Yoshihiro Takeuchi

WAVE PACKET APPROACH TO THE EQUAL-ENERGY/MOMENTUM/VELOCITY PRESCRIPTIONS OF NEUTRINO OSCILLATION

Neutrino oscillation is discussed with emphasis placed more on its conceptual aspects. After reviewing the two conventional formulations, referred to as the equal-energy prescription and the equal-momentum prescription, wave packet treatments are developed for each of these two prescriptions. Both wave packets localized in space and those localized in time are considered, and, by invoking relativistic kinematics as well, the necessary conditions for oscillation to occur are derived, which appear to have a form more well-defined and quantitative than what have been noted before. Some phenomenological implications suggested by the wave packet treatments are briefly mentioned. Finally, as a possible third prescription, the equal-velocity prescription is given.

How Do Neutrinos Propagate?: Wave-Packet Treatment of Neutrino Oscillation

The wave-packet treatment of neutrino oscillation developed previously is extended to the case in which momentum distribution functions are taken to be a Gaussian form with both central values and dispersions depending on the mass eigenstates of the neutrinos. It is shown among other things that the velocity of the neutrino wave packets does not in general agree with what one would expect classically and that relativistic neutrinos emitted from pions nevertheless do follow, to a good approximation, the classical trajectory.The wave-packet treatment of neutrino oscillation developed previously is extended to the case in which momentum distribution functions are taken to be a Gaussian form with both central values and dispersions depending on the mass eigenstates of the neutrinos. It is shown among other things that the velocity of the neutrino wave packets does not in general agree with what one would expect classically and that relativistic neutrinos emitted from pions nevertheless do follow, to a good approximation, the classical trajectory.

CP, T and/or CPT violations in the

Possible violation of CP, T and/or CPT symmetries in the

K^0 - \overline K^0

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system: Implications of the KTeV, NA48 and CPLEAR results

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CP, T AND CPT VIOLATIONS IN THE

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K^0-\overline{K^0}

system is studied from a phenomenological point of view. For this purpose, we first introduce parameters which represent violation of these symmetries in mixing parameters and decay amplitudes in a convenient and well-defined way and, treating these parameters as small, derive formulas which relate them to the experimentally measured quantities. We then perform numerical analyses, with the aid of the Bell-Steinberger relation, to derive constraints to these symmetry-violating parameters, firstly paying particular attention to the results reported by KTeV Collaboration and NA48 Collaboration, and then with the results reported by CPLEAR Collaboration as well taken into account. A case study, in which either CPT symmetry or T symmetry is assumed, is also carried out. It is demonstrated that CP and T symmetries are violated definitively at the level of 10^{-4} in

SYSTEM: PRESENT STATUS

2\pi

CP, T and CPT violations in the K0−K0 system: present status

decays and presumably at the level of 10^{-3} in the

How Do Neutrinos Propagate? \subtitleWave-Packet Treatment of Neutrino Oscillation %use this when you want a subtitle

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