Nagoya University · 물리·천문학
Teppei Kitahara 교수의 연구실은 초임계 입자물리학과 새로운 물리학의 융합을 중심으로, CP 위반, K→ππ 붕괴에서의 직접 CP 위반, 그리고 K_L→π⁰νν 붕괴와 같은 고에너지 물리 현상에서의 새로운 물리학 신호를 탐색합니다. 특히 표준모형의 예측과 실험 간의 괴리(예: ε′/ε_K 이상현상, KOTO 실험의 이상 신호)를 설명하기 위해 초과중량 슈퍼대칭, 경량 장수 입자, 또는 새로운 보손 메커니즘을 포함한 다양한 새로운 물리 모델을 제안하고 분석합니다. 연구는 라티스 QCD 계산과 고차원 양자장 이론의 재규격화군 기법을 결합하여 정밀도를 높입니다.
표시된 성과는 수집된 데이터 기준으로 산출되며, 일부 차이가 있을 수 있습니다.
Recent progress in the determination of hadronic matrix elements has revealed a tension between the measured value of ε_{K}^{'}/ε_{K}, which quantifies direct CP violation in K→ππ decays, and the standard-model prediction. The well-understood indirect CP violation encoded in the quantity ε_{K} typically precludes large new-physics contributions to ε_{K}^{'}/ε_{K} and challenges such an explanation of the discrepancy. We show that it is possible to cure the ε_{K}^{'}/ε_{K} anomaly in the minimal
New physics contributions to the Z penguin are revisited in the light of the recently-reported discrepancy of the direct CP violation in K→ππ. Interference effects between the standard model and new physics contributions to ΔS=2 observables are taken into account. Although the effects are overlooked in the literature, they make experimental bounds significantly severer. It is shown that the new physics contributions must be tuned to enhance B(KL→π0νν¯), if the discrepancy of the direct CP violat
The KOTO experiment recently reported four candidate events in the signal region of K_{L}→π^{0}νν[over ¯] search, where the standard model only expects 0.10±0.02 events. If confirmed, this requires physics beyond the standard model to enhance the signal. We examine various new physics interpretations of the result including these: (1) heavy new physics boosting the standard model signal, (2) reinterpretation of "νν[over ¯]" as a new light long-lived particle, or (3) reinterpretation of the whole
The standard analytic solution of the renormalization group (RG) evolution for the ΔS = 1 Wilson coefficients involves several singularities, which complicate analytic solutions. In this paper we derive a singularity-free solution of the next-to-leading order (NLO) RG equations, which greatly facilitates the calculation of ϵ ′ , the measure of direct CP violation in K → ππ decays. Using our new RG evolution and the latest lattice results for the hadronic matrix elements, we calculate the ratio ϵ
The observation of a protophobic 16.7 MeV vector boson has been reported by a $^{8}\mathrm{Be}$ nuclear transition experiment. Such a new particle could mediate between the Standard Model and a dark sector, which includes the dark matter. In this paper, we show some simple models of the dark matter which satisfy the thermal relic abundance under the current experimental bounds from the direct and the indirect detections. In a model, it is found that an appropriate self-scattering cross section t
Abstract Recently, the CMS collaboration has reported a di-tau excess with a local significance of 2.6–3.1 $$\sigma $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mi>σ</mml:mi> </mml:math> where the invariant mass is $$m_{\tau \tau } =95$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mi>m</mml:mi> <mml:mrow> <mml:mi>τ</mml:mi> <mml:mi>τ</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>95</mml:mn> </mml:mrow> </mml:math> –100 G
We study the possibility to determine the supersymmetric (SUSY) contribution to the muon anomalous magnetic dipole moment by using ILC measurements of the properties of superparticles. Assuming that the contribution is as large as the current discrepancy between the result of the Brookhaven E821 experiment and the standard-model prediction, we discuss how and how accurately the SUSY contribution can be reconstructed. We will show that, in a sample point, the reconstruction can be performed with
The ATLAS and CMS collaborations discovered a new boson particle. If the new boson is the Higgs boson, the diphoton signal strength is 1.5 - 1.8 times larger than the Standard Model (SM) prediction, while the WW and ZZ signal strengths are in agreement with the SM one. In the Minimal Supersymmetric Standard Model (MSSM), overall consistency can be achieved by a light stau and the large left-right mixing of staus. However, a light stau and large left-right mixing of staus may suffer from vacuum i
Recently the ATLAS experiment has reported 3.0 σ excess in an on-Z signal region in searches for supersymmetric particles. We find that the next-to-minimal supersymmetric standard model can explain this excess by the production of gluinos which mainly decay via $$ \tilde{g}\to g{\tilde{\chi}}_{2,3}^0\to gZ{\tilde{\chi}}_1^0 $$ where $$ {\tilde{\chi}}_{2,3}^0 $$ and $$ {\tilde{\chi}}_1^0 $$ are the Higgsino and the singlino-like neutralinos, respectively. We show that the observed dark matter den
