Rubin-LSST

Abstract:

We report on the physics potential of a proposed conversion of the CESR machine and the CLEO detector to a charm and QCD factory: CLEO-c and CESR-c that will make crucial contributions to flavor physics in this decade and offers our best hope for mastering non-perturbative QCD which is essential if we are to understand strongly coupled sectors in the new physics that lies beyond the Standard Model.

Abstract:

Current methods of determining V_ub are dominated by theoretical uncertainties. We present Monte Carlo simulations of three promising methods of determining V_ub with small theoretical and experimental errors. We find that with data samples of order 1,000 fb-1 the B factories will attain combined experimental errors of a few % on V_ub, much smaller than the theoretical errors associated with new inclusive methods. Lattice QCD offers the promise of rate calculations of exclusive semileptonic decays with errors of a few %. A data sample of order 10,000 fb-1, beyond the capabilities of the current B factories, may be required to achieve an experimental error on the exclusive rate comparable to the theoretical error.

Abstract:

We have searched for evidence of physics beyond the standard model in events that include an energetic photon and an energetic b-quark jet, produced in 85 pb^-1 of p̄p collisions at 1.8 TeV at the Tevatron Collider at Fermilab. This signature, containing at least one gauge boson and a third-generation quark, could arise in the production and decay of a pair of new particles, such as those predicted by supersymmetry, leading to a production rate exceeding standard model predictions. We also search these events for anomalous production of missing transverse energy, additional jets and leptons (e, μ, and τ), and additional b quarks. We find no evidence for any anomalous production of γb or γb + X events. We present limits on two supersymmetric models: a model where the photon is produced in the decay χ̃2⁰→ γχ̃1⁰, and a model where the photon is produced in the neutralino decay into the gravitino LSP, χ̃1⁰→ γG̃. We also present our limits in a model-independent form and test methods of applying model-independent limits.

Abstract:

We present a detailed examination of the heavy flavor content of the W+jet data sample collected with the Collider Detector at Fermilab during the 1992-1995 collider run at the Fermilab Tevatron. Jets containing heavy flavor quarks are selected via the identification of secondary vertices or semileptonic decays of b and c quarks. There is generally good agreement between the rates of secondary vertices and soft leptons in the data and in the standard model simulation including single and pair production of top quarks. An exception is the number of events in which a single jet has both a soft lepton and a secondary vertex tag. In W+2,3 jet data, we find 13 such events where we expected 4.4±0.6 events. The kinematic properties of this small sample of events are statistically difficult to reconcile with the simulation of standard model processes.