WW scattering at the CERN LHC

A detailed study is presented of elastic WW scattering in the scenario that there are no new particles discovered prior to the commissioning of the CERN LHC. We work within the framework of the electroweak chiral Lagrangian and two different unitarization protocols are investigated. Signals and backgrounds are simulated to the final-state-particle level. A new technique for identifying the hadronically decaying W is developed, which is more generally applicable to massive particles which decay to jets where the separation of the jets is small. The effect of different assumptions about the underlying event is also studied. We conclude that the channel WW-->jj+lν may contain scalar and/or vector resonances which could be measurable after 100 fb-1 of LHC data

Partial Degree Formulae for Plane Offset Curves

In this paper we present several formulae for computing the partial degrees of the defining polynomial of the offset curve to an irreducible affine plane curve given implicitly, and we see how these formulae particularize to the case of rational curves. In addition, we present a formula for computing the degree w.r.t the distance variable.Comment: 24 pages, no figure

Conchoidal transform of two plane curves

The conchoid of a plane curve $C$ is constructed using a fixed circle $B$ in the affine plane. We generalize the classical definition so that we obtain a conchoid from any pair of curves $B$ and $C$ in the projective plane. We present two definitions, one purely algebraic through resultants and a more geometric one using an incidence correspondence in \PP^2 \times \PP^2. We prove, among other things, that the conchoid of a generic curve of fixed degree is irreducible, we determine its singularities and give a formula for its degree and genus. In the final section we return to the classical case: for any given curve $C$ we give a criterion for its conchoid to be irreducible and we give a procedure to determine when a curve is the conchoid of another.Comment: 18 pages Revised version: slight title change, improved exposition, fixed proof of Theorem 5.3 Accepted for publication in Appl. Algebra Eng., Commun. Comput

Diffractive Dijet Production

We explore the diffractive interaction of a proton with an anti-proton which results in centrally produced dijets. This process has been recently studied at the Tevatron. We make predictions within an Ingelman-Schlein approach and compare them to the recent data presented by the CDF collaboration. Earlier calculations resulted in theoretical cross-sections which are much larger than those observed by CDF. We find that, after consideration of hadronisation effects and the parton shower, and using parton density functions extracted from diffractive deep inelastic scattering at HERA, it is possible to explain the CDF data. We need to assume a gap survival probability of around 10% and this is in good agreement with the value predicted by theory. We also find that the non-diffractive contribution to the process is probably significant in the kinematical region probed by the Tevatron.Comment: 12 pages, 6 figures, 3 table

Encoding points on hyperelliptic curves over finite fields in deterministic polynomial time

We present families of (hyper)elliptic curve which admit an efficient deterministic encoding function

Application of density functional theory in the synthesis of electroactive polymers

A wide range of conjugated organic compounds undergo anodic electropolymerisation to produce polymers of high conductivity. However, electrooxidation does not always result in the formation of electroactive materials, since some reactions produce insulating films or soluble oligomers. Density functional theory (DFT) has been used to predict the outcome of electropolymerisation reactions by calculating the unpaired electron π-spin density distribution of monomeric radical cations, in order to determine coupling positions in the resultant polymers. π-Spin densities calculated for pyrrole, thiophene and (E)-stilbene are found to be in good agreement with experimental values. DFT has been used to investigate the low conductivity and redox inactivity of poly[(E)-3-styrylthiophenes] and poly[(E)-2-styrylheterocycles]. High positive spin densities at the alkene spacer linkage in the corresponding monomeric radical cations were found, suggesting crosslinking of the polymers via the double bond. In contrast, electroactive polymers of improved conductivity are formed from the electropolymerisation of some (Z)-2-α,β-diarylacrylonitriles. For these monomers, DFT calculations show the positions of highest spin density to be located at the α-positions of the heterocyclic rings, suggesting the presence of α,α′-linked monomeric couplings necessary for electroactivity

Double Diffraction Dissociation at High t

Diffractive scattering in the presence of a large momentum transfer is an ideal place to study the short distance rapidity gap producing mechanism. Previous studies (experimental and theoretical) in this area have focussed on gaps between jets and on high-$t$ vector meson production. We propose the measurement of double dissociation at high-$t$. We examine the numerous advantages to studying this more inclusive process and conclude that it is an ideal place to study short distance diffraction.Comment: 12 pages, 8 figure

Diffractive upsilon production at the LHC

We compute the rate for diffractive upsilon meson production at the Tevatron and the LHC. The upsilon is produced diffractively via the subprocess gamma + p -> upsilon + p where the initial photon is radiated off an incoming proton (or antiproton). We consider the possibility to use low angle proton detectors to make a measurement of the gamma p cross-section and conclude that a measurement of the cross-section at a centre of mass energy in excess of 1 TeV is possible at the LHC. This is in the region where saturation effects are likely to reveal themselves.Comment: 14 page

Cryptic photosynthesis, Extrasolar planetary oxygen without a surface biological signature

On the Earth, photosynthetic organisms are responsible for the production of virtually all of the oxygen in the atmosphere. On the land, vegetation reflects in the visible, leading to a red edge that developed about 450 Myr ago and has been proposed as a biosignature for life on extrasolar planets. However, in many regions of the Earth, and particularly where surface conditions are extreme, for example in hot and cold deserts, photosynthetic organisms can be driven into and under substrates where light is still sufficient for photosynthesis. These communities exhibit no detectable surface spectral signature to indicate life. The same is true of the assemblages of photosynthetic organisms at more than a few metres depth in water bodies. These communities are widespread and dominate local photosynthetic productivity. We review known cryptic photosynthetic communities and their productivity. We link geomicrobiology with observational astronomy by calculating the disk-averaged spectra of cryptic habitats and identifying detectable features on an exoplanet dominated by such a biota. The hypothetical cryptic photosynthesis worlds discussed here are Earth-analogs that show detectable atmospheric biomarkers like our own planet, but do not exhibit a discernable biological surface feature in the disc-averaged spectrum.Comment: 23 pages, 2 figures, Astrobiology (TBP) - updated Table 1, typo in detectable O2 correcte

Soft gluons in Higgs plus two jet production

We investigate the effects of an all order QCD resummation of soft gluon emissions for Higgs boson production in association with two hard jets. We consider both the gluon-gluon fusion and weak boson fusion processes and show how to resum a large part of the leading logarithms in the jet veto scale. Our resummation improves on previous analyses which also aim to include the effects of multiple soft gluon radiation. In addition we calculate the interference between weak boson fusion and gluon-gluon fusion and find that it is small.Comment: 15 pages and 5 figure