238 research outputs found
Compressed electroweakino spectra at the LHC
In this work, we examine the sensitivity of monojet searches at the LHC to
directly produced charginos and neutralinos (electroweakinos) in the limit of
small mass splitting, where the traditional multilepton plus missing energy
searches loose their sensitivity. We first recast the existing 8 TeV monojet
search at CMS in terms of a SUSY simplified model with only light gauginos
(winos and binos) or only light higgsinos. The current searches are not
sensitive to MSSM like production cross sections, but would be sensitive to
models with 2-20 times enhanced production cross section, for particle masses
between 100 GeV and 250 GeV. Then we explore the sensitivity in the 14 TeV run
of the LHC. Here we emphasise that in addition to the pure monojet search, soft
leptons present in the samples can be used to increase the sensitivity.
Exclusion of electroweakino masses up to 200 GeV is possible with 300 fb
at the LHC, if the systematic error can be reduced to the 1% level. Discovery
is possible with 3000 fb in some regions of parameter space.Comment: 22 pages, 10 figures. Minor corrections, references added, matched
published versio
Cognitive skills and the LOGSE reform in Spain: evidence from PIAAC
We use data from the Spanish sample of the Programme for the International Assessment of Adult Competencies to analyze the effect of the LOGSE (Spanish acronym for General Law of the Education System) reform passed in 1990 on numeracy and literacy proficiency of the adult population. The LOGSE effect is identified by exploiting the variability of the rate of implementation among cohorts and regions. The results change depending on the specification of the econometric model and mainly on the type of birth year trend assumed. Nonetheless, overall results suggest that the LOGSE reform did not help to increase cognitive skills of the population despite an extension of compulsory years of education and postponement of the age of initial tracking into vocational and academic studies
Dark Higgs Models at the 7 TeV LHC
We study how collider data and electroweak precision observables affect the
parameter space of models including a new dark force mediated by a massive U(1)
gauge boson. It acquires mass via a Higgs mechanism in the dark sector which is
connected to the Standard Model through kinetic mixing of the two U(1) gauge
bosons and the Higgs potential. We assess the impact of the 7 TeV LHC and show
that most of the parameter space of the model can be probed with an integrated
luminosity of 15 fb^-1.Comment: 20 pages, 8 figures; references, clarification and note added;
conclusions unaltered; version accepted for publication in JHEP; v3: added
reference
BMSSM Higgs Bosons at the Tevatron and the LHC
We study extensions of the Minimal Supersymmetric Standard Model (MSSM) with
new degrees of freedom that couple sizably to the MSSM Higgs sector and lie in
the TeV range. After integrating out the physics at the TeV scale, the
resulting Higgs spectrum can significantly differ from typical supersymmetric
scenarios, thereby providing a window Beyond the MSSM (BMSSM). Taking into
account current LEP and Tevatron constraints, we perform an in-depth analysis
of the Higgs collider phenomenology and explore distinctive characteristics of
our scenario with respect to both the Standard Model and the MSSM.
We propose benchmark scenarios to illustrate specific features of BMSSM Higgs
searches at the Tevatron and the LHC.Comment: 18 pages, 9 figures; added parameters for each benchmark point, typos
corrected, final version published by Phys. Rev.
Closing the window for compressed Dark Sectors with disappearing charged tracks
We investigate the sensitivity at current and future hadron colliders to a
heavy electrically-charged particle with a proper decay length below a
centimetre, whose decay products are invisible due to below-threshold energies
and/or small couplings to the Standard Model. A cosmologically-motivated
example of a framework that contains such a particle is the Minimal
Supersymmetric Standard Model in the limit of pure Higgsinos. The current
hadron-collider search strategy has no sensitivity to the upper range of pure
Higgsino masses that are consistent with the thermal relic density, even at a
future collider with 100 TeV centre-of-mass energy. We show that performing a
disappearing track search within the inner 10 cm of detector volume would
improve the reach in lifetime by a factor of 3 at the 14 TeV LHC and a further
factor of 5 at a 100 TeV collider, resulting in around 10 events for 1.1 TeV
thermal Higgsinos. In order to include the particles with the largest boost in
the analysis, we furthermore propose a purely track-based search in both the
central and forward regions, each of which would increase the number of events
by another factor of 5, improving our reach at small lifetimes. This would
allow us to definitively discover or exclude the experimentally-elusive
pure-Higgsino thermal relic at a 100 TeV collider.Comment: 20 pages, 11 figure
New Physics Opportunities for Long-Lived Particles at Electron-Proton Colliders
Future electron-proton collider proposals like the LHeC or the FCC-eh can
supply 1/ab of collisions with a center-of-mass energy in the TeV range, while
maintaining a clean experimental environment more commonly associated with
lepton colliders. We point out that this makes electron-proton colliders
ideally suited to probe BSM signatures with final states that look like
"hadronic noise" in the high-energy, pile-up-rich environment of hadron
colliders. We focus on the generic vector boson fusion production mechanism,
which is available for all BSM particles with electroweak charges at mass
scales far above the reach of most lepton colliders. This is in contrast to
previous BSM studies at these machines, which focused on BSM processes with
large production rates from the asymmetric initial state. We propose to exploit
the unique experimental environment in the search for long-lived particle
signals arising from Higgsinos or exotic Higgs decays. At electron-proton
colliders, the soft decay products of long-lived Higgsinos can be explicitly
reconstructed ("displaced single pion"), and very short lifetimes can be
probed. We find that electron-proton colliders can explore significant regions
of BSM parameter space inaccessible to other collider searches, with important
implications for the design of such machines.Comment: 16 pages, 11 figure
Closing the light gluino gap with electron-proton colliders
The future electron-proton collider proposals, LHeC and FCC-he, can deliver
(TeV) center-of-mass energy collisions, higher than most of the
proposed lepton accelerators, with (ab) luminosity, while
maintaining a much cleaner experimental environment as compared to the hadron
machines. This unique capability of colliders can be harnessed in
probing BSM scenarios giving final states that look like hadronic noise at
machines. In the present study, we explore the prospects of detecting such a
prompt signal having multiple soft jets at the LHeC. Such a signal can come
from the decay of gluino in RPV or Stealth SUSY, where there exists a gap in
the current experimental search with GeV. We
perform a simple analysis to demonstrate that, with simple signal selection
cuts, we can close this gap at the LHeC at 95 % confidence level, even in the
presence of a reasonable systematic error. More sophisticated signal selection
strategies and detailed knowledge of the detector can be used to improve the
prospects of signal detection.Comment: 7 pages, 5 figure
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