M -theory compactification on a manifold X of G2 holonomy can give chiral fermions in four dimensions only if X is singular. A number of examples of conical singularity that give chiral fermions are known; the present paper is devoted to describing some additional examples. In some of them, the physics can be determined but the metric is not known explicitly, while in others the metric can be d...

We describe a method for evaluating chiral gauge theories that is not plagued by the doubling problem. To demonstrate the efficiency of the approach, we apply our ideas to the chiral Schwinger model.

Neutrinos can have naturally small Dirac masses if the Standard Model singlet right-handed neutrinos are light composite fermions. Theories which produce light composite fermions typically generate many of them, three of which can marry the left-handed neutrinos with small Dirac masses. The rest can serve as sterile states which can mix with the Standard Model neutrinos. We present explicit mod...

We investigate single sneutrino production in the context of R-parity-violating Supersymmetry at future γγ linear colliders. The sneutrino is produced in association with fermion pairs and it is shown that its decays into two further fermions will lead to a clean signal. We also discuss possible Standard Model backgrounds and the effects of beam polarisation. PACS Nos.: 12.60.Jv, 13.10.+q, 14.8...

We utilize the KOH theorem to prove the unimodality of integer partitions with at most a parts, all parts less than or equal to b, that are required to contain either repeated or consecutive parts. We connect this result to an open question in quantum physics relating the number of distinct total angular momentum multiplets of a system of N fermions, each with angular momentum L, to those of a ...

We present a complete and detailed derivation of the finite lattice spacing corrections to staggered fermion matrix elements. Expanding upon arguments of Sharpe, we explicitly implement the Symanzik improvement program demonstrating the absence of order a terms in the Symanzik improved action. We propose a general program to improve fermion operators to remove O(a) corrections from their matrix...

Indirect CP violation is analyzed in the framework of the electroweak gauge theory of J = 0 mesons proposed in [1] in which they transform like composite fermion-antifermion operators by the chiral U (N) L × U (N) R group and by the SU (2) L × U (1) gauge group of the Glashow-Salam-Weinberg model [2]. It is shown that, in this model where, in particular, mass terms are introduced for the mesons...

We re-examine the so-called Nambu-Jona-Lasinio mechanism suggested by Song, Xu and Chin in breaking the supersymmetry in the Wess-Zumino model and show that this mechanism cannot be justified without assuming special effects between fermions. The fermion condensation suggested by them corresponds to an unstable vacuum configuration. As a result, there is no fermion condensation and no supersymm...

We reconsider in this paper the old aim of trying to understand if the observed realization of discrete symmetries as Parity or CP in theQCD vacuum can be satisfied from first principles. We show how under the appropiate assumptions implicitely done by Vafa and Witten in their old paper on parity realization in vector-like theories, all parity and CP odd operators constructed from fermion bilin...

The filled skutterudite compound PrOs4Sb12 has been found to exhibit superconductivity with a critical temperature Tc = 1.85 K that develops out of a heavy Fermi liquid with an effective mass m ∗ ≈ 50 me. The current experimental situation regarding the heavy fermion state, the superconducting state, and a high field, low temperature phase that is apparently associated with magnetic or quadrupo...