8346546
Integrable open spin chain in super Yang-Mills and the plane-wave/SYM duality
We investigate the integrable structures in an = 2 superconformal Sp(N) Yang-Mills theory with matter, which is dual to an open+closed string system. We restrict ourselves to the BMN operators that correspond to free string states. In the closed string sector, an integrable structure is inherited from its parent theory, = 4 SYM. For the open string sector, the planar one-loop mixing matrix for gauge invariant holomorphic scalar operators is identified with the hamiltonian of an integrable SU(3) open spin chain. Using the K-matrix formalism we identify the integrable open-chain boundary conditions that correspond to string boundary conditions. The solutions to the algebraic Bethe ansatz equations (ABAE) with a few impurities are shown to recover the anomalous dimensions that exactly match the spectrum of free open string in the plane-wave background. We also discuss the properties of the solutions of ABAE beyond the BMN regime.
119076367
D3-branes in conifold and D5-brane wrapping on a supersymmetric 2-cycle
The paper has been withdraw by author due to a crucial error in equation 10.
2902347
Strings in Noncommutative Spacetime
Free bosonic strings in noncommutative spacetime are investigated. The string spectrum is obtained in terms of light-cone quantization. We construct two different models. In the first model the critical dimension is still required to be 26 while only extreme high energy spectrum is modified by noncommutative effect. In the second model, however, the critical dimension is reduced to be less than 26 while low-energy (massless) spectrum only contains degrees of freedom of our four dimensional physics.
119481484
Open spin chain and open spinning string
In this Letter, we study the open spinning strings and their SYM duals. A new class of folded open spinning strings is found. At planar one-loop level in SYM, by solving the thermodynamic limit of the Bethe ansatz equations for an integrable open spin chain, we find good agreement with string theory predictions for energies of both circular and folded two-spin solutions. A universal relation between the open and closed spinning strings is verified in the spin chain approach.
121460213
Hard processes in hadronic interactions
We summarize the theoretical description of charmonium and bottonium production in hadronic collisions and compare it. to the available data from hadron-nucleon interactions. With the parameters of the theory established by these data, we obtain predictions for quarkonium production at RHIC and LHC energies. The production of quarkonium states below the open charm/bottom thresholds presents a particular challenge to QCD. Because of the relatively large quark masses, cc and bb production should be pert.urbatively calculable. However, the subsequent transition from the predominantly colour octet QQ pairs to physical quarkonium states can introduce nonperturbative aspects. These may lead to some model-dependence, requiring cross checks with as much data as possible. A generalisation of the colour evaporation model [1, 2, 3, 4, 5] provides a unified approach to the production of the different quarkonium states below the open charm (bottom) thresholds. As a specific example, we consider charmonium production, although all arguments apply to bottonium production as well. Parton-parton interactions lead to the production of cc pairs, as shown in Fig. 1. We calculate the total "hidden" charm cross section, i1cc. by integrating over the cc pair mass from 2mc to 2mv. At high energy, the dominant production mechanism is gluon fusion (Fig. 1a), so that
122959126
Shear viscosity of a multi-component hadronic system
The shear viscosity and entropy density s of a hadron gas with zero baryon number density are calculated using the Chapman-Enskog and virial expansion approaches, respectively. Interactions are included via the K-matrix parametrization of cross sections preserving the unitarity of the S-matrix. In the four component mixture ( K N ), a total of 57 resonances up to 2 GeV mass are included. Interactions forming resonances reduce the magnitude of and increase s, both eects serving to progressively reduce =s as the temperature nears the QCD phase transition temperature.
118720520
Twist-4 contributions to the azimuthal asymmetry in SIDIS
We calculate the differential cross section for the unpolarized semi-inclusive deeply inelastic scattering (SIDIS) process e +N → e + q+X in leading order (LO) of perturbative QCD and up to twist-4 in power corrections and study in particular the azimuthal asymmetry 〈cos 2φ〉. The final results are expressed in terms of transverse momentum dependent (TMD) parton matrix elements of the target nucleon up to twist-4. We also apply it to e+A → e+q+X and illustrate numerically the nuclear dependence of the azimuthal asymmetry 〈cos 2φ〉 by using a Gaussian ansatz for the TMD parton matrix elements.
14203442
Quantum-classical phase transition of escape rates in biaxial spin particles
By using a stereographic projection of the unit sphere of magnetization vector onto a complex plane for the equations of motion, the effect of an external magnetic field for integrability of the system is discussed. The properties of the Jest solutions and the scattering data are then investigated through introducing transformations other than the Riemann surface in order to avoid double-valued functions of the usual spectral parameter. The exact multisoliton solutions are investigated by means of the Binet-Cauchy formula. The results showed that under the action of an external magnetic field nonlinear magnetization depends essentially on two parameters: its center moves with a constant velocity, while its shape changes with another constant velocity; its amplitude and width vary periodically with time, while its shape is also dependent on time and is unsymmetric with respect to its center. The orientation of the nonlinear magnetization in the plane orthogonal to the anisotropy axis changes with an external magnetic field. The total magnetic momentum and the integral of the motion coincident with its z component depend on time. The mean number of spins derivated from the ground state in a localized magnetic excitations is dependent on time. The asymptotic behavior of multisoliton solutions, the total displacement of center, and the phase shift of the jth peak an also analyzed. [S0163-1829(99)07121-0].
118156864
Fermi Hyper-Netted Chain Theory on a Lattice: The Hubbard Model
We review a new lattice version of Fermi Hyper-Netted Chain method for the study of strongly interacting electrons. The ordinary paramagnetic and the spin density wave functions have been correlated with Jastrow-type and e — d correlations, and the corresponding FHNC equations for the pair distribution function, the one body density matrix and the staggered magnetization are discussed. Results for the 1D chain and 2D square lattice models are presented and compared with the available results obtained within Quantum Monte Carlo, variational Monte Carlo and exact diagonalization of a 4x4 Hubbard cluster. Particularly interesting are the strong effects of e — d correlations on E/Nt and on the momentum distribution as well as antiferromagnetic behavior away from half filling found in our FHNC calculations in agreement with other studies.