5204481
D0-brane recoil revisited
One-loop string scattering amplitudes computed using the standard D0-brane conformal field theory (CFT) suffer from infrared divergences associated with recoil. A systematic framework to take recoil into account is the worldline formalism, where fixed boundary conditions are replaced by dynamical D0-brane worldlines. We show that, in the worldline formalism, the divergences that plague the CFT are automatically cancelled in a non-trivial way. The amplitudes derived in the worldline formalism can be reproduced by deforming the CFT with a specific ``recoil operator'', which is bilocal and different from the ones previously suggested in the literature.
17332770
Notes on the S-matrix of bosonic and topological non-critical strings
We show that the equivalence between the c = 1 non-critical bosonic string and the = 2 topologically twisted coset SL(2)/U(1) at level one can be checked very naturally on the level of tree-level scattering amplitudes with the use of the Stoyanovsky-Ribault-Teschner map, which recasts H3+ correlation functions in terms of Liouville field theory amplitudes. This observation can be applied equally well to the topologically twisted SL(2)n/U(1) coset with n > 1, which has been argued recently to be equivalent with a c < 1 non-critical bosonic string whose matter part is defined by a time-like linear dilaton CFT.
117758947
OFF-SHELL BOUNDARY/CROSSCAP STATES AND ORIENTIFOLD PLANES ∗
It is well-known that extending string theory off-shell is a hard problem. In the first quantized string theory based on an action of a single string, the guiding principle is a local Weyl invariance of string worldsheets. This immediately translates into on-shellness of string scattering amplitudes. Off-shellness alone does not suggest any particular symmetry and one has to consider insertions of operators carrying dimensions of arbitrarily high degrees on the bulk of the string worldsheets: this is a hard task to carry out. Situation can be more manageable to handle if the local Weyl invariance is broken only on the boundaries of the worldsheets. To date there are two proposals for off-shell string theory through deformation on the boundary of the string worldsheets. The one is the boundary string field theory (BSFT) of Witten [1] on a unit disc and the other is the sigma model approach of open strings to the spacetime action S. (See for example Ref. [2] and the references therein.) To put simply,
121911984
Hydrodynamic Constants from Cosmic Censorship
We study a gravity dual of Bjorken flow of N = 4 SYM-theory plasma. We point out that the cosmic censorship hypothesis may explain why the regularity of the dual geometry constrains the hydrodynamic constants. We also investigate the apparent horizon of the dual geometry. We find that the dual geometry constructed on Fefferman-Graham (FG) coordinates is not appropriate for examination of the apparent horizon since the coordinates do not cover the trapped region. However, the preliminary analysis on FG coordinates suggests that the location of the apparent horizon is very sensitive to the hydrodynamic parameters.
31657279
Gravity dual of spatially modulated phase
We show that the five-dimensional Maxwell theory with the Chern-Simons term is tachyonic in the presence of a constant electric field. When coupled to gravity, a sufficiently large Chern-Simons coupling causes instability of the Reissner-Nordstrom black holes in anti-de Sitter space. The instability happens only at nonvanishing momenta, suggesting a spatially modulated phase in the holographically dual quantum field theory in (3+1) dimensions, with spontaneous current generation in a helical configuration. The three-charge extremal black hole in the type IIB superstring theory on AdS_5×S^5 barely satisfies the stability condition.
124769063
Holographic Mean-Field Theory for Baryon Many-Body Systems
85451103
Extraction of Meson Resonances from Three-pions Photo-production Reactions
We have investigated the model dependence of meson resonance properties extracted from the Dalitz-plot analysis of the three-pions photoproduction reactions on the nucleon. Within a unitary model developed in Phys. Rev. D 84, 114019 (2011), we generate Dalitz-plot distributions as data to perform an isobar model fit that is similar to most of the previous analyses of three-pion production reactions. It is found that the resonance positions from the two models agree well when both fit the data accurately, except for the resonance poles near branch points. The residues of the resonant amplitudes extracted from the two models and by the usual Breit-Wigner procedure agree well only for the isolated resonances with narrow widths. For overlapping resonances, most of the extracted residues could be drastically different. Our results suggest that even with high precision data, the resonance extraction should be based on models within which the amplitude parametrization is constrained by three-particle unitarity condition.
1110514
Renormalization group analysis of nuclear force
We study a relation between nuclear forces based on phenomenological approach ( V ph ) and nuclear effective field theory ( V EFT ) from a viewpoint of renormalization group. We find the relation between these two types of nuclear force using Wilsonian renormalization group equation. Considering the fact that V EFT is defined in a certain small model space, we show that a simple contact interaction accurately simulates short-distance physics, and that V EFT is free from dependence on modelling the details of the short-distance physics. Based on our result, we discuss some features of nuclear effective field theory.
14437805
Consideration of nuclear forces from the viewpoint of the renormalization group: Relation of nuclear forces between phenomenological approach and nuclear effective field theory
A relation between nuclear forces derived using a phenomenological approach and nuclear effective field theory (NEFT) is proposed from a renormalization group point of view. A phenomenological nuclear force (V ph ) and an NEFT-based NN-potential (V EFT ) are satisfactorily related to each other through the Wilsonian renormalization group (WRG) method. It is clearly shown that use of the simple contact interactions in NEFT is adequate to simulate small scale phenomena, and that an NEFT-based NN-potential (V EFT ) is free from dependence on the model used to describe small scale phenomena. We study the characteristics of V EFT from a WRG point of view, emphasizing points that have not previously been fully recognized. We also use the V low k method and a unitary transformation method to relate V ph to V EFT . It is found that they are not appropriate for this purpose.
117947270
Meson spectroscopy with unitary coupled-channels model for heavy-meson decay into three mesons
We develop a model for describing excited mesons decay into three mesons. The properties of the excited mesons can be extracted with this model. The model maintains the three-body unitarity that has been missed in previous data analyses based on the conventional isobar models. We study an importance of the three-body unitarity in extracting hadron properties from data. For this purpose, we use the unitary and isobar models to analyze the same pseudo data of gamma p -> pi+pi+pi-n, and extract the properties of excited mesons. We find a significant difference between the unitary and isobar models in the extracted properties of excited mesons, such as the mass, width and coupling strength to decay channels.
122375456
Renormalization group analysis of nuclear current operators
A Wilsonian renormalization group (WRG) equation for nuclear current operators in two-nucleon systems is derived. Nuclear current operators relevant to low-energy Gamow-Teller transitions are analyzed using the WRG equation. We employ the axial two-body current operators from phenomenological models and heavy-baryon chiral perturbation theory, which are quite different from one another in describing small-scale physics. After reducing the model space of the operators using the WRG equation, we find that there still remains a significant model dependence at {lambda}=200 MeV, where {lambda} is the sharp cutoff specifying the size of the model space. A model-independent effective current operator is found at a rather small cutoff value, {lambda}=70 MeV. By simulating the effective current operator at {lambda}=70 MeV, we obtain a current operator based on a pionless theory, thereby arguing that an equivalence relation exists between nuclear current operators of phenomenological models and those of effective field theories.