Solving cosmological problem in universal extra dimension models by introducing Dirac neutrino

Universal extra dimension (UED) models with right-handed neutrinos are studied. The introduction of the neutrinos makes us possible not only to describe Dirac neutrino masses but also to solve the cosmological problem called the KK graviton problem. This problem is essentially caused by the late time decay of a KK photon into a KK graviton and a photon, and it distorts the spectrum of the cosmic microwave background or the diffuse photon. We point out that, once we introduce right-handed neutrinos to UED models, the KK photon decays dominantly into neutrinos and does not emit a photon. We also discuss sub-dominant modes with a photon in the decay quantitatively, and show that their branching ratios are so small that the spectra are not distorted.Comment: Some discussions are added

The neutrino masses and the change of allowed parameter region in universal extra dimension models

Relic abundance of dark matter is investigated in the framework of universal extra dimension models with right-handed neutrinos. These models are free from the serious Kaluza-Klein (KK) graviton problem that the original universal extra dimension model possesses. The first KK particle of the right-handed neutrino is a candidate for dark matter in this framework. When ordinary neutrino masses are large enough such as the degenerate mass spectrum case, the dark matter relic abundance can change significantly. The scale of the extra dimension consistent with cosmological observations can be 500 GeV in the minimal setup of universal extra dimension models with right-handed neutrinos.Comment: 3 pages, to appear in the conference proceedings of TAUP 200

Relic abundance of dark matter in universal extra dimension models with right-handed neutrinos

Relic abundance of dark matter is investigated in the framework of universal extra dimension models with right-handed neutrinos. These models are free from the serious Kaluza-Klein (KK) graviton problem that the original universal extra dimension model has. The first KK particle of the right-handed neutrino is a candidate for dark matter in this framework, and its relic abundance is determined by three processes, (1) the decay of the KK photon into the first KK right-handed neutrino in the late universe, (2) production of the first KK right-handed neutrino from the thermal bath in the early universe, and (3) the decay of higher KK right-handed neutrinos into the first KK right-handed neutrino in the late universe. When ordinary neutrino masses are large enough such as the degenerate mass spectrum case, the last process contribute to the abundance significantly, even if the reheating temperature is low. The scale of the extra dimension consistent with cosmological observations can be 500 GeV in the minimal setup of universal extra dimension models with right-handed neutrinos.Comment: added references, changed figure 3 and figure

Production Rate of Second KK Gauge Bosons in UED Models at LHC

We calculate the production rates of the second Kaluza-Klein (KK) photon $\gamma^{(2)}$ and Z boson $Z^{(2)}$ at the LHC including all significant processes in the minimal universal extra dimension (MUED) model. For discrimination of the MUED model from other TeV scale models in hadron collider experiments, $\gamma^{(2)}$ and $Z^{(2)}$ play a crucial role. In order to discuss the discrimination and calculate their production rates, we derive effective Lagrangian containing KK number violating operators. We show that KK number violating processes are extremely important for the compactification scale larger than 800 GeV. We find that, with an integrated luminosity of 100 fb$^{-1}$, $\gamma^{(2)}$ and $Z^{(2)}$ are produced 10$^6$ - 10$^2$ for the compactification scale between 400 GeV and 2000 GeV.Comment: To appear in the proceedings of Particle Physics, Astrophysics and Quantum Field Theory: 75 Years since Solvay, Nanyang Executive Center, Singapore, 27-29 Nov 200

Productions of second Kaluza-Klein gauge bosons in the minimal universal extra dimension model at LHC

We calculate the production rates of the second Kaluza-Klein (KK) photon $\gamma^{(2)}$ and Z boson $Z^{(2)}$ at the LHC including all significant processes in the minimal Universal Extra Dimension (MUED) model. For discrimination of the MUED model from other TeV scale models at the LHC, $\gamma^{(2)}$ and $Z^{(2)}$ play a crucial role. In order to discuss the discrimination and calculate their production rates, we derive KK number violating operators including the contribution of the top Yukawa coupling. Using these operators, we accurately calculate branching ratios of second KK particles. In addition we find that these KK number violating operators provide new processes for $\gamma^{(2)}$ and $Z^{(2)}$ productions, such as cascade decay from second KK quarks produced through these operators. They have large contributions to their total production rates. In particular, these production processes give the dominant contribution for $\gamma^{(2)}$ production for $1/R \gtrsim 800$ GeV. As a result, with an integrated luminosity of 100 fb$^{-1}$, the number of produced $\gamma^{(2)}$ and $Z^{(2)}$ are estimated as 10$^6$ - 10$^2$ for the compactification scale between 400 GeV and 2000 GeV.Comment: 21 pages, reference added, version to appear in PR

Nonexponential decay of an unstable quantum system: Small-QQ-value s-wave decay

We study the decay process of an unstable quantum system, especially the deviation from the exponential decay law. We show that the exponential period no longer exists in the case of the s-wave decay with small $Q$ value, where the $Q$ value is the difference between the energy of the initially prepared state and the minimum energy of the continuous eigenstates in the system. We also derive the quantitative condition that this kind of decay process takes place and discuss what kind of system is suitable to observe the decay.Comment: 17 pages, 6 figure

Universal Extra Dimension models with right-handed neutrinos

Relic abundance of dark matter is investigated in the framework of universal extra dimension (UED) models with right-handed neutrinos. These models are free from the KK graviton problem in the minimal UED model. The first KK particle of the right-handed neutrino is a dark matter candidate in this framework. When ordinary neutrino masses are large enough such as the degenerate mass spectrum case, the dark matter relic abundance can increase significantly. The scale of the extra dimension consistent with cosmological observations can be 500 GeV in the minimal setup of UED models with right-handed neutrinos.Comment: The proceedings of UAE - CERN Workshop On High Energy Physics And Applications, 26-28 Nov 2007, Al Ain, Abu Dhabi, United Arab Emirate

Re-Evaluation of the PBAN Receptor Molecule: Characterization of PBANR Variants Expressed in the Pheromone Glands of Moths

Sex pheromone production in most moths is initiated following pheromone biosynthesis activating neuropeptide receptor (PBANR) activation. PBANR was initially cloned from pheromone glands (PGs) of Helicoverpa zea and Bombyx mori. The B. mori PBANR is characterized by a relatively long C-terminus that is essential for ligand-induced internalization, whereas the H. zea PBANR has a shorter C-terminus that lacks features present in the B. mori PBANR critical for internalization. Multiple PBANRs have been reported to be concurrently expressed in the larval CNS of Heliothis virescens. In the current study, we sought to examine the prevalence of multiple PBANRs in the PGs of three moths and to ascertain their potential functional relevance. Multiple PBANR variants (As, A, B, and C) were cloned from the PGs of all species examined with PBANR-C the most highly expressed. Alternative splicing of the C-terminal coding sequence of the PBAN gene gives rise to the variants, which are distinguishable only by the length and composition of their respective C-terminal tails. Transient expression of fluorescent PBANR chimeras in insect cells revealed that PBANR-B and PBANR-C localized exclusively to the cell surface while PBANR-As and PBANR-A exhibited varying degrees of cytosolic localization. Similarly, only the PBANR-B and PBANR-C variants underwent ligand-induced internalization. Taken together, our results suggest that PBANR-C is the principal receptor molecule involved in PBAN signaling regardless of moth species. The high GC content of the C-terminal coding sequence in the B and C variants, which makes amplification using conventional polymerases difficult, likely accounts for previous “preferential” amplification of PBANR-A like receptors from other species