3,798 research outputs found
Measuring the Mass of the Lightest Chargino at the CERN LHC
Results are presented of a feasibility study of techniques for measuring the
mass of the lightest chargino at the CERN LHC. These results suggest that for
one particular mSUGRA model a statistically significant chargino signal can be
identified and the chargino mass reconstructed with a precision of order 11%
for of order 100 fb-1 of data.Comment: 6 pages, 5 figures. To appear in the proceedings of the workshop: Les
Houches 2003: Physics at TeV Scale Collider
Signatures of Spherical Compactification at the LHC
TeV-scale extra dimensions may play an important role in electroweak or
supersymmetry breaking. We examine the phenomenology of such dimensions,
compactified on a sphere , , and show that they possess distinct
features and signatures. For example, unlike flat toroidal manifolds, spheres
do not trivially allow fermion massless modes. Acceptable phenomenology then
generically leads to "non-universal" extra dimensions with "pole-localized"
4- fermions; the bosonic fields can be in the bulk. Due to spherical
symmetry, some Kaluza-Klein (KK) modes of bulk gauge fields are either stable
or extremely long-lived, depending on the graviton KK spectrum. Using precision
electroweak data, we constrain the lightest gauge field KK modes to lie above
TeV. We show that some of these KK resonances are within the reach
of the LHC in several different production channels. The models we study can be
uniquely identified by their collider signatures.Comment: 21 pages, 5 fig
Measuring the SUSY Breaking Scale at the LHC in the Slepton NLSP Scenario of GMSB Models
We report a study on the measurement of the SUSY breaking scale sqrt(F) in
the framework of gauge-mediated supersymmetry breaking (GMSB) models at the
LHC. The work is focused on the GMSB scenario where a stau is the
next-to-lightest SUSY particle (NLSP) and decays into a gravitino with lifetime
c*tau_NLSP in the range 0.5 m to 1 km. We study the identification of
long-lived sleptons using the momentum and time of flight measurements in the
muon chambers of the ATLAS experiment. A realistic evaluation of the
statistical and systematic uncertainties on the measurement of the slepton mass
and lifetime is performed, based on a detailed simulation of the detector
response. Accessible range and precision on sqrt(F) achievable with a counting
method are assessed. Many features of our analysis can be extended to the study
of different theoretical frameworks with similar signatures at the LHC.Comment: 28 pages, 12 figures (18 eps files). Revised version v2(published in
JHEP): Some important corrections and additions to v
Aspects of GMSB Phenomenology at TeV Colliders
The status of two on-going studies concerning important aspects of the
phenomenology of gauge-mediated supersymmetry breaking (GMSB) models at TeV
colliders is reported. The first study deals with the characteristics of the
light Higgs boson spectrum allowed by the (minimal and non-minimal) GMSB
framework. Today's most accurate GMSB model generation and two-loop
Feynman-diagrammatic calculation of m_h have been combined. The Higgs masses
are shown in dependence of various model parameters at the messenger and
electroweak scales. In the minimal model, an upper limit on m_h of about 124
GeV is found for m_t = 175 GeV. The second study is focused on the measurement
of the fundamental SUSY breaking scale sqrt(F) at the LHC in the GMSB scenario
where a stau is the next-to-lightest SUSY particle (NLSP) and decays into a
gravitino with c*tau_NLSP in the range 0.5 m to 1 km. This implies the
measurement of mass and lifetime of long lived sleptons. The identification is
performed by determining the time of flight in the ATLAS muon chambers.
Accessible range and precision on sqrt(F) achievable with a counting method are
assessed.Comment: 22 pages, 9 figures (12 eps files). Report of the GMSB SUSY Working
Group, Workshop "Physics at TeV Colliders", Les Houches, 7-18 June 1999.
Revised version v3: A few typos correcte
A study on the detection of a light stop squark with the ATLAS Detector at the LHC
The search for light supersymmetric partners of the top quark (stop squark) could result into the early discovery of physics beyond the Standard Model at the LHC. We present here a detailed analysis based on a parametrized simulation of the ATLAS detector. We study a benchmark model in the framework of the Minimal Supersymmetric Standard Model, with a stop squark lighter than the top quark, yielding a final state similar to the one for production. It is demonstrated that a signal for the stop squark can be extracted in this case, and the kinematic features of the stop decay studied. A technique to subtract the SM background based on the data is developed to achieve this result
Reconstructing Supersymmetry at ILC/LHC
Coherent analyses of experimental results from LHC and ILC will allow us to
draw a comprehensive and precise picture of the supersymmetric particle sector.
Based on this platform the fundamental supersymmetric theory can be
reconstructed at the high scale which is potentially close to the Planck scale.
This procedure will be reviewed for three characteristic examples: minimal
supergravity as the paradigm; a left-right symmetric extension incorporating
intermediate mass scales; and a specific realization of string effective
theories.Comment: published in Proceedings of the Ustron Conference 2005; technical
LaTeX problem correcte
A New SUSY mass reconstruction method at the CERN LHC
We propose a new mass reconstruction technique for SUSY processes at the LHC.
The idea is to completely solve the kinematics of the SUSY cascade decay by
using the assumption that the selected events satisfy the same mass shell
conditions of the sparticles involved in the cascade decay. Using this
technique, we study the measurement of the mass of the bottom squarks in the
cascade decay of the gluino. Based on the final state including two high p_T
leptons and two b-jets, we investigate different possible approaches to the
mass reconstruction of the gluino and the two bottom squarks. In particular we
evaluate the performance of different algorithms in discriminating two bottom
squark states with a mass difference as low as 5%.Comment: Revtex 16 pages, 8 figure
Constraining Dark Matter in the MSSM at the LHC
In the event that R-Parity conserving supersymmetry (SUSY) is discovered at
the LHC, a key issue which will need to be addressed will be the consistency of
that signal with astrophysical and non-accelerator constraints on SUSY Dark
Matter. This issue is studied for the SPA benchmark model based on measurements
of end-points and thresholds in the invariant mass spectra of various
combinations of leptons and jets. These measurements are used to constrain the
soft SUSY breaking parameters at the electroweak scale in a general MSSM model.
Based on these constraints, we assess the accuracy with which the Dark Matter
relic density can be measured.Comment: 21 pages, 12 figure
- âŠ