システム及びそれを用いた測定結果について報告する。Speaker: Yuya Takemasa (Chiba University) -
40
On-site performance of GroundBIRD, a CMB polarization telescope for large angular scale observations 6
6
Virtual
GroundBIRD is a millimeter-wave telescope to observe the polarization patterns of the cosmic microwave background (CMB). The target science topics are primordial gravitational waves from cosmic inflation and reionization optical depth. Therefore, this telescope is designed to achieve the highest sensitivity at large angular scales, $\ell =$ 6 - 300. For wide sky observations ($\sim 40\%$ full-sky), scanning at a high rotation speed (120$\rm^\circ/s$) is important to remove atmospheric fluctuations. Microwave kinetic inductance detector (MKID) is utilized with the fast GroundBIRD rotation since its good time response. We have started the commissioning run at the Teide Observatory in the Canary Islands. We report the performance of the telescope, receiver, and data acquisition system, including cooling achievements, observations of astronomical objects, and observations taken during several days ahead of our main survey observations.Speaker: Shunsuke Honda (Kyoto University) -
41
Performance evaluation of 3-inch photomultiplier tube used for Hyper-Kamiokande intermediate water Cherenkov detector 3
3
Virtual
ニュートリノ振動の測定精度向上を目的としてJ-PARCニュートリノビームライン上に建設される前置検出器には、3インチPMTを19本組み合わせたマルチPMTが導入される予定である。マルチPMTは現在開発の最終段階であり、大量生産の前にPMTの基本性能を把握しておく必要がある。本研究では3インチPMTのアフターパルス(遅延信号)などの測定結果を報告する。 Hyper-Kamiokande is the next generation underground water Cherenkov detector, aiming for the precision measurement such as long baseline neutrino oscillation. To suppress the systematic uncertainty, 1kton scale Intermediate water Cherenkov detector(IWCD) is planned to be constructed on the J-PARC neutrino beamline. As the photo sensors for Hyper-Kamiokande and IWCD, multi-PMT modules instruments with 19 3-inch PMTs are considered. Before the mass production, we need to study the characteristics of 3-inch PMT. I will present the measurement of after pulse which is fake noise detected after the main signal.Speaker: Tatsushi Kinoshita (TUS) -
42
Simulation study for proton decay by p->mu+K0 mode in Super Kamiokande 11
11
Virtual
核子崩壊は大統一理論の検証につながる非常に重要な事象であり、スーパーカミオカンデ実験では様々な崩壊モードが探索されている。 本研究では陽子がミューオンと中性K中間子に崩壊するモード($p\to \mu^++K^0$)についての探索を目的としている。 $K^0$は$K^0_L$による長寿命の崩壊モードを有しており、陽子崩壊による$\mu$の発生点と$K^0_L$の崩壊点が離れる事象が現れる。 本発表では時間的に離れた崩壊事象を分離するよう改良した再構成アルゴリズムと今後の解析予定について述べる。Speaker: Mr Ryo Matsumoto (Tokyo University of Science) -
43
Status of muon track connection in the NINJA physics run 8
8
Virtual
NINJA experiment measures neutrino-nucleus interactions with nuclear emulsion detector called Emulsion Cloud Chamber. Thanks to its fine granularity and good spatial resolution, it allows us to detect short range charged particles’ tracks from the interactions. From November 2019 to February 2020, we accumulated $\sim 4.7 \times 10^{21}$ protons on target neutrino beam in the detector. We aim to measure $\nu_\mu$-water charged current (CC) differential cross section with the data and the analysis is now ongoing. In this poster, status of the muon track matching, which is essential for the $\nu_\mu$ CC interaction study, will be presented.Speaker: Mr Takahiro Odagawa (Kyoto University) -
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The measurement of noise level of the readout module for CMB observation 4
4
Virtual
To reduce statistic noise of the Cosmic Microwave Background observation, it is important to increase the number of detectors. In the Simons Observatory, the microwave SQUID multiplexing (uMUX) are used. I report the result of measurement of noise level of the uMUX module.Speaker: Mr Tomoki Terasaki (the University of Tokyo) -
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Current status of 16-electrode beam monitor of J-PARC MR 9
9
Virtual
現在J-PARC MRにはビームの大強度化に合わせ、新しいビームプロファイルモニターである16電極ビームモニターがインストールされている。16電極ビームモニターは非破壊型を採用することによりモニター自身によるビームロスを軽減し、大強度のビームの環境下で精度良くビームのプロファイル測定が可能になるのを目標としている。このビームモニターの開発の現状と現在新しく導入しようとしているアルゴリズムについて報告する。Speaker: Mr YOHAN LEE (Kyoto University) -
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Evaluation of DAQ board of new photodetector D-Egg used for IceCube experiment upgrade 8
8
Virtual
IceCube-Upgrade project is underway for a more detailed understanding of lower-energy neutrino events and light propagation characteristics in glaciers. In this project, in order to improve the light detection efficiency in all directions, D-Egg in which two photodetectors are put in one glass container is used. We are proceeding with mass production of this D-Egg front-end DAQ board, and prior to the full-scale production of the D-Egg, we conducted a unit evaluation test of the DAQ board. In this poster, I will report the results of evaluating noise, sensor performance, variation among boards.Speaker: Mr Yasutsugu Morii (Chiba University) -
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Evaluation of energy reconstruction and water transparency before and after Gd sulfate dissolving in the Super-Kamiokande detector 4
4
Virtual
In the Super-Kamiokande detector, decay electrons from cosmic ray muons are continuously observed at the rate of approximately 1,500 event per day. Decay electrons enable the SK detector to monitor the water transparency and to evaluate its energy scale. The SK-Gd project in which Gd sulfate is loaded into pure water as a new target started from July 2020 and it is expected that water transparency would change before and after Gd sulfate dissolving. In this presentation, we will report study of decay electrons.Speaker: Mr Hussain Kitagawa (Okayama Univ.) -
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Experimental and simulation studies with retro-reflectors for water Cherenkov detectors 6
6
Virtual
It has been suggested to use retro-reflectors to improve precision of Water Cherenkov detector like Super-Kamiokande or Hyper-Kamiokande. Here we study the impact on reconstruction of low-energy(<10MeV) neutrino events. We tested performance of retro-reflectors by optical measurement. We introduced its result in simulation, developed reconstruction tool, and studied improvement of position resolution.Speaker: Mr shunsuke fujigami (Tokyo Institute of Technology Kuze group) -
49
Improvement and Modelling for the Output Linearity of the Photomultiplier Tube for High-Precision Neutrino Measurement 1
1
Virtual
Hyper-Kamiokande is aiming at high-precision measurement of neutrinos. However, output of 20-inch photomultiplier tubes is not linearly amplified in a certain range of the amount of incident light. The output nonlinearity was measured with the photomultiplier tube used in Hyper-Kamiokande. It depended on bias voltage and bleeder circuit. In order to suppress these effects, we improved the built-in bleeder circuit. We are also trying to construct modelling for calculating energy precisely. I will present the stable output linearity by improving the bleeder circuit and the trial of the nonlinearity modelling.Speaker: Ms Chiori Fujisawa (Keio University) -
50
NINJA実験における次期ニュートリノ照射（RUN9）の準備状況 2
2
Virtual
NINJA実験はニュートリノと原子核との反応の精密測定を目的とした実験である。 現在我々はNINJAのテスト実験としてRUN9を2月末から3月末にニュートリノビームを照射する為の準備を進めている。 RUN9の主な目的は2つある。一つは新開発の原子核乾板検出器を設置し、その結果を今後の実験にフィードバックすること。もう一つはこの実験は主に大学生及び大学院生が主導となって行い、経験を積むということである。 現在主に原子核乾板フィルムの作成及び試験、飛跡の時間記録用のシフターの試験を行っており、その開発の改良を行いながら進めている。Speaker: Hiiragi Inamoto (Nagoya-university) -
51
Production of AR coatings used for half wave plate and Alumina plate for CMB polarimetry 3
3
Virtual
Cosmic Microwave Background (CMB) polarization experiments require high accuracy. Sapphire, used for Half-Wave plates which is one of the optical elements of the telescopes, has high index (~3.1) and high reflectivity. This can cause errors, so we need to reduce reflectance by coating with anti-reflection (AR) coatings. AR coatings can reduce systematic errors as well as statistical errors by increasing the optical efficiency of the telescope. In order to use it for polarization observation, it is important to realize low reflectance in broadband (MF:90/150 GHz), and it is necessary to develop coatings with a large diameter (φ≃50cm). I will present about the design, fabrication, and evaluation of the optimal coating for CMB polarization experiments especially about MF band.Speaker: Kana Sakaguri (UTokyo) -
52
The effect of interstellar extinction on cosmic microwave background polarization and temperature anisotropy 7
7
Virtual
Recently Nashimoto, Hattori, Chinone has shown that the interstellar extinction of CMB monopole have non negligible effect on high precision measurements of CMB polarization and temperature anisotropy. They named the effect as CMB shadow since it looks like a shadow by the sunlight of a plastic sheet. However, their analysis was limited to an order of magnitude estimation. Therefore, more precise quantitative studies based on realistic data are required. In this paper, we show the results of the CMB shadow obtained by map based studies.Speaker: Ms Tamaki Murokoshi (Tohoku univ.) -
53
Water-target fine grained neutrino detector using hollow scintillator cubes 5
5
Virtual
We are now developing a new T2K near detector, Super-FGD. The Super-FGD consists of about two million plastic scintillator cubes read out along three orthogonal directions by wavelength shifting fibers and MPPCs. This detector will provide the large acceptance as well as the low momentum threshold for the detection of charged particles from neutrino interactions. However, it can provide the only the neutrino interactions on hydrocarbon while the neutrino interaction target for the T2K far detector, Super-Kamiokande is water. A precise measurement of neutrino interactions on water is our challenge. I devised an idea of a new neutrino detector which is expected to provide the precise measurement of neutrino interactions on water. This detector consists of hollow scintillator cubes in water tank. In this poster, the idea of the new detector and the expected capabilities are presented.Speaker: Tatsuya Kikawa (Kyoto University)
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10:20 AM
Coffee Break
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12:50 PM
Lunch
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公募研究（ポスターセッション）
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66
Electron chirality of amino acid molecules and the origin of homochirality in natureOur group proposed and study a scenario to explain the origin of homochirality by the difference of the weak interaction reaction rate between enantiomers of amino acid molecules. Biological molecules on the Earth have strong imbalance between enantiomers; amino acid molecules are L-type enantiomers and sugar molecueles are D-type ones. In our previous work, the total electron chirality of enantiomers is found to be nonzero, and one type of an enantiomer has larger reaction rates of the weak interaction than the other type. Hence one type of the enantiomer may be more broken by the interaction with astrophysical particles by the weak interaction. In the present work, the computational results of the total electron chirality in alanine, serine, and valine, are reported. L-alanine, L-serine, and L-valine have positive total electron chirality and this result implies that D-amino acid molecules might be more broken in the evolution of the universe. The total chirality of the amino acid molecules cannot be derived within usual computational conditions of quantum chemical computations. We also report computational conditions to derive reliable value of the chirality.Speakers: Dr Masato Senami (Kyoto University), Mr Naoya Kuroda (Kyoto University)
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67
Low Energy Atmospheric Neutrino flux below 100 MeVA progress report to study of low energy atmospheric neutrino flux below 100 MeV is presented. The study here is for the neutrino produced by the decay atmospheric muon in the materials at the surface of the earth, including the neutrino from the muon capture by nucleus. These fluxes are relatively small compared with the neutrinos produced in the atmosphere in all direction average. However, they have sharp peak at the horizontal direction. The amplitude is related to the geographical structure near the neutrino detector, and is difficult to estimate.Speaker: Dr Morihiro Honda (ICRR university of Tokyo)
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68
Neutrino interaction in the resonance regionWe report on our recent results of the neutrino interaction in the resonance region. 1) Role of the axial vector form factor of resonance. We examined the transition form factor of nucleon resonances by using the analyss of electron scattering data. We found increased strength neutrino cross section with large Q2 in the higher resonance region. (Collaborato S. X. Nakamura) 2) Polarization of tau in charge current reaction. Tau neutrino production is studied for QE, RES and DIS region. Using ANL-Osaka model of neutrino induced meson production reaction, description of polarization of tau lepton beyond delta resonance energy is examined. (Collaborators Rafi Alam, Luis Alvarez Ruso)Speaker: Dr Toru Sato (Osaka University, RCNP)
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69
New Development of Neutrino Research Using Superconducting TechnologyWe present our development of superconducting detectors for neutrino physics. One of our aims is to develop an In target detector for electron neutrino detections. Three technologies need to be newly developed: an In target that can be connected to the superconducting detectors, the superconducting detectors, and the coupling between them. So far we have developed the first two items. In the poster presentation we present the development results for those.Speaker: Prof. Hirokazu Ishino (Okayama University)
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70
Properties of neutrinos in lepton flavor model with modular symmetryWe discuss the lepton flavor model with modular symmetry in the torus compactification. Especially, we propose a model with modular A4 symmetry which works in the so-called large volume limit. In this model a gauge singlet field is introduced in order to explain the origins of the Higgs mu term as well as the Majorana masses for right-handed neutrinos. It is then presented the predictions of the model on the observables of neutrino properties, which may be tested by various future experiments.Speaker: Dr Takehiko Asaka (Niigata University)
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71
Real-Time Optics Correction using Magnet CurrentIn high-intensity proton synchrotrons, beam optics parameters must be precisely controlled to minimize beam losses. Central orbit distortion, which is called COD, is one of such important parameters. When CODs are large at sextupole magnets, additional focusing (de-focusing) forces are produced. These forces distort a betatron tune, which is defined as a number of oscillations per one turn in a ring accelerator. An undesired betatron tune increases the amplitude of the transverse oscillation so that many particles are lost from the ring sooner than designed. One of the reasons for CODs is the current error of bending magnets. Our proposed system employs FPGA to predict CODs using measured magnet currents. Since FPGA can convert measured currents to CODs faster than the time scale of the current error, the real-time correction is possible. We will present the details of our developed system including the hardware, firmware and beam test.Speaker: Dr Yoshinori Kurimoto (KEK/J-PARC)
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72
Recent status of basic studies toward neutrino mass spectroscopyWe, the SPAN (SPectroscopy with Atomic Neutrino) collaboration, aims to uncover unknown neutrino properties such as absolute neutrino masses and the nature of neutrino masses, Majorana/Dirac distinction. To obtain information on neutrino properties, we uses a decay process from metastable state(s) of atoms or molecules with emission of a neutrino pair. One of the most serious problem when we use this process is its extremely small emission rate. In order to overcome this problem, our group proposed to amplify the emission rate by atomic coherence in macroscopic volume. We have been studying experimental validity of the amplification mechanism. In this poster, We will present the principle of this coherent amplification mechanism and recent experimental progresses.Speaker: Dr Hiraki Takahiro (Okayama University)
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73
Search for long lived neutral leptons at the LHCModels with addition of three right-handed neutrinos to the Standard Model can explain the big three questions of the universe, neutrino masses, asymmetry between matter and anti-matter, dark matter. Neutrino Minimal Standard Model ($\nu$MSM) is one of such models and predicts three right-handed neutrinos with sizable masses, as known as Heavy Neutral Leptons (HNLs). HNLs with masses of about 10 GeV will be long lived and can be searched using $W$ boson decays at the LHC. This poster presentation gives the status of the HNL search with the LHC Run 2 full data by the ATLAS experiment.Speaker: Susumu Oda (Kyushu University)
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74
Study on neutrino interaction using T2K beam at KamLANDT2K experiment which is a long-baseline neutrino oscillation experiment in Japan is measuring CP-violation phase, $\delta_{CP}$. This experiment generates neutrino beam at J-PARC in Ibaraki prefecture and detects it at Super-Kamiokande in Kamioka-mine, Gifu prefecture. Since Super-Kamiokande is a water-Cherenkov detector, it cannot detect low energy events whose energy is below Cherenkov threshold. Due to this feature, it is challenging to measure Neutral Current (NC) interactions. On the other hand, KamLAND which is the world's largest liquid scintillator detector in Kamioka-mine achieved large light emission. This feature makes us to study on low energy neutrino events and neutron capture events further than Super-Kamiokande. Fortunately, the distance between KamLAND and Super-Kamiokande is very small (~80 m) and KamLAND is surely detecting T2K neutrino events. Using this lucky condition and KamLAND unique features, we are studying T2K neutrino events at KamLAND from a different point of view. We created timing synchronization with GPS and confirmed that KamLAND is surely detecting T2K neutrino events. Furthermore, we have estimated the expected T2K events using simulations and discussed the consistency of the number of T2K neutrino events and delayed neutron events. Because the physics data plots are still confidential, I will present the current status of detector studies and simulations.Speaker: Mr Seisho Abe (Tohoku University)
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75
Study on superconductor low-energy particle detectors for measurement of angular correlation between neutrino and electron in beta decayMeasurement of the angular correlation between neutrino and electron in beta decay is a good probe of the validity of the Standard Model. The actual experiments rely on the measurement of the precise energy spectrum of the recoil proton, whose energy ranges up to 700 eV. It is challenging to measure such small energy particles directly using conventional detectors. This study aims to discuss the feasibility of the angular correlation measurement based on direct measurement experiments of the low-energy proton using superconductor tunnel junctions that can measure small energy particles less than 1 keV. We will report recent progress in numerical simulation and experiments.Speaker: Prof. Masamitsu Tanaka (Nagoya University)
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76
Water-based liquid scintillator using fluorochemical surfactantThe water Cherenkov detectors, such as Kamiokande and Super-Kamiokande, have led the study of neutrinos so far, as seen in the observation of supernova neutrinos and discovery of neutrino oscillations. In the next-generation neutrino experiment, a large-scale scintillator experiment of the same size as Super-Kamiokande is necessary. Because organic scintillators are toxic and flammable, we are developing safe and clean water scintillators suitable for large-scale experiments. The light emission was confirmed with a water scintillator prepared by mixing pseudocumene with water, fluorescence and surfactant, and it was revealed that the amount of light emission depends on the amount of pseudocumene. However, the transmittance of this water scintillator was low. When a laser was injected, a trajectory of light was seen which could not be seen in water, so we judged that scattering occurred inside and the transmittance was lowered. Because of the difference between the refractive index of the surfactant and the refractive index of water, it is considered that reflection occurred on the micell surface. We are developing a fluorochemical surfactant with a refractive index close to that of water. In this report, we report the performance of the water scintillator using hydrocarbon surfactant, and transparency of five different surfactant including a fluorochemical surfactant.Speaker: Dr Takashi Iida (University of Tsukuba)
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66
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2:50 PM
Coffee break
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公募研究#2
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77
Direct Measurement of Cosmic-Ray Proton and Nuclei Spectra with CALETCALETは国際宇宙ステーションにおける高エネルギー宇宙線の直接観測実験であり、2015年10月から現在まで順調に観測を継続している。検出器はTeV領域の電子観測に最適化した30放射長の物質量をもつ解像型のカロリメータで、宇宙線近傍加速源や暗黒物質の探索を主目的としている。さらに、陽子・原子核成分の高精度なエネルギースペクトルの観測を通じて、宇宙線の加速・伝播機構の解明を目指している。本講演では、これまでの約5年間の観測で得られた観測結果、特に宇宙線原子核成分の観測結果について報告する。Speaker: Dr Yosui Akaike (Waseda University)
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78
Gain and time resolution characterization of GasPM, a large cheap photon detector with an excellent time resolutionGasPMは大規模素粒子実験の発展を加速させるために発明された安価かつ大型なガス増倍を用いた高時間分解能光検出器である。この検出器は現在開発の初期段階で、我々は試作機を用いて高時間分解能であることを実証することを目指しており、そのために基本動作を理解する必要がある。 検出器の時間分解能は信号のS/N比で決まるため、信号の増倍率を最大化する必要がある。私は、検出器の増倍率の印加電圧依存性、光子検出レート依存性を測定した。 印加電圧については3kVの時に増倍率が最大となり、それ以上の印加電圧では増倍率が低下することを明らかとした。光子検出レートは1Hzの時に増倍率が最大となり、それ以上の検出レートとすると検出器内部に増幅された電子が蓄積され、電場が低下することで増倍率が低下することが明らかとなった。これは試作器特有の性質であり、この影響が小さい1Hz程度のヒットレートで評価をすることが適切である。 また、時間分解能に影響を与える可能性のある特性を評価した。まずは、信号の増倍率の位置依存性を測定し、位置により最大40%変動することを明らかにした。このことで場所により異なる電場で電子が増倍されるため、信号の検出タイミングがずれる可能性を示した。次に、ストリーマ放電などにより複数の信号を一つの信号として扱うことでタイムウォーク補正ができなくなる可能性について測定し、増倍率の高い領域で約20%程度このような影響があることを明らかにした。 この結果から、増倍率が最大となる印加電圧、ヒットレートで時間分解能測定を行い、その結果、電場の一様性やストリーマ放電の影響でゲインが高い領域で信号のタイミングがずれることを確認した。これは試作器特有の特性であるため、原理的な時間分解能を求めるためにこれらの影響のない領域で時間分解能を評価した。この時、σ=57 ps (読み出し回路の分解能σ≃35 ps ,レーザーの分解能σ≃17 psを含む)の高い時間分解能を持つことを示すことに成功し、GasPMは今後の開発によって高い時間分解能を達成できることを明らかにした。Speaker: Ryogo Okubo (Nagoya University)
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79
Demonstration of reduction method for Tl-208 backgrounds using topological information of Cherenkov light for ZICOS experimentZICOS is one of future project of Neutrinoless double beta decay search using a liquid scintillator containing $^{96}$Zr. In order to achieve the sensitivity over $10^{27}$ years, ZICOS will use tons of $^{96}$Zr, and need to remove $^{208}$Tl backgrounds efficiently. For this purpose, we have developed new technique to distinguish signal and background using a topological information of Cherenkov light, and succeeded that 93% of $^{208}$Tl events could be removed even though remaining 80% of 0$\nu \beta \beta$ signal. In order to realize this technique, we have to select PMTs which receive Cherenkov lights. From recent measurement using several gamma-ray sources, there was a clear difference of the pulse shape between Cherenkov light and scintillation, and the technique of pulse shape discrimination was developed. Here, we will explain this technique in detail, and will report the current status of HUNI-ZICOS which measures directly the topological information of Cherenkov lights.Speaker: Prof. Yoshiyuki Fukuda (Miyagi University of Education)
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77
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公募研究#3
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80
MeV-scale reheating temperature and neutrino oscillation in the early UniverseFrom a theoretical point of view, there is a strong motivation to consider an MeV-scale reheating temperature induced by long-lived massive particles with masses around the weak scale, decaying only through gravitational interaction. In this study, we investigate lower limits on the reheating temperature imposed by big-bang nucleosynthesis assuming both radiative and hadronic decays of such massive particles. For the first time, effects of neutrino self-interactions and oscillations are taken into account in the neutrino thermalization calculations. By requiring consistency between theoretical and observational values of light element abundances, we find that the reheating temperature should conservatively be TRH≳1.8 MeV in the case of the 100% radiative decay, and TRH≳ 4-5 MeV in the case of the 100% hadronic decays for particle masses in the range of 10 GeV to 100 TeV. We also discuss an idea for a possible production mechanism of sterile neutrino in this scenario.Speaker: Dr Kazunori Kohri (KEK / Sokendai)
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81
Cosmological bound on neutrino masses in the light of $H_0$ tensionIt is now widely recognized that the value of the Hubble-Lemaitre constant measured by cosmic microwave background (CMB) is in strong tension with the one obtained from local direct measurements, which is called the $H_0$ tension. Since CMB is now the most powerful cosmological probe of neutrino masses and $H_0$ is correlated with neutrino masses in CMB, one can expect that the $H_0$ tension would significantly affect the cosmological bound on neutrino masses. In this talk, we discuss the impact of the $H_0$ tension on the cosmological bound on neutrino masses and argue that, by assuming a model with modified recombination which has been shown to resolve the $H_0$ tension significantly, cosmological constraints on neutrino masses can be greatly affected by the $H_0$ tension.Speaker: Dr Tomo Takahashi (Saga University)
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82
Light mass window of lepton portal dark matterWe explore a novel possibility that dark matter has a light mass below 1GeV in a lepton portal dark matter model. There are Yukawa couplings involving dark matter, left-handed leptons and an extra scalar doublet in the model. In the light mass region, dark matter is thermally produced via its annihilation into neutrinos. In order to obtain the correct relic abundance and avoid collider bounds, a neutral scalar is required to be light while charged scalars need to be heavier than the electroweak scale. Such a mass spectrum is realized by adjusting quartic couplings in the scalar potential or introducing an extra singlet scalar. It turns out that the mass region of 10MeV-10GeV is almost free from experimental and observational constraints. We also point out that searches for extra neutrino flux from galactic dark matter annihilations with neutrino telescopes are the best way to test our model.Speaker: Dr Yuji Omura (Kindai)
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80
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Closing
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83
Award celemony
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84
Closing remark
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83
