Photon Cross Sections at Ecm = 2 TeV

Photon production rates have been studied by the D0 and CDF experiments in Run II of the Fermilab Tevatron Collider. Measurements of the inclusive isolated photon cross section and the di-photon cross section are presented, based on integrated luminosities of 0.3 fb-1 and 0.2 fb-1, respectively. The results are compared to perturbative QCD calculations in various approximations.Comment: 4 pages 2 figures, presented at XLIrst Rencontres de Moriond on ``QCD and High Energy Hadronic Interactions'', La Thuile, Italy, March 18-25, 2006, on behalf of the CDF and D0 collaboration

Towards a precise measurement of the top quark Yukawa coupling at the ILC

A precise measurement of the top quark Yukawa coupling is of great importance, since it may shed light on the mechanism of EWSB. We study the prospects of such measurement during the first phase of the ILC at sqrt(s)=500 GeV, focusing in particular on recent theoretical developments as well as the potential benefits of beam polarization. It is shown that both yield improvements that could possibly lead to a measurement competitive with the LHC.Comment: Invited talk at 2005 International Linear Collider Physics and Detector Workshop and Second ILC Accelerator Workshop, Snowmass, CO (Snowmass05) 3 pages, LaTeX, 3 eps figure

Status of the LBNE Neutrino Beamline

The Long Baseline Neutrino Experiment (LBNE) will utilize a neutrino beamline facility located at Fermilab to carry out a compelling research program in neutrino physics. The facility will aim a beam of neutrinos toward a detector placed at the Homestake Mine in South Dakota. The neutrinos are produced in a three-step process. First, protons from the Main Injector (60-120 GeV) hit a solid target and produce mesons. Then, the charged mesons are focused by a set of focusing horns into the decay pipe, towards the far detector. Finally, the mesons that enter the decay pipe decay into neutrinos. The parameters of the facility were determined taking into account several factors including the physics goals, the Monte Carlo modeling of the facility, spacial and radiological constraints and the experience gained by operating the NuMI facility at Fermilab. The initial beam power is expected to be ~700 kW, however some of the parameters were chosen to be able to deal with a beam power of 2.3 MW. We discuss here the status of the conceptual design and the associated challenges.Comment: 6 pages, 3 figure

Architecture of a Silicon Strip Beam Position Monitor

A collaboration between Fermilab and the Institute for High Energy Physics (IHEP), Beijing, has developed a beam position monitor for the IHEP test beam facility. This telescope is based on 5 stations of silicon strip detectors having a pitch of 60 microns. The total active area of each layer of the detector is about 12x10 cm2. Readout of the strips is provided through the use of VA1` ASICs mounted on custom hybrid printed circuit boards and interfaced to Adapter Cards via copper-over-kapton flexible circuits. The Adapter Cards amplify and level-shift the signal for input to the Fermilab CAPTAN data acquisition nodes for data readout and channel configuration. These nodes deliver readout and temperature data from triggered events to an analysis computer over gigabit Ethernet links.Comment: Submitted to TWEPP 201

New states above charm threshold

We revise and extend expectations for the properties of charmonium states that lie above charm threshold, in light of new experimental information. We refine the Cornell coupled-channel model for the coupling of c-cbar levels to two-meson states, defining resonance masses and widths by pole positions in the complex energy plane, and suggest new targets for experiment.Comment: 12 pages, 4 figures, uses RevTeX. Added references. Corrects transcription error for 3D1 states in Table II

Conjecture on the Physical Implications of the Scale Anomaly

Murray Gell-Mann, after co-inventing QCD, recognized the interplay of the scale anomaly, the renormalization group, and the origin of the strong scale, Lambda_{QCD}. I tell a story, then elaborate this concept, and for the sake of discussion, propose a conjecture that the physical world is scale invariant in the classical, \hbar -> 0, limit. This principle has implications for the dimensionality of space-time, the cosmological constant, the weak scale, and Planck scale.Comment: Invited talk delivered at the Santa Fe Institute on the Occasion of the Celebration of the 75th Birthday of Murray Gell-Mann. July 23, 200

Supersymmetric Higgs Bosons and Beyond

We consider supersymmetric models that include particles beyond the Minimal Supersymmetric Standard Model (MSSM) with masses in the TeV range, and that couple significantly to the MSSM Higgs sector. We perform a model-independent analysis of the spectrum and couplings of the MSSM Higgs fields, based on an effective theory of the MSSM degrees of freedom. The tree-level mass of the lightest CP-even state can easily be above the LEP bound of 114 GeV, thus allowing for a relatively light spectrum of superpartners, restricted only by direct searches. The Higgs spectrum and couplings can be significantly modified compared to the MSSM ones, often allowing for interesting new decay modes. We also observe that the gluon fusion production cross section of the SM-like Higgs can be enhanced with respect to both the Standard Model and the MSSM.Comment: References added. Mistake in Eq. 14 corrected, conclusions unchanged. Typos corrected. Version accepted for publication in PRD. 50 pages, 29 figure

Top Mass Measurements at the Tevatron Run II

The latest top quark mass measurements by the CDF and D\O~ experiments are presented here. The mass has been determined in the dilepton (\ttbar \to e\mu,ee,\mu\mu + jets +\met) and lepton plus jets (\ttbar \to e or $\mu$ + jets +\met) final states. The most accurate single result from lepton plus jets channel is 173.5$^{+3.7}_{-3.6}$(stat. + Jet Energy Scale Systematic)$\pm1.3$(syst.) ~GeV/c$^{2}$, which is better than the combined CDF and D\O~ Run~I average. A preliminary and unofficial average of the best experimental Run~II results gives $M_{top}$ = $172.7\pm3.5$ GeV/c${^2}$.Comment: 19 pages, 8 figures, presented at 19th Rencontres de Physique De La Vallee D'Aoste, La Thuil

Bucket shaking stops bunch dancing in Tevatron

Bunches in Tevatron are known to be longitudinally unstable: their collective oscillations, also called "dancing bunches," persist without any signs of decay. Typically, a damper is used to stop these oscillations, but recently, it was theoretically predicted that the oscillations can be stabilized by means of small bucket shaking. Dedicated measurements in Tevatron have shown that this method does stop the dancing.Comment: 3 pp. Particle Accelerator, 24th Conference (PAC'11) 2011. 28 Mar - 1 Apr 2011. New York, US