7,181 research outputs found
Virtual Data in CMS Analysis
The use of virtual data for enhancing the collaboration between large groups
of scientists is explored in several ways:
- by defining ``virtual'' parameter spaces which can be searched and shared
in an organized way by a collaboration of scientists in the course of their
analysis;
- by providing a mechanism to log the provenance of results and the ability
to trace them back to the various stages in the analysis of real or simulated
data;
- by creating ``check points'' in the course of an analysis to permit
collaborators to explore their own analysis branches by refining selections,
improving the signal to background ratio, varying the estimation of parameters,
etc.;
- by facilitating the audit of an analysis and the reproduction of its
results by a different group, or in a peer review context.
We describe a prototype for the analysis of data from the CMS experiment
based on the virtual data system Chimera and the object-oriented data analysis
framework ROOT. The Chimera system is used to chain together several steps in
the analysis process including the Monte Carlo generation of data, the
simulation of detector response, the reconstruction of physics objects and
their subsequent analysis, histogramming and visualization using the ROOT
framework.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics
(CHEP03), La Jolla, Ca, USA, March 2003, 9 pages, LaTeX, 7 eps figures. PSN
TUAT010. V2 - references adde
Visible and near infrared observation on the Global Aerosol Backscatter Experiment (GLOBE)
The Global Aerosol Backscatter Experiment (GLOBE) was intended to provide data on prevailing values of atmospheric backscatter cross-section. The primary intent was predicting the performance of spaceborne lidar systems, most notably the Laser Atmospheric Wind Sounder (LAWS) for the Earth Observing System (EOS). The second and related goal was to understand the source and characteristics of atmospheric aerosol particles. From the GLOBE flights, extensive data was obtained on the structure of clouds and the marine planetary boundary layer. A notable result for all observations is the consistency of the large increases in the aerosol scattering ratio for the marine boundary layer. Other results are noted
Frequentist Analysis of the Parameter Space of Minimal Supergravity
We make a frequentist analysis of the parameter space of minimal supergravity
(mSUGRA), in which, as well as the gaugino and scalar soft
supersymmetry-breaking parameters being universal, there is a specific relation
between the trilinear, bilinear and scalar supersymmetry-breaking parameters,
A_0 = B_0 + m_0, and the gravitino mass is fixed by m_{3/2} = m_0. We also
consider a more general model, in which the gravitino mass constraint is
relaxed (the VCMSSM). We combine in the global likelihood function the
experimental constraints from low-energy electroweak precision data, the
anomalous magnetic moment of the muon, the lightest Higgs boson mass M_h, B
physics and the astrophysical cold dark matter density, assuming that the
lightest supersymmetric particle (LSP) is a neutralino. In the VCMSSM, we find
a preference for values of m_{1/2} and m_0 similar to those found previously in
frequentist analyses of the constrained MSSM (CMSSM) and a model with common
non-universal Higgs masses (NUHM1). On the other hand, in mSUGRA we find two
preferred regions: one with larger values of both m_{1/2} and m_0 than in the
VCMSSM, and one with large m_0 but small m_{1/2}. We compare the probabilities
of the frequentist fits in mSUGRA, the VCMSSM, the CMSSM and the NUHM1: the
probability that mSUGRA is consistent with the present data is significantly
less than in the other models. We also discuss the mSUGRA and VCMSSM
predictions for sparticle masses and other observables, identifying potential
signatures at the LHC and elsewhere.Comment: 18 pages 27 figure
Recommended from our members
Genomic signatures of heterokaryosis in the oomycete pathogen Bremia lactucae.
Lettuce downy mildew caused by Bremia lactucae is the most important disease of lettuce globally. This oomycete is highly variable and rapidly overcomes resistance genes and fungicides. The use of multiple read types results in a high-quality, near-chromosome-scale, consensus assembly. Flow cytometry plus resequencing of 30 field isolates, 37 sexual offspring, and 19 asexual derivatives from single multinucleate sporangia demonstrates a high incidence of heterokaryosis in B. lactucae. Heterokaryosis has phenotypic consequences on fitness that may include an increased sporulation rate and qualitative differences in virulence. Therefore, selection should be considered as acting on a population of nuclei within coenocytic mycelia. This provides evolutionary flexibility to the pathogen enabling rapid adaptation to different repertoires of host resistance genes and other challenges. The advantages of asexual persistence of heterokaryons may have been one of the drivers of selection that resulted in the loss of uninucleate zoospores in multiple downy mildews
The NUHM2 after LHC Run 1
We make a frequentist analysis of the parameter space of the NUHM2, in which
the soft supersymmetry (SUSY)-breaking contributions to the masses of the two
Higgs multiplets, , vary independently from the universal soft
SUSY-breaking contributions to the masses of squarks and sleptons. Our
analysis uses the MultiNest sampling algorithm with over points
to sample the NUHM2 parameter space. It includes the ATLAS and CMS Higgs mass
measurements as well as their searches for supersymmetric jets + MET signals
using the full LHC Run~1 data, the measurements of by
LHCb and CMS together with other B-physics observables, electroweak precision
observables and the XENON100 and LUX searches for spin-independent dark matter
scattering. We find that the preferred regions of the NUHM2 parameter space
have negative SUSY-breaking scalar masses squared for squarks and sleptons,
, as well as . The tension present in the
CMSSM and NUHM1 between the supersymmetric interpretation of and
the absence to date of SUSY at the LHC is not significantly alleviated in the
NUHM2. We find that the minimum with 21 degrees of freedom
(dof) in the NUHM2, to be compared with in the
CMSSM, and in the NUHM1. We find that the
one-dimensional likelihood functions for sparticle masses and other observables
are similar to those found previously in the CMSSM and NUHM1.Comment: 20 pages latex, 13 figure
The pMSSM10 after LHC Run 1
We present a frequentist analysis of the parameter space of the pMSSM10, in
which the following 10 soft SUSY-breaking parameters are specified
independently at the mean scalar top mass scale Msusy = Sqrt[M_stop1 M_stop2]:
the gaugino masses M_{1,2,3}, the 1st-and 2nd-generation squark masses M_squ1 =
M_squ2, the third-generation squark mass M_squ3, a common slepton mass M_slep
and a common trilinear mixing parameter A, the Higgs mixing parameter mu, the
pseudoscalar Higgs mass M_A and tan beta. We use the MultiNest sampling
algorithm with 1.2 x 10^9 points to sample the pMSSM10 parameter space. A
dedicated study shows that the sensitivities to strongly-interacting SUSY
masses of ATLAS and CMS searches for jets, leptons + MET signals depend only
weakly on many of the other pMSSM10 parameters. With the aid of the Atom and
Scorpion codes, we also implement the LHC searches for EW-interacting
sparticles and light stops, so as to confront the pMSSM10 parameter space with
all relevant SUSY searches. In addition, our analysis includes Higgs mass and
rate measurements using the HiggsSignals code, SUSY Higgs exclusion bounds, the
measurements B-physics observables, EW precision observables, the CDM density
and searches for spin-independent DM scattering. We show that the pMSSM10 is
able to provide a SUSY interpretation of (g-2)_mu, unlike the CMSSM, NUHM1 and
NUHM2. As a result, we find (omitting Higgs rates) that the minimum chi^2/dof =
20.5/18 in the pMSSM10, corresponding to a chi^2 probability of 30.8 %, to be
compared with chi^2/dof = 32.8/24 (31.1/23) (30.3/22) in the CMSSM (NUHM1)
(NUHM2). We display 1-dimensional likelihood functions for SUSY masses, and
show that they may be significantly lighter in the pMSSM10 than in the CMSSM,
NUHM1 and NUHM2. We discuss the discovery potential of future LHC runs, e+e-
colliders and direct detection experiments.Comment: 47 pages, 29 figure
Supersymmetric Dark Matter after LHC Run 1
Different mechanisms operate in various regions of the MSSM parameter space
to bring the relic density of the lightest neutralino, neutralino_1, assumed
here to be the LSP and thus the Dark Matter (DM) particle, into the range
allowed by astrophysics and cosmology. These mechanisms include coannihilation
with some nearly-degenerate next-to-lightest supersymmetric particle (NLSP)
such as the lighter stau (stau_1), stop (stop_1) or chargino (chargino_1),
resonant annihilation via direct-channel heavy Higgs bosons H/A, the light
Higgs boson h or the Z boson, and enhanced annihilation via a larger Higgsino
component of the LSP in the focus-point region. These mechanisms typically
select lower-dimensional subspaces in MSSM scenarios such as the CMSSM, NUHM1,
NUHM2 and pMSSM10. We analyze how future LHC and direct DM searches can
complement each other in the exploration of the different DM mechanisms within
these scenarios. We find that the stau_1 coannihilation regions of the CMSSM,
NUHM1, NUHM2 can largely be explored at the LHC via searches for missing E_T
events and long-lived charged particles, whereas their H/A funnel, focus-point
and chargino_1 coannihilation regions can largely be explored by the LZ and
Darwin DM direct detection experiments. We find that the dominant DM mechanism
in our pMSSM10 analysis is chargino_1 coannihilation: {parts of its parameter
space can be explored by the LHC, and a larger portion by future direct DM
searches.Comment: 21 pages, 8 figure
- …