Strong First Order EWPT and Strong Gravitational Waves in Z3Z_3-symmetric Singlet Scalar Extension

The nature of electroweak (EW) phase transition (PT) is of great importance. It may give a clue to the origin of baryon asymmetry if EWPT is strong first order. Although it is second order within the standard model (SM), a great many extensions of the SM are capable of altering the nature. Thus, gravitational wave (GW), which is supposed to be relics of strong first order PT, is a good complementary probe to new physics beyond SM (BSM). We in this paper elaborate the patterns of strong first order EWPT in the next to simplest extension to the SM Higgs sector, by introducing a $Z_3$-symmetric singlet scalar. We find that, in the $Z_3$-symmetric limit, the tree level barrier could lead to strong first order EWPT either via three or two-step PT. Moreover, they could produce two sources of GW, despite of the undetectability from the first-step strong first order PT for the near future GW experiments. But the other source with significant supercooling which then gives rise to $\alpha\sim{\cal O}(0.1)$ almost can be wholly covered by future space-based GW interferometers such as eLISA, DECIGO and BBO.Comment: references adde

New Avenues to Heavy Right-handed Neutrinos with Pair Production at Hadronic Colliders

In many models incorporating the type-I seesaw mechanism, the right-handed neutrino ($N$) couples to heavy vector/scalar bosons and thereby has resonant pair production. It barely receives attention thus far, however, it may provide the best avenue to probe TeV scale $N$ without requiring anomalously large mixing between $N$ and the active neutrino $\nu_L$. In this paper we explore the discovery prospects of (mainly heavy) $N$ pair production at the 14 TeV LHC and future 100 TeV $pp$ collider, based on the three signatures: 1) trilepton from $N(\rightarrow \ell W_\ell)N(\rightarrow \ell W_h)$ with $W_{\ell/h}$ the leptonically/hadronically decaying $W$; 2) boosted di-Higgs boson plus MET from $N(\rightarrow \nu_L h)N(\rightarrow \nu_L h)$; 3) a single boosted Higgs with leptons and MET from $N(\rightarrow \ell W_\ell)N(\rightarrow \nu_L h)$. At the 100 TeV collider, we also consider the situation when the Higgs boson is over boosted thus losing its jet substructure. Interpreting our tentative results in the benchmark model, the local $B-L$ model, we find that the (multi-) TeV scale $N$ can be probed at the (100) 14 TeV colliders.Comment: 34 pages, 8 figures, version to be published in Phys. Rev.

Neutrino Oscillations and Lepton Flavor Mixing

In view of the recent announcement on non-zero neutrino mass from Super-Kamiokande experiment, it would be very timely to investigate all the possible scenarios on masses and mixings of light neutrinos. Recently suggested mass matrix texture for the quark CKM mixing, which can be originated from the family permutation symmetry and its suitable breakings, is assumed for the neutrino mass matrix and determined by the four combinations of solar, atmospheric and LSND neutrino data and cosmological hot dark matter bound as input constraints. The charged-lepton mass matrix is assumed to be diagonal so that the neutrino mixing matrix can be identified directly as the lepton flavor mixing matrix and no CP invariance violation originates from the leptonic sector. The results favor hierarchical patterns for the neutrino masses, which follow from the case when either solar-atmospheric data or solar-HDM constraints are used.Comment: Latex, 9 page

Empirical Evidences from a Coffee Paradox: An Export Supply/Price Asymmetry Approach

This paper aims to determine the solidity of the notion of the "coffee paradox" using annual data from 1977 to 2007. In the confines of an export supply model, we analyze the effects of export coffee price on export volume. Price and profit equation are used to determine the effects of market power on export coffee price and measure changes in the retail and export price. We also estimate the elasticity of transmission and price asymmetry as a means of verifying the "coffee paradox." Ordinary Least Square (OLS), Instrumental Variables (IV), and simultaneous equation with Seemingly Unrelated Regressions (SUR) methods of econometric analysis are employed. Empirical results suggest that the world coffee market is characterized by "coffee paradox" due to different changes between retail and export prices of coffee, and that it is the existence of market power in importing countries that is the main contributor to the condition of price asymmetry.export supply model, coffee paradox, elasticity of transmission, price asymmetry, price equation, profit equation, Agribusiness, Agricultural and Food Policy, Consumer/Household Economics, Demand and Price Analysis, International Relations/Trade,

Bilateral Trade and Economic Growth: The Empirical Evidence Between U.S. and South Korea

This paper analyzes the relationships between bilateral trade and economic growth in the U.S. and Korean economies. Using quarterly data from 1990 to 2008, the theoretical procedures utilize Ordinary Least Square (OLS) and Seemingly Unrelated Regression (SUR) models under the static model assumption, an Impulse Response Function (IRF) and Forecast Error Variation Decomposition (FEVD) under the Vector Autoregressive (VAR) model, and Granger causality tests. Empirical results indicate a causal relationship between bilateral export growth and economic growth for the U.S. and Korean economies. The export-led growth (ELG) hypothesis is strongly supported by the results of Granger causality tests on Korean exports.export-led growth, bilateral trade, Granger causality, South Korea, United States, International Relations/Trade, Political Economy, Production Economics,

Effect of Charge Fluctuations on the Persistent Current through a Quantum Dot

We study coherent charge transfer between an Aharonov-Bohm ring and a side-attached quantum dot. The charge fluctuation between the two sub-structures is shown to give rise to algebraic suppression of the persistent current circulating the ring as the size of the ring becomes relatively large. The charge fluctuation at resonance provides transition between the diamagnetic and the paramagnetic states. Universal scaling, crossover behavior of the persistent current from a continuous to a discrete energy limit in the ring is also discussed.Comment: 5 pages, 4 figure

Spin Fluctuation Induced Dephasing in a Mesoscopic Ring

We investigate the persistent current in a hybrid Aharonov-Bohm ring - quantum dot system coupled to a reservoir which provides spin fluctuations. It is shown that the spin exchange interaction between the quantum dot and the reservoir induces dephasing in the absence of direct charge transfer. We demonstrate an anomalous nature of this spin-fluctuation induced dephasing which tends to enhance the persistent current. We explain our result in terms of the separation of the spin from the charge degree of freedom. The nature of the spin fluctuation induced dephasing is analyzed in detail.Comment: 4 pages, 4 figure