6,334 research outputs found
Muon capture in the front end of the IDS neutrino factory
We discuss the design of the muon capture front end of the neutrino factory
International Design Study. In the front end, a proton bunch on a target
creates secondary pions that drift into a capture transport channel, decaying
into muons. A sequence of rf cavities forms the resulting muon beams into
strings of bunches of differing energies, aligns the bunches to (nearly) equal
central energies, and initiates ionization cooling. The muons are then
accelerated to high energy where their decays provide neutrino beams. For the
International Design Study (IDS), a baseline design must be developed and
optimized for an engineering and cost study. We present a baseline design that
can be used to establish the scope of a future neutrino Factory facility.Comment: 3 pp. 1st International Particle Accelerator Conference: IPAC'10,
23-28 May 2010: Kyoto, Japa
Muon capture for the front end of a muon collider
We discuss the design of the muon capture front end for a \mu+-\mu- Collider.
In the front end, a proton bunch on a target creates secondary pions that drift
into a capture transport channel, decaying into muons. A sequence of rf
cavities forms the resulting muon beams into strings of bunches of differing
energies, aligns the bunches to (nearly) equal central energies, and initiates
ionization cooling. The muons are then cooled and accelerated to high energy
into a storage ring for high-energy high luminosity collisions. Our initial
design is based on the somewhat similar front end of the International Design
Study (IDS) neutrino factory.Comment: 3 pp. Particle Accelerator, 24th Conference (PAC'11) 28 Mar - 1 Apr
2011: New York, US
X-Ray Emission from the Warm Hot Intergalactic Medium
The number of detected baryons in the Universe at z<0.5 is much smaller than
predicted by standard big bang nucleosynthesis and by the detailed observation
of the Lyman alpha forest at red-shift z=2. Hydrodynamical simulations indicate
that a large fraction of the baryons today is expected to be in a ``warm-hot''
(10^5-10^7K) filamentary gas, distributed in the intergalactic medium. This
gas, if it exists, should be observable only in the soft X-ray and UV bands.
Using the predictions of a particular hydrodynamic model, we simulated the
expected X-ray flux as a function of energy in the 0.1-2 keV band due to the
Warm-Hot Intergalactic Medium (WHIM), and compared it with the flux from local
and high red-shift diffuse components. Our results show that as much as 20% of
the total diffuse X-ray background (DXB) in the energy range 0.37-0.925keV
could be due to X-ray flux from the WHIM, 70% of which comes from filaments at
redshift z between 0.1 and 0.6. Simulations done using a FOV of 3', comparable
with that of Suzaku and Constellation-X, show that in more than 20% of the
observations we expect the WHIM flux to contribute to more than 20% of the DXB.
These simulations also show that in about 10% of all the observations a single
bright filament in the FOV accounts, alone, for more than 20% of the DXB flux.
Red-shifted oxygen lines should be clearly visible in these observations.Comment: 19 pages, 6 figure
Systematic Investigation of Possibilities for New Physics Effects in b --> s Penguin Processes
Although recent experimental results in b-->s penguin process seem to be
roughly consistent with the standard model predictions, there may be still
large possibilities of new physics hiding in this processes. Therefore, here we
investigate systematically the potential new physics effects that may appear in
time-dependent CP asymmetries of B --> phi K^0, B--> eta^\prime K^0 and B-->
K^0 \pi^0 decay modes, by classifying the cases for the values of the
mixing-induced indirect CP asymmetries, S_{phi K^0}, S_{eta^\prime K^0}, S_{K^0
pi^0} which are compared to S_{J/psi K^0}. We also show that several B_s decay
modes may help to resolve the ambiguities in such an analysis. Through
combining analysis with the time-dependent CP asymmetries of B_s decay modes
such as B_s --> phi eta^\prime, B_s--> eta^\prime pi^0 and B_s --> K^0
bar{K}^0, we can determine where the new CP phases precisely come from.Comment: 17 pages, version to be published in Prog.Theor.Phy
Gay-Straight Alliances as Settings to Discuss Health Topics: Individual and Group Factors Associated with Substance Use, Mental Health, and Sexual Health Discussions
Sexual minority (e.g. lesbian, gay, bisexual, questioning; LGBQ) and gender minority (e.g. transgender) youth experience myriad health risks. Gay-Straight Alliances (GSAs) are school-based settings where they may have opportunities to discuss substance use, mental health, and sexual health issues in ways that are safe and tailored to their experiences. Attention to these topics in GSAs could aid in developing programming for these settings. Among 295 youth from 33 Massachusetts high-school GSAs (69% LGBQ, 68% cisgender female, 68% White, Mage = 16.06), we examined how often youth discussed these topics within their GSA and identified factors associated with having more of these discussions. Youth and GSAs as a whole varied in their frequency of discussing these topics. Youth who accessed more information/resources in the GSA and did more advocacy more frequently engaged in discussions around substance use, mental health and sexual health. Youth who reported greater victimization more often discussed substance use and mental health, but not sexual health. Finally, GSAs whose members collectively reported greater victimization more frequently discussed these topics. These findings can assist the development of health programming to be delivered within GSAs
Optimization of the Target Subsystem for the New g-2 Experiment
A precision measurement of the muon anomalous magnetic moment, , was previously performed at BNL with a result of 2.2 - 2.7 standard
deviations above the Standard Model (SM) theoretical calculations. The same
experimental apparatus is being planned to run in the new Muon Campus at
Fermilab, where the muon beam is expected to have less pion contamination and
the extended dataset may provide a possible deviation from the SM,
creating a sensitive and complementary bench mark for proposed SM extensions.
We report here on a preliminary study of the target subsystem where the
apparatus is optimized for pions that have favorable phase space to create
polarized daughter muons around the magic momentum of 3.094 GeV/c, which is
needed by the downstream g 2 muon ring.Comment: 4 pp. 3rd International Particle Accelerator Conference (IPAC 2012)
20-25 May 2012, New Orleans, Louisian
Shifting with
Precision measurements at the resonance agree well with the standard
model. However, there is still a hint of a discrepancy, not so much in by
itself (which has received a great deal of attention in the past several years)
but in the forward-backward asymmetry together with . The two
are of course correlated. We explore the possibilty that these and other
effects are due to the mixing of and with one or more heavy quarks.Comment: 11 pages, 1 Figure, LaTex fil
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