Triphoton production at hadron colliders

We present next-to-leading order predictions for the production of triphoton final states at the LHC and the Tevatron. Our results include the effect of photon fragmentation for the first time and we are able to quantify the impact of different isolation prescriptions. We find that calculations accounting for fragmentation effects at leading order, and those employing a smooth cone isolation where no fragmentation contribution is required, are in reasonable agreement with one another. However, larger differences in the predicted rates arise when higher order corrections to the fragmentation functions are included. In addition we present full analytic results for the $\gamma\gamma\gamma$ and $\gamma\gamma+$jet one-loop amplitudes. These amplitudes, which are particularly compact, may be useful to future higher-order calculations. Our results are available in the Monte Carlo code MCFM.Comment: 16 pages, 4 figure

ZγZ\gamma production at NNLO including anomalous couplings

In this paper we present a next-to-next-to-leading order (NNLO) QCD calculation of the processes $pp\rightarrow l^+l^-\gamma$ and $pp\rightarrow \nu\bar\nu\gamma$ that we have implemented in MCFM. Our calculation includes QCD corrections at NNLO both for the Standard Model (SM) and additionally in the presence of $Z\gamma\gamma$ and $ZZ\gamma$ anomalous couplings. We compare our implementation, obtained using the jettiness slicing approach, with a previous SM calculation and find broad agreement. Focusing on the sensitivity of our results to the slicing parameter, we show that using our setup we are able to compute NNLO cross sections with numerical uncertainties of about $0.1\%$, which is small compared to residual scale uncertainties of a few percent. We study potential improvements using two different jettiness definitions and the inclusion of power corrections. At $\sqrt{s}=13$ TeV we present phenomenological results and consider $Z\gamma$ as a background to $H\to Z\gamma$ production. We find that, with typical cuts, the inclusion of NNLO corrections represents a small effect and loosens the extraction of limits on anomalous couplings by about $10\%$.Comment: 30 pages, 14 figure

NLO predictions for a lepton, missing transverse momentum and dijets at the Tevatron

n this letter we investigate the various processes that can contribute to a final state consisting of a lepton, missing transverse momentum and two jets at Next to Leading Order (NLO) at the Tevatron. In particular we consider the production of W/Z + 2 jets, diboson pairs, single top and the tt process with both fully leptonic and semi-leptonic decays. We present distributions for the invariant mass of the dijet system and normalisations of the various processes, accurate to NLO.Comment: 4 pages, 5 figure

Fibonacci type semigroups

We study "Fibonacci type" groups and semigroups. By establishing asphericity of their presentations we show that many of the groups are infinite. We combine this with Adjan graph techniques and the classification of the finite Fibonacci semigroups (in terms of the finite Fibonacci groups) to extend it to the Fibonacci type semigroups

Hadronic production of a Higgs boson and two jets at next-to-leading order

We perform an update of the next-to-leading order calculation of the rate for Higgs boson production in association with two jets. Our new calculation incorporates the full analytic result for the one-loop virtual amplitude. This new theoretical information allows us to construct a code including the decay of the Higgs boson without incurring a prohibitive penalty in computer running time. Results are presented for the Tevatron, where implications for the Higgs search are sketched, and also for a range of scenarios at the LHC.Comment: 16 pages, 4 figure

Letter from Cammie Williams to Mims Williams

Letter from Cammie Williams to his brother, Mims Williams, regarding the education of Gordon Williams (Cammie\u27s son) and Mims Williams (Mims\u27 son).https://scholarsjunction.msstate.edu/mss-williams-papers/1049/thumbnail.jp

Letter to Mims Williams

Letter from Cammie Williams to his brother, Mims Williams, regarding his insurance and general health.https://scholarsjunction.msstate.edu/mss-williams-papers/1053/thumbnail.jp

Letter to Mims Williams

Letter to Mims Williams from his brother, Cammie Williams, in Dry Grove, Mississippi, regarding the closing of the W. C. Ellis Co. (where Mims worked). He also asks if Mims will go to Washington on March 4; March 4, 1913 was the inauguration of President Woodrow Wilson.https://scholarsjunction.msstate.edu/mss-williams-papers/1166/thumbnail.jp