113 research outputs found
Semileptonic form factors - a model-independent approach
We demonstrate that the B->D(*) l nu form factors can be accurately predicted
given the slope parameter rho^2 of the Isgur-Wise function. Only weak
assumptions, consistent with lattice results, on the wavefunction for the light
degrees of freedom are required to establish this result. We observe that the
QCD and 1/m_Q corrections can be systematically represented by an effective
Isgur-Wise function of shifted slope. This greatly simplifies the analysis of
semileptonic B decay. We also investigate what the available semileptonic data
can tell us about lattice QCD and Heavy Quark Effective Theory. A rigorous
identity relating the form factor slope difference rho_D^2-rho_A1^2 to a
combination of form factor intercepts is found. The identity provides a means
of checking theoretically evaluated intercepts with experiment.Comment: 18 pages, Revtex, 4 postscript figures, uses epsfig.st
Distinguishing WH and WBBbar production at the Fermilab Tevatron
The production of a Higgs boson in association with a W-boson is the most
likely process for the discovery of a light Higgs at the Fermilab Tevatron.
Since it decays primarily to b-quark pairs, the principal background for this
associated Higgs production process is WBBbar, where the BBbar pair comes from
the splitting of an off mass shell gluon. In this paper we investigate whether
the spin angular correlations of the final state particles can be used to
separate the Higgs signal from the WBBbar background. We develop a general
numerical technique which allows one to find a spin basis optimized according
to a given criterion, and also give a new algorithm for reconstructing the W
longitudinal momentum which is suitable for the WH and WBBbar processes.Comment: latex, 12 pages, 19 postscript figure
Direct experimental test of scalar confinement
The concept of Lorentz scalar quark confinement has a long history and is
still widely used despite its well-known theoretical faults. We point out here
that the predictions of scalar confinement also conflict directly with
experiment. We investigate the dependence of heavy-light meson mass differences
on the mass of the light quark. In particular, we examine the strange and
non-strange D mesons. We find that the predictions of scalar confinement are in
considerable conflict with measured values.Comment: REVTeX4, 7 pages, 4 EPS figure
Decay constants of P and D-wave heavy-light mesons
We investigate decay constants of P and D-wave heavy-light mesons within the
mock-meson approach. Numerical estimates are obtained using the relativistic
quark model. We also comment on recent calculations of heavy-light
pseudo-scalar and vector decay constants.Comment: REVTeX, 22 pages, uses epsf macro, 8 postscript figures include
The EPICS Software Framework Moves from Controls to Physics
The Experimental Physics and Industrial Control System (EPICS), is an open-source software framework for high-performance distributed control, and is at the heart of many of the world’s large accelerators and telescopes. Recently, EPICS has undergone a major revision, with the aim of better computing supporting for the next generation of machines and analytical tools. Many new data types, such as matrices, tables, images, and statistical descriptions, plus users’ own data types, now supplement the simple scalar and waveform types of the former EPICS. New computational architectures for scientific computing have been added for high-performance data processing services and pipelining. Python and Java bindings have enabled powerful new user interfaces. The result has been that controls are now being integrated with modelling and simulation, machine learning, enterprise databases, and experiment DAQs. We introduce this new EPICS (version 7) from the perspective of accelerator physics and review early adoption cases in accelerators around the world
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