2,688 research outputs found
6D Muon Ionization Cooling with an Inverse Cyclotron
A large admittance sector cyclotron filled with LiH wedges surrounded by
helium or hydrogen gas is explored. Muons are cooled as they spiral
adiabatically into a central swarm. As momentum approaches zero, the momentum
spread also approaches zero. Long bunch trains coalesce. Energy loss is used to
inject the muons into the outer rim of the cyclotron. The density of material
in the cyclotron decreases adiabatically with radius. The sector cyclotron
magnetic fields are transformed into an azimuthally symmetric magnetic bottle
in the center. Helium gas is used to inhibit muonium formation by positive
muons. Deuterium gas is used to allow captured negative muons to escape via the
muon catalyzed fusion process. The presence of ionized gas in the center may
automatically neutralize space charge. When a bunch train has coalesced into a
central swarm, it is ejected axially with an electric kicker pulse.Comment: Five pages. LaTeX, three postscript figure files. To appear in the
AIP Conference Proceedings for COOL05: International Workshop on Beam
Cooling, Galena, IL, 18-23 Sept. 200
Resolution of Nearly Mass Degenerate Higgs Bosons and Production of Black Hole Systems of Known Mass at a Muon Collider
The direct s-channel coupling to Higgs bosons is 40000 times greater for
muons than electrons; the coupling goes as mass squared. High precision
scanning of the lighter and the higher mass and is thus
possible with a muon collider. The and are expected to be nearly
mass degenerate and to be CP even and odd, respectively. A muon collider could
resolve the mass degeneracy and make CP measurements. The origin of CP
violation in the and meson systems might lie in the the
Higgs bosons. If large extra dimensions exist, black holes with
lifetimes of seconds could be created and observed via Hawking
radiation at the LHC. Unlike proton or electron colliders, muon colliders can
produce black hole systems of known mass. This opens the possibilities of
measuring quantum remnants, gravitons as missing energy, and scanning
production turn on. Proton colliders are hampered by parton distributions and
CLIC by beamstrahlung. The ILC lacks the energy reach.Comment: Latex, 5 pages, 2 figures, proceedings to the DPF 2004: Annual
Meeting of the Division of Particles and Fields of APS, 26 August-31 August
2004, Riverside, CA, US
Multi-Terabyte EIDE Disk Arrays running Linux RAID5
High-energy physics experiments are currently recording large amounts of data
and in a few years will be recording prodigious quantities of data. New methods
must be developed to handle this data and make analysis at universities
possible. Grid Computing is one method; however, the data must be cached at the
various Grid nodes. We examine some storage techniques that exploit recent
developments in commodity hardware. Disk arrays using RAID level 5 (RAID-5)
include both parity and striping. The striping improves access speed. The
parity protects data in the event of a single disk failure, but not in the case
of multiple disk failures.
We report on tests of dual-processor Linux Software RAID-5 arrays and
Hardware RAID-5 arrays using a 12-disk 3ware controller, in conjunction with
250 and 300 GB disks, for use in offline high-energy physics data analysis. The
price of IDE disks is now less than $1/GB. These RAID-5 disk arrays can be
scaled to sizes affordable to small institutions and used when fast random
access at low cost is important.Comment: Talk from the 2004 Computing in High Energy and Nuclear Physics
(CHEP04), Interlaken, Switzerland, 27th September - 1st October 2004, 4
pages, LaTeX, uses CHEP2004.cls. ID 47, Poster Session 2, Track
The RFOFO Ionization Cooling Ring for Muons
Practical ionization cooling rings could lead to lower cost or improved
performance in neutrino factory or muon collider designs. The ring modeled here
uses realistic three-dimensional fields. The performance of the ring compares
favorably with the linear cooling channel used in the second US Neutrino
Factory Study. The normalized 6D emittance of an ideal ring is decreased by a
factor of approximately 240, compared with a factor of only 15 for the linear
channel. We also examine such \textit{real-world} effects as windows on the
absorbers and rf cavities and leaving empty lattice cells for injection and
extraction. For realistic conditions the ring decreases the normalized 6D
emittance by a factor of 49.Comment: 27 pages, 18 figures and 5 tables. Submitted to Phys. Rev. ST-A
Interpreting experimental bounds on D^0 - \bar{D^0} mixing in the presence of CP violation
We analyse the most recent experimental data regarding D^0 - \bar{D^0}
mixing, allowing for CP violation. We focus on the dispersive part of the
mixing amplitude, M^D_{12}, which is sensitive to new physics contributions. We
obtain a constraint on the mixing amplitude: |M^D_{12}| < 6.2\times 10^{-11}
MeV at 95% C.L. . This constraint is weaker by a factor of about three than the
one which is obtained when no CP violation is assumed.Comment: 9 pages, revtex4; One reference updated, one reference added,
footnote 3 correcte
Averages of b-hadron Properties at the End of 2005
This article reports world averages for measurements on b-hadron properties
obtained by the Heavy Flavor Averaging Group (HFAG) using the available results
as of at the end of 2005. In the averaging, the input parameters used in the
various analyses are adjusted (rescaled) to common values, and all known
correlations are taken into account. The averages include lifetimes, neutral
meson mixing parameters, parameters of semileptonic decays, branching fractions
of B meson decays to final states with open charm, charmonium and no charm, and
measurements related to CP asymmetries
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