Conformal perturbation theory for twisted fields

Chiral perturbation theory for twisted mass QCD

Quantum Chromodynamics on a lattice with Wilson fermions and a chirally twisted mass term for two degenerate quark flavours is considered in the framework of chiral perturbation theory. The pion masses and decay constants are calculated in next-to-leading order including terms linear in the lattice spacing a. We treat both unquenched and partially quenched QCD. We also discuss the phase structu...

Perturbation Theory for Unstable Fundamental Fields

Unstable particles (Z , W and higgs bosons and top quark) are at the focus of current high energy physics research. However, a satisfactory theoretical formalism that would allow systematic calculations for the processes involving such particles at the high level of precision required, say, for LEP2 where the planned experimental precision warrants theoretical calculations at the twoloop level ...

Twisted Conformal Symmetry in Noncommutative Two-Dimensional Quantum Field Theory

Boundary conformal fields and Tomita–Takesaki theory

Motivated by formal similarities between the continuum limit of the Ising model and the Unruh effect, this paper connects the notion of an Ishibashi state in boundary conformal field theory with the Tomita–Takesaki theory for operator algebras. A geometrical approach to the definition of Ishibashi states is presented, and it is shown that, when normalisable the Ishibashi states are cyclic separ...

Nucleon and Delta masses in twisted mass chiral perturbation theory

We calculate the masses of the nucleons and deltas in twisted mass heavy baryon chiral perturbation theory. We work to quadratic order in a power counting scheme in which we treat the lattice spacing, a, and the quark masses, mq, to be of the same order. We give expressions for the mass and the mass splitting of the nucleons and deltas both in and away from the isospin limit. We give an argumen...