Resource Type

Negative hydrogen ion sources for accelerators (open access)

Negative hydrogen ion sources for accelerators

A variety of H{sup -} ion sources are in use at accelerator laboratories around the world. A list of these ion sources includes surface plasma sources with magnetron, Penning and surface converter geometries as well as magnetic-multipole volume sources with and without cesium. Just as varied is the means of igniting and maintaining magnetically confined plasmas. Hot and cold cathodes, radio frequency, and microwave power are all in use, as well as electron tandem source ignition. The extraction systems of accelerator H{sup -} ion sources are highly specialized utilizing magnetic and electric fields in their low energy beam transport systems to produce direct current, as well as pulsed and/or chopped beams with a variety of time structures. Within this paper, specific ion sources utilized at accelerator laboratories shall be reviewed along with the physics of surface and volume H{sup -} production in regard to source emittance. Current research trends including aperture modeling, thermal modeling, surface conditioning, and laser diagnostics will also be discussed.
Date: August 1, 2005
Creator: Moehs, D. P.; Peters, J. & Sherman, J.
System: The UNT Digital Library
Search for the Higgs boson in H ---> WW(*) decays in p anti-p collisions at s**(1/2) = 1.96-TeV (open access)

Search for the Higgs boson in H ---> WW(*) decays in p anti-p collisions at s**(1/2) = 1.96-TeV

We present a search for the standard model Higgs boson in H {yields} WW{sup (*)} decays with e{sup +}e{sup -}, e{sup {+-}}{mu}{sup {-+}} and {mu}{sup +}{mu}{sup -} final states in p{bar p} collisions at a center-of-mass energy of {radical}s = 1.96 TeV. The data, collected from April 2002 to June 2004 with the D0 detector, correspond to an integrated luminosity of 300-325 pb{sup -1}, depending on the final state. The number of events observed is consistent with the expectation from backgrounds. Limits from the combination of all three channels on the Higgs production cross section times branching ratio {sigma} x BR(H {yields} WW{sup (*)}) are presented.
Date: August 1, 2005
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
System: The UNT Digital Library