Effects of SUSY-QCD in hadronic Higgs production at next-to-next-to-leading order

An estimate of the NNLO supersymmetric QCD effects for Higgs production at hadron colliders is given. Assuming an effective gluon-Higgs interaction, these corrections enter only in terms of process-independent, factorizable terms. We argue that the current knowledge of these terms up to NLO is sufficient to derive the NNLO hadronic cross section within the limitations of the standard theoretical uncertainties arising mainly from renormalization and factorization scale variations. The SUSY contributions are small with respect to the QCD effects, which means that the NNLO corrections to Higgs production are very similar in the Standard Model and the MSSM.Comment: LaTeX, 5 pages, 3 embedded PostScript figure

Towards Higgs boson production in gluon fusion to NNLO in the MSSM

We consider the Higgs boson production in the gluon-fusion channel to next-to-next-to-leading order within the Minimal Supersymmetric Standard Model. In particular, we present analytical results for the matching coefficient of the effective theory and study its influence on the total production cross section in the limit where the masses of all MSSM particles coincide. For supersymmetric masses below 500 GeV it is possible to find parameters leading to a significant enhancement of the Standard Model cross section, the $K$-factors, however, change only marginally.Comment: 20 pages; v2: modification of discussion of numerical effect, version to appear in EPJC; v3: eq.(18) corrected, minor correction

MSSM Higgs bosons associated with high-pT jets at hadron colliders

The cross section for the production of the lightest neutral Higgs boson in association with a high-pT hadronic jet, calculated in the framework of the minimal supersymmetric standard model (MSSM), is presented. The expectations for the hadronic cross section at the Large Hadron Collider are discussed using reasonable kinematical cuts. In particular the contributions from superpartner loops to the cross section and their dependence on the parameters of the MSSM are investigated and found to be significant. Comparisons show that the production rate for h0 + jet in the MSSM can differ widely from the corresponding standard-model prediction.Comment: 20 page

Global Aerosol Health Impacts: Quantifying Uncertainties

Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).Atmospheric fine particulate matter <2.5 μm (PM2.5) can cause cardiovasculatory and respiratory damages and mortalities. Assessing population exposure to and damages from PM2.5 is important for policy, but measurement networks are only available in a few regions. We assess variation resulting from using different sources of concentration information to constrain PM2.5 exposure worldwide, and compare the magnitude of this variation to uncertainties in epidemiological exposure-response functions and economic valuation of health impacts. We find that only 10% of global population is in areas constrained by ground-based data. We calculate and compare regionally-averaged population-weighted concentrations using two atmospheric models: the MIT/NCAR CAM3 aerosol-climate model, and the GEOS-Chem atmospheric chemistry model; and a satellite-derived PM2.5 product. We examine the contributions of different aerosol components to population-weighted PM2.5, and find large differences in exposure between U.S. and global populations. We use the MIT Emissions Prediction and Policy Analysis Health Effects model (EPPA-HE) to assess global health impacts and related economic costs, and conduct probabilistic uncertainty analysis of concentration-response functions. We use these combined approaches to project uncertainty ranges for health impacts and related economic costs from present-day PM2.5. We find large uncertainties in simulated PM2.5, especially globally; the magnitude of concentration variation among estimation methods is comparable to uncertainties in epidemiological functions and economic valuations. We identify major contributors to concentration variation, notably the parameterization of atmospheric dust. We estimate an annual global welfare cost of present-day (2000-2005) PM2.5 of $US 280 billion (range$120 – 510 billion), and related annual mortalities at 1.3 million per year (630,000 – 2.1 million).United States Environmental Protection Agency’s Science to Achieve Results (STAR) program (RD-83427901-0) and the MIT Joint Program on the Science and Policy of Global Change, which is funded by a consortium of government, industry and foundation sponsor

Pseudoscalar Higgs boson production at hadron colliders in NNLO QCD

We compute the total cross-section for direct production of the pseudoscalar Higgs boson in hadron collisions at next-to-next-to-leading order (NNLO) in perturbative QCD. The O(alpha_s^2) QCD corrections increase the NLO production cross-section by approximately 20-30 per cent.Comment: 5 pages, revtex

MSSM Higgs Boson Production via Gluon Fusion: The Large Gluino Mass Limit

Scalar MSSM Higgs boson production via gluon fusion gg -> h,H is mediated by heavy quark and squark loops. The higher order QCD corrections to these processes turn out to be large. The full supersymmetric QCD corrections have been calculated recently. In the limit of large SUSY masses a conceptual problem appears, i.e. the proper treatment of the large gluino mass limit. In this work we will describe the consistent decoupling of heavy gluino effects and derive the effective Lagrangian for decoupled gluinos.Comment: 11 pages, 3 figures, latex, references added, slight rewording, version accepted by JHE

Comparison and evaluation of anthropogenic emissions of SO2 and NO2 over China

Bottom-up emission inventories provide primary understanding of sources of air pollution and essential input of chemical transport models. Focusing on SO2 and NOx, we conducted a comprehensive evaluation of two widely-used anthropogenic emission inventories over China, ECLIPSE and MIX, to explore the potential sources of uncertainties and find the clues in improving emission inventories. We first compared the activity rates and emission factors used in two inventories, and investigated the reasons of differences and the impacts on emission estimates. We found that SO2 emission estimates are consistent between two inventories (with 1 % differences), while NOx emissions in ECLIPSE's estimates are 16 % lower than those of MIX. Discrepancies at sectorial and provincial level are much higher. We then examined the impacts of different inventories on model performance, by using the nested GEOS-Chem model. We finally derived top-down NOx emissions by using the NO2 columns from the Ozone Monitoring Instrument (OMI) and compared with the bottom-up estimates. To our knowledge, this is the first work where source-sector comparisons are made along with the remote sensing retrievals and chemical transport modeling. Through the comparison between bottom-up emission inventories and evaluation with top-down information, we summarized the potential directions for further improvement in inventory development

Net ecosystem fluxes of isoprene over tropical South America inferred from Global Ozone Monitoring Experiment (GOME) observations of HCHO columns

We estimate isoprene emissions over tropical South America during 1997-2001 using column measurements of formaldehyde (HCHO) from the Global Ozone Monitoring Experiment (GOME) satellite instrument, the GEOS-Chem chemistry transport model, and the MEGAN (Model of Emissions of Gases and Aerosols from Nature) bottom-up isoprene inventory. GEOS-Chem is qualitatively consistent with in situ ground-based and aircraft concentration profiles of isoprene and HCHO, and GOME HCHO column data (r = 0.41; bias = +35%), but has less skill in reproducing wet season observations. Observed variability of GOME HCHO columns over South America is determined largely by isoprene and biomass burning. We find that the column contributions from other biogenic volatile organic compounds (VOC) are typically smaller than the column fitting uncertainty. HCHO columns influenced by biomass burning are removed using Along Track Scanning Radiometer (ATSR) firecounts and GOME NO2 columns. We find that South America can be split into eastern and western regions, with fires concentrated over the eastern region. A monthly mean linear transfer function, determined by GEOS-Chem, is used to infer isoprene emissions from observed HCHO columns. The seasonal variation of GOME isoprene emissions over the western region is broadly consistent with MEGAN (r = 0.41; bias = -256%), with largest isoprene emissions during the dry season when the observed variability is consistent with knowledge of temperature dependence. During the wet season other unknown factors play a significant role in determining observed variability. Copyright 2008 by the American Geophysical Union

Invisible Higgs Boson Decay into Massive Neutrinos of 4th Generation

Results from several recent experiments provide inderect evidences in the favor of existence of a 4th generation neutrino. Such a neutrino of mass about 50 GeV is compatible with current physical and astrophysical constraints and well motivated in the framework of superstring phenomenology. If sufficiently stable the existence of such a neutrino leads to the drastic change of Higgs boson physics: for a wide range of Higgs boson masses the dominant mode of Higgs boson decay is invisible and the branching ratios for the most promising modes of Higgs boson search are significantly reduced. The proper strategy of Higgs boson searches in such a framework is discussed. It is shown that in the same framework the absence of a signal in the search for invisible Higgs boson decay at LEP means either that the mass of Higgs is greater than 113.5 GeV or that the mass difference between the Higgs mass and doubled neutrino mass is small.Comment: 8 pages, 2 figure