2007 Fiscal Year Final Research Report Summary
Study of Pentaquark Baryons uainp String Theories
| Project/Area Number |
17540238
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Particle/Nuclear/Cosmic ray/Astro physics
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| Research Institution | Ochanomizu University |
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Principal Investigator |
SUGAMOTO Akio Ochanomizu University, Graduate School of Humanities and Sciences, Professor (70132686)
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| Co-Investigator(Kenkyū-buntansha) |
BANDO Masako Aichi U, Department of Law, Professor (20025365)
KUGO Taichi Kyoto U., Yukawa Institute for Fundamental Research, Professor (00115833)
CHO Gi-chol Ochanomizu U., Graduate School of Humanities and Sciences, Associate Professor (10323859)
IMAMURA Yosuke Tokyo U., Graduate School of Sciences, Assistant Professor (80323492)
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| Project Period (FY) |
2005 – 2007
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| Keywords | Pentaquarks / Superstrings / Dual Gravity Theory |
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| Research Abstract |
This research project is to study the lightness of the mass and the smallness of the decay width of Pentaquark baryons found in 2003 at Spring-8. Energy of string junctions existing in the string model of Pentaquarks is estimated, using a QCD-like string theory. The negative value for the junction energy is obtained. Therefore, increasing the number of junctions, we may have a fullerene-like objects having strings and junctions. In the study of the shape of mesons and of the potential between quarks, we have found that the shape of string is changed depending on its length. At a certain length the potential between quarks is found to have a point of inflection. Hence the potential inside the hadronic matter becomes deep if heavy flavor is included, so that we may understand the phenomenon of such a hadronic matter being more dense.
Introduction of spin into hadrons in string theory is studied using two dimensional non-linear sigma model. We have found that the more than 60% of the spin of hadron is distributed in the middle part of the string, and so the result may explain the spin crisis. The kinetic term of string is necessary in evaluating the mass and the decay width of hadrons. The method to include this term is studied using the string field theory and the WKB approximation. The mass of glueballs is studied using the duality between the non-commutative gauge theory and the gravity. Using the Bars-Hanson string model in which the fields are placed at both ends of an open string, the non-Abelian Born-Infeld action, the effective action of string, is derived naturally.
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