Noncommutative Inspired Black Holes in Extra Dimensions

In a recent string theory motivated paper, Nicolini, Smailagic and Spallucci (NSS) presented an interesting model for a noncommutative inspired, Schwarzschild-like black hole solution in 4-dimensions. The essential effect of having noncommutative co-ordinates in this approach is to smear out matter distributions on a scale associated with the turn-on of noncommutativity which was taken to be near the 4-d Planck mass. In particular, NSS took this smearing to be essentially Gaussian. This energy scale is sufficiently large that in 4-d such effects may remain invisible indefinitely. Extra dimensional models which attempt to address the gauge hierarchy problem, however, allow for the possibility that the effective fundamental scale may not be far from $\sim$ 1 TeV, an energy regime that will soon be probed by experiments at both the LHC and ILC. In this paper we generalize the NSS model to the case where flat, toroidally compactified extra dimensions are accessible at the Terascale and examine the resulting modifications in black hole properties due to the existence of noncommutativity. We show that while many of the noncommutativity-induced black hole features found in 4-d by NSS persist, in some cases there can be significant modifications due the presence of extra dimensions. We also demonstrate that the essential features of this approach are not particularly sensitive to the Gaussian nature of the smearing employed by NSS.Comment: 30 pages, 12 figures; slight text modifications and references adde

Chiral bosonization for non-commutative fields

A model of chiral bosons on a non-commutative field space is constructed and new generalized bosonization (fermionization) rules for these fields are given. The conformal structure of the theory is characterized by a level of the Kac-Moody algebra equal to $(1+ \theta^2)$ where $\theta$ is the non-commutativity parameter and chiral bosons living in a non-commutative fields space are described by a rational conformal field theory with the central charge of the Virasoro algebra equal to 1. The non-commutative chiral bosons are shown to correspond to a free fermion moving with a speed equal to $c^{\prime} = c \sqrt{1+\theta^2}$ where $c$ is the speed of light. Lorentz invariance remains intact if $c$ is rescaled by $c \to c^{\prime}$. The dispersion relation for bosons and fermions, in this case, is given by $\omega = c^{\prime} | k|$.Comment: 16 pages, JHEP style, version published in JHE

Linear Collider Capabilities for Supersymmetry in Dark Matter Allowed Regions of the mSUGRA Model

Recent comparisons of minimal supergravity (mSUGRA) model predictions with WMAP measurements of the neutralino relic density point to preferred regions of model parameter space. We investigate the reach of linear colliders (LC) with $\sqrt{s}=0.5$ and 1 TeV for SUSY in the framework of the mSUGRA model. We find that LCs can cover the entire stau co-annihilation region provided \tan\beta \alt 30. In the hyperbolic branch/focus point (HB/FP) region of parameter space, specialized cuts are suggested to increase the reach in this important ``dark matter allowed'' area. In the case of the HB/FP region, the reach of a LC extends well past the reach of the CERN LHC. We examine a case study in the HB/FP region, and show that the MSSM parameters $\mu$ and $M_2$ can be sufficiently well-measured to demonstrate that one would indeed be in the HB/FP region, where the lightest chargino and neutralino have a substantial higgsino component.Comment: 29 pages, 15 EPS figures; updated version slightly modified to conform with published versio

Quark mixing from softly broken symmetries

Quark flavor mixing may originate in the soft breaking of horizontal symmetries. Those symmetries, which in the simplest case are three family U(1) groups, are obeyed only by the dimension-4 Yukawa couplings and lead, when unbroken, to the absence of mixing. Their breaking may arise from the dimension-3 mass terms of SU(2)-singlet vector-like quarks. Those gauge-singlet mass terms break the horizontal symmetries at a scale much higher than the Fermi scale, yet softly, leading to quark mixing while the quark masses remain unsuppressed.Comment: 9 pages, plain Latex, no figure

Common European Sales Law (CESL) and Private International Law: Some Critical Remarks

This article is an updated and revised version of the contribution published by the author in XI Anuario Español de Derecho Internacional Privado, 2011, 25-61, under the title: “La Propuesta de Reglamento relativo a una normativa común de compraventa europea y el Derecho internacional privado”.La Propuesta de Reglamento del Parlamento Europeo y del Consejo relativo a una normativa común de compraventa europea de 11 de octubre de 2011 (PCESL) introduce una reglamentación material para algunas compraventas transfronterizas que no desplaza la aplicación de las normas de conflicto (en particular de las contenidas de los Reglamentos “Roma I” y “Roma II”). Al contrario, el instrumento opcional contenido en la Propuesta de Reglamento (CESL) presupone la aplicación de la ley de un Estado miembro, como lex contractus. Una vez escogida por las partes, la CESL desplaza a las normas internas cobre compraventa de la ley del Estado miembro. Esta opción del legislador comunitario plantea numerosos problemas e interrogantes acerca de las relaciones entre la CESL y las normas de Derecho internacional privado y en torno a su coexistencia con otros convenios internacionales y el propio acervo comunitario. El análisis de estas relaciones es el objeto del presente estudio, que permite concluir con una valoración negativa de la competitividad internacional de este nuevo instrumento comunitario.The Proposal for a Regulation of the European Parliament and of the Council on a Common European Sales Law of 11 October 2011 (PCESL) introduces a substantive regulation for some cross-border sales contracts that does not displace the application of conflict-of-laws rules (especially those included in “Rome I” and “Rome II” Regulations). On the contrary, the optional instrument included in the Proposal (CESL) presupposes the application of the law of a Member State as lex contractus. Once the parties have chosen the CESL, this regime prevails over the internal rules on sales contracts of the law of that Member State. The formula used by the European legislator gives rise to many concerns and questions about the relationships between the CESL and the conflict-of-laws rules and about its cohabitation with other international conventions and the European acquis itself. The analysis of these relationships is the subject of this article, which concludes with a negative assessment on the international competitiveness of the new European instrument