Early Electroweak and Top Quark Physics with CMS

The Large Hadron Collider is an ideal place for precision measurements of the properties of the electroweak gauge bosons W^\pm, Z^0, as well as of the top quark. In this article, a few highlights of the prospects for performing such measurements with the CMS detector are summarized, with an emphasis on the first few 1/fb of data.Comment: 4 pages, to appear in the proceedings of DIS 2007, Munich, April 200

Diffractive DIS Cross Sections and Parton Distributions

Highlights are presented mainly from two recent measurements of the diffractive Deep Inelastic Scattering cross section at HERA. In the first, the process $ep\to eXp$ is studied by tagging the leading final state proton. In the second, events of this type are selected by requiring a large rapidity gap devoid of hadronic activity in the proton direction. The two measurements are compared in detail and the kinematic dependences are interpreted within the framework of a factorisable diffractive exchange. Diffractive parton distributions are determined from a next-to-leading order QCD analysis of the large rapidity gap data, which can be applied to the prediction of diffractive processes, also at the TEVATRON and the LHC.Comment: to appear in the proceedings of the 33rd Intl. Conference on High Energy Physics, ICHEP 2006 (Moscow, July 2006

Status and Commissioning of the CMS Experiment

After a brief overview of the Compact Muon Solenoid (CMS) experiment, the status of construction and installation is described in the first part of the note. The second part of the document is devoted to a discussion of the general commissioning strategy of the CMS experiment, with a particular emphasis on trigger, calibration and alignment. Aspects of b-physics, as well as examples for early physics with CMS are also presented. CMS will be ready for data taking in time for the first collisions in the Large Hadron Collider (LHC) at CERN in late 2007.Comment: Talks given at the 11th Intl. Conference on B-Physics at Hadron Machines BEAUTY 2006, Oxford (UK), September 200

Novel crystal phase in suspensions of hard ellipsoids

We present a computer simulation study on the crystalline phases of hard ellipsoids of revolution. For aspect ratios greater than or equal to 3 the previously suggested stretched-fcc phase [D. Frenkel and B. M. Mulder, Mol. Phys. 55, 1171 (1985)] is replaced by a novel crystalline phase. Its unit cell contains two ellipsoids with unequal orientations. The lattice is simple monoclinic. The angle of inclination of the lattice, beta, is a very soft degree of freedom, while the two right angles are stiff. For one particular value of beta, the close-packed version of this crystal is a specimen of the family of superdense packings recently reported [Donev et al., Phys. Rev. Lett. 92, 255506 (2004)]. These results are relevant for studies of nucleation and glassy dynamics of colloidal suspensions of ellipsoids.Comment: 4 pages, 4 figure

Solid-solid phase transition in hard ellipsoids

We present a computer simulation study of the crystalline phases of hard ellipsoids of revolution. A previous study [Phys. Rev. E, \textbf{75}, 020402 (2007)] showed that for aspect ratios $a/b\ge 3$ the previously suggested stretched-fcc phase [Mol. Phys., \textbf{55}, 1171 (1985)] is unstable with respect to a simple monoclinic phase with two ellipsoids of different orientations per unit cell (SM2). In order to study the stability of these crystalline phases at different aspect ratios and as a function of density we have calculated their free energies by thermodynamic integration. The integration path was sampled by an expanded ensemble method in which the weights were adjusted by the Wang-Landau algorithm. We show that for aspect ratios $a/b\ge 2.0$ the SM2 structure is more stable than the stretched-fcc structure for all densities above solid-nematic coexistence. Between $a/b=1.55$ and $a/b=2.0$ our calculations reveal a solid-solid phase transition

Crystallization in Glassy Suspensions of Hard Ellipsoids

We have carried out computer simulations of overcompressed suspensions of hard monodisperse ellipsoids and observed their crystallization dynamics. The system was compressed very rapidly in order to reach the regime of slow, glass-like dynamics. We find that, although particle dynamics become sub-diffusive and the intermediate scattering function clearly develops a shoulder, crystallization proceeds via the usual scenario: nucleation and growth for small supersaturations, spinodal decomposition for large supersaturations. In particular, we compared the mobility of the particles in the regions where crystallization set in with the mobility in the rest of the system. We did not find any signature in the dynamics of the melt that pointed towards the imminent crystallization events

Threshhold analysis of phase locked loops

Computer technique for predicting threshold in phased locked loops with and without frequency modulatio

QED radiative correction to spin-density matrix elements in exclusive vector meson production

QED radiative effects are considered in the case of measurement of spin-density matrix elements of diffractive $\rho$-meson electroproduction. Large radiative correction for $r^5_{00}$ is found in the kinematics of collider experiments at HERA.Comment: 7 pages, 5 figure

Response of mouse epidermal cells to single doses of heavy-particles

The survival of mouse epidermal cells to heavy-particles has been studied In Vivo by the Withers clone technique. Experiments with accelerated helium, lithium and carbon ions were performed. The survival curve for the helium ion irradiations used a modified Bragg curve method with a maximum tissue penetration of 465 microns, and indicated that the dose needed to reduce the original cell number to 1 surviving cell/square centimeters was 1525 rads with a D sub o of 95 rads. The LET at the basal cell layer was 28.6 keV per micron. Preliminary experiments with lithium and carbon used treatment doses of 1250 rads with LET's at the surface of the skin of 56 and 193 keV per micron respectively. Penetration depths in skin were 350 and 530 microns for the carbon and lithium ions whose Bragg curves were unmodified. Results indicate a maximum RBE for skin of about 2 using the skin cloning technique. An attempt has been made to relate the epidermal cell survival curve to mortality of the whole animal for helium ions