12,100 research outputs found
Exotic Decays of Heavy B quarks
Heavy vector-like quarks of charge , , have been searched for at the
LHC through the decays . In models where the
quark also carries charge under a new gauge group, new decay channels may
dominate. We focus on the case where the is charged under a
and describe simple models where the dominant decay mode is . With the inclusion of dark matter such
models can explain the excess of gamma rays from the Galactic center. We
develop a search strategy for this decay chain and estimate that with
integrated luminosity of 300 fb the LHC will have the potential to
discover both the and the for quarks with mass below
TeV, for a broad range of masses. A high-luminosity run can extend this
reach to TeV.Comment: 28 pages, 10 figures, 3 table
A magnetic isolation and pointing system for the astrometric telescope facility
The astrometric telescope facility (ATF), a 20-meter telescope designed for long-term detection and observation of planetary systems outside of the solar system, is scheduled to be a major user of the Space Station's payload pointing system (PPS) capabilities. However, because the ATF has such a stringent pointing stability specification (as low as 0.01 arcsec error over the frequency range from 5 to 200 hertz) and requires +/- 180-degree roll rotation around the telescope's line of sight, the ATF's utilization of the PPS requires the addition of a mechanism or mechanisms to enhance the basic PPS capabilities. The results of a study conducted to investigate the ATF pointing performance achievable by the addition of a magnetic isolation and pointing (MIPS) system between the PPS upper gimbal and the ATF, and separately, by the addition of a passive isolation system between the Space Station and the PPS base are presented. In addition, the study produced requirements on magnetic force and gap motion as a function of the level of Space Station disturbance. These results were used to support the definition of a candidate MIPS. Pointing performance results from the study indicate that a MIPS can meet the ATF pointing requirements in the presence of a PPS base transitional acceleration of up to 0.018g, with reasonable restrictions placed on the isolation and pointing bandwidths. By contrast, the passive base isolator system must have an unrealistically low isolation bandwidth on all axes (less than 0.1 hertz) to meet ATF pointing requirements. The candidate MIPS is based on an assumed base translational disturbance of 0.01g. The system fits within the available annular region between the PPS and ATF while meeting power and weight limitations and providing the required payload roll motion. Payload data and power services are provided by noncontacting transfer devices
An Effective Z'
We describe a method to couple Z' gauge bosons to the standard model (SM),
without charging the SM fields under the U(1)', but instead through effective
higher dimension operators. This method allows complete control over the
tree-level couplings of the Z' and does not require altering the structure of
any of the SM couplings, nor does it contain anomalies or require introduction
of fields in non-standard SM representations. Moreover, such interactions arise
from simple renormalizable extensions of the SM - the addition of vector-like
matter that mixes with SM fermions when the U(1)' is broken. We apply effective
Z' models as explanations of various recent anomalies: the D0 same-sign dimuon
asymmetry, the CDF W+di-jet excess and the CDF top forward-backward asymmetry.
In the case of the W+di-jet excess we also discuss several complementary
analyses that may shed light on the nature of the discrepancy. We consider the
possibility of non-Abelian groups, and discuss implications for the
phenomenology of dark matter as well.Comment: 44 pages; 5 figures. References added, discussion of gamma+jj
constraints update
Solomon\u27s Mines: The Explosion Over On-Campus Military Recruiting and Why the Solomon Amendment Trumps Law School Non-Discrimination Policies
A Method for the Madness: Restorative Justice as a Valid Mode of Punishment and an Advancement of Catholic Social Thought
A Method for the Madness: Restorative Justice as a Valid Mode of Punishment and an Advancement of Catholic Social Thought
Rings Over Which Cyclics are Direct Sums of Projective and CS or Noetherian
R is called a right WV -ring if each simple right R-module is injective
relative to proper cyclics. If R is a right WV -ring, then R is right uniform
or a right V -ring. It is shown that for a right WV-ring R, R is right
noetherian if and only if each right cyclic module is a direct sum of a
projective module and a CS or noetherian module. For a finitely generated
module M with projective socle over a V -ring R such that every subfactor of M
is a direct sum of a projective module and a CS or noetherian module, we show M
= X \oplus T, where X is semisimple and T is noetherian with zero socle. In the
case that M = R, we get R = S \oplus T, where S is a semisimple artinian ring,
and T is a direct sum of right noetherian simple rings with zero socle. In
addition, if R is a von Neumann regular ring, then it is semisimple artinian.Comment: A Para\^itre Glasgow Mathematical Journa
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