Combination and QCD analysis of charm production cross section measurements in deep-inelastic ep scattering at HERA

Measurements of open charm production cross sections in deep-inelastic ep scattering at HERA from the H1 and ZEUS Collaborations are combined. Reduced cross sections sigma(c (c) over bar)(red) for charm production are obtained in the kinematic range of photon virtuality 2.5 LT = Q(2) LT = 2000 GeV2 and Bjorken scaling variable 3 . 10(-5) LT = x LT = 5 . 10(-2). The combination method accounts for the correlations of the systematic uncertainties among the different data sets. The combined charm data together with the combined inclusive deep-inelastic scattering cross sections from HERA are used as input for a detailed NLO QCD analysis to study the influence of different heavy flavour schemes on the parton distribution functions. The optimal values of the charm mass as a parameter in these different schemes are obtained. The implications on the NLO predictions for W-+/- and Z production cross sections at the LHC are investigated. Using the fixed flavour number scheme, the running mass of the charm quark is determined

Realizing the business benefits of enterprise IT

The development and implementation of IT/IS systems inherently requires a deep understanding of user requirements. However, experience shows that a key barrier to the success of an IT/IS system, is the manner by which it is adopted by end users. As such, this viewpoint article presents an overview of those typical enterprise IT user traits as experience by the author. These traits are placed in the context of the steps that need to be taken in terms of a lifecycle approach to business systems implementation. Thus, the paper describes those drivers which inhibit the adoption of enterprise IT/IS projects from a user expectation point of view. By outlining key benefits of such systems, the author presents a 6-stage approach to benefits realisation, known as the acronym, ASSIST. By applying such an approach, the management of business process change and delivery of IT/IS should be more achievable, by addressing the specific needs and expectations of different types of users, as identified in the text of the article. In doing so, the definition of those key IT/IS benefits as outlined in the ASSIST phase approach described is therefore a useful addition to existing project management and business analysis tools and techniques, that can be utilised by enterprise IT system delivery managers as well as Senior IT/IS managemen

The complex Grothendieck for 2x2 matrices

We show that the complex Grothendieck constant for 2x2 matrices is 1

Ecological Consequences of Lost Anadromous Forage Fish in Freshwater Ecosystems

Beginning in the early 1600s, dam construction in New England obstructed anadromous fish access to spawning grounds during migration. As a result, anadromous forage fish populations have declined, which has impacted freshwater, marine, and terrestrial ecosystems. To determine the impacts of dams on anadromous forage fish and freshwater ecosystems, I used historical and current data to estimate population changes in alewives (Alosa pseudoharengus) from 1600-1900. A significant reduction in spawning habitat occurred in New England as a result of 1,642 dams constructed between 1600 and 1900, resulting in 14.8% and 16.6% lake and stream habitat remaining by 1900, respectively. In eight New England watersheds, this translates to an estimated cumulative annual loss of 30 B juvenile alewives available as freshwater forage and 538 M year 1, 2 and 3 alewives available as marine forage. The cumulative annual lost number of adult return spawners was conservatively 17 M fish, or 3,642 metric tons. Lost marine-derived nutrients from adult return spawners were 11 T phosphorus, 64 T nitrogen, and 410 T carbon. A comparison of predator fish growth and condition in alewife and non-alewife lakes showed that white perch (Morone Americana) and yellow perch (Perca flavescens) have higher condition in early summer in lakes with alewives. Predator growth rates (length-at-age) were significantly higher in early life stages (ages 1 and 2) when alewives were present, but significantly lower in late life stages (ages 3 and older). Results indicate a greater maximum length obtained by mature fish when alewives are absent, and an earlier age and length at maturity when alewives are present. These results indicate significant ecosystem impacts of lost anadromous forage fish, with bottom-up trophic effects across multiple time scales and biological processes. An ecosystem-based management approach should be used by inland and marine aquatic managers, and ecosystem connectivity and trophic interactions should be considered when managing migratory fish and prioritizing restoration goals

Diffractive Dijet Production with a Leading Proton in ep Collisions at HERA

The cross section of the diffractive process e^+p -> e^+Xp is measured at a centre-of-mass energy of 318 GeV, where the system X contains at least two jets and the leading final state proton p is detected in the H1 Very Forward Proton Spectrometer. The measurement is performed in photoproduction with photon virtualities Q^2 <2 GeV^2 and in deep-inelastic scattering with 4 GeV^2<Q^2<80 GeV^2. The results are compared to next-to-leading order QCD calculations based on diffractive parton distribution functions as extracted from measurements of inclusive cross sections in diffractive deep-inelastic scattering

Erratum to: Measurement of jet production cross sections in deep-inelastic ep scattering at HERA

The measurement of the jet cross sections by the H1 collaboration had been compared to various predictions including the next-to-next-to-leading order (NNLO) QCD calculations which are corrected in this erratum for an implementation error in one of the components of the NNLO calculations. The jet data and the other predictions remain unchanged. Eight figures, one table and conclusions are adapted accordingly, exhibiting even better agreement between the corrected NNLO predictions and the jet data

Measurement of lepton-jet correlation in deep-inelastic scattering with the H1 detector using machine learning for unfolding

The first measurement of lepton-jet momentum imbalance and azimuthal correlation in lepton-proton scattering at high momentum transfer is presented. These data, taken with the H1 detector at HERA, are corrected for detector effects using an unbinned machine learning algorithm OmniFold, which considers eight observables simultaneously in this first application. The unfolded cross sections are compared to calculations performed within the context of collinear or transverse-momentum-dependent (TMD) factorization in Quantum Chromodynamics (QCD) as well as Monte Carlo event generators. The measurement probes a wide range of QCD phenomena, including TMD parton distribution functions and their evolution with energy in so far unexplored kinematic regions

Measurement of Jet Production Cross Sections in Deep-inelastic ep Scattering at HERA

A precision measurement of jet cross sections in neutral current deep-inelastic scattering for photon virtualities $5.5<Q^2<80\,{\rm GeV}^2$ and inelasticities $0.2<y<0.6$ is presented, using data taken with the H1 detector at HERA, corresponding to an integrated luminosity of $290\,{\rm pb}^{-1}$. Double-differential inclusive jet, dijet and trijet cross sections are measured simultaneously and are presented as a function of jet transverse momentum observables and as a function of $Q^2$. Jet cross sections normalised to the inclusive neutral current DIS cross section in the respective $Q^2$-interval are also determined. Previous results of inclusive jet cross sections in the range $150<Q^2<15\,000\,{\rm GeV}^2$ are extended to low transverse jet momenta $5<P_{T}^{\rm jet}<7\,{\rm GeV}$. The data are compared to predictions from perturbative QCD in next-to-leading order in the strong coupling, in approximate next-to-next-to-leading order and in full next-to-next-to-leading order. Using also the recently published H1 jet data at high values of $Q^2$, the strong coupling constant $\alpha_s(M_Z)$ is determined in next-to-leading order.A precision measurement of jet cross sections in neutral current deep-inelastic scattering for photon virtualities $5.5<Q^2<80\,{\rm GeV}^2$ and inelasticities $0.2<y<0.6$ is presented, using data taken with the H1 detector at HERA, corresponding to an integrated luminosity of $290\,{\rm pb}^{-1}$. Double-differential inclusive jet, dijet and trijet cross sections are measured simultaneously and are presented as a function of jet transverse momentum observables and as a function of $Q^2$. Jet cross sections normalised to the inclusive neutral current DIS cross section in the respective $Q^2$-interval are also determined. Previous results of inclusive jet cross sections in the range $150<Q^2<15\,000\,{\rm GeV}^2$ are extended to low transverse jet momenta $5<P_{T}^{\rm jet}<7\,{\rm GeV}$. The data are compared to predictions from perturbative QCD in next-to-leading order in the strong coupling, in approximate next-to-next-to-leading order and in full next-to-next-to-leading order. Using also the recently published H1 jet data at high values of $Q^2$, the strong coupling constant $\alpha_s(M_Z)$ is determined in next-to-leading order.A precision measurement of jet cross sections in neutral current deep-inelastic scattering for photon virtualities $5.5<Q^2 <80\,\mathrm {GeV}^2$ and inelasticities $0.2<y<0.6$ is presented, using data taken with the H1 detector at HERA, corresponding to an integrated luminosity of $290\,\mathrm {pb}^{-1}$ . Double-differential inclusive jet, dijet and trijet cross sections are measured simultaneously and are presented as a function of jet transverse momentum observables and as a function of $Q^2$ . Jet cross sections normalised to the inclusive neutral current DIS cross section in the respective $Q^2$ -interval are also determined. Previous results of inclusive jet cross sections in the range $150<Q^2 <15{,}000\,\mathrm {GeV}^2$ are extended to low transverse jet momenta $5<P_\mathrm{T}^\mathrm{jet} <7\,\mathrm {GeV}$ . The data are compared to predictions from perturbative QCD in next-to-leading order in the strong coupling, in approximate next-to-next-to-leading order and in full next-to-next-to-leading order. Using also the recently published H1 jet data at high values of $Q^2$ , the strong coupling constant $\alpha _s(M_Z)$ is determined in next-to-leading order

Colombeau generalized functions on manifolds

Eduard NigschZsfassung in dt. SpracheWien, Techn. Univ. u. Univ., Dipl.-Arb., 2006OeBB(VLID)161012