15,309 research outputs found
A Review of the Mass Measurement Techniques proposed for the Large Hadron Collider
We review the methods which have been proposed for measuring masses of new
particles at the Large Hadron Collider paying particular attention to the
kinematical techniques suitable for extracting mass information when invisible
particles are expected.Comment: 72 pages - in form to be published in JPhys
Re-weighing the evidence for a Higgs boson in dileptonic W-boson decays
We reconsider observables for discovering and measuring the mass of a Higgs
boson via its di-leptonic decays: H --> WW* --> l nu l nu. We define an
observable generalizing the transverse mass that takes into account the fact
that one of the intermediate W-bosons is likely to be on-shell. We compare this
new variable with existing ones and argue that it gives a significant
improvement for discovery in the region m_h < 2 m_W.Comment: 3 pages, 2 figures. Changes in v2: (i) implemented a model of
detector smearing, (ii) switched LHC simulation from 14 TeV to 7 TeV running,
(iii) presenting results for 10 rather than 3 inverse femtobarns, (iv)
corrected a typo in Fig 2 legend. Changes in v3: included published erratu
Finding Higgs bosons heavier than 2 m_W in dileptonic W-boson decays
We reconsider observables for discovering a heavy Higgs boson (with m_h >
2m_W) via its di-leptonic decays h -> WW -> l nu l nu. We show that observables
generalizing the transverse mass that take into account the fact that both of
the intermediate W bosons are likely to be on-shell give a significant
improvement over the variables used in existing searches. We also comment on
the application of these observables to other decays which proceed via
narrow-width intermediates.Comment: v1:4 pages, 1 figure; v2: 6 pages, 2 figures, substantially revise
Threshold Effects in Slepton-Pair Production at the LHC
We present a study of threshold resummation effects for slepton pair
production at the Large Hadron Collider (LHC). After confirming the known NLO
QCD corrections and generalizing the NLO SUSY-QCD corrections to the case of
mixing squarks in the virtual loop contributions, we employ the Mellin N-space
resummation formalism to compute logarithmically enhanced soft-gluon terms to
all perturbative orders.Comment: 3 pages, 1 figure, presented at HEP 2007 (Manchester, July 2007
The Precision Determination of Invisible-Particle Masses at the LHC
We develop techniques to determine the mass scale of invisible particles
pair-produced at hadron colliders. We employ the constrained mass variable
m_2C, which provides an event-by-event lower-bound to the mass scale given a
mass difference. We complement this variable with a new variable m_2C,UB which
provides an additional upper bound to the mass scale, and demonstrate its
utility with a realistic case study of a supersymmetry model. These variables
together effectively quantify the `kink' in the function Max m_T2 which has
been proposed as a mass-determination technique for collider-produced dark
matter. An important advantage of the m_2C method is that it does not rely
simply on the position at the endpoint, but it uses the additional information
contained in events which lie far from the endpoint. We found the mass by
comparing the HERWIG generated m_2C distribution to ideal distributions for
different masses. We find that for the case studied, with 100 fb^-1 of
integrated luminosity (about 400 signal events), the invisible particle's mass
can be measured to a precision of 4.1 GeV. We conclude that this technique's
precision and accuracy is as good as, if not better than, the best known
techniques for invisible-particle mass-determination at hadron colliders.Comment: 20 pages, 11 figures, minor correction
A comment on "Amplification of endpoint structure for new particle mass measurement at the LHC"
We present a comment on the kinematic variable recently proposed in
"Amplification of endpoint structure for new particle mass measurement at the
LHC". The variable is designed to be applied to models such as R-parity
conserving Supersymmetry (SUSY) when there is pair production of new heavy
particles each of which decays to a single massless visible and a massive
invisible component. It was proposed in "Amplification of endpoint structure
for new particle mass measurement at the LHC" that a measurement of the peak of
the distribution could be used to precisely constrain the masses of
the SUSY particles. We show that when Standard Model backgrounds are included
in simulations, the sensitivity of the variable to the SUSY particle
masses is more seriously impacted for than for other previously
proposed variables.Comment: 5 page
Research on the application of satellite remote sensing to local, state, regional, and national programs involved with resource management and environmental quality
Project summaries and project reports are presented in the area of satellite remote sensing as applied to local, regional, and national environmental programs. Projects reports include: (1) Douglas County applications program; (2) vegetation damage and heavy metal concentration in new lead belt; (3) evaluating reclamation of strip-mined land; (4) remote sensing applied to land use planning at Clinton Reservoir; and (5) detailed land use mapping in Kansas City, Kansas
Preliminary Skylab MSS channel evaluation
The author has identified the following significant results. A set of 18 channels which were considered of usable quality were identified. These were channels 1-14, 17, 19-21. Channels 15, 16, 18, and 22 were dropped out because they were of poor quality; channels 7 and 11 were dropped to limit the total channel number to 16. From these 16 channels, a total of 22 signatures were obtained. Eight were developed from uniform blocks of the UMAP, and 14 from use of the DCLUS program. These signatures fell into six basic categories and classified more than 90% of the five scenes mapped: agriculture land (6 signatures); forest aland (4); water (2); open nonagriculture land (2); urban (6); and disturbed land (2)
Detection of quantitative trait loci for locomotion and osteochondrosis-related traits in Large White x Meishan pigs.
Natural Gauge Hierarchy in SO(10)
It is shown that a natural gauge hierarchy and doublet-triplet splitting can
be achieved in SO(10) using the Dimopoulos-Wilczek mechanism. Artificial
cancellations (fine-tuning) and arbitrary forms of the superpotential are
avoided, the superpotential being the most general compatible with a symmetry.
It is shown by example that the Dimopoulos-Wilczek mechanism can be protected
against the effects of higher-dimension operators possibly induced by
Planck-scale physics. Natural implementation of the mechanism leads to an
automatic Peccei-Quinn symmetry. The same local symmetries that would protect
the gauge hierarchy against Planck-scale effects tend to protect the axion
also. It is shown how realistic quark and lepton masses might arise in this
framework. It is also argued that ``weak suppression'' of proton decay can be
implemented more economically than can ``strong suppression'', offering some
grounds to hope (in the context of SO(10)) that proton decay could be seen at
Superkamiokande.Comment: 26 pages in plain LaTeX, 5 figures available on request, BA-94-0
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