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.
118980773
Green Functions of N=1 SYM and Radial/Energy-Scale Relation
We study counter-terms of one- and two-point Green functions of some special operators in ${\cal N}=1$ SYM from their SUGRA duals from the consideration of AdS/CFT or gauge/gravity correspondence. We consider both the Maldacena-Nunez solution and the Klebanov-Strassler-Tseytlin solution that are proposed to be SUGRA duals of ${\cal N}=1$ SYM. We obtain radial/energy-scale relation for each solution by comparing SUGRA calculations with the field theory results. Using these relations we evaluate the $\beta$-function of ${\cal N}=1$ SYM. We find that the leading order term can be accurately obtained for both solutions and the higher order terms exhibit some ambiguities. We discuss the origin of these ambiguities and conclude that more studies are needed to check whether these SUGRA solutions are exactly dual to ${\cal N}=1$ SYM.
119063228
A note on brane/flux annihilation and dS vacua in string theory
We reconsider the dynamics of p anti-D3 branes inside the Klebanov-Strassler geometry, in which M units of R-R 3-form flux and K units of NS-NS 3-form flux are presented in deformed conifold. We find that anti-D3 branes blow up into a spherical D5-brane at weak string coupling via quantum tunnelling. The D5-brane can be either stable or unstable, depending on number of background flux. The nucleation rate of D5-brane is suppressed by \exp{-Mp^2}. The classical mechanically the evolution of unstable D5-brane annihilates one unit of R-R flux and ends with (K-p) D3-branes. This observation is consistent with one by Kachru, Pearson and Verlinde, who shew that anti-D3 branes in KS geometry can blow up into a spherical NS5 brane at strong string coupling, because NS5-brane is lighter that D5-brane at strong string coupling. We also argue that the system can end with a meta-stable dS vacuum by fine tuning of number of background flux.
119095268
Cosmological Constant as Vacuum Energy Density of Quantum Field Theories on Noncommutative Spacetime
We propose a new approach to understand hierarchy problem for cosmological constant in terms of considering noncommutative nature of space-time. We calculate that vacuum energy density of the noncommutative quantum field theories in nontrivial background, which admits a smaller cosmological constant by introducing an higher noncommutative scale $\mu_{NC}\sim M_p$. The result $\rho_\Lambda\sim 10^{-6}\Lambda_{SUSY}^8M_p^4/\mu_{NC}^8$ yields cosmological constant at the order of current observed value for supersymmetry breaking scale at 10TeV. It is the same as Banks' phenomenological formula for cosmological constant.
119502040
Spinning strings on deformed AdS(5) x T**1,1 with NS B-fields
We study classical spinning closed string configuration on logarithmically deformed AdS_5 x T^{1,1} background with non-trivial Neveu-Schwarz B-field in which IIB string theory is dual to a non-conformal N=1 SU(N+M) x SU(N) gauge theory. The integrability on original AdS_5 x T^{1,1} background are significantly reduced by B-field. We find several spinning string solutions with two different ansatzs. Solutions for point-like strings and few circular strings are explicitly obtained. Folded spinning string solutions along radial direction are shown to be allowed in this background. These solutions exhibit novel properties and bring some challenges to understand them from dual quantum field theory.
94690392
Isovector channel of quarkmeson-coupling model and its effect on symmetry energy
Abstract The non-relativistic approximation of the quark–meson-coupling model has been discussed and compared with the Skyrme–Hartree–Fock model which includes spin exchanges. Calculations show that the spin-exchange interaction has important effect on the descriptions of finite nuclei and nuclear matter through the Fock exchange. Also in the quark–meson-coupling model, it is the Fock exchange that leads to a nonlinear density-dependent isovector channel and changes the density-dependent behavior of the symmetry energy.
123633000
The Higgs Boson Mass in MSM and the New Data
In this paper we study the implications of the top quark mass measurement at CDF for the Higgs boson mass . We find that the present data are most likely in favor of heavy Higgs boson, for , but no realistic constraints on could be derived until the measurement of reaches high precision.
123905333
THE MESON DISTRIBUTION AMPLITUDE OF EXCLUSIVE PROCESSES IN QCD
The behavior of the meson distribution amplitude is discussed through a phenomenological analysis of some exclusive processes in QCD. It is found that the pionic distribution amplitude at moderate energies is much broader than its asymptotic form and the broad distribution amplitude has to suppress the endpoint contribution to the process in order that the perturbative QCD contribution is dominant. In addition, a possible meson distribution amplitude, which is a generalization of the harmonic oscillator model, is proposed. The results are compatible with experimental data.
118357163
Effects of initial flow velocity fluctuation in event-by-event (3+1)D hydrodynamics
Hadron spectra and elliptic flow in high-energy heavy-ion collisions are studied within a (3+1)D ideal hydrodynamic model with fluctuating initial conditions given by the AMPT Monte Carlo model. Results from event-by-event simulations are compared with experimental data at both RHIC and LHC energies. Fluctuations in the initial energy density come from not only the number of coherent soft interactions of overlapping nucleons but also incoherent semi-hard parton scatterings in each binary nucleon collision. Mini-jets from semi-hard parton scatterings are assumed to be locally thermalized through a Gaussian smearing and give rise to non-vanishing initial local flow velocities. Fluctuations in the initial flow velocities lead to harder transverse momentum spectra of final hadrons due to non-vanishing initial radial flow velocities. Initial fluctuations in rapidity distributions lead to expanding hot spots in the longitudinal direction and are shown to cause a sizable reduction of final hadron elliptic flow at large transverse momenta.
30060191
Kinetic equation with exact charge conservation.
A kinetic master equation for multiplicity distributions is formulated for charged particles which are created or destroyed only in pairs due to the conservation of their Abelian charge. It allows one to study time evolution of the multiplicity distributions in a relativistic many-body system with arbitrary average particle multiplicities. It is shown to reproduce the equilibrium results for both canonical (rare particles) and grand canonical (abundant particles) systems. For canonical systems, the equilibrium multiplicity is much lower and the relaxation time is much shorter than the naive extrapolation from grand canonical results. Implications for chemical equilibration in heavy-ion collisions are also discussed.