Next-to-Next-to-Leading Order Higgs Production at Hadron Colliders

The Higgs boson production cross section at pp and p\bar{p} colliders is calculated in QCD at next-to-next-to-leading order (NNLO). We find that the perturbative expansion of the production cross section is well behaved and that scale dependence is reduced relative to the NLO result. These findings give us confidence in the reliability of the prediction. We also report an error in the NNLO correction to Drell-Yan production.Comment: 5 pages, 4 figures, minor change

Attitudes toward and experiences of gender issues among physician teachers: A survey study conducted at a university teaching hospital in Sweden

<p>Abstract</p> <p>Background</p> <p>Gender issues are important to address during medical education, however research about the implementation of gender in medical curricula reports that there are obstacles. The aim of this study was to explore physician teachers' attitudes to gender issues.</p> <p>Methods</p> <p>As part of a questionnaire, physician teachers at Umeå University in Sweden were given open-ended questions about explanations for and asked to write examples why they found gender important or not. The 1 469 comments from the 243 respondents (78 women, 165 men) were analyzed by way of content analysis. The proportion of comments made by men and women in each category was compared.</p> <p>Results</p> <p>We found three themes in our analysis: Understandings of gender, problems connected with gender and approaches to gender. Gender was associated with differences between women and men regarding behaviour and disease, as well as with inequality of life conditions. Problems connected with gender included: delicate situations involving investigations of intimate body parts or sexual attraction, different expectations on male and female physicians and students, and difficulty fully understanding the experience of people of the opposite sex. The three approaches to gender that appeared in the comments were: 1) avoidance, implying that the importance of gender in professional relationships was recognized but minimized by comparing gender with aspects, such as personality and neutrality; 2) simplification, implying that gender related problems were easy to address, or already solved; and 3) awareness, implying that the respondent was interested in gender issues or had some insights in research about gender. Only a few individuals described gender as an area of competence and knowledge. There were comments from men and women in all categories, but there were differences in the relative weight for some categories. For example, recognizing gender inequities was more pronounced in the comments from women and avoidance more common in comments from men.</p> <p>Conclusion</p> <p>The surveyed physician teachers gave many examples of gender-related problems in medical work and education, but comments describing gender as an area of competence and knowledge were few. Approaches to gender characterized by avoidance and simplification suggest that faculty development programs on gender need to address and reflect on attitudes as well as knowledge.</p

The light-cone gauge and the calculation of the two-loop splitting functions

We present calculations of next-to-leading order QCD splitting functions, employing the light-cone gauge method of Curci, Furmanski, and Petronzio (CFP). In contrast to the `principal-value' prescription used in the original CFP paper for dealing with the poles of the light-cone gauge gluon propagator, we adopt the Mandelstam-Leibbrandt prescription which is known to have a solid field-theoretical foundation. We find that indeed the calculation using this prescription is conceptionally clear and avoids the somewhat dubious manipulations of the spurious poles required when the principal-value method is applied. We reproduce the well-known results for the flavour non-singlet splitting function and the N_C^2 part of the gluon-to-gluon singlet splitting function, which are the most complicated ones, and which provide an exhaustive test of the ML prescription. We also discuss in some detail the x=1 endpoint contributions to the splitting functions.Comment: 41 Pages, LaTeX, 8 figures and tables as eps file

One-loop corrections to the Drell--Yan process in SANC (II). The neutral current case

Radiative corrections to the neutral current Drell--Yan-like processes are considered. Complete one-loop electroweak corrections are calculated within the SANC system. Theoretical uncertainties are discussed. Numerical results are presented for typical conditions of LHC experiments.Comment: 17 pages, 9 figures, 3 table

QCD and Yukawa corrections to single-top-quark production via q qbar -> t bbar

We calculate the O(alpha_s) and O(alpha_W m_t^2/M_W^2) corrections to the production of a single top quark via the weak process q qbar -> t bbar at the Fermilab Tevatron and the CERN Large Hadron Collider. An accurate calculation of the cross section is necessary in order to extract |V_tb| from experiment.Comment: LaTeX, 13 pages, replaced with version to appear in Phys. Rev.

Electroweak radiative corrections to W-boson production at hadron colliders

The complete set of electroweak O(alpha) corrections to the Drell--Yan-like production of W bosons is calculated and compared to an approximation provided by the leading term of an expansion about the W-resonance pole. All relevant formulae are listed explicitly, and particular attention is paid to issues of gauge invariance and the instability of the W bosons. A detailed discussion of numerical results underlines the phenomenological importance of the electroweak corrections to W-boson production at the Tevatron and at the LHC. While the pole expansion yields a good description of resonance observables, it is not sufficient for the high-energy tail of transverse-momentum distributions, relevant for new-physics searches.Comment: 29 pages, latex, 17 postscript files, revised version that is to appear in Phys.Rev.D, some explanations added and results extended by a discussion of the QED factorization scale dependenc

High-precision QCD at hadron colliders: electroweak gauge boson rapidity distributions at NNLO

We compute the rapidity distributions of W and Z bosons produced at the Tevatron and the LHC through next-to-next-to leading order in QCD. Our results demonstrate remarkable stability with respect to variations of the factorization and renormalization scales for all values of rapidity accessible in current and future experiments. These processes are therefore ``gold-plated'': current theoretical knowledge yields QCD predictions accurate to better than one percent. These results strengthen the proposal to use W and Z production to determine parton-parton luminosities and constrain parton distribution functions at the LHC. For example, LHC data should easily be able to distinguish the central parton distribution fit obtained by MRST from that obtained by Alekhin.Comment: 47 pages, 17 figures. Minor typos, 1 reference correcte

Drell-Yan forward-backward and spin asymmetries for arbitrary vector boson production at next-to-leading order

Longitudinally polarized, unpolarized and forward-backward mass differential cross sections for Drell-Yan lepton-pair production by arbitrary vector bosons are calculated in next-to-leading order (NLO) QCD. Analytical results are presented in a form valid for all consistent $n$-dimensional regularization schemes, with the mass factorization scheme kept general. NLO predictions for all Drell-Yan type processes ($W^\pm$, $Z$ and $\gamma^*$) at BNL's relativistic heavy ion collider (RHIC) are made using polarized parton distributions which fit the recent deep-inelastic scattering data. These are examined as tools in the determination of the polarized parton distributions and the unpolarized $\bar{u}/\bar{d}$ ratio. NLO predictions for the forward-backward lepton asymmetry at Fermilab are made and the precision determination of $\sin^2 \theta_W$ from future runs is studied. In all the above, the QCD corrections are found to be significant. An introductory discussion is given of various theoretical issues, such as allowable factorization and regularization schemes, and scale dependences.Comment: 34 pages, figures included, revtex. Some discussions and references added/modified. In more compact form. To appear in Phys. Rev.

Implementation of electroweak corrections in the POWHEG BOX: single W production

We present a fully consistent implementation of electroweak and strong radiative corrections to single W hadroproduction in the POWHEG BOX framework, treating soft and collinear photon emissions on the same ground as coloured parton emissions. This framework can be easily extended to more complex electroweak processes. We describe how next-to-leading order (NLO) electroweak corrections are combined with the NLO QCD calculation, and show how they are interfaced to QCD and QED shower Monte Carlo. The resulting tool fills a gap in the literature and allows to study comprehensively the interplay of QCD and electroweak effects to W production using a single computational framework. Numerical comparisons with the predictions of the electroweak generator HORACE, as well as with existing results on the combination of electroweak and QCD corrections to W production, are shown for the LHC energies, to validate the reliability and accuracy of the approachComment: 31 pages, 7 figures. Minor corrections, references added and updated. Final version to appear in JHE

Vector boson production at hadron colliders: hard-collinear coefficients at the NNLO

We consider QCD radiative corrections to vector-boson production in hadron collisions. We present the next-to-next-to-leading order (NNLO) result of the hard-collinear coefficient function for the all-order resummation of logarithmically-enhanced contributions at small transverse momenta. The coefficient function controls NNLO contributions in resummed calculations at full next-to-next-to-leading logarithmic accuracy. The same coefficient function is used in applications of the subtraction method to perform fully-exclusive perturbative calculations up to NNLO.Comment: 13, pages, no figures. arXiv admin note: text overlap with arXiv:1106.465