4,770 research outputs found
Recent results from HERA and their impact for LHC
Recent measurements of inclusive and semi-inclusive deep inelastic scattering
in electron-proton collisions at HERA are reviewed. These measurements are used
to determine the parton distribution functions (PDFs) of the proton, a
necessary input to theory predictions for hadron colliders. An introduction to
the PDF determination with an emphasis on HERA PDFs is presented. Theory
predictions based on HERAPDF are compared to a selection of recent LHC and
Tevatron measurements. The impact of jet and charm production measurements on
the PDFs is discussed.Comment: Presented at the 2011 Hadron Collider Physics symposium (HCP-2011),
Paris, France, November 14-18 2011, 6 pages, 13 figure
Determination of Strange Sea Quark Distributions from Fixed-target and Collider Data
We present an improved determination of the strange sea distribution in the
nucleon with constraints coming from the recent charm production data in
neutrino-nucleon deep-inelastic scattering by the NOMAD and CHORUS experiments
and from charged current inclusive deep-inelastic scattering at HERA. We
demonstrate that the results are consistent with the data from the ATLAS and
the CMS experiments on the associated production of -bosons with
-quarks. We also discuss issues related to the recent strange sea
determination by the ATLAS experiment using LHC collider data.Comment: 23 pages, 14 figure
Determination of the top quark mass from the tÂŻt cross section measured by CMS at âs = 7TeV
Higher-order QCD predictions are used to extract the top quark mass, both in the pole and in the MS scheme, from the top quark pair production cross section measured in the dilepton final state. The analyzed dataset corresponds to an integrated luminosity of 1.14 fbâ1 collected by the CMS experiment in 2011 in pp collisions at âs = 7TeV
Prompt neutrino fluxes in the atmosphere with PROSA parton distribution functions
Effects on atmospheric prompt neutrino fluxes of present uncertainties
affecting the nucleon composition are studied by using the PROSA fit to parton
distribution functions (PDFs). The PROSA fit extends the precision of the PDFs
to low x, which is the kinematic region of relevance for high-energy neutrino
production, by taking into account LHCb data on charm and bottom
hadroproduction. In the range of neutrino energies explored by present Very
Large Volume Neutrino Telescopes, it is found that PDF uncertainties are far
smaller with respect to those due to renormalization and factorization scale
variation and to assumptions on the cosmic ray composition, which at present
dominate and limit our knowledge of prompt neutrino fluxes. A discussion is
presented on how these uncertainties affect the expected number of atmospheric
prompt neutrino events in the analysis of high-energy events characterized by
interaction vertices fully contained within the instrumented volume of the
detector, performed by the IceCube collaboration.Comment: 36 pages, 17 figures, 1 tabl
A Critical Appraisal and Evaluation of Modern PDFs
We review the present status of the determination of parton distribution
functions (PDFs) in the light of the precision requirements for the LHC in Run
2 and other future hadron colliders. We provide brief reviews of all currently
available PDF sets and use them to compute cross sections for a number of
benchmark processes, including Higgs boson production in gluon-gluon fusion at
the LHC. We show that the differences in the predictions obtained with the
various PDFs are due to particular theory assumptions made in the fits of those
PDFs. We discuss PDF uncertainties in the kinematic region covered by the LHC
and on averaging procedures for PDFs, such as advocated by the PDF4LHC15 sets,
and provide recommendations for the usage of PDF sets for theory predictions at
the LHC.Comment: 70 pages pdflatex, 19 figures, 17 tables; final versio
Moonlighting function of Phytochelatin synthase1 in extracellular defense against fungal pathogens
Phytochelatin synthase (PCS) is a key component of heavy metal detoxification in plants. PCS catalyzes both the synthesis of the peptide phytochelatin from glutathione and the degradation of glutathione conjugates via peptidase activity. Here, we describe a role for PCS in disease resistance against plant pathogenic fungi. The pen4 mutant, which is allelic to cadmium insensitive1 (cad1/pcs1) mutants, was recovered from a screen for Arabidopsis mutants with reduced resistance to the nonadapted barley fungal pathogen Blumeria graminis f. sp. hordei. PCS1, which is found in the cytoplasm of cells of healthy plants, translocates upon pathogen attack and colocalizes with the PEN2 myrosinase on the surface of immobilized mitochondria. pcs1 and pen2 mutant plants exhibit similar metabolic defects in the accumulation of pathogen-inducible indole glucosinolate-derived compounds, suggesting that PEN2 and PCS1 act in the same metabolic pathway. The function of PCS1 in this pathway is independent of phytochelatin synthesis and deglycination of glutathione conjugates, as catalytic-site mutants of PCS1 are still functional in indole glucosinolate metabolism. In uncovering a peptidase-independent function for PCS1, we reveal this enzyme to be a moonlighting protein important for plant responses to both biotic and abiotic stresses
Plasminogen activatorâ1 overexpression decreases experimental postthrombotic vein wall fibrosis by a nonâvitronectinâdependent mechanism
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108289/1/jth12644.pd
- âŠ