Mitsuru Kakizaki

Relic abundance of dark matter in the minimal universal extra dimension model

We investigate the relic abundance of dark matter in the minimal universal extra dimension model including resonance processes by second Kaluza-Klein (KK) particles in all coannihilation processes. After including second KK resonance processes, the relic abundance of dark matter is reduced by about 30%. Thus, the compactification scale 1/R of the extra dimension consistent with the WMAP observation is increased by a few hundred GeV. As a result, the cosmologically allowed compactification scale is 600 GeV < 1/R < 1400 GeV for Lambda R = 20.

Significant effects of second Kaluza-Klein particles on dark matter physics

We point out that Kaluza-Klein (KK) dark matter physics is drastically affected by second KK particles. In this work various interesting phenomena caused by the second KK modes are discussed. In particular, we reevaluate the annihilation cross section relevant to the thermal relic density of KK dark matter in universal extra dimension models. In these models, the first KK mode of a

Relic abundance of LKP dark matter in UED model including effects of second KK resonances

B

Abundance of cosmological relics in low-temperature scenarios

boson is a viable dark matter candidate by virtue of KK parity. We demonstrate that the KK dark matter annihilation cross section can be enhanced, compared with the tree-level cross section mediated only by first KK particles. The mass of the first KK mode of the

Hadronic EDMs in SUSY SU(5) GUTs with right-handed neutrinos

B

Hadronic EDM constraints on orbifold GUTs

boson consistent with the Wilkinson Microwave Anisotropy Probe observation is increased.

Cosmological Constraint on the Minimal Universal Extra Dimension Model

Abstract We re-evaluate the thermal relic density of the Kaluza–Klein (KK) dark matter in universal extra dimension models. In particular, we consider the effect of the resonance caused by second KK particles on the density. We find that the annihilation cross sections relevant to the density are significantly enhanced due to the resonance when the Higgs boson mass is large enough ( m h ≳ 200 GeV ). As a result, the mass of the dark matter particle consistent with the WMAP observation is increased compared to the result which does not include any resonance.

Hadronic EDMs in SUSY GUTs

We investigate the relic density n_\chi of non-relativistic long-lived or stable particles \chi in cosmological scenarios in which the temperature T is too low for \chi to achieve full chemical equilibrium. The case with a heavier particle decaying into \chi is also investigated. We derive approximate solutions for n_\chi(T) which accurately reproduce numerical results when full thermal equilibrium is not achieved. If full equilibrium is reached, our ansatz no longer reproduces the correct temperature dependence of the \chi number density. However, it does give the correct final relic density, to an accuracy of about 3% or better, for all cross sections and initial temperatures.

Report by the Committee on the Scientific Case of the ILC Operating at 250 GeV as a Higgs Factory

Abstract We discuss hadronic EDM constraints on the neutrino sector in the SUSY SU(5) GUT with the right-handed neutrinos. The hadronic EDMs are sensitive to the right-handed down-type squark mixings, especially between the second and third generations and between the first and third ones, compared with the other low-energy hadronic observables, and the flavor mixings are induced by the neutrino Yukawa interaction. The current experimental bound of the neutron EDM may imply that the right-handed tau neutrino mass is smaller than about 10 14 GeV in the minimal supergravity scenario, and it may be improved furthermore in future experiments, such as the deuteron EDM measurement.

Constraints on the Very Early Universe from WIMP Dark Matter

We point out that the null results of the hadronic electric dipole moment (EDM) searches constrain orbifold grand unified theories (GUTs), where the GUT symmetry and supersymmetry (SUSY) are both broken by boundary conditions in extra dimensions and it leads to rich fermion and sfermion flavor structures. A marginal chromoelectric dipole moment (CEDM) of the up quark is induced by the misalignment between the CP violating left- and right-handed up-type squark mixings, in contrast to the conventional four-dimensional SUSY GUTs. The up quark CEDM constraint is found to be as strong as those from charged lepton flavor violation (LFV) searches. The interplay between future EDM and LFV experiments will probe the structures of the GUTs and the SUSY breaking mediation mechanism.