A Measurement of the Ratio of the W + 1 Jet to Z + 1 Jet Cross Sections with ATLAS

The measurement of hadronic activity recoiling against W and Z vector bosons provides an important test of perturbative QCD, as well as a method of searching for new physics in a model independent fashion. We present a study of the cross-section ratio for the production of W and Z gauge bosons in association with exactly one jet Rjet = {\sigma}(W + 1jet)/{\sigma}(Z + 1jet), in pp collisions at \surds = 7 TeV. The study is performed in the electron and muon channels with data collected with the ATLAS detector at the LHC. The ratio Rjet is studied as a function of the cumulative transverse momentum distribution of the jet. This result can be compared to NLO pQCD calculations and the prediction from LO matrix element + parton shower generators.Comment: 8 pages, 4 figures, conference proceedings for DPF 201

Comment on "Quantum mechanics of smeared particles"

In a recent article, Sastry has proposed a quantum mechanics of smeared particles. We show that the effects induced by the modification of the Heisenberg algebra, proposed to take into account the delocalization of a particle defined via its Compton wavelength, are important enough to be excluded experimentally.Comment: 2 page

On the modification of Hamiltonians' spectrum in gravitational quantum mechanics

Different candidates of Quantum Gravity such as String Theory, Doubly Special Relativity, Loop Quantum Gravity and black hole physics all predict the existence of a minimum observable length or a maximum observable momentum which modifies the Heisenberg uncertainty principle. This modified version is usually called the Generalized (Gravitational) Uncertainty Principle (GUP) and changes all Hamiltonians in quantum mechanics. In this Letter, we use a recently proposed GUP which is consistent with String Theory, Doubly Special Relativity and black hole physics and predicts both a minimum measurable length and a maximum measurable momentum. This form of GUP results in two additional terms in any quantum mechanical Hamiltonian, proportional to $\alpha p^3$ and $\alpha^2 p^4$, respectively, where $\alpha \sim 1/M_{Pl}c$ is the GUP parameter. By considering both terms as perturbations, we study two quantum mechanical systems in the framework of the proposed GUP: a particle in a box and a simple harmonic oscillator. We demonstrate that, for the general polynomial potentials, the corrections to the highly excited eigenenergies are proportional to their square values. We show that this result is exact for the case of a particle in a box.Comment: 11 pages, to appear in Europhysics Letter

Center Domains and their Phenomenological Consequences

We argue that the domain structure of deconfined QCD matter, which can be inferred from the properties of the Polyakov loop, can simultaneously explain the two most prominent experimentally verified features of the quark-gluon plasma, namely its large opacity as well as its near ideal fluid properties

Auxiliary field method and analytical solutions of the Schr\"{o}dinger equation with exponential potentials

The auxiliary field method is a new and efficient way to compute approximate analytical eigenenergies and eigenvectors of the Schr\"{o}dinger equation. This method has already been successfully applied to the case of central potentials of power-law and logarithmic forms. In the present work, we show that the Schr\"{o}dinger equation with exponential potentials of the form $-\alpha r^\lambda \exp(-\beta r)$ can also be analytically solved by using the auxiliary field method. Formulae giving the critical heights and the energy levels of these potentials are presented. Special attention is drawn on the Yukawa potential and the pure exponential one

The history of the viola and an analysis of its literature

The origin of the viola, like the violin, is still a puzzle to our musical historians and archaeologists. True, they realize that the first real viola and violin made its appearance on the musical horizon about the middle of the 16th century in Italy. And they know also that they did not spring into existence - to use a familiar phrase, like rabbits out of a magician’s hat. Their gradual development from inferior forms of bow instruments is proved beyond doubt, and has been traced, more or less clearly, for centuries back, with the help of such instruments of monuments, bas reliefs, wood carvings, miniatures, etc., and occasional allusions to them in contemporary literature

Sufficient conditions for the existence of bound states in a central potential

We show how a large class of sufficient conditions for the existence of bound states, in non-positive central potentials, can be constructed. These sufficient conditions yield upper limits on the critical value, $g_{\rm{c}}^{(\ell)}$, of the coupling constant (strength), $g$, of the potential, $V(r)=-g v(r)$, for which a first $\ell$-wave bound state appears. These upper limits are significantly more stringent than hitherto known results.Comment: 7 page

Upper and lower bounds on the mean square radius and criteria for occurrence of quantum halo states

In the context of non-relativistic quantum mechanics, we obtain several upper and lower limits on the mean square radius applicable to systems composed by two-body bound by a central potential. A lower limit on the mean square radius is used to obtain a simple criteria for the occurrence of S-wave quantum halo sates.Comment: 12 pages, 2 figure

Hydrogen atom as an eigenvalue problem in 3D spaces of constant curvature and minimal length

An old result of A.F. Stevenson [Phys. Rev.} 59, 842 (1941)] concerning the Kepler-Coulomb quantum problem on the three-dimensional (3D) hypersphere is considered from the perspective of the radial Schr\"odinger equations on 3D spaces of any (either positive, zero or negative) constant curvature. Further to Stevenson, we show in detail how to get the hypergeometric wavefunction for the hydrogen atom case. Finally, we make a comparison between the ``space curvature" effects and minimal length effects for the hydrogen spectrumComment: 6 pages, v