We consider a consistent extension of the SIMP models with dark mesons by including a dark U(1) D gauge symmetry. Dark matter density is determined by a thermal freeze-out of the 3 → 2 self-annihilation process, thanks to the Wess-Zumino-Witten term. In the presence of a gauge kinetic mixing between the dark photon and the SM hypercharge gauge boson, dark mesons can undergo a sufficient scattering off the Standard Model particles and keep in kinetic equilibrium until freeze-out in this SIMP scenario. Taking the SU(N f )×SU(N f )/SU(N f ) flavor symmetry under the SU(N c ) confining group, we show how much complementary the SIMP constraints on the parameters of the dark photon are for current experimental searches for dark photon. *

Noting the hierarchy between three mixing angles, θ2,3 = O(θ 2 1 ), we present an exact form of the quark mixing matrix, replacing Wolfenstein's approximate form. In addition, we suggest to rotate the unitarity triangle, using the weak CP phase convention where the phase is located at the (31) element sin θ1 sin θ2e iδ while the (13) element sin θ1 sin θ3 is real. For the (ab) unitarity triangle, the base line (x-axis) is defined from the product of the first row elements, V1aV * 1b , and the angle between two sides at the origin is defined to be the phase δ. This is a useful definition since every Jarlskog triangle has the angle δ at the origin, defined directly from the unitarity condition. It is argued that δ represents the barometer of the weak CP violation, which can be used to relate it to possible Yukawa textures.

Thermal production of light dark matter with sub-GeV scale mass can be attributed to 3 → 2 self-annihilation processes. We consider the thermal average for annihilation cross sections of dark matter at 3 → 2 and general higher-order interactions. A correct thermal average for initial dark matter particles is important, in particular, for annihilation cross sections with overall velocity dependence and/or resonance poles. We apply our general results to benchmark models for SIMP dark matter and discuss the effects of the resonance pole in determining the relic density.

Axino, related to the SUSY transformation of axion, can mix with goldstino in principle. This case is realized when some superfields carrying nonvanishing Peccei-Quinn charges develop both scalar VEVs and F-terms. In this case, we present a proper definition of axion and axino. With this definition, we present the QCD axino mass in the most general framework, including non-minimal K\"ahler potential. The axino mass is known to have a hierarchical mass structure depending on accidental symmetries. With only one axino, if $G_A=0$ where $G=K+\ln|W|^2$, we obtain $m_{\tilde a}=m_{3/2}$. For $G_A\ne 0$, the axino mass depends on the details of the K\"ahler potential. In the gauge mediation scenario, the gaugino mass is the dominant axino mass parameter. Therefore, we can take the theoretical QCD axino mass as a free parameter in the study of its cosmological effects, ranging from eV to multi-TeV scales, without a present knowledge on its ultraviolet completion.Comment: 11 pages, 5 figures, Formulae correcte

The dark axion portal is a recently introduced portal between the standard model and the dark sector. It connects both the dark photon and the axion (or axionlike particle) to the photon simultaneously through an anomaly triangle. While the vector portal and the axion portal have been popular venues to search for the dark photon and axion, respectively, the new portal provides new detection channels if they coexist. The dark axion portal is not a result of the simple combination of the two portals, and its value is not determined by the other portal values; it should be tested independently. In this paper, we discuss implications of the new portal for the leptonic g − 2, B factories, fixed target neutrino experiments and beam dumps. We provide the model-independent constraints on the axion-photon-dark photon coupling and discuss the sensitivities of the recently activated Belle-II experiment, which will play an important role in testing the new portal.

Nuclear factor E2-related factor 2 (Nrf2) is one of the most important redox-sensitive transcription factors regulating expression of antioxidative genes and cytoprotective enzymes, which constitute the cellular response to oxidative stress and xenobiotic damage. In this study, we investigated the functional role of Nrf2 during normal epidermal keratinocyte (NHEK) differentiation. Immunohistochemical staining showed that Nrf2 is expressed from basal to granular layer of epidermis. When cultured NHEKs were treated with 1.2 mM calcium, Nrf2 expression was increased gradually in protein levels and Nrf2 translocated into the nucleus in a differentiation-dependent manner. When Nrf2 was overexpressed in NHEK by adenoviral transduction, the expression of the NHEK differentiation marker loricrin and keratin 10 was increased and overexpression of Nrf2 also increased the luciferase activity of loricrin in the absence of calcium. These results suggest that Nrf2 helps to promote the differentiation of epidermal keratinocytes.

It is well known that the memory effect in flat spacetime is parametrized by the BMS supertranslation. We investigate the relation between the memory effect and diffeomorphism in de Sitter spacetime. We find that gravitational memory is parametrized by a BMS-like supertranslation in the static patch of de Sitter spacetime. We also show a diffeomorphism that corresponds to gravitational memory in the Poincare/cosmological patch. Our method does not need to assume the separation between the source and the detector to be small compared with the Hubble radius, and can potentially be applicable to other FLRW universes, as well as "ordinary memory" mediated by massive messenger particles.

We study the quantum mechanical evolution of the tensor perturbations during inflation with non-linear tensor interactions. We first obtain the Lindblad terms generated by non-linear interactions by tracing out unobservable sub-horizon modes. Then we calculate explicitly the reduced density matrix for the super-horizon modes, and show that the probability of maintaining the unitarity of the squeezed state decreases in time. The decreased probability is transferred to other elements of the reduced density matrix including off-diagonal ones, so the evolution of the reduced density matrix describes the quantum-to-classical transition of the tensor perturbations. This is different from the classicality accomplished by the squeezed state, the suppression of the non-commutative effect, which is originated from the quadratic, linear interaction, and also maintains the unitarity. The quantum-to-classical transition occurs within 5 -10 e-folds, faster than the curvature perturbation. state, they still maintain the trace of the density matrix unity. Then the pure state evolves into the mixed state, giving a non-trivial density matrix elements representing classical probability. This indeed invites us to use the Lindblad operators to describe the information paradox in Hawking radiation [17] and also similar phenomena in the inflationary cosmology. Therefore, we have two different aspects for the quantum-to-classical transition. First, the linear evolution leading to the squeezed state is evidently unitary process. Moreover, it corresponds to the quadratic sector in the action, in which the system-environment interaction does not appear. On the contrary, the Lindblad operators lead to non-unitary time evolution in both decoherence and generation of the mixed state. It comes from the system-environment interaction, which appears through non-linear interactions beyond quadratic order. Tiny non-Gaussianity constrained by recent observations on the CMB [30] implies that the non-linear effect is sub-dominant. Then we expect that the WKB-like "unitary" classicality achieved by the squeezed state, often referred to as the semi-classicality, is slowly converted into the "nonunitary" classicality through the Lindblad operators as a perturbation. The Lindblad operators provide the rate of such conversion, reflecting the specific form of the non-linear interactions.Previous studies on the non-unitary classicality considered the curvature perturbation as an example [25,26,27,28]. The curvature perturbation is interpreted as a Goldstone boson resulting from the spontaneous breaking of dS isometry by quasi dS background, which is parametrized by the slow-roll parameters [31] (see also [32,33]). This implies that small slowroll parameters make the conversion rate of unitary to non-unitary classicality very small, as analyzed in e.g. [27]. For the tensor perturbations, on the other hand, situation is different. Unlike the curvature perturbation, they are well defined even in perfect dS space-time, so the leading effect is irrelevant to the...