4 Matching Results

Search Results

Advanced search parameters have been applied.

Radiative b to d Penguins

Description: This article gives an overview of the recent searches and measurements of b {yields} d penguin transitions with the BaBar experiment. The branching fraction of these decays in the Standard Model (SM) is expected to be a factor of 10 or more lower than the corresponding b {yields} s penguin transitions, but a deviation from the SM prediction would be an equally striking sign of new physics. The exclusive decay B {yields} {pi}{ell}{ell} is searched by BaBar with no excess over the background found. The BaBar measurement of B {yields} ({rho}, {omega}){gamma} provides the first evidence of B{sup +} {yields} {rho}{sup +}{gamma}, {sup c} is in good agreement with the previous Belle results and provides a measurement of |V{sub td}/V{sub ts}| independent of the one from Bs mixing. No deviation from the SM is found.
Date: June 13, 2007
Creator: Bechtle, P.
Partner: UNT Libraries Government Documents Department

SUSY Parameter Measurements with Fittino

Description: This article presents the results of a realistic global fit of the Lagrangian parameters of the Minimal Supersymmetric Standard Model with no assumptions on the SUSY breaking mechanism using the fit program Fittino. The fit is performed using the precision of future mass measurements of superpartners at the LHC and mass and polarized topological cross-section measurements at the ILC. Higher order radiative corrections are accounted for wherever possible to date. Results are obtained for a modified SPS1a MSSM benchmark scenario (general MSSM without assumptions on the breaking mechanism) and for a specific mSUGRA scenario. Exploiting a simulated annealing algorithm, a stable result is obtained without any a priori assumptions on the fit parameters. Most of the Lagrangian parameters can be extracted at the percent level or better if theoretical uncertainties are neglected. Neither LHC nor ILC measurements alone will be sufficient to obtain a stable result.
Date: December 14, 2005
Creator: Bechtle, P.; /SLAC; Desch, K.; Wienemann, P. & U., /Freiburg
Partner: UNT Libraries Government Documents Department

Supersymmetry Parameter Analysis: SPA Convention andProject

Description: High-precision analyses of supersymmetry parameters aim at reconstructing the fundamental supersymmetric theory and its breaking mechanism. A well defined theoretical framework is needed when higher-order corrections are included. We propose such a scheme, Supersymmetry Parameter Analysis SPA, based on a consistent set of conventions and input parameters. A repository for computer programs is provided which connect parameters in different schemes and relate the Lagrangian parameters to physical observables at LHC and high energy e{sup +}e{sup -} linear collider experiments, i.e., masses, mixings, decay widths and production cross sections for supersymmetric particles. In addition, programs for calculating high-precision low energy observables, the density of cold dark matter (CDM) in the universe as well as the cross sections for CDM search experiments are included. The SPA scheme still requires extended efforts on both the theoretical and experimental side before data can be evaluated in the future at the level of the desired precision. We take here an initial step of testing the SPA scheme by applying the techniques involved to a specific supersymmetry reference point.
Date: December 2, 2005
Creator: Aguilar-Saavedra, J.A.; Ali, A.; Allanach, B.C.; Arnowitt, R.; Baer, H.A.; Bagger, J.A. et al.
Partner: UNT Libraries Government Documents Department

From the LHC to Future Colliders

Description: Discoveries at the LHC will soon set the physics agenda for future colliders. This report of a CERN Theory Institute includes the summaries of Working Groups that reviewed the physics goals and prospects of LHC running with 10 to 300 fb{sup -1} of integrated luminosity, of the proposed sLHC luminosity upgrade, of the ILC, of CLIC, of the LHeC and of a muon collider. The four Working Groups considered possible scenarios for the first 10 fb{sup -1} of data at the LHC in which (i) a state with properties that are compatible with a Higgs boson is discovered, (ii) no such state is discovered either because the Higgs properties are such that it is difficult to detect or because no Higgs boson exists, (iii) a missing-energy signal beyond the Standard Model is discovered as in some supersymmetric models, and (iv) some other exotic signature of new physics is discovered. In the contexts of these scenarios, theWorking Groups reviewed the capabilities of the future colliders to study in more detail whatever new physics may be discovered by the LHC. Their reports provide the particle physics community with some tools for reviewing the scientific priorities for future colliders after the LHC produces its first harvest of new physics from multi-TeV collisions.
Date: June 11, 2010
Creator: De Roeck, A.; Ellis, J.; Grojean, C.; Heinemeyer, S.; Jakobs, K.; Weiglein, G. et al.
Partner: UNT Libraries Government Documents Department