9420748
Noncommutative superspace and super Heisenberg group
In this paper, we consider noncommutative superspace in relation with super Heisenberg group. We construct a matrix representation of super Heisenberg group and apply this to the two-dimensional deformed = (2,2) superspace that appeared in string theory. We also construct a toy model for non-centrally extended `super Heisenberg group'.
118847627
Interaction between M2-branes and bulk form fields
We construct the interaction terms between the world-volume fields of multiple M2-branes and the 3-and 6-form fields in the context of ABJM theory with U(N)×U(N) gauge symmetry. A consistency check is made in the simplest case of a single M2-brane i.e., our construction matches the known effective action of M2-brane coupled to antisymmetric 3-form field. We show that when dimensionally reduced, our couplings coincide with the effective action of D2-branes coupled to R-R 3-and 5-form fields in type IIA string theory. We also comment on the relation between a coupling with a specific 6-form field configuration and the supersymmetry preserving mass deformation in ABJM theory.
14300277
Morita equivalence of noncommutative supertori
In this paper we study the extension of Morita equivalence of noncommutative tori to the supersymmetric case. The structure of the symmetry group yielding Morita equivalence appears to be intact but its parameter field becomes supersymmetrized having both body and soul parts. Our result is mainly in the two dimensional case in which noncommutative supertori have been constructed recently: The group SO(2,2,VZ0), where VZ0 denotes Grassmann even number whose body part belongs to Z, yields Morita equivalent noncommutative supertori in two dimensions.
15745084
Deformation of super Yang-Mills theories in R-R 3-form background
We study deformation of = 2 and = 4 super Yang-Mills theories, which are obtained as the low-energy effective theories on the (fractional) D3-branes in the presence of constant Ramond-Ramond 3-form background. We calculate the Lagrangian at the second order in the deformation parameter from open string disk amplitudes. In = 4 case we find that all supersymmetries are broken for generic deformation parameter but part of supersymmetries are unbroken for special case. We also find that classical vacua admit fuzzy sphere configuration. In = 2 case we determine the deformed supersymmetries. We rewrite the deformed Lagrangians in terms of = 1 superspace, where the deformation is interpreted as that of coupling constants.
18268747
Central charges in non(anti)commutative N=2 supersymmetric U(N) gauge theory
Abstract We study the central charge of the deformed N = ( 1 , 0 ) supersymmetry algebra in non(anti)commutative N = 2 supersymmetric U ( N ) gauge theory. In the cases of N = 1 / 2 superspace and N = 2 harmonic superspace with the singlet deformation, we find that the central charge is deformed by the non(anti)commutative parameters but depends on the electric and magnetic charges. For generic deformation of N = 2 harmonic superspace, we compute the O ( C ) correction to the central charges in the case of U ( 1 ) gauge group.
56166210
Fermionic T-duality and Morita equivalence
In this paper we investigate the relationship between the so-called fermionic T-duality and the Morita equivalence of noncommutative supertori. We first get an action satisfying the BRST invariance under nonvanishing constant R-R and NS-NS backgrounds in the hybrid formalism. We investigate the effect of bosonic T-duality transformation together with fermionic T-duality transformation in this background and look for the resultant symmetry of transformations. We find that the duality transformations correspond to Morita equivalence of noncommutative supertori. In particular, we obtain the symmetry group $ {\text{SO}}\left( {2,2,\mathcal{V}_\mathbb{Z}^0} \right) $ in two dimensions, where $ \mathcal{V}_\mathbb{Z}^0 $ denotes Grassmann even number whose body part belongs to $ \mathbb{Z} $.
16605019
Testing the seesaw mechanism at collider energies in the Randall-Sundrum model
The Randall-Sundrum model with gauge fields and fermions in the bulk has several attractive features including the gauge coupling unification, a candidate for the dark matter, and an explanation for the hierarchical Yukawa couplings. 
In this paper, we point out that the 1st Kaluza-Klein modes of right-handed neutrinos may be produced at colliders, for both Dirac and Majorana neutrino cases. Furthermore, we can see whether the neutrino masses are Dirac type or Majorana type from the mass spectrum of KK particles.
123268891
Regge pole analysis of inelastic e - p scattering data
Abstract Based on the Regge pole fit to the high energy data on the e-p structure functions the q 2 -dependence of the Pomeranchuk and A 2 residues is determined in the non-scaling region. A FESR for vW 2 together with knowledge of these Regge residues is employed to confirm the existence of the J = 0 fixed pole in the virtual Compton amplitude.
119514655
What the Gribov copy tells about confinement and the theory of dynamical chiral symmetry breaking
We performed lattice Landau gauge QCD simulation on {beta}=6.0,16{sup 4},24{sup 4},32{sup 4} and {beta}=6.4,32{sup 4},48{sup 4} and 56{sup 4} by adopting the gauge fixing that minimizes the norm of the gauge field, and measured the running coupling by using the gluon propagator and the ghost propagator. In view of ambiguity in the vertex renormalization factor Z{sub 1} in the lattice, we adjust the normalization of the running coupling by the perturbative QCD results near the highest momentum point. It has a maximum {alpha}{sub s}(q){approx_equal}2.1(3) at around q=0.5 GeV and decreases as q approaches 0, and the Kugo-Ojima parameter reached -0.83(2). The infrared exponent of the ghost propagator at 0.4 GeV region is {alpha}{sub G}=0.20 but there is an exceptional Gribov copy with {alpha}{sub G}=0.27. The features of the exceptional Gribov copy are investigated by measuring four one-dimensional Fourier transform (1-d FT) of the gluon propagator transverse to each lattice axis. We observe, in general, correlation between absolute value of the Kugo-Ojima parameter and the degree of reflection positivity violation in the 1-d FT of the gluon propagator. The 1-d FT of the exceptional Gribov copy has an axis whose samplewise gluon propagator manifestly violates reflection positivity, and the average ofmore » the Cartan subalgebra components of the Kugo-Ojima parameter along this axis is consistent to -1. The running coupling of the ensemble average shows a suppression at 0 momentum, but when the ghost propagator of the exceptional Gribov copy is adopted, the suppression disappears and the data implies presence of the infrared fixed point {alpha}{sub s}(0){approx}2.5(5) and {kappa}=0.5 suggested by the Dyson-Schwinger approach in the multiplicative renormalizable scheme. Comparison with the SU(2) QCD and N{sub f}=2 unquenched SU(3) QCD are also made.« less
15752905
Landau gauge fixing supported by genetic algorithm
Abstract A class of algorithms for the Landau gauge fixing is proposed, which makes the steepest ascent (SA) method be more efficient by concepts of genetic algorithm. Main concern is how to incorporate random gauge transformation (RGT) to gain higher achievement of the minimal Landau gauge fixing, and to keep lower time consumption. One of these algorithms uses the block RGT, and another uses RGT controlled by local fitness density, and the last uses RGT determined by Ising Monte Carlo process. We tested these algorithms on SU(2) lattice gauge theory in 4 dimension with small βs, 2.0, 1.75 and 1.5, and report improvements in hit rate and/or in time consumption, compared to other methods.
10853977
Lectures on instanton counting
These notes have two parts. The first is a study of Nekrasov's deformed partition functions $Z(\ve_1,\ve_2,\vec{a};\q,\vec{\tau})$ of N=2 SUSY Yang-Mills theories, which are generating functions of the integration in the equivariant cohomology over the moduli spaces of instantons on $\mathbb R^4$. The second is review of geometry of the Seiberg-Witten curves and the geometric engineering of the gauge theory, which are physical backgrounds of Nekrasov's partition functions. 
The first part is continuation of math.AG/0306198, where we identified the Seiberg-Witten prepotential with $Z(0,0,\vec{a};\q,0)$. 
We put higher Casimir operators to the partition function and clarify their relation to the Seiberg-Witten $u$-plane. We also determine the coefficients of $\ve_1\ve_2$ and $(\ve_1^2+\ve_2^2)/3$ (the genus 1 part) of the partition function, which coincide with two measure factors $A$, $B$ appeared in the $u$-plane integral. 
The proof is based on the blowup equation which we derived in the previous paper.