7,960 research outputs found
Overview of the SiLC R&D Activities
The R&D Collaboration SiLC (Silicon tracking for Linear Colliders) is based
on generic R&D aiming to develop the next generation of large Silicon tracking
systems for the Linear collider experiments; it serves all three ILC detector
concepts. There is a strong involvement in ILD, a natural collaboration with
SiD and recent 4th concept interest to use Silicon tracking technology as well.
Here is a very brief summary of the latest results on sensors, Front End
Electronics, Mechanics and Integration issues, test bench and test beam results
and where to go from there.Comment: 3 pages, 3 figures, LCWS08 Worksho
On Metastability in Supersymmetric Models
We make a critical reappraisal of `unbounded-from-below' (UFB) constraints in
the MSSM and R-parity violating models. We explain why the `traditional' UFB
bounds are neither necessary nor sufficient and propose, instead, a sufficient
condition which ensures that there are no local minima along the flat
directions. This conservative (but meaningful) condition divides the parameter
space into regions which are allowed, regardless of cosmology, and regions in
which cosmology is expected to play a major role. We study both conditions at
low tan-beta and obtain analytic approximations to the UFB bounds for all low
tan-beta (<15). Finally we show that R-parity violation just below current
experimental limits avoids UFB problems by lifting the dangerous flat
directions.Comment: 28 Pages plain latex; includes 4 eps figures, numerical errors
corrected plus additional reference, final version to appear in Nucl Phys
Models with Inverse Sfermion Mass Hierarchy and Decoupling of the SUSY FCNC Effects
We study the decoupling of the first two squark and slepton families in order
to lower the flavour changing neutral current effects. Models with inverse
sfermion mass hierarchy based upon gauged U(1) flavour symmetries provide a
natural framework where decoupling can be implemented. Decoupling requires a
large gap between the Fermi scale and the supersymmetry breaking scale.
Maintaining the electroweak symmetry breaking at the Fermi scale requires some
fine-tuning that we investigate by solving the two-loop renormalization group
equations. We show that the two-loop effects are governed by the anomaly
compensated by the Green-Schwarz mechanism and can be determined from the quark
and lepton masses. The electroweak breaking constraints lead to a small
scenario where the LSP is Higgsino-like.Comment: 19 pages, Latex, 1 Postscript figur
Sleptonarium (Constraints on the CP and Flavour Pattern of Scalar Lepton Masses)
The constraints on the flavour and CP structure of scalar lepton mass
matrices are systematically collected. The display of the resulting upper
bounds on the lepton -slepton misalignment parameters is designed for an easy
inspection of very large classes of models and the formula are arranged so as
to suggest useful approximations. Interferences among the different
contributions to lepton flavour violating transitions and lepton electric and
magnetic dipole moments of generic character can either tighten or loose the
bounds. A combined analysis of all rare leptonic transitions can disentangle
the different contributions to yield hints on several phenomenological issues.
The possible impact of these results on the study of the slepton misalignment
originated in the seesaw mechanism and grand-unified theories is emphasized
since the planned experiments are getting close to the precision required in
such tests.Comment: 29 pages, 13 figures; v3: corrected misprints in appendix
Supersymmetric Flat Directions and Analytic Gauge Invariants
We review some aspects of the correspondence between analytic gauge
invariants and supersymmetric flat directions for vanishing D-terms and propose
a criterion to include the F-term constraints.Comment: 8 pages, Late
Level-1 pixel based tracking trigger algorithm for LHC upgrade
The Pixel Detector is the innermost detector of the tracking system of the
Compact Muon Solenoid (CMS) experiment at CERN Large Hadron Collider (LHC). It
precisely determines the interaction point (primary vertex) of the events and
the possible secondary vertexes due to heavy flavours ( and quarks); it
is part of the overall tracking system that allows reconstructing the tracks of
the charged particles in the events and combined with the magnetic field to
measure their impulsion. The pixel detector allows measuring the tracks in the
region closest to the interaction point. The Level-1 (real-time) pixel based
tracking trigger is a novel trigger system that is currently being studied for
the LHC upgrade. An important goal is developing real-time track reconstruction
algorithms able to cope with very high rates and high flux of data in a very
harsh environment. The pixel detector has an especially crucial role in
precisely identifying the primary vertex of the rare physics events from the
large pile-up (PU) of events. The goal of adding the pixel information already
at the real-time level of the selection is to help reducing the total level-1
trigger rate while keeping an high selection capability. This is quite an
innovative and challenging objective for the experiments upgrade for the High
Luminosity LHC (HL-LHC). The special case here addressed is the CMS experiment.
This document describes exercises focusing on the development of a fast pixel
track reconstruction where the pixel track matches with a Level-1 electron
object using a ROOT-based simulation framework.Comment: Submitted to JINST; 12 pages, 10 figures, Contribution to the JINST
proceedings for the INFIERI2014 School in Paris, France, July 14-25, 201
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