22 research outputs found
Running into New Territory in SUSY Parameter Space
The LEP-II bound on the light Higgs mass rules out the vast majority of
parameter space left to the Minimal Supersymmetric Standard Model (MSSM) with
weak-scale soft-masses. This suggests the importance of exploring extensions of
the MSSM with non-minimal Higgs physics. In this article, we explore a theory
with an additional singlet superfield and an extended gauge sector. The theory
has a number of novel features compared to both the MSSM and Next-to-MSSM,
including easily realizing a light CP-even Higgs mass consistent with LEP-II
limits, tan(beta) < 1, and a lightest Higgs which is charged. These features
are achieved while remaining consistent with perturbative unification and
without large stop-masses. Discovery modes at the Tevatron and LHC are
discussed.Comment: 15 pages, 5 figures; Typo in equation (4.5) corrected; submitted to
JHE
Supersymmetry Without Prejudice at the LHC
The discovery and exploration of Supersymmetry in a model-independent fashion
will be a daunting task due to the large number of soft-breaking parameters in
the MSSM. In this paper, we explore the capability of the ATLAS detector at the
LHC ( TeV, 1 fb) to find SUSY within the 19-dimensional
pMSSM subspace of the MSSM using their standard transverse missing energy and
long-lived particle searches that were essentially designed for mSUGRA. To this
end, we employ a set of k previously generated model points in the
19-dimensional parameter space that satisfy all of the existing experimental
and theoretical constraints. Employing ATLAS-generated SM backgrounds and
following their approach in each of 11 missing energy analyses as closely as
possible, we explore all of these k model points for a possible SUSY
signal. To test our analysis procedure, we first verify that we faithfully
reproduce the published ATLAS results for the signal distributions for their
benchmark mSUGRA model points. We then show that, requiring all sparticle
masses to lie below 1(3) TeV, almost all(two-thirds) of the pMSSM model points
are discovered with a significance in at least one of these 11 analyses
assuming a 50\% systematic error on the SM background. If this systematic error
can be reduced to only 20\% then this parameter space coverage is increased.
These results are indicative that the ATLAS SUSY search strategy is robust
under a broad class of Supersymmetric models. We then explore in detail the
properties of the kinematically accessible model points which remain
unobservable by these search analyses in order to ascertain problematic cases
which may arise in general SUSY searches.Comment: 69 pages, 40 figures, Discussion adde
A very cool brown dwarf in UKIDSS DR1
The definitive version is available at www.blackwell-synergy.com. Copyright Blackwell Publishing DOI : 10.1111/j.1365-2966.2007.12348.xPeer reviewe
Eight new T4.5-T7.5 dwarfs discovered in the UKIDSS large area survey data release 1
The definitive version is available at www.blackwell-synergy.com Copyright Blackwell Publishing DOI : 10.1111/j.1365-2966.2007.12023.xPeer reviewe
Understanding sub-stellar populations using wide-field infrared surveys
This paper discusses benchmark brown dwarfs in various environments, and focuses on those in wide binary systems. We present a summary of the recently discovered T dwarf population from the UKIDSS Large Area Survey, and describe the constraints that it places on our knowledge of the sub-stellar initial mass function. We also present some exciting results from our ongoing search for wide companions to this sample, that has so far revealed an M4-T8.5 binary system at âŒ12 parsecs and also the first ever Tdwarf-white dwarf binary system. The T dwarfs in these binaries have their properties constrained by the primary object and are thus benchmark objects that are already testing the predictions of theoretical model atmospheres