Mayumi Aoki
KEK
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Featured researches published by Mayumi Aoki.
Physics Letters B | 2000
Mayumi Aoki; Eri Asakawa; Makiko Nagashima; Noriyuki Oshimo; Akio Sugamoto
Abstract We study the decay B → X s γ in a minimal extension of the standard model with extra up- and down-type quarks whose left- and right-handed components are both SU(2) singlets. Constraints on the extended Cabibbo–Kobayashi–Maskawa matrix are obtained from the experimental results for the branching ratio. Even if the extra quarks are too heavy to be detected in near-future colliders, the branching ratio could have a value which is non-trivially different from the prediction of the standard model.
Physics Letters B | 2005
Mayumi Aoki; Kaoru Hagiwara; Naotoshi Okamura
Abstract We study the potential of a very long baseline neutrino oscillation experiment with a neutrino factory and a large segmented water-Cerenkov calorimeter detector in resolving the degeneracies in the neutrino oscillation parameters; the sign of the larger mass-squared difference δ m 13 2 , the sign of | U μ 3 | 2 ( ≡ sin 2 θ ATM ) − 1 / 2 , and a possible two-fold ambiguity in the determination of the CP phase δ MNS . We find that the above problems can be resolved even if the particle charges are not measured. The following results are obtained in our exploratory study for a neutrino factory which delivers 10 21 decaying μ + and μ − at 10 GeV and a 100 kton detector which is placed 2100 km away and is capable of measuring the event energy and distinguishing e ± from μ ± , but not their charges. The sign of δ m 13 2 can be determined for 4 | U e 3 | 2 ( 1 − | U e 3 | 2 ) ≡ sin 2 2 θ RCT ≳ 0.008 . That of sin 2 θ ATM − 1 / 2 can be resolved for sin 2 2 θ ATM = 0.96 when sin 2 2 θ RCT ≳ 0.06 . The CP-violating phase δ MNS can be uniquely constrained for sin 2 2 θ RCT ≳ 0.02 if its true value is around 90° or 270°, while it can be constrained for sin 2 2 θ RCT ≳ 0.03 if its true value is around 0° or 180°.
arXiv: High Energy Physics - Phenomenology | 2002
Mayumi Aoki
Abstract We study physics potential of Very Long Base-Line (VLBL) Neutrino-Oscillation Experiments with the High Intensity Proton Accelerator, which will be completed by the year 2007 in Tokai-village, Japan. As a target, a 100 kton-level water-Cerenkov detector is considered at 2,100 km away. Assuming the pulsed narrow-band ν μ beams, we study sensitivity of such experiments to the neutrino mass hierarchy, the mass-squared differences, one CP phase and three angles of the lepton-flavor-mixing matrix. We find that experiments at a distance 2,100 km can determine the neutrino mass hierarchy if the mixing matrix element | U e3 | is not too small. The CP phase and | U e3 | can be constrained if the large-mixing-angle solution of the solar-neutrino deficit is realized.
Physical Review D | 2001
Mayumi Aoki; Gi-Chol Cho; Makiko Nagashima; Noriyuki Oshimo
We calculate the contributions of the vector-like quark model to
arXiv: High Energy Physics - Phenomenology | 2006
Mayumi Aoki; Kaoru Hagiwara; Kentarou Mawatari; Hiroshi Yokoya
\BsBs
Nuclear Physics | 2005
Mayumi Aoki; Kaoru Hagiwara; K. Mawatari; Hiroshi Yokoya
mixing, taking into account the constraints from the decay
Journal of Physics G | 2001
F Borzumati; T J Champion; Mayumi Aoki; Adrian John Bevan; W. N. Cottingham; Amol Dighe; Paolo Gambino; N. De Groot; P F Harrison; Shaaban Khalil; C. S. Kim; P Liniger; M Misiak; Laura Reina; G Ricciardi; E. I. Shibata; Nikolai Uraltsev; Daniel Wyler
B\to X_s\gamma
Journal of Physics G | 2001
Mayumi Aoki
. In this model the neutral bosons mediate flavor-changing interactions at the tree level. However,
arXiv: High Energy Physics - Phenomenology | 2000
Mayumi Aoki
\BsBs
Physical Review D | 2005
A. G. Akeroyd; Mayumi Aoki
mixing is dominated by contributions from the box diagrams with the top quark and the extra up-type quark. In sizable ranges of the model parameters, the mixing parameter