A reduction method of ODEs not possessing Lie point symmetries makes use of the so called λ-symmetries (C. Muriel and J. L. Romero, IMA J. Appl. Math. 66, 111-125, 2001). The notion of covering for an ODE Y is used here to recover λ-symmetries of Y as nonlocal symmetries. In this framework, by embedding Y into a suitable system Y ′ determined by the function λ, any λ-symmetry of Y can be recove...

If spacetime contains large compact extra dimensions, the fundamental mass scale of nature, Λ, may be close to the weak scale, allowing gravitational physics to significantly modify electroweak symmetry breaking. Operators of the form (1/Λ2)|φ†Dμφ|2 and (1/Λ)φWμνB φ, where Wμν and B μν are the SU(2) and U(1) field strengths and φ is the Higgs field, remove the precision electroweak bound on the...

Models with a dynamic cosmological term Λ (t) are becoming popular as they solve the cosmological constant problem in a natural way. Instead of considering any ad-hoc assumption for the variation of Λ, we consider a particular symmetry, the contracted Ricci-collineation along the fluid flow, in Einstein’s theory. We show that apart from having interesting properties, this symmetry does demand Λ...

The Higgs mechanism, as responsible for the first inflation, powers initial accelerated expansion and further preheating via symmetry breaking from its false vacuum state corresponding to Sitter of GUT scale with Λ=8πGρΛ, whose decay provides necessary energetic support. Here we address question possibility restoration field at presently observed which would make it today value cosmological con...

We consider the quadratic eigenvalue problem (QEP) (λ2M + λG + K)x = 0, where M = MT is positive definite, K = KT is negative definite, and G = −GT . The eigenvalues of the QEP occur in quadruplets (λ, λ,−λ,−λ) or in real or purely imaginary pairs (λ,−λ). We show that all eigenvalues of the QEP can be found efficiently and with the correct symmetry, by finding a proper solvent X of the matrix e...

Abstract The Λ baryon spectrum is studied within the SU(3) flavor symmetry in a constituent quark model. We found that it rather difficult to accommodate some negative-parity resonances as single q 2 s ( = u , d quarks) states conventional three-quark picture. ground <mm...

A fine tuned hierarchy between a strongly coupled high energy compos-iteness scale and a much lower chiral symmetry breaking scale is a requisite ingredient in many models of dynamical electroweak symmetry breaking. Using a nonperturbative continuous Wilson renormalization group equation approach, we explore the stability of such a hierarchy against quantum fluctuations. Many of the currently s...