String Junction Model, Cluster Hypothesis, Penta-Quark Baryon and Tetra-Quark Meson

Thirty years ago we proposed string junction model of hadrons and examined structure and reaction of hadrons including exotic ones. Mass $m$ of exotic hadrons of light quarks is roughly given by $m \sim N_J\cdot m_B$, where $N_J$ is the total number of junctions and $m_B \sim 1$ GeV is the ordinary light baryon mass. In this paper we introduce "cluster hypothesis" into the model by which mass of a complex hadron is given by the sum of masses of clusters composing it. The hypothesis guarantees the established picture that mass differences of hadrons of the same string junction structure are due to those of the constituent quarks. A candidate for penta-quark baryon $\Theta$(1530 MeV, $S=+1)$ including a strange anti-quark {\sb} and that for tetra-quark meson $Z^+$(4430 MeV) recently reported by the Bell collaboration are examined in parallel. $\Theta$ is considered to have non-strange partners, which are lighter by the mass difference $\Delta_s$ between strange and non-strange quarks. Mass of such light penta-quark baryons with $N_J=3$ is expected to be about 3 GeV. Several parameters of the model are estimated such as mass of junction of $m_J \sim O(10)$ MeV. While mass of light tetra-quark meson with $N_J=2$ is expected to be about 2 GeV, $Z^+$(4430 MeV) containing (u,c,{\db},{\cb}) gives a clue to determine some parameters of the model, e.g., inter-junction string energy $m_{IJ}$.Comment: 17 pages, 4 figures, correction is made, extensively revise

Fermion Scattering off CP-Violating Electroweak Bubble Wall

A general prescription to solve the Dirac equation in the presence of CP-violating electroweak bubble wall is presented. The profile of the bubble wall is not specified except that the wall height is $m_0$ and zero deep in the broken- and the symmetric-phase regions, respectively, where $m_0$ is a fermion mass given by the Higgs-vacuum-expectation value and the Yukawa coupling. The CP-violating effects are evaluated by regarding CP-violating part of the bubble wall as a perturbation to CP-conserving solutions. The basic quantity, $R_{R\rightarrow L}-\bar R_{R\rightarrow L}$, which would contribute to the cosmological baryon asymmetry, is estimated for some typical profiles of the wall, where $R_{R\rightarrow L}$($\bar R_{R\rightarrow L}$) is the reflection coefficient of right-handed chiral fermion (anti-fermion).Comment: 30 pages, 2 figures ( uuencoded tar.Z file of PS files is appended ), plain TeX with phyzzx, tables and epsf,SAGA-HE-55--KYUSHU-HET-1

Transitional CP Violation in the MSSM and Electroweak Baryogenesis

Electroweak baryogenesis depends on the profile of the bubble wall created in the first-order phase transition. It is pointed out that CP violation in the Higgs sector of the MSSM could become large enough to explain the baryon asymmetry. We confirm this by solving the equations of motion for the Higgs fields with the effective potential at the transition temperature. That is, we present an example such that the transitional CP violation is realized and show the possibility that the baryon asymmetry of the universe may be produced, if marginally, by the $\tau$ lepton interacting with the wall, when an explicit CP breaking in the Higgs sector, which is consistent with experimental bounds, is induced at the phase transition.Comment: LaTeX2e, 18 pages with 7 eps files of figure

Low-dose versus standard-dose alteplase in acute ischemic stroke in Asian stroke registries: an individual patient data pooling study

10.1177/1747493019858777INTERNATIONAL JOURNAL OF STROKE147670-67

Direct oral anticoagulants versus vitamin K antagonists after recent ischemic stroke in patients with atrial fibrillation

Objective: We compared outcomes after treatment with direct oral anticoagulants (DOAC) and Vitamin‐K antagonists (VKA) in patients with atrial fibrillation (AF) and a recent cerebral ischemia. Methods: We conducted an individual patient data analysis of 7 prospective cohort studies. We included patients with AF and a recent cerebral ischemia (<3 months before starting oral anticoagulation) and a minimum follow‐up of 3 months. We analyzed the association between type of anticoagulation (DOAC vs. VKA) with the composite primary endpoint (recurrent ischemic stroke [AIS], intracerebral hemorrhage [ICH], or mortality) using mixed effects Cox proportional hazards regression models; we calculated adjusted hazard ratios (HR) with 95% confidence intervals (95% CI). Results: We included 4912 patients (median age 78 years [IQR 71‐84]; 2331 [47.5%] women, median NIHSS at onset 5 [IQR 2‐12]); 2256 (45.9%) patients received VKA and 2656 (54.1%) DOAC. The median time from index event to starting oral anticoagulation was 5 days (IQR 2‐14) for VKA and 5 days (IQR 2‐11) for DOAC (p=0.53). There were 262 AIS (4.4%/year), 71 ICH (1.2%/year) and 439 deaths (7.4%/year) during the total follow‐up of 5970 patient‐years. Compared to VKA, DOAC treatment was associated with reduced risks of the composite endpoint (HR 0.82, 95%CI 0.67‐1.00, p=0.05) and ICH (HR 0.42, 95%CI 0.24‐0.71, p<0.01); we found no differences for the risk of recurrent AIS (HR 0.91, 95%CI 0.70‐1.19, p=0.5) and mortality (HR 0.83, 95%CI 0.68‐1.03, p=0.09). Interpretation: DOAC treatment commenced early after recent cerebral ischemia related to AF was associated with reduced risk of poor clinical outcomes compared to VKA, mainly due to lower risks of ICH