Supersymmetry Searches at the Tevatron

We present the current status of searches for supersymmetry performed at the Tevatron accelerator at Fermilab by the CDF and D0 collaborations using luminosity of up to 2.1 fb-1. We focus on searches for charginos, neutralinos, squarks, gluinos and sneutrinos in several supersymmetric scenarios. No supersymmetric signal is detected and limits on the masses and production cross sections for the supersymmetric particles are set.Comment: 4 pages, 6 figures, Proceedings of the XLIII Rencontres de Moriond, International Conference on QCD and High Energy Interactions (2008

Study of the angular coefficients and corresponding helicity cross sections of the W boson in hadron collisions

We present the Standard Model prediction for the eight angular coefficients of the W boson, which completely describe its differential cross section in hadron collisions. These coefficients are ratios of the W helicity cross sections and the total unpolarized cross section. We also suggest a technique to experimentally extract the coefficients.Comment: 8 pages, 13 figure

Search for RS-gravitons at CDF

We present a search for Randall-Sundrum (RS) gravitons decaying to diphotons or dielectrons or dimuons, performed with the CDF II detector and using up to 5.7 fb-1 of integrated luminosity. The respective mass spectra are consistent with the ones expected by the standard model. For the RS-model parameter k/M_Pl=0.1, RS-gravitons with mass less than 1111 GeV/c^2 are excluded at 95% CL.Comment: XIX International Workshop on Deep Inelastic Scattering and related subjects -- DIS11, Newport News, VA, USA Apr. 11-15, 2011 [4 pages, 4 figures

Non-SUSY Searches at the Tevatron

We present recent results from searches for new physics beyond supersymmetry performed at the Tevatron accelerator at Fermilab. The CDF and D0 analyses presented here utilized data of integrated luminosity up to 6 fb-1. We cover leptonic and bosonic resonances interpreted in the Randall-Sundrum graviton and new-boson models, rare final states, and the search for vector-like quarks.Comment: Proceedings of the XLVI Rencontres de Moriond, International Conference on QCD and High Energy Interactions, La Thuile, Italy, Mar. 20-127, 2011, 33

Track Extrapolation and Distribution for the CDF-II Trigger System

The CDF-II experiment is a multipurpose detector designed to study a wide range of processes observed in the high energy proton-antiproton collisions produced by the Fermilab Tevatron. With event rates greater than 1MHz, the CDF-II trigger system is crucial for selecting interesting events for subsequent analysis. This document provides an overview of the Track Extrapolation System (XTRP), a component of the CDF-II trigger system. The XTRP is a fully digital system that is utilized in the track-based selection of high momentum lepton and heavy flavor signatures. The design of the XTRP system includes five different custom boards utilizing discrete and FPGA technology residing in a single VME crate. We describe the design, construction, commissioning and operation of this system.Comment: 34 pages, 9 figures, submitted to Nucl.Inst.Meth.

Impacts of the Tropical Pacific/Indian Oceans on the Seasonal Cycle of the West African Monsoon

The current consensus is that drought has developed in the Sahel during the second half of the twentieth century as a result of remote effects of oceanic anomalies amplified by local land–atmosphere interactions. This paper focuses on the impacts of oceanic anomalies upon West African climate and specifically aims to identify those from SST anomalies in the Pacific/Indian Oceans during spring and summer seasons, when they were significant. Idealized sensitivity experiments are performed with four atmospheric general circulation models (AGCMs). The prescribed SST patterns used in the AGCMs are based on the leading mode of covariability between SST anomalies over the Pacific/Indian Oceans and summer rainfall over West Africa. The results show that such oceanic anomalies in the Pacific/Indian Ocean lead to a northward shift of an anomalous dry belt from the Gulf of Guinea to the Sahel as the season advances. In the Sahel, the magnitude of rainfall anomalies is comparable to that obtained by other authors using SST anomalies confined to the proximity of the Atlantic Ocean. The mechanism connecting the Pacific/Indian SST anomalies with West African rainfall has a strong seasonal cycle. In spring (May and June), anomalous subsidence develops over both the Maritime Continent and the equatorial Atlantic in response to the enhanced equatorial heating. Precipitation increases over continental West Africa in association with stronger zonal convergence of moisture. In addition, precipitation decreases over the Gulf of Guinea. During the monsoon peak (July and August), the SST anomalies move westward over the equatorial Pacific and the two regions where subsidence occurred earlier in the seasons merge over West Africa. The monsoon weakens and rainfall decreases over the Sahel, especially in August.Peer reviewe

Search for heavy resonances decaying to two Higgs bosons in final states containing four b quarks

A search is presented for narrow heavy resonances X decaying into pairs of Higgs bosons (H) in proton-proton collisions collected by the CMS experiment at the LHC at root s = 8 TeV. The data correspond to an integrated luminosity of 19.7 fb(-1). The search considers HH resonances with masses between 1 and 3 TeV, having final states of two b quark pairs. Each Higgs boson is produced with large momentum, and the hadronization products of the pair of b quarks can usually be reconstructed as single large jets. The background from multijet and t (t) over bar events is significantly reduced by applying requirements related to the flavor of the jet, its mass, and its substructure. The signal would be identified as a peak on top of the dijet invariant mass spectrum of the remaining background events. No evidence is observed for such a signal. Upper limits obtained at 95 confidence level for the product of the production cross section and branching fraction sigma(gg -> X) B(X -> HH -> b (b) over barb (b) over bar) range from 10 to 1.5 fb for the mass of X from 1.15 to 2.0 TeV, significantly extending previous searches. For a warped extra dimension theory with amass scale Lambda(R) = 1 TeV, the data exclude radion scalar masses between 1.15 and 1.55 TeV

Measurement of the Splitting Function in &ITpp &ITand Pb-Pb Collisions at root&ITsNN&IT=5.02 TeV

Data from heavy ion collisions suggest that the evolution of a parton shower is modified by interactions with the color charges in the dense partonic medium created in these collisions, but it is not known where in the shower evolution the modifications occur. The momentum ratio of the two leading partons, resolved as subjets, provides information about the parton shower evolution. This substructure observable, known as the splitting function, reflects the process of a parton splitting into two other partons and has been measured for jets with transverse momentum between 140 and 500 GeV, in pp and PbPb collisions at a center-of-mass energy of 5.02 TeV per nucleon pair. In central PbPb collisions, the splitting function indicates a more unbalanced momentum ratio, compared to peripheral PbPb and pp collisions.. The measurements are compared to various predictions from event generators and analytical calculations.Peer reviewe