Quark tensor charge and electric dipole moment within the Schwinger-Dyson formalism

We calculate the tensor charge of the quark in the QCD-like theory in the Landau gauge using the Schwinger-Dyson formalism. It is found that the dressed tensor charge of the quark is significantly suppressed against the bare quark contribution, and the result agrees qualitatively with the analyses in the collinear factorization approach and lattice QCD. We also analyze the quark confinement effect with the phenomenological strong coupling given by Richardson, and find that this contribution is small. We show that the suppression of the quark tensor charge is due to the superposition of the spin flip of the quark arising from the successive emission of gluons which dress the tensor vertex. We also consider the relation between the quark and the nucleon electric dipole moments by combining with the simple constituent quark model.Comment: 16 pages, 11 figures. arXiv admin note: text overlap with arXiv:1401.285

Quark scalar, axial, and pseudoscalar charges in the Schwinger-Dyson formalism

We calculate the scalar, axial, and pseudoscalar charges of the quark in the Schwinger-Dyson formalism of Landau gauge QCD. It is found that the dressed quark scalar density of the valence quark is significantly enhanced against the bare quark contribution, and the result explains qualitatively the phenomenologically known value of the pion-nucleon sigma term and also that given by lattice QCD. Moreover, we show that the Richardson's interquark potential suppresses the quark scalar density in the Higashjima-Miransky approximation. This fact suggests that the quark scalar density is an observable that is sensitive to quark confinement. For the quark axial charge, we find that it is suppressed due to the gluon dynamics. The result of the quenched analysis agrees qualitatively with the experimental data of the isovector axial coupling constant $g_A$. We show that the suppression of the quenched axial charge is due to a mechanism similar to that of the quark tensor charge. In the Schwinger-Dyson equation with the leading unquenching quark-loop contribution the quark axial charge is more suppressed, due to the anomaly effect. The quark pseudoscalar density is found to be large, and is divergent as the bare quark becomes massless. This result is in agreement with the phenomenological current algebraic analysis, and explains well the dominance of the pion-pole contribution.Comment: 28 pages, 22 figure

ANALYSIS OF ROLES OF TAXI SERVICE AND TAXI SUBSIDY SCHEME FOR MOBILITY OF ELDERLY PEOPLE LIVING IN DEPOPULATED AREAS

With an increasingly aging population and the deregulation of policies concerning public transportation, securing the mobility of elderly people, especially those living in rural areas, has become a serious problem. This study aimed to clarify the actual conditions and issues for elderly people when using taxi services, and to examine the role of a taxi subsidy scheme (TSS) as a future policy for securing the mobility of elderly people in rural areas. By using a web questionnaire survey with 300 people over 65 years old and able to go out by themselves, a comparative analysis was conducted between three focus groups: people with private cars, people without a private car and with no TSS, and people supported by a TSS. The results show that the TSS has a certain effect on ensuring mobility for the elderly in depopulated areas. People without the ability to use public or private transportation freely showed a strong desire to increase the subsidy rate and number of usage instances. In view of this, the utilization of a “shared taxi” reservation type is suggested for improving the subsidy rate

AN ANALYSIS FOR BUSINESS CONDITION OF SMALL AND MEDIUM-SIZED TAXI COMPANIES IN LOCAL AREAS OF JAPAN : SITUATION UNDER COVID-19 CRISIS AND ROLE OF TAXI SUBSIDY SCHEME

Taxi is an important means of transportation that forms local public transportation. However, the declining trend of users in the long-term did not change, in addition to this, taxi business is facing various challenges increasingly during the COVID-19 crisis. In this paper, a survey was conducted to examine the actual condition and perspectives of small and medium sized taxi companies in whole Japan, impact of COVID-19 crisis on business management and the role of Taxi Subsidy Scheme (TSS). As a result, more than 50% of companies are facing the 60% drop on business sale compared to last year caused by the pandemic. As a role of Taxi Subsidy Scheme (TSS) on taxi business, about half of the companies said that TSS is an important service content, especially with small and medium sized companies, and by quantitative analysis of the business sale, we found that TSS has significant effect on the sale for taxi companies with 6 to 10 vehicles