9 research outputs found
Massive Metastable Charged (S)Particles at the LHC
This brief review deals with recent interest in the prospects of observing a
Massive Metastable Charged Particle (MMCP) at the Large Hadron Collider (LHC),
and measuring its properties there. We discuss the motivation for scenarios
with MMCPs in a phenomenological context, focusing on supersymmetric models
that allow us to explore the expected experimental signatures of MMCPs at the
LHC. We review current bounds and give estimates of the LHC reach in terms of
MMCP masses
Constraining the MSSM with Dark Matter indirect detection data
Recently, a claim of possible evidence for Dark Matter in data from the Fermi
LAT experiment was made by Goodenough and Hooper [8]. We test the Dark Matter
properties consistent with their claim in terms of the MSSM by a 24-dimensional
parameter scan using nested sampling, excluding all but a very small region of
the MSSM. Although this claim is very preliminary, and not made by the Fermi
LAT experiment, our scan shows a possible approach for the analysis of future
firm evidence from an indirect detection experiment, and its potential for
heavily constraining models
Gravitino Dark Matter and the Flavour Structure of R-violating Operators
We study gravitino dark matter and slow gravitino decays within the framework
of R-violating supersymmetry, with particular emphasis on the flavour
dependence of the branching ratios and the allowed R-violating couplings. The
dominant decay modes and final state products turn out to be very sensitive to
the R-violating hierarchies. Mixing effects can be crucial in correctly
deriving the relative magnitude of the various contributions, particularly for
heavy flavours with phase space suppression. The study of the strength of
different decay rates for the gravitino is also correlated to collider
signatures expected from decays of the Next-to-Lightest Supersymmetric Particle
(NLSP) and to single superparticle production
Neutralino reconstruction at the LHC from decay-frame kinematics
Decay-frame Kinematics (DK) has previously been introduced as a technique to
reconstruct neutralino masses from their three-body decays to leptons. This
work is an extension to the case of two-body decays through on-shell sleptons,
with Monte Carlo simulation of LHC collisions demonstrating reconstruction of
neutralino masses for the SPS1a benchmark point
LHC Searches for Non-Chiral Weakly Charged Multiplets
Because the TeV-scale to be probed at the Large Hadron Collider should shed
light on the naturalness, hierarchy, and dark matter problems, most searches to
date have focused on new physics signatures motivated by possible solutions to
these puzzles. In this paper, we consider some candidates for new states that
although not well-motivated from this standpoint are obvious possibilities that
current search strategies would miss. In particular we consider vector
representations of fermions in multiplets of with a lightest neutral
state. Standard search strategies would fail to find such particles because of
the expected small one-loop-level splitting between charged and neutral states.Comment: 16 pages, 9 figure
Direct stau production at hadron colliders in cosmologically motivated scenarios
We calculate dominant cross section contributions for stau pair production at
hadron colliders within the MSSM, taking into account left-right mixing of the
stau eigenstates. We find that b-quark annihilation and gluon fusion can
enhance the cross sections by more than one order of magnitude with respect to
the Drell-Yan predictions. These additional production channels are not yet
included in the common Monte Carlo analysis programs and have been neglected in
experimental analyses so far. For long-lived staus, we investigate differential
distributions and prospects for their stopping in the collider detectors. New
possible strategies are outlined to determine the mass and width of the heavy
CP-even Higgs boson H0. Scans of the relevant regions in the CMSSM are
performed and predictions are given for the current experiments at the LHC and
the Tevatron. The obtained insights allow us to propose collider tests of
cosmologically motivated scenarios with long-lived staus that have an
exceptionally small thermal relic abundance.Comment: 49 pages, 13 figures; v2: references added, typos corrected, text
streamlined, results unchange
NMSSM in disguise: discovering singlino dark matter with soft leptons at the LHC
We suggest an NMSSM scenario, motivated by dark matter constraints, that may
disguise itself as a much simpler mSUGRA scenario at the LHC. We show how its
non-minimal nature can be revealed, and the bino--singlino mass difference
measured, by looking for soft leptons
Boosted objects: A Probe of beyond the Standard Model physics
We present the report of the hadronic working group of the BOOST2010 workshop
held at the University of Oxford in June 2010. The first part contains a review
of the potential of hadronic decays of highly boosted particles as an aid for
discovery at the LHC and a discussion of the status of tools developed to meet
the challenge of reconstructing and isolating these topologies. In the second
part, we present new results comparing the performance of jet grooming
techniques and top tagging algorithms on a common set of benchmark channels. We
also study the sensitivity of jet substructure observables to the uncertainties
in Monte Carlo predictions.Comment: Report of the hadronic working group of the BOOST2010 workshop,
University of Oxford, 22-25 June, 2010. Editors: M. Karagoz, G. Salam, M.
Spannowsky and M. Vos. v2 published in EPJ C. 19 pages, double column, uses
EPJ C style for late