http://repositorium.sdum.uminho.pt/bitstream/1822/48763/1/1-s2.0-S037026931200857X-main.pdf

Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC

https://digital.csic.es/bitstream/10261/108964/1/experiment%20at%20the%20LHC.pdf

Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC

We discuss the theoretical bases that underpin the automation of the computations of tree-level and next-to-leading order cross sections, of their matching to parton shower simulations, and of the merging of matched samples that differ by light-parton multiplicities. We present a computer program, MadGraph5 aMC@NLO, capable of handling all these computations — parton-level fixed order, shower-matched, merged — in a unified framework whose defining features are flexibility, high level of parallelisation, and human intervention limited to input physics quantities. We demonstrate the potential of the program by presenting selected phenomenological applications relevant to the LHC and to a 1-TeV e + e − collider. While next-to-leading order results are restricted to QCD corrections to SM processes in the first public version, we show that from the user viewpoint no changes have to be expected in the case of corrections due to any given renormalisable Lagrangian, and that the implementation of these are well under way.

/pdf/the-automated-computation-of-tree-level-and-next-to-leading-4etm0g6w46.pdf

The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations

http://risa.stanford.edu/teaching/362/particledarkmatter.pdf

Particle dark matter: Evidence, candidates and constraints

We present updated leading-order, next-to-leading order and next-to-next-to-leading order parton distribution functions (“MSTW 2008”) determined from global analysis of hard-scattering data within the standard framework of leading-twist fixed-order collinear factorisation in the $\overline{\mathrm{MS}}$
 
scheme. These parton distributions supersede the previously available “MRST” sets and should be used for the first LHC data taking and for the associated theoretical calculations. New data sets fitted include CCFR/NuTeV dimuon cross sections, which constrain the strange-quark and -antiquark distributions, and Tevatron Run II data on inclusive jet production, the lepton charge asymmetry from W decays and the Z rapidity distribution. Uncertainties are propagated from the experimental errors on the fitted data points using a new dynamic procedure for each eigenvector of the covariance matrix. We discuss the major changes compared to previous MRST fits, briefly compare to parton distributions obtained by other fitting groups, and give predictions for the W and Z total cross sections at the Tevatron and LHC.

/pdf/parton-distributions-for-the-lhc-4lvvi85r8i.pdf

Parton distributions for the LHC

We establish an efficient polynomial-complexity algorithm for one-loop calculations, based on generalized $D$-dimensional unitarity. It allows automated computations of both cut-constructible {\it and} rational parts of one-loop scattering amplitudes from on-shell tree amplitudes. We illustrate the method by (re)-computing all four-, five- and six-gluon scattering amplitudes in QCD at one-loop.

Full one-loop amplitudes from tree amplitudes

Abstract We derive the dominant part of the O ( α s 2 ) correction to the photon energy spectrum in the inclusive decay B → X s + γ . The detailed knowledge of the spectrum is important for relating the theoretical calculations of the B → X s + γ decay rate and the experimental measurements where a cut on the photon energy is applied. In addition, moments of the photon energy spectrum are used for the determination of the b-quark mass and other fundamental parameters of heavy quark physics. Our calculation reduces the theoretical uncertainty associated with uncalculated higher orders effects and shows that, for B → X s + γ , QCD radiative corrections to the photon energy spectrum are under theoretical control.

The photon energy spectrum in B-> X_s + γin perturbative QCD through O(α_s^2)

Relating bottom quark mass in DR ¯ and MS ¯ regularization schemes

Charmonium decays: J/ψ→e+e− and ηc→γγ

The $O({\ensuremath{\alpha}}^{2}\mathrm{ln}{(m}_{\ensuremath{\mu}}{/m}_{e}))$ corrections to the electron energy spectrum in muon decay are computed using the perturbative fragmentation function approach. The magnitude of these corrections is comparable to the anticipated precision of the TWIST experiment where the Michel parameters will be extracted from the measurement of the electron energy spectrum in muon decay.

Kirill Melnikov

Papers

Full one-loop amplitudes from tree amplitudes

The photon energy spectrum in B-> X_s + γin perturbative QCD through O(α_s^2)

Relating bottom quark mass in DR ¯ and MS ¯ regularization schemes

Charmonium decays: J/ψ→e+e− and ηc→γγ

O ( α 2 ln ( m μ / m e ) ) corrections to the electron energy spectrum in muon decay