Longitudinal structure function <Emphasis Type="Italic">F</Emphasis><Subscript>L</Subscript>: Perturbative QCD and <Emphasis Type="Italic">k</Emphasis><Subscript>T</Subscript>-factorization versus experimental data at fixed <Emphasis Type="Italic">W</Emphasis>

We use the results for the structure function F_L for a gluon target with a nonzero transverse momentum squared at the order α_s, obtained in our previous paper, for comparison with recent H1 experimental data for F_L at fixed W values and with collinear GRV predictions in the leading-order and next-to-leading-order approximations.     

Fermion Localization on the <Emphasis Type="Italic">orbifold</Emphasis><Emphasis Type="Italic">S</Emphasis><Subscript>1</Subscript>/<Emphasis Type="Italic">Z</Emphasis><Subscript>2</Subscript>

The hierarchical structure of fermion masses of the Standard Model is explained in split fermion models by localizing the fermions at different points in an extra dimension. We consider split fermion models with two bulk scalars compactified on an orbifold. In the static case we find analytical expression for the localizer. We also address the issue of stability of the localizer. We also find exact solutions for the fermion zero modes. We explore the parameter space of the model. We find ample opportunity for construction of phenomenologically viable theories exist.     

Electron paramagnetic resonance of spin-variable metallomesogens [Fe<Emphasis Type="Italic">L</Emphasis><Subscript>2</Subscript>]<Emphasis Type="Italic">X</Emphasis> (<Emphasis Type="Italic">X</Emphasis> = PF<Subscript>6</Subscript>, SCN)

Significant differences in the manifestation of spin-crossover properties of the mesogen compounds [FeL ₂]X with oxysalicylidene-N′-ethyl-N-ethylenediamine ligands L and anions X = PF₆⁻ and SCH⁻ have been found by means of electron paramagnetic resonance. The electron paramagnetic resonance data and the quantum-chemical calculation within the density functional theory enables us to establish that the observed specific features are associated with the incorporation of the SCH⁻ ion into the first coordination sphere of the Fe(III) ion. The role of the transition of the material to the liquid-state phase in the formation of a low-dimensional (two-dimensional) structure with stronger intermolecular interactions has been revealed.     

A Geometric Construction of the Exceptional Lie Algebras <Emphasis Type="Italic">F</Emphasis><Subscript>4</Subscript> and <Emphasis Type="Italic">E</Emphasis><Subscript>8</Subscript>

We present a geometric construction of the exceptional Lie algebras F ₄ and E ₈ starting from the round spheres S ⁸ and S ¹⁵, respectively, inspired by the construction of the Killing superalgebra of a supersymmetric supergravity background.     

Accelerating universe from <Emphasis Type="Italic">F</Emphasis>(<Emphasis Type="Italic">T</Emphasis>) gravity

It is shown that the acceleration of the universe can be understood by considering a F(T) gravity models. For these F(T) gravity models, a variant of the accelerating cosmology reconstruction program is developed. Some explicit examples of F(T) are reconstructed from the background FRW expansion history.     

Top-quark <Emphasis Type="Italic">p</Emphasis><Subscript><Emphasis Type="Italic">T</Emphasis></Subscript>-spectra at CMS and flavor independence of <Emphasis Type="Italic">z</Emphasis>-scaling

We present new results of analysis of top-quark differential cross sections obtained by the CMS Collaboration in pp collisions in the framework of the z-scaling approach. The spectra are measured over a wide range of collision energy \(\sqrt s = 7,8,13TeV\) and transverse momentum p _T = 30?500 GeV/c of top-quark using leptonic and jet decay modes. Flavor independence of the scaling function ψ(z) is verified in the new kinematic range. The results of analysis of the top-quark spectra obtained at the LHC are compared with similar spectra measured in \(\overline p p\) collisions at the Tevatron energy \(\sqrt s = 1.96TeV\). A tendency to saturation of ψ(z) for the process at low z and a power-law behavior of ψ(z) at high z is observed. The measurements of high-p _T is observed. The measurements of highspectra of the top-quark production at highest LHC energy is of interest for verification of self-similarity of particle production, understanding flavor origin and search for new physics symmetries with top-quark probe.     

Analysis of the logarithmic slope of <Emphasis Type="Italic">F</Emphasis><Subscript>2</Subscript> from the Regge gluon density behavior at small <Emphasis Type="Italic">x</Emphasis>

We study the accuracy of the Regge behavior of the gluon distribution function for an approximate relation that is frequently used to extract the logarithmic slopes of the structure function from the gluon distribution at small x. We show that the Regge behavior analysis results are comparable with HERA data and are also better than other methods that expand the gluon density at distinct points of expansion. We also show that for Q ² = 22.4 GeV², the x dependence of the data is well described by gluon shadowing corrections to the GLR-MQ equation. The resulting analytic expression allows us to predict the logarithmic derivative ∂F ₂(x, Q ²)/∂lnQ ² and to compare the results with the H1 data and a QCD analysis fit with the MRST parameterization input.     

Radiative <Emphasis Type="Italic">K</Emphasis><Subscript><Emphasis Type="Italic">e</Emphasis>3</Subscript> decays revisited

Motivated by recent experimental results and ongoing measurements, we review the chiral perturbation theory prediction for decays. Special emphasis is given to the stability of the inner bremsstrahlung-dominated relative branching ratio versus the K _e3 form factors, and on the separation of the structure-dependent amplitude in differential distributions over the phase space. For the structure-dependent terms, an assessment of the order p ⁶ corrections is given, in particular, a full next-to-leading order calculation of the axial component is performed. The experimental analysis of the photon energy spectrum is discussed, and other potentially useful distributions are introduced.Received: 9 December 2004, Published online: 21 February 2005PACS: 13.20.Eb, 11.30.Rd, 12.39.Fe     

The <Emphasis Type="Italic">N</Emphasis> = <Emphasis Type="Italic">Z</Emphasis><Emphasis Type="Italic">f</Emphasis><Subscript>7/2</Subscript>-shell nuclei: Experimental highlights

During the last decade, as the experimental and computing means and techniques have rapidly evolved, the experimental investigation of the f_7/2-shell nuclei has gained renewed interest. TheN = Z nuclei studied with the GASP array range from ⁴⁴Ti to ⁵²Fe. The results extended the knowledge of their structure up to high spins and excitation energies, above band terminations, where the competition with the charged-particles emission was initially thought to obscure the possibility of gamma-ray spectroscopy investigation. The paper highlights some of the most outstanding properties of these nuclei such as the nuclear rotation and backbending effects, band termination states, yrast traps, non-natural parity bands, competition between T = 0 and T = 1 pn pairing modes.Received: 30 October 2002, Published online: 16 March 2004PACS: 21.10.-k Properties of nuclei; nuclear energy levels - 21.60.Cs Shell model - 23.20.Lv transitions and level energies - 27.40. + z C.A. Ur: On leave from NIPNE Bucharest, Romania     

<Emphasis Type="Italic">z</Emphasis>-Scaling and high-<Emphasis Type="Italic">p</Emphasis><Subscript><Emphasis Type="Italic">T</Emphasis></Subscript> particle production in hadron-hadron and hadron-nucleus collisions at high energies

The general features of particle production in hadron-hadron and hadron-nucleus collisions at high energy and transverse momentum using the concept of z-scaling are reviewed. z-Presentation of experimental data on the inclusive cross sections obtained at ISR, SPS, and Tevatron is presented and its properties are discussed. It is argued that the properties reflect the fundamental symmetries such as self-similarity, locality, and fractality. z-Scaling is used to predict particle yields in hadron-hadron and hadron-nucleus collisions at RHIC and LHC energies. The violation of z-scaling is considered as a signature of new physics phenomena.     

Summary on high <Emphasis Type="Italic">p</Emphasis><Subscript><Emphasis Type="Italic">T</Emphasis></Subscript> probes

Results on high-p _T probes shown at the Hard Probes 2008 Conference are summarized, with an appreciation of the improvements in precision of the measurements and experimental techniques since the beginning of RHIC operation. Particular attention is given to the latest measurements of the nuclear modification factor of identified particles, photon-hadron correlation measurements, and full jet reconstruction.     

Formation energy and geometry of vacancies at BN and B<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>C<Subscript><Emphasis Type="Italic">y</Emphasis></Subscript>N<Subscript><Emphasis Type="Italic">z</Emphasis></Subscript> nanocones

We have studied, through ab initio calculations, the stability of 60° and 120° boron nitride nanocones containing mono and multiple boron, nitrogen, and carbon vacancies. The stability of the vacancies as well as the structures reconstruction mechanism have been investigated. Our results indicate that the stability of the cones presenting such vacancies strongly depends on growth conditions. We have also found that multiple vacancies display formation energies that are comparable, and in some cases, even lower to the ones presented by monovacancies. Therefore, our results allow us to conclude that the formation energy does not depend on the vacancy size. Finally, for 120° cones, we can verify that the stability of the boron and nitrogen vacancies depends on the position where the atom has been removed.     

Polynomial Realization of <Emphasis Type="Italic">s</Emphasis>l<Subscript><Emphasis Type="Italic">q</Emphasis></Subscript>(2) and Fusion Rules at Exceptional Values of <Emphasis Type="Italic">q</Emphasis>

Representations of the sℓ_q(2) algebra are constructed in the space of polynomials of real (complex) variable for q^N=1. The spin addition rule based on eigenvalues of Casimir operator is illustrated on few simplest cases and conjecture for general case is formulated.     

<Emphasis Type="Italic">J</Emphasis><Subscript><Emphasis Type="Italic">AW,WA</Emphasis></Subscript> functions in Passarino-Veltman reduction

We continue to study a special class of Passarino-Veltman functions J arising at the reduction of infrared divergent box diagrams. We describe a procedure of separation of two types of singularities, infrared and mass singularities, which are absorbed in simple C ₀ functions. The infrared divergences of C ₀’s can be regularized then by any method: photon mass, dimensionally or by the width of an unstable particle. Functions D ₀ are represented as certain linear combinations of the standard C ₀ Passarino-Veltman functions and infrared finite functions J. Then mass singularities are extracted from J to other combinations of C ₀. The rests are free of both types of singularities and are expressed as explicit and compact linear combination of logarithms and dilogarithm functions. The extensive comparison of numerical results with those obtained with the aid of the Loop Tools package is presented.     

Classification of the Phenomenological Models of Phase Transitions with Two Interacting Order Parameters Using the Catastrophe Theory: <Emphasis Type="Italic">L</Emphasis> = <Emphasis Type="Italic">C</Emphasis><Subscript>2<Emphasis Type="Italic">v</Emphasis></Subscript>

The phenomenological models of phase transitions for two one-component interacting order parameters have been classified using the methods of the equivariant catastrophe theory. The models have been constructed based on the number of control parameters, which depend on the thermodynamic parameters varied in experiments (temperature, pressure, chemical potentials of impurities, etc.), rather than by simple expansion of the thermodynamic potential in series of order-parameter powers. The models with the order-parameter symmetry group L = C_2v are classified in terms of the number of control parameters from two to five. An infinite series of the phenomenological models with biquadratic interaction of the order parameters was also obtained.     

<Emphasis Type="Italic">K</Emphasis><Subscript><Emphasis Type="Italic">e</Emphasis>3</Subscript> decays and CKM unitarity

We present a detailed numerical study of the K_e3 decays to in chiral perturbation theory with virtual photons and leptons. We describe the extraction of the CKM matrix element |V_us| from the experimental K_e3 decay parameters. We propose a consistency check of the K ⁺ _e3 and K⁰_e3 data that is largely insensitive to the dominating theoretical uncertainties, in particular the contributions of . Our analysis is highly relevant in view of the recent high statistics measurement of the K ⁺ _e3 branching ratio by E865 at Brookhaven which does not indicate any significant deviation from CKM unitarity but rather a discrepancy with the present K⁰_e3 data.Received: 22 January 2004, Published online: 30 April 2004Work supported in part by IHP-RTN, Contract No. HPRN-CT2002-00311 (EURIDICE) and by Acciones Integradas, Project No. 19/2003 (Austria), HU2002-0044 (MCYT, Spain)