2018 Fiscal Year Research-status Report
Next Generation of Neutrino CP measurement with TNT2K and Its Physical Potentials
| Project/Area Number |
18K13536
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| Research Institution | The University of Tokyo |
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Principal Investigator |
GE SHAOFENG 東京大学, カブリ数物連携宇宙研究機構, 特任研究員 (20817639)
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| Project Period (FY) |
2018-04-01 – 2020-03-31
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| Keywords | Neutrino / Neutrino Oscillation / Matter Effect / Dark Matter / Collider / Effective Operator / New Physics / Scalar Boson |
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| Outline of Annual Research Achievements |
My study on neutrino physics focuses on the leptonic CP phase in the neutrino oscillation. 1) My PLB paper generalized our earlier idea of residual symmetry for predicting the neutrino mixing pattern to incorporating anarchical perturbations. Our paper is the first to combine residual symmetry and anarchy model. And the prediction shows a clear peak at the maximal CP value. 2) My PRL paper with Stephen Parke pointed out the importance of the scalar type non-standard interactions (NSI). For the last 10 years or so, the study of NSI focuses on only the vector type. We pointed out that the scalar NSI is totally different from the vector one and has very important phenomenological consequences. It can make big difference for the CP phase measurement at the current T2K and the future T2HK experiments in Japan. 3) I have also been studying the possibility of using the reactor neutrino (TEXONO) and muon decay at rest (COHERENT) experiments to constrain the properties of light dark photon and scalar mediators between the dark sector and the ordinary Standard Model particles. Our result provides significantly enhanced sensitivity. 4) In addition, I have also studied the flavor structure of dark matter decay or annihilation observed in the indirect probe of dark matter at the CALET (Japan) and DAMPE (China) satellite experiments. 5) I have also studies the propests of probing the new physics scale through effective operators at the LHC (Europe), ILC (Japan), and CEPC (China) colliders.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
As planned, I have published several papers on the CP phase measurement
at neutrino experiments in Japan. Especially the possiblity of combining 1) reactor neutrino oscillation at KamLAND; 2) the solar neutrino data at Super-K; 3) the current and planned measured at T2K and T2K; 4) the muon decay at rest configuration TNT2K. This combination is very important for excluding the possible scalar non-standard interactions. My paper with Stephen Parke has already been accepted by the Physical Review Letters and has attracted much attention across the community. Our paper shows how important these neutrino experiments based in Japan can be and pointed out at least one more physics potential for experiments as planned in my proposal. I have also got invitations to talk about our paper at several important international conferences, including 1) The Neutrino Theory Network workshop in US; 2) New Physics at the Low Energy Scales (NEPLES-2019); 3) Topics in Astroparticle and Underground Physics (TAUP 2019). In addition, I have published multiple papers in different directions, including dark matter and collider phenomenology. These efforts together enhance our understanding of the possible new physics beyond the Standard Model of particle physics.
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| Strategy for Future Research Activity |
I plan to further study the physical consequences of new physics on neutrino oscillation. Especially, the neutrino CP phase measurement can be disturbed by these new physics possibilities, including 1) The non-unitary mixing between light and heavy neutrinos; 2) The vector non-standard interactions that act as matter potential; 3) The scalar non-standard interactions that change the neutrino mass term. For some cases, the CP sensitivity can significantly decrease. This is a very serious problem for those CP phase measurement experiments, such as T2K and T2HK in Japan. If these possibilities of new physics cannot be experimentally excluded, the interpretation of data can not
be conclusive. At least we shall try to design different experimental
configurations to exclude all other exotic possibilities. Imagine that in 10 years, T2K and T2HK would probably gather enough data to make 5 sigma discovery of nonzero CP phase in neutrino oscillation. Then people would start thinking seriously whether the experimentalists of T2K and T2HK deserve a Nobel Prize. If we have not excluded other possible theories other than the standard three-neutrino oscillation, how can we be sure the T2K/T2HK result is sound enough to deserve a Nobel Prize? This issue is very important to experimentalists. As a
theorist, I believe this is a correct direction to push further.
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| Causes of Carryover |
I efficiently saved the Kakenhi fund in FY2018. I plan to make several trips during the fiscal year of 2019: 1) US trip to University of Massachusetts for a workshop; 2) Invited talk at the FLASY 2019 Conference in China; 3) The Neutrino Factory workshop 2019 in Korea; 4) Invited talk at the Topics on Astroparticle and Undergrand Physics at Toyama; 5) Invited talk at the workshop New Physics at the Low Energy Scales (NEPLES-2019) in Korea. Since four of them are international trips, I need these funding to cover the expenses.
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