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S. Baek

Publications and source records attributed to S. Baek.

26 records · Page 2Linked to original sources
arXiv2001

Data Acquisition and Database Management System for Samsung Superconductor Test Facility

In order to fulfill the test requirement of KSTAR (Korea Superconducting Tokamak Advanced Research) superconducting magnet system, a large scale superconducting magnet and conductor test facility, SSTF (Samsung Superconductor Test Facility), has been constructed at Samsung Advanced Institute of Technology. The computer system for SSTF DAC (Data Acquisition and Control) is based on UNIX system and VxWorks is used for the real-time OS of the VME system. EPICS (Experimental Physics and Industrial Control System) is used for the communication between IOC server and client. A database program has been developed for the efficient management of measured data and a Linux workstation with PENTIUM-4 CPU is used for the database server. In this paper, the current status of SSTF DAC system, the database management system and recent test results are presented.

cs.DB↗
arXiv2001

Muon anomalous magnetic moment, $B\to X_s γ$ and dark matter detection in the string models with dilaton domination

We consider the muon anomalous magnetic moment $a_μ$ in the string models with dilaton domination with two different string scales : the usual GUT scale and the intermediate scale. After imposing the direct search limits on the lightest neutral Higgs and SUSY particle masses and the lightest neutralino LSP, the $a_μ^{\rm SUSY}$ is predicted to be less than $65 (55) \times 10^{-10}$ for $M_{string} = 2 \times 10^{16}$ GeV ($3 \times 10^{11}$ GeV). If we further impose the $B\to X_s γ$ branching ratio, the predicted $a_μ^{\rm SUSY}$ becomes lower to $35 \times 10^{-10}$ for intermediate string scale. The resulting LSP - proton scattering cross section is less than $\sim 10^{-7}$ pb, which is below the sensitivity of the current direct dark matter search experiments, but could be covered by future experiments.

hep-ph↗
arXiv2001

Gluino-squark contributions to CP violations in the kaon system

Recently it was shown, within the mass insertion approximation (MIA), that the gluino mediated flavor changing neutral current (FCNC) interactions can saturate both epsilon_K and Re(epsilon'/epsilon_K) even for the real Cabibbo-Kobayashi-Maskawa (CKM) matrix through a single CP violating parameter (delta^d_12)_LL. In this work, we extend our previous analysis to the nonvanishing KM phase, and to the effective SUSY model where the MIA is no longer a good approximation. In our model, epsilon_K and B0 - B0 bar mixing can receive significant SUSY contributions. Therefore the usual constraints on rho and eta in the Wolfenstein parametrization of the CKM matrix can be relaxed except for the |V_ub/V_cb| from the semileptonic b -> u transition. This affects K -> pi nu nu bar and K_L -> mu+ mu- indirectly, even if they are not directly induced by gluino-mediated FCNC, while K_L -> pi0 e+ e- is influenced both directly and indirectly. Differences between our model and other SUSY models enhancing Re(epsilon'/epsilon_K) are discussed in detail.

hep-ph↗
arXiv2001

Muon Anomalous $g -2$ and Gauged $L_μ- L_τ$ Models

In this paper we study $Z'$ contribution to $g -2$ of the muon anomalous magnetic dipole moment in gauged $U(1)_{L_μ- L_τ}$ models. Here $L_i$ are the lepton numbers. We find that there are three classes of models which can produce a large value of $g-2$ to account for possible discrepancy between the experimental data and the Standard Model prediction. The three classes are: a) Models with an exact $U(1)_{L_μ- L_τ}$. In these models, $Z'$ is massless. The new gauge interaction coupling $e a/\cosθ_W$ is constrained to be $ 0.8\times 10^{-3} < |a| < 2.24\times 10^{-3}$. b) Models with broken $U(1)_{L_μ- L_τ}$ and the breaking scale is not related to electroweak symmetry breaking scale. The $Z'$ gauge boson is massive. The allowed range of the coupling and the $Z'$ mass are constrained, but $Z'$ mass can be large; And c) The $U(1)_{L_μ-L_τ}$ is broken and the breaking scale is related to the electroweak scale. In this case the $Z'$ mass is constrained to be $\sim 1.2$ GeV. We find that there are interesting experimental signatures in $μ^+μ^-\to μ^+μ^-, τ^+τ^-$ in these models.

hep-ph↗
arXiv2000

Fully supersymmetric CP violations in the kaon system

We show that, on the contrary to the usual claims, fully supersymmetric CP violations in the kaon system are possible through the gluino mediated flavor changing interactions. Both $ε_K$ and ${\rm Re} (ε' / ε_K)$ can be accommodated for relatively large $\tanβ$ without any fine tunings or contradictions to the FCNC and EDM constraints.

hep-ph↗
arXiv2000

Fully supersymmetric CP violations in the kaon system

We show that, on the contrary to the usual claims, fully supersymmetric CP violations in the kaon system are possible through the gluino mediated flavor changing interactions. Both $ε_K$ and ${\rm Re} (ε' / ε_K)$ can be accommodated for relatively large $\tanβ$ without any fine tunings or contradictions to the FCNC and EDM constraints.

hep-ph↗
arXiv2000

Single Charged Higgs production as a probe of CP violation at a Muon Collider

We consider single charged Higgs ($H^{\pm}$) production in association with a $W^{\pm}$ boson at $μ^+μ^-$ colliders, in the context of the general CP violating Two Higgs Doublet Model (2HDM). We find that large cross-sections for the processes $μ^+μ^-\to H^+W^-,H^-W^+$ are possible, and offer an attractive way of producing $H^{\pm}$ at $μ^+μ^-$ colliders. The difference in the cross-sections for $H^+W^-$ and $H^-W^+$ may exceed 1000 fb, and this represents a novel way of probing CP violation in the Higgs sector.

hep-ph↗
arXiv1999

Effects of $A_t$ and $μ$ phases on B and K physics in the effective supersymmetric models

In the minimal supersymmetric standard model (MSSM), the $μ-$parameter and the trilinear coupling $A_t$ may be generically complex and can affect various observables at B factories. Working in the effective SUSY models and imposing the edm constraints from Chang-Keung-Pilaftsis (CKP) mechanism, we find that (i) there is no new large phase shift in the $B^0 - \bar{B^0}$ mixing from the A_t and $μ$ phases, (ii) CP violating dilepton asymmetry is smaller than 0.1%, (iii) the direct CP violation in $B\to X_s γ$ can be as large as $\sim \pm 16 %$, (iv) the ${\rm Br} (B\to X_s l^+ l^-)$ can be enhanced by upto $\sim 85 %$ compared to the standard model (SM) prediction, and its correlation with ${\rm Br} (B \to X_s γ)$ is distinctly different from the minimal supergravity scenario. Also, we find $1 \leq ε_K / ε_K^{SM} \leq 1.4$, and $ε_K$ cannot be saturated by the A_t and $μ$ phases alone : namely, $|ε_K^{\rm SUSY}| \leq O(10^{-5})$ if the phases of $μ$ and A_t are the sole origin of CP violation.

hep-ph↗