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Home , Ghost (physics), Muon neutrino, T2K experiment

Exploration of Physics and Cosmology with Unification and Development of the Science Frontier What are the neutrinos? Neutrino means “Neutral = no ” and “-ino = small (in Italian).” They are one of the elementary .

“Neutral” and“ino” “neutrino”! Then, what are elementary particles?

Elementary particles are the smallest elements that make up ! Well water that doesn’t explain much about them so here we go!

For example, water is a bunch of water water molecules, and each water molecule is made with two hydrogen and one oxygen .

Inside of an atom, are oxygen hydrogen atom atom atom orbiting around a nucleus sitting in the middle.

Further inside of a nucleus, there are and . These two oxygen nucleus nucleus types of particles are called (A hydrogen nucleus is made up of one only).

Then, what about the inside of proton nucleons? Nucleons are made with three .

There are no smaller particles up down than these quarks and electrons, quark quark the elementary particles. At this moment, we think we cannot further break down these particles. elementary particles (matter) The elementary particles include; six u c t types of quarks, six types of (including electrons), gauge Quark which carry forces between particles, d s b and Higgs bosons which give a mass (weight) to other particles. Furthermore, all these particles have e µ τ partners called anti-particles which electron have opposite electric charges. Quarks Lepton bind to other quarks strongly and they νe νµ ντ make up nucleons. On the other hand, electron muon neutrino neutrino leptons bind weakly and they stay Bosons alone. Water, flowers, the universe, and

W+ W- even ourselves, everything around us Gauge γ Z 0 is made by these elementary particles. Neutrinos are a type of lepton.

Higgs H 0 boson

Discovery of Neutrinos!

In 1930, a scientist named Dr Pauli found a problem while he was studying neutrons. Pauli thought the problem could be solved by the existence of very light particles without electric charges. However, such a small light particle can pass through any object and Pauli thought it would be impossible to find such a particle. Three years later, Dr Fermi, who had studied these ghost particles, named these particles neutrinos. In 1956, two more scientists, Dr Reines and Dr Cowan, finally succeeded the first saw neutrinos with an experiment that used a nuclear reactor. Dr. Reines won the for this achievement. What are the properties of neutrinos?

These are so many! There are so many neutrinos around us. Lots of neutrinos are produced by the Sun during the production of heat, by the supernova explosion at the end of the life of a star, and by nuclear reactors. About 100 trillion neutrinos are passing through our bodies every second, but we cannot feel them and they can't hurt us.

Invisible ghost particle. Neutrinos are neutral particles without either a positive or negative electric charge. This means neutrinos do not attract, repel, or affect any materials. Furthermore, they are extremely small and they can pass through any atoms. Neutrinos can pass through our bodies and the Earth. Scientists have a hard time to see them because these particles are like ghosts - they even pass through detectors!

They have mass! For a long time, people believed neutrinos do not have mass. However, the Super-Kamiokande experiment led by Dr Kajita and the SNO experiment led by Dr McDonald overturned this myth. These experiments confirm neutrinos have mass by measuring neutrino oscillations, the phenomena through which 1 type of neutrino can change to another type. The laws of elementary particles, the “”, say that neutrinos are massless, but they are not! This discovery was a breakthrough in ! What can we learn?

Neutrinos are the second most abundant particles in the universe only after light. By studying their properties scientists think it may be possible to understand the mystery of the beginning of the universe and the origin of matter. Although neutrinos are extremely important to understand the universe, neutrinos have many mysterious features.

What are the projects of “Unification and development of the Neutrino Science Frontier” and “Exploration of Particle Physics and Cosmology with Neutrinos”?

Scientists from different fields of science are collaborating to study neutrinos, including the world’s first study using neutrinos to understand the “difference between matter and antimatter”, and observation of neutrinos from the universe to uncover the mystery of the origin of the universe, such as “why do we exist?”

We perform a high-precision measurement of neutrino oscillations using a neutrino beam produced by the world-class accelerator J-PARC at Tokai-village, Ibaraki prefecture and the Super-Kamiokande detector located at Hida-city, Gifu prefecture, Japan. ()

Neutrino oscillations can be studied by measuring neutrinos from nuclear reactors (Double- experiment). Furthermore, we aim to establish the technology to monitor nuclear reactors by applying this technology.

We observe neutrinos from the atmosphere. On top of measurements by the Super-Kamiokande experiment, we are developing the next generation “Hyper-Kamiokande”.

We observe neutrinos from the universe. These neutrinos carry information from the deep-universe nobody has ever seen (IceCube Neutrino Observatory).

We are developing state-of-the-art particle detectors. They improve the nuclear reactor safeguard system, nuclear-imaging technology, and new various other applications.

Theoretical studies of neutrinos across particle physics, , and cosmology are important to answer fundamental questions such as “what is space- time?”. T2K! Hi, Super- T2K Experiment Kamiokande- chan! Super-

Kamiokande- lives in Tokai-mura, Ibaraki, Japan. Naka-gun, J-PARC-chan: chan is a fascinating phenomenon in which a neutrino changes its identity. In order to study neutrino oscillations, a neutrino beam is shot from the large accelerator facility J-PARC in Tokai village and the neutrinos are observed at the Super-Kamiokande Wow ! detector in Kamioka town, 295 km away. The experiment is named T2K (Tokai-to[2]- J-PARC-chan Kamioka). In the T2K experiment, a new type of oscillation from a to an was discovered. Recently, we produced a beam of anti-neutrinos, the Watch out, neutrino's anti-particle, and studied the violation of between a particle and its muon neutrinos! anti-particle, called CP symmetry violation. T2K has the interesting result that CP symmetry may really be violated in neutrinos. This might be a big hint that neutrinos help explain the Wow ! mystery of our universe, where anti-matter is rare compared to matter.

Something different...? lives in Kamioka-cho, Hida-city, Gifu, Japan. Hida-city, Gifu, lives in Kamioka-cho, Super-Kamiokande-chan:

……

View of the T2K experiment A neutrino beam is shot from the J-PARC accelerator in Tokai village to the Super-Kamiokande detector in Kamioka town.

Particle Physics elucidates the mystery of invisible tiny elements It's a constituting our universe. In Particle Physics research, we have miracle! a dream and passion challenging the mystery with large-scale experiments, such as using a kilometer-scale accelerator or a gigantic detector located 1000 m underground. Let’s discover together how our universe is created. No! It’s Neutrino Oscillation! Dr. Tsuyoshi Nakaya Professor in Physics, Faculty of Science, Kyoto University J-PARC-chan: Super-Kamiokande-chan: lives in Tokai-mura, Naka-gun, Ibaraki, Japan. lives in Kamioka-cho, Hida-city, Gifu, Japan.

Wow ! Super- Kamiokande- chan Wow ! No! NeutrinoIt’s Oscillation! …… Something different...?

Watch out,Watch neutrinos! muon

It's a miracle! J-PARC-chan

Hi, Super- Hi, Kamiokande- chan! T2K! Near and Far Reactor Neutrino Hi! Super- We are watching Double Chooz Experiment Sisters, Kamiokande nuclear power What are chan! plant there. you doing? from the reactors. neutrinos the together measure They France. in plant power nuclear Chooz near Twins living Double Chooz Sisters:

Nuclear power plants produce electric power from the thermal energy obtained from Uranium nuclear fission. Did you know that a huge amount of neutrinos are produced at the same time? Those neutrinos escape to outer space without being used. The Double Chooz experiment at the Chooz nuclear power plant in France investigated such reactor Double Chooz Sisters neutrinos precisely and measured the θ13 mixing angle, an important parameter for the study of neutrino oscillation phenomena. It is an international collaboration with seven Wow! anti electron neutrinos Exactly! countries, and the Japanese group is playing a central role in it. Furthermore, we are We detect There are many them from conducting R&D application studies for new measures of nuclear non-proliferation by anti electron different placing a small neutrino detector outside of the reactor building. neutrinos! positions.

And we investigate the difference of I detect I detect numbers of detected anti electrion neutrinos.

near by. far away. are investigated in detail. parameters oscillation neutrino distances, two at reactors the from neutrinos electron anti detecting By Far: and Near from Observe

The Double Chooz detector during its construction, which has a double- acrylic vessel for liquid and It's neutrino 390 photo-multiplier tubes contained in oscillation! magnetic shields. 400m 1km

In experiments such as neutrino experiments, Let's study I'm going Right! young graduate students and researchers work in large neutrinos more to help too! closely, international collaborations together with others from all over the combining results world, with an ambition to “see for the first time what mankind has from your T2K never seen”. Why don’t you come and join us? experiment.

Dr. Masahiro Kuze Professor at Tokyo Institute of Technology Near and Far

Double Chooz Hi! Super- We are watching Sisters, Kamiokande nuclear power What are chan! plant there. you doing? from the reactors. neutrinos the together measure They France. in plant power nuclear Chooz near Twins living Double Chooz Sisters:

Double Chooz Sisters

Wow! anti electron neutrinos Exactly! We detect There are many them from anti electron different neutrinos! positions.

And we investigate the difference of I detect I detect numbers of detected anti electrion neutrinos.

near by. far away. are investigated in detail. parameters oscillation neutrino distances, two at reactors the from neutrinos electron anti detecting By Far: and Near from Observe

It's neutrino 400m 1km oscillation!

Let's study I'm going neutrinos more Right! to help too! closely, combining results from your T2K experiment. Atmospheric Neutrino How to find Neutrino Super-Kamiokande and How do you Hyper-Kamiokande Experiments find neutrinos? It's difficult to find them can be detected. neutrinos more the is, it bigger The water. ultra-pure of tons 50,000 with filled is It tank: Gigantic because they We observe neutrinos born in the Earth's atmosphere (atmospheric neutrinos) using the go through everything... Super-Kamiokande detector to determine the order which type of neutrino is heaviest It's my and which is lightest (called the "Mass ordering"). The mass ordering can cause a small special enhancement of neutrino oscillations when the atmospheric neutrinos pass through talent! the high density core of the Earth. We examined a lot of data in detail and found that the hypothesis that the third generation neutrino has a heavier mass than the first and I prepare ultrapure water neutrino second generation neutrinos matches the data better. However, further study is needed in big tank. to conclude the order of the masses. The Hyper-Kamiokande detector will provide major Neutrinos collide electrons and new capabilities to make new discoveries in particle and astroparticle physics. It is a nuclei in water priority project listed in the Roadmap2017 of the Japanese Ministry of Education, Culture, molecules, so electron Sports, Science and Technology, and we are preparing to start the detector construction. or muon escapes.

electron or muon water molecule

When electrons and Cherenkov By operating the Super-Kamiokande are traveling in water, radiations detector, we observe natural Cherenkov radiations are 11,129There inside sensors the tank. (PMTs). tubes photomultiplier called sensors Light sensors: light of A lot neutrinos from the Sun, atmosphere, are generated. and Supernova explosions, and artificial neutrinos from the J-PARC accelerator to study elementary I find them by particles and celestial bodies. We also using light sensors look for not-yet-discovered proton on the walls decay phenomena in the tank water. of my tank.

Detailed measurements of properties of neutrinos and I can find 20-30 neutrinos Uh-huh.... in a day by using spontaneous proton decays have the potential to make great 50,000 tons of water progress in understanding the laws of nature. I would like to and 10,000 construct the Hyper-Kamiokande detector with sensitivity light sensors. exceeding Super-Kamiokande and advance this research. This is too big of a problem to Dr. Masato Shiozawa understand... Professor at Institute for Research, the University of Tokyo How to find Neutrino

How do you find neutrinos? It's difficult to find them can be detected. neutrinos more the is, it bigger The water. ultra-pure of tons 50,000 with filled is It tank: Gigantic because they go through everything... It's my special talent!

I prepare ultrapure water neutrino in big tank.

Neutrinos collide electrons and nuclei in water molecules, so electron or muon escapes.

electron or muon water molecule

When electrons and muons Cherenkov are traveling in water, radiations

Cherenkov radiations are 11,129There inside sensors the tank. (PMTs). tubes photomultiplier called sensors Light sensors: light of A lot are generated.

I find them by using light sensors on the walls of my tank.

I can find 20-30 neutrinos Uh-huh.... in a day by using 50,000 tons of water and 10,000 light sensors.

This is too big of a problem to understand... Neutrino Hunter! High Energy Cosmic Neutrino Like this, IceCube Experiment I'm hanging many light sensor balls called DOM in the ice... to such remote places to hunt for neutrinos. for hunt to places remote such to go they as incredible are experimentalists These glacier using ice. Antarctic neutrinos is observing IceCube-san:

Large amounts of highly energetic matter travels through the cosmos at nearly the . This matter is called 'cosmic rays', and mostly consist of protons, the very basic building blocks of matter in our universe. Some of these cosmic rays have energies IceCube-san DOM thousands of thousands of billion times higher than visible light. How are all these products of the extreme Universe generated? In fact astronomical objects radiating cosmic rays are also expected to yield neutrinos. Neutrinos, chargeless elementary and neutrinos coming Cherenkov particles only sensitive to the "weak force", are traveling straight over huge distances, in the ice collide with radiations nuclei and electrons, unattenuated. Hunting of these neutrinos can indeed reveal the new image of the high energy universe we would never see otherwise. We "watch" our cosmos by the world's and I look for largest neutrino telescope, IceCube, built at the South Pole. Cherenkov radiations from muons and muon neutrino electrons from interactions.

It's like doing Super- It's so cool Kamiokande-chan's experiment like you're IceCube Neutrino Observatory but not with a water tank, fishing

built at the South Pole. The 5165 but with a large clear ice. neutrinos! neutrino. a cosmic from a signal for waiting ice, deep the in deployed been have them of pcs 5,000 About Module. Optical Digital for stands It DOM: photo-detectors are deployed in the deep glacier ice. Signals from the in-ice detectors are transmitted via cables to the observatory, where the primary data processing to select Super-K neutrino signals takes place. Super-Kamiokande IceCube -chan

Your life is one time. Let's challenge whatever stimulates your why don't you But!!! do that at other enthusiasm. Action first, then you have a plenty of time later to place not the worry if your challenge is successful or not. South Pole..., it's so cold... but you know only the South Pole has so much Dr. Shigeru Yoshida clear ice. Professor at Graduate school of Science, Chiba University Neutrino Hunter!

Like this, I'm hanging many light sensor balls called DOM in the ice... to such remote places to hunt for neutrinos. for hunt to places remote such to go they as incredible are experimentalists These glacier using ice. Antarctic neutrinos is observing IceCube-san:

IceCube-san DOM

and neutrinos coming Cherenkov in the ice collide with radiations nuclei and electrons,

and I look for Cherenkov radiations from muons and muon neutrino electrons from interactions.

It's like doing Super- It's so cool Kamiokande-chan's experiment like you're but not with a water tank, fishing

but with a large clear ice. neutrinos! neutrino. a cosmic from a signal for waiting ice, deep the in deployed been have them of pcs 5,000 About Module. Optical Digital for stands It DOM:

Super-K Super-Kamiokande IceCube -chan

why don't you But!!! do that at other place not the South Pole..., it's so cold... but you know only the South Pole has so much clear ice. Novel Neutrino detector: Emulsion as popular trend device Nuclear Emulsion J-PARC-chan, what's that? nuclear emulsion of particle physics. particle of dawn the from observations particle fundamental for used been has films, photographic as principle same detector, particle of A kind Nuclear emulsion:

Nuclear emulsion has been contributing to fundamental particle physics for a long time, especially for charm particles and tau neutrinos so far. To apply a nuclear emulsion detector for the next step of neutrino physics, neutrino CP violation or physics beyond This is nuclear the standard model probed by neutrinos, we are developing and improving the emulsion! technology of nuclear emulsion. In the era of digital photography, the commercial photo film market has shrunk. We When charged installed a nuclear emulsion production machine in Nagoya University and have particles pass through, been producing nuclear emulsion films with the help of retired technicians from a the trajectories are recorded develop photographic company. The development and production of optimized nuclear emulsion -ment as lines. for a variety of observations is resulting in fruitful output for not only neutrino physics, but also observations such as a dark matter search, balloon-borne gamma ray telescope, charged particle and cosmic-ray muon radiography. (electron etc)

This device needs Recently it looked Production machine no electric power through the inside for nuclear emulsion gel and has fine of a pyramid by

This system makes nuclear emulsion resolution tracking, using cosmic-ray by J-PARC-chan. produced neutrinos measure precisely to planned is experiment NINJA emulsion: and J-PARC-chan gel by carefully controlling the very useful! muons. temperature and mixing of a solution of silver nitrate and sodium bromide. The nuclear emulsion gels provided by this machine hava been used in the neutrino muon experiment at J-PARC, gamma-ray telescopes and muon radiography.

Two dimensional photographic films have largely been replaced by I kinda want to I want to use this, too! digital photographic techniques. However nuclear emulsion, as three measure the dimensional photographic films, still continues to grow. Since an neutrinos that I throw to Super- infrastructure to make nuclear emulsion gel was installed at our laboratory Kamiokande-chan You have in this research , we can try to test easily new methods as soon as we precisely by this think up a new idea. This has quickened young scientists drafting and Photomul, don't you...? performing new experimental projects with nuclear emulsion.

Dr. Mitsuhiro Nakamura Professor at Institute of Materials and System for Sustainability, Nagoya University Emulsion as popular trend device

J-PARC-chan, what's that? nuclear emulsion of particle physics. particle of dawn the from observations particle fundamental for used been has films, photographic as principle same detector, particle of A kind Nuclear emulsion:

This is nuclear emulsion!

When charged particles pass through, the trajectories are recorded develop -ment as lines.

charged particle (electron etc)

This device needs Recently it looked no electric power through the inside and has fine of a pyramid by

resolution tracking, using cosmic-ray by J-PARC-chan. produced neutrinos measure precisely to planned is experiment NINJA emulsion: and J-PARC-chan very useful! muons.

muon

I kinda want to I want to measure the use this, too! neutrinos that I throw to Super- Kamiokande-chan You have precisely by this Photomul, don't you...? Search for Neutrino Decay: For Neutrino Watching I want to see heavy COBAND Experiment a heavy neutrino neutrino decaying into a light neutrino... photon seconds the Big-Bang. after a few free became which Neutrinos Background Cosmic with filled be to thought is universe The Cosmic Background Neutrino: Cosmic background neutrinos are predicted to exist uniformly in space. To perform the COBAND rocket experiment to search for the cosmic neutrino background, we are But this developing the Superconducting Tunnel Junction (STJ) detector which measures the phenomenon light would happen energy of far-infrared from neutrino decays with an accuracy of 2%. We have COBAND-san neutrino so rarely... developed a cryogenic amplifier which is a key component of the cryogenic far-infrared photon detector, consisting of the Nb/Al-STJ detector and a diffraction grating, and Perhaps! succeeded in amplifying the Nb/Al-STJ signal for the visible laser pulse light. We have There are a lot of developed the Hf-STJ detector using Hf as a superconductor with a very narrow energy neutrinos that were made in a few gap for the future satellite experiment, and succeeded in observing the Hf-STJ signal for seconds after the the visible laser pulse light. We are preparing the whole equipment including the optical universe was born, But the light coming and I may be able from the neutrino system and the 0.4K refrigerator for the rocket experiment. to see their decays! decay is too weak, it may be difficult to see...

Perhaps! I may be able to STJ SOI see it in outer space not on the earth! by observing neutrino decay. neutrino by observing masses neutrino the Try determine to COBAND-san:

The Nb/Al-STJ detector is connected to the SOI cryogenic But there is amplifier on the same chip no detector carrier as the Nb/Al-STJ at 0.4K that is optimal 4.7μF refrigerator. for this...

To perform the COBAND experiment which searches for the That's why Wow... you start from cosmic background neutrino decay, we have developed the making chips? Superconducting Tunnel Junction (STJ) detector which measures It’s amazing... the energy of the far-infrared photon from the neutrino decay. This technology of superconducting particle detectors is expected I decided to make a chip to be used for the dark matter search, the coherent neutrino optimal for scattering experiment and so on in the future. a photo-sensor to see neutrino Dr. Shinhong Kim decays University of Tsukuba, Faculty of Pure and Applied Science, Professor For Neutrino Watching

I want to see heavy a heavy neutrino neutrino decaying into a light neutrino... photon seconds the Big-Bang. after a few free became which Neutrinos Background Cosmic with filled be to thought is universe The Cosmic Background Neutrino:

But this phenomenon light would happen COBAND-san neutrino so rarely...

Perhaps!

There are a lot of neutrinos that were made in a few seconds after the universe was born, But the light coming and I may be able from the neutrino to see their decays! decay is too weak, it may be difficult to see...

Perhaps! I may be able to see it in outer space not on the earth! by observing neutrino decay. neutrino by observing masses neutrino the Try determine to COBAND-san:

But there is no detector that is optimal for this...

That's why Wow... you start from making chips? It’s amazing...

I decided to make a chip optimal for a photo-sensor to see neutrino decays Novel Neutrino detector: Even neutrinos are seen? gas is electron The ion-electron pairs Liquid Ar Time Projection Chamber cooled down and are created along filled in the tank the tracks of charged

as the liquid…. particles such Chamber” Projection “Time of abbreviation an is TPC volume. argon the pass particles charged when signals track the has detector This TPC: Argon The as muons! The liquid argon 3D imaging detector provides the 3D image of elementary particles visually with online. It is a kind of the modern updated version of “the bubble chamber”, Due to its high capability of the detector, it is an ideal and ultimate candidate of the positive ion muon future neutrino or nucleon decay experiments. liquid Argon The largest size of the liquid argon 3D imaging detector so far is the ICARUS detector which has 600 tons, however the enlarged size of the detector is necessary for the The electrons are electric signal future experiments. For those experiments, R&D of the detector, especially R&D for moved to plus charged plane. the technology with reasonable costs is highly desired. Also the test-beam of the So, we can recode detector using well defined charged particles such as energy, momentum, angles and signal from electrons and the track of identification is quite important to understand the response of the detector to the charged particles finally… elementary particles. For this purpose, this research program has large amount of R&D for the key device with the reasonable costs for the future experiments, and the test-beams. Awesome!! Ahem! ..but, even they cannot see the produced by the neutrino-argon interactions. neutrino-argon by the produced were which tracks particles’ charged the see can we but charge, electric have not do Neutrinos Neutrinos and TPC: neutrinos directly because of no electric charge of neutrino?

Argon TPC LHC-chan KEK 30L liquid argon 3D imaging detector.

The liquid argon 3D imaging detector is one of ultimate detectors Muons or electrons Argon neucleus This method is for the neutrino and nucleon decay physics, therefore there are which have electric charge are similar to mine! a lot of R&D activities around the world. There are also some on- produced when going experiments which have order of 100 tons level. In this neutrinos are research program, we have done a lot of R&D of the detector key interacted with argon nucleus!! I want to devices and the test-beam for the future experiments. make a large detector like SK-chan Dr. Takasumi Maruyama by this. Associate Professor at KEK, Institute of Particle and Nuclear Studies Even neutrinos are seen?

Argon gas is electron The ion-electron pairs cooled down and are created along filled in the tank the tracks of charged

as the liquid…. particles such Chamber” Projection “Time of abbreviation an is TPC volume. argon the pass particles charged when signals track the has detector This TPC: Argon The as muons!

positive ion muon liquid Argon

The electrons are electric signal moved to plus charged plane. So, we can recode signal from electrons and the track of charged particles finally…

Awesome!! Ahem! ..but, even they cannot see the produced by the neutrino-argon interactions. neutrino-argon by the produced were which tracks particles’ charged the see can we but charge, electric have not do Neutrinos Neutrinos and TPC: neutrinos directly because of no electric charge of neutrino?

Argon TPC LHC-chan

Muons or electrons Argon which have electric neucleus This method is charge are similar to mine! produced when neutrinos are interacted with argon nucleus!! I want to make a large detector like SK-chan by this. Exactly like...?

Muon neutrino and Are they really Neutrino Phenomenology anti muon neutrino different? look exactly like

each other. Hey! reactions. by the produced particles the of charges electric the of because anti-particle and a particle are they that tell We can Electrically neutral neutrino and anti neutrino: I got an idea. A theory called the Standard Model of particle physics explains most of all the phenomena of elementary particles, but neutrino mass is one of the mysteries which cannot be explained by the Standard Model. One important subject in particle physics is to search for new physics beyond the Standard Model, and research on neutrinos is muon neutrino anti muon neutrino believed to bring a breakthrough along that direction. Various experimental results have been announced since the Superkamiokande experiment in 1998, and research Both of you, on neutrinos is now entering a new stage. In our group we are doing researches, such why don't you run from here to as phenomenology of experiments to determine precisely the parameters of neutrino Super-Kamiokande -chan's place mixing, phenomenology of new physics which can be probed by neutrinos, constraints in Gifu. Can they arrive on new physics which can be obtained through charged leptons at large accelerator here at the same time? experiments, etc.

– e γ

e+ γ Z’ neutrino. muon and neutrino muon anti of properties the between difference a tiny see to beginning are we experiment T2K the From moved: a hat with neutrino-chan muon Anti q q

A process which was proposed to experimentally check a model which was invented to explain mysterious phenomena.

Research on particle physics, including that on neutrinos, does not Gee! anti Wow, you have particle-chan's sharp eyes. have any direct application to our daily life. Because of such hat is moved …… nature, however, we do not have conflict of interest and we have a little. This is the first time we see that quite active international collaboration. We are carrying on they are not research to find out the ultimate law of the universe. identical.

Dr. Osamu Yasuda Professor at Faculty of Science, Tokyo Metropolitan University Exactly like...?

Muon neutrino and Are they really anti muon neutrino different? look exactly like

each other. Hey! reactions. by the produced particles the of charges electric the of because anti-particle and a particle are they that tell We can Electrically neutral neutrino and anti neutrino: I got an idea.

muon neutrino anti muon neutrino

Both of you, why don't you run from here to Super-Kamiokande -chan's place in Gifu. Can they arrive here at the same time? of anti muon neutrino and muon neutrino. muon and neutrino muon anti of properties the between difference a tiny see to beginning are we experiment T2K the From moved: a hat with neutrino-chan muon Anti

Gee! anti Wow, you have particle-chan's sharp eyes. hat is moved …… a little. This is the first time we see that they are not identical. muon Nucleus and Neutrino neutrino Neutrino-Nucleus reactions What are Yaah! you doing? SK-chan? Yaah! by reaction. muon-neutrino produced is a muon while nucleus, with reaction by electron-neutrino produced is electron An Production of and electron muon: Precise description of neutrino-nucleus reaction is crucial to extract neutrino properties muon from current and next-generation neutrino oscillation experiments. We are working neutrino to understand how particles such as muon, electron, nucleon and are produced Super-Kamiokande from the neutrino-nucleus reactions in wide neutrino energy region. One of our main SK-chan IceCube-san muon nucleus efforts is production in the nucleon resonances region. A model of lepton- nucleon reactions for both electromagnetic and weak meson production reactions I am kinda hitting Wouldn’t in the resonance region is developed. The other is neutrino reactions in the deep neutrinos and electrons, antineutrinos muons, inelastic region. Nuclear effects in charged lepton reactions and neutrino reactions are on to a nucleus protons, to see what and neutrons investigated. happens. muon come out? like we always see.

proton

electron muon Yeah, neutrino neutrino For high energy but sometimes neutrinos, even other weird stuff weirder stuff

comes out with might come out… by step. step descriptions our improving are we available, yet not region energy whole the in reactions While description unified the neutrino-nucleus reaction: neutrino-nucleus Understanding the protons nucleus so much and neutrons. we don’t know. neutron Workshop on 'Neutrino-Nucleus Interaction in the Few-GeV Region' held at Osaka in 2015 electron (NuInt2015). muon proton weird stuff

Through ice Theoretical description of the neutrino-nucleus reactions is a To become a and water! Gotta challenging subject. Collaboration among researchers in nuclear ”neutrino master”, we need to catch'em all! structure, nuclear reaction, physics and particle physics are study nuclei and important. We hope that young researchers join the field, enjoy all phenomena working with people from various field, and develop new ideas. at everywhere!

Dr. Toru Sato Guest Professor at RCNP, Osaka University muon Nucleus and Neutrino neutrino

What are Yaah! you doing? SK-chan? Yaah! by reaction. muon-neutrino produced is a muon while nucleus, with reaction by electron-neutrino produced is electron An Production of and electron muon: muon neutrino

Super-Kamiokande SK-chan IceCube-san muon nucleus

I am kinda hitting Wouldn’t neutrinos and electrons, antineutrinos muons, on to a nucleus protons, to see what and neutrons happens. muon come out? like we always see.

proton

electron muon Yeah, neutrino neutrino For high energy but sometimes neutrinos, even other weird stuff weirder stuff

comes out with might come out… by step. step descriptions our improving are we available, yet not region energy whole the in reactions While description unified the neutrino-nucleus reaction: neutrino-nucleus Understanding the protons nucleus so much and neutrons. we don’t know. neutron

electron muon proton weird stuff

Through ice To become a and water! ”neutrino master”, Gotta we need to catch'em all! study nuclei and all phenomena at everywhere! Neutrino physics and Neutrino Magic! Have a I see! the origin of the Universe good look! give the reason for the Universe being made of matter rather than anti-matter. anti-matter. than rather matter of made being Universe the for reason the give Universe, early the in happened really has it if phenomenon, violating CP This them. between imbalance an created cloth the under magic some anti-neutrinos, and neutrinos of numbers same the with Starting More anti-neutrinos than neutrinos?:

How did the Universe started and how has it evolved into the current form of structures made of galaxies and clusters of galaxies? The properties of elementary particles are quite important to answer these fundamental questions of our world. Our group has been studying the properties of neutrinos in the early Universe. Recently, we found that neutrinos anti-neutrinos the neutrino oscillation phenomena during the Big Bang can explain why there are no anti-particles around us. We are now studying how this hypothesis can be tested. We Neutrino have also proposed various new possibilities of particle/cosmology phenomena, such as oscillation! explaining the origin of the high-energy neutrinos discovered in the IceCube experiment as the decay products of dark matter particles, the hypothesis of dark matter made of the Higgs particles, to explain the mysteries of the Universe, and the relation between the vacuum structure of and the history of the Universe. The flavor content of neutrinos and that of anti-neutrinos are modified differently by the CP violation in the neutrino oscillation.

And hit Higgs boson Higgs bosons!

The theory/experiment joint regular meetings, “New Physics Forum,” have been held in Tokyo area. “New Physics Forum” offers good opportunities to form new collaborations among The numbers of the heavy neutrinos and the heavy anti-neutrinos physicists. are equalized by hitting the Higgs bosons.

Our theory team works on particle physics and cosmology such Ta-da! There are as the origin of baryonic matter in the Universe, nature of dark more anti- neutrinos?! matter, and also physics beyond the Standard Model through the studies of neutrinos. We build up new hypothesis to attack unsolved questions in particle physics and cosmology aiming at finding new facts of our Universe.

Dr. Ryuichiro Kitano Professor at KEK, Institute of Particle and Nuclear Studies. Neutrino Magic!

Have a I see! good look! give the reason for the Universe being made of matter rather than anti-matter. anti-matter. than rather matter of made being Universe the for reason the give Universe, early the in happened really has it if phenomenon, violating CP This them. between imbalance an created cloth the under magic some anti-neutrinos, and neutrinos of numbers same the with Starting More anti-neutrinos than neutrinos?:

neutrinos anti-neutrinos

Neutrino oscillation!

The flavor content of neutrinos and that of anti-neutrinos are modified differently by the CP violation in the neutrino oscillation.

And hit Higgs boson Higgs bosons!

The numbers of the heavy neutrinos and the heavy anti-neutrinos are equalized by hitting the Higgs bosons.

Ta-da! There are more anti- neutrinos?! electron neutrino muon neutrino tau neutrino

time projection chamber nuclear emulsion

anti electron neutrino anti muon neutrino anti tau neutrino

Published in March 2019 Exploration of Particle Physics and Cosmology with Neutrinos https://www-he.scphys.kyoto-u.ac.jp/nucosmos/en/index.html Editor, Designer: Yuki Akimoto (Higgstan / higgstan.com) Translator: Teppei Katori (Queen Mary University of London)