Sung-chan Park

Recently a weak X-ray emission around Eγ≃3.5keV was detected in the Andromeda galaxy and various galaxy clusters including the Perseus galaxy cluster but its source has been unidentified. Axino, the superpartner of axion, with a mass 2Eγ is suggested as a possible origin of the line with R-parity violating decay into photon and neutrino. Moreover, most of parameter space is consistent with recent observation by the BICEP2 experiment.

Motivated by the recent observation of the high energy electron and positron excesses in cosmic ray by PAMELA and ATIC/PPB-BETS, we suggest an anomaly-free scenario for the universal extra dimension that localizes the standard model quarks and splits the spectrum of Kaluza-Klein (KK) quarks from KK leptons. When the SM quarks are ``well localized'' at the boundaries, the most stringent bound of the model ($1/R>510\text{ }\text{ }\mathrm{GeV}$) comes from the resonance search for the Tevatron

The recently reported excess in XENON1T is explained by new leptonic forces, which are free from gauge anomalies. We focus on two scenarios with and without dark matter. In Scenario #1, the gauge boson of gauged lepton number U(1)Le−Lj, j=μ or τ provides non-standard interaction between solar neutrino and electron that enhances the number of electron recoil events in the XENON1T detector. In Scenarino #2, the new gauge boson exclusively couples to electron and dark matter, then cosmic-ray electr

We single out the Starobinsky model and its extensions among generic f(R) gravity as attractors at large field values for chaotic inflation. Treating a R3 curvature term as a perturbation of the Starobinsky model, we impose the phenomenological bounds on the additional term satisfying the successful inflationary predictions. We find that the scalar spectral index can vary in both the red or blue tilted direction, depending on the sign of the coefficient of the R3 term, whereas the tensor-to-scal

Two non-motile, orange- or yellow-pigmented bacteria, designated strains KYW48(T) and KYW147(T), were isolated from seawater collected from the South Sea, Republic of Korea. Cells of both strains were Gram-reaction-negative, aerobic and catalase- and oxidase-positive. The major fatty acids of strain KYW48(T) were C(18 : 1)ω7c (35.3 %), summed feature 3 (iso-C(15 : 0) 2-OH and/or C(16 : 1)ω7c) (22.7 %), C(17 : 1)ω6c (19.8 %), C(14 : 0) 2-OH (7.4 %) and C(16 : 0) (5.9 %), and those of strain KYW14

The refined de Sitter derivative conjecture provides constraints to potentials that are low energy effective theories of quantum gravity. It can give direct bounds on inflationary scenarios and determine whether the theory is in the Landscape or the Swampland. We consider the ‘Higgs inflation’ scenario taking the refined de Sitter derivative conjecture into account. Obtaining the critical lines for the potential, we find a conjecture parameter space in which the ‘Higgs inflation’ is to be in the

We comprehensively study in the littlest Higgs model the phenomenology of the heavy $U(1)$ gauge boson ${B}_{H},$ which is the lightest of the newly introduced heavy gauge bosons and toplike vector quarks. Some unexpected behavior is that in the parameter space where the mass of ${B}_{H}$ is minimized the corrections to the electroweak precision observables are also suppressed. For the global symmetry breaking scale $f\ensuremath{\lesssim}3\mathrm{TeV},$ the ${B}_{H}$ is light enough to be produ

The refined de Sitter (dS) conjecture provides two consistency conditions for an effective theory potential of a quantum gravity theory. Any inflationary model can be checked by these conditions and minimal gauge inflation is not an exception. We develop a generic method to analyze a monotonically growing potential with an inflection point on the way to the plateau near the top such as the potential in minimal gauge inflation model and the Higgs inflation. Taking the latest observational data in

A new setup of cosmic inflation with a periodic inflaton potential and conformal factor is discussed in the metric and Palatini formulations of gravity. As a concrete example, we focus on a natural-inflation-like inflaton potential, and show that the inflationary predictions fall into the allowed region of cosmic microwave background observations in both formulations.

The recently observed excess in gamma-ray signal near the Galactic center suggests that dark matter particles may annihilate into charged fermions that produce gamma-ray to be observed. In this paper, we consider a leptonic dark matter, which annihilates into the standard model leptons , μ + μ − and τ + τ − , by the interaction of the gauged lepton number U ( 1 ) L μ − L τ and fits the observed excess. Interestingly, the necessary annihilation cross section for the observed gamma-ray flux provid

Split-UED allows for the possibility that the lowest lying KK excitations of the Standard Model fermions can be much lighter than the corresponding gauge or Higgs KK states. This can happen provided the fermion bulk masses are chosen to be large, in units of the inverse compactification radius, 1/R, and negative. In this setup, all of the other KK states would be effectively decoupled from low energy physics. Such a scenario would then lead to an apparent vector-like fourth generation with an as

An orange, rod-shaped, gliding bacterium, designated strain PSC33(T), was isolated from the gut microflora of a mussel collected from Gwangyang Bay, South Sea (Republic of Korea). Cells were Gram-reaction-negative, strictly aerobic, and catalase- and oxidase-positive. The major fatty acids were iso-C(15:0), iso-C(17:0) 3-OH, iso-C(15:1) G, C(15:0) 3-OH and iso-C(17:1)ω9c. The only isoprenoid quinone was menaquinone-6 (MK-6). The DNA G+C content of strain PSC33(T) was 37.9 mol%. A phylogenetic tr

Abstract The running of the Higgs self coupling may lead to numerous phenomena in early universe cosmology. In this paper we introduce a scenario where the Higgs running induces turns in the trajectory passing a region with tachyonic mass, leading to a temporal tachyonic growth in the curvature power spectrum. This effect induced by the Higgs leaves phenomena in the form of primordial black holes and stochastic gravitational waves, where proposed GW observatories will be able to probe in the nea