Unintegrated parton distributions and electroweak boson production at hadron colliders

We describe the use of doubly-unintegrated parton distributions in hadron-hadron collisions, using the (z,k_t)-factorisation prescription where the transverse momentum of the incoming parton is generated in the last evolution step. We apply this formalism to calculate the transverse momentum (P_T) distributions of produced W and Z bosons and compare the predictions to Tevatron Run 1 data. We find that the observed P_T distributions can be generated almost entirely by the leading order q_1 q_2 -> W,Z subprocesses, using known and universal doubly-unintegrated quark distributions. We also calculate the P_T distribution of the Standard Model Higgs boson at the LHC, where the dominant production mechanism is by gluon-gluon fusion.Comment: 20 pages, 8 figures. Version to appear in Phys. Rev. D; correction to Higgs P_T distribution made in Erratu

Effect of absorptive corrections on inclusive parton distributions

We study the effect of absorptive corrections due to parton recombination on the parton distributions of the proton. A more precise version of the GLRMQ equations, which account for non-linear corrections to DGLAP evolution, is derived. An analysis of HERA F_2 data shows that the small-x gluon distribution is enhanced at low scales when the absorptive effects are included, such that a negative gluon distribution at 1 GeV is no longer required.Comment: 10 pages, 3 figure

Diffractive parton distributions: the role of the perturbative Pomeron

We consider the role of the perturbative Pomeron-to-parton splitting in the formation of the diffractive parton distributions.Comment: 8 pages, 4 figures. To appear in the proceedings of the 12th International Conference on Elastic and Diffractive Scattering: Forward Physics and QCD, DESY, Hamburg, Germany, 21-25 May 200

On Tits' Centre Conjecture for Fixed Point Subcomplexes

We give a short and uniform proof of a special case of Tits' Centre Conjecture using a theorem of J-P. Serre and a result from our earlier work. We consider fixed point subcomplexes $X^H$ of the building $X = X(G)$ of a connected reductive algebraic group $G$, where $H$ is a subgroup of $G$.Comment: 4 pages; minor changes, to appear in C. R. Acad. Sci. Paris Ser. I Mat

The dimer-RVB State of the Four-Leg Heisenberg Ladder: Interference among Resonances

We study the ground state of the 4-leg spin ladder using a dimer-RVB ansatz and the Lanczos method. Besides the well known resonance mechanism between valence bond configurations we find novel interference effects among nearby resonances.Comment: 4 pages, RevTex, 7 eps fig

Confirming what we know: Understanding questionable research practices in intro physics labs

Many institutions are changing the focus of their introductory physics labs from verifying physics content towards teaching students about the skills and nature of science. As instruction shifts, so too will the ways students approach and behave in the labs. In this study, we evaluated students' lab notes from an early activity in an experimentation-focused lab course. We found that about 30% of student groups (out of 107 groups at three institutions) recorded questionable research practices in their lab notes, such as subjective interpretations of results or manipulating equipment and data. The large majority of these practices were associated with confirmatory goals, which we suspect stem from students' prior exposure to verification labs. We propose ways for experimentation-focused labs to better engage students in the responsible conduct of research and authentic scientific practice.Comment: 4 pages, 4 figure

Reputation of Oral and Maxillofacial Surgery in the UK:the patients' perspective

Our intention is to shed theoretical and practical light on the professional reputation of Oral and Maxillofacial Surgery (OMFS) in the UK by drawing on theories from management literature, particularly concerning reputation. Since professional reputation is socially constructed by stakeholders, we used interpretivist methods to conduct a qualitative study of patients (stakeholders) to gain an insight into their view of the profession. Findings from our focus groups highlighted the importance of “soft-wired skills” and showed a perception – reality gap in the interaction between patients and doctors. They also highlighted the importance of consistency, relational coordination, mechanisms to enable transparent feedback, and professional processes of governance. To help understand how best to manage the reputation of the specialty, we also explored how this is affected by the media and the Internet