17557629
Vector Boson Pair Production via Vector Boson Fusion at NLO QCD
NLO QCD corrections to Vector Boson Pair Production via Vector Boson Fusion have recently been calculated and implemented in a parton-level Monte-Carlo program with full experimental cuts. We briefly sketch the elements of the calculation and show numerical results for the Large Hadron Collider.
118888006
NLO QCD corrections to processes with multiple electroweak bosons
The VBFNLO program package is a collection of Monte Carlo programs for the calculation of NLO QCD corrections to vector boson fusion cross sections, double and triple vector boson production, or the production of two electroweak bosons in association with an additional jet. An overview is given of the processes and features implemented in VBFNLO. WWγ and Wγ j production are discussed as examples.
54521266
LONGITUDINAL GLUON POLARIZATION IN RHIC DOUBLE-SPIN ASYMMETRIES.
The longitudinally polarized gluon density is probed sensitively in hard collisions of polarized protons under the condition that the dominant dynamics are perturbative and of leading twist origin. First data have recently been presented by PHENIX on the double-spin asymmetry A{sub LL}{sup {pi}} for {pi}{sup 0} production at moderate transverse momentum p {perpendicular} {approx_equal} 1 {divided_by} 4 GeV and central rapidity. By means of a systematic investigation of the relevant degrees of freedom we show that the perturbative QCD framework at leading power in p{perpendicular} produces an asymmetry that is basically positive definite in this kinematic range, i.e. A{sub LL}{sup {pi}} {approx}> {Omicron}(-10{sup -3}).
116950712
Les Houches 2013: Physics at TeV Colliders: Standard Model Working Group Report
This Report summarizes the proceedings of the 2013 Les Houches workshop on Physics at TeV Colliders. Session 1 dealt primarily with (1) the techniques for calculating standard model multi-leg NLO and NNLO QCD and NLO EW cross sections and (2) the comparison of those cross sections with LHC data from Run 1, and projections for future measurements in Run 2.
118535972
Next-to-leading order QCD corrections to Higgs boson production in association with a photon via weak-boson fusion at the LHC
Higgs boson production in association with a hard central photon and two forward tagging jets is expected to provide valuable information on Higgs boson couplings in a range where it is difficult to disentangle weak-boson fusion processes from large QCD backgrounds. We present next-to-leading order QCD corrections to Higgs production in association with a photon via weak-boson fusion at a hadron collider in the form of a flexible parton-level Monte Carlo program. The QCD corrections to integrated cross sections are found to be small for experimentally relevant selection cuts, while the shape of kinematic distributions can be distorted by up to 20% in some regions of phase space. Residual scale uncertainties at next-to-leading order are at the few-percent level.
11547130
Longitudinally polarized photoproduction of inclusive hadrons at fixed-target experiments
Abstract.We present a detailed phenomenological study of spin-dependent single-inclusive high- pT hadron photoproduction with particular emphasis on the kinematics relevant for the Compass and Hermes fixed-target experiments. We carefully examine the theoretical uncertainties associated with the only moderate transverse momenta accessible in such measurements and analyze the sensitivity of the relevant spin asymmetries to the gluon polarization in the nucleon as well as to the completely unknown parton content of circularly polarized photons.
119285776
Study of the anomalous magnetic moment of the muon computed from the Adler function
We compute the Adler function on the lattice from vacuum polarization data with twisted boundary conditions using numerical derivatives. The study is based on CLS ensembles with two flavours of $O(a)$ improved Wilson fermions. We extrapolate the lattice data for the Adler function to the continuum limit and to the physical pion mass and analyze its dependence on the momentum transfer. We discuss the application of this method to the extraction of the $u,d$ contribution to $a_\mu^{\mathrm{HLO}}$.
118604862
Suppression of excited-state effects in lattice determination of nucleon electromagnetic form factors
We study the ability of a variety of fitting techniques to extract the ground state matrix elements of the vector current from ratios of nucleon three- and two-point functions that contain contaminations from excited states. Extending our high-statistics study of nucleon form factors, we are able to demonstrate that the treatment of excited-state contributions in conjunction with approaching the physical pion mass has a significant impact on the $Q^2$-dependence of the form factors.
59145986
Exploring the phase diagram of QCD with complex Langevin simulations
I Real Langevin simulations converge to the expected result. For gauge theories simulations with complexified degrees of freedom are no longer in a compact group, SU(3)→ SL(3,C), and convergence is no longer guaranteed and needs to be checked [2]. I Empirical studies and theoretical arguments show that convergence is achieved, if the distribution is localised (compact) in the imaginary part. I We use gauge-invariance to get gauge-links to the proximity of the SU(3) manifold, this method is known as gauge cooling [3] Uμ(x)→ V (x)Uμ(x)V(x + aμ) U ,V ∈ SL(3,C).
118500967
Improved interpolating fields for hadrons at non-vanishing momentum
We demonstrate that a reduction in the noise-to-signal ratio may be obtained for hadrons at non-zero momenta whilst maintaining a good overlap with the ground state through a generalisation of Gaussian/Wuppertal smearing. The use of an anisotropic smearing wavefunction is motivated by the physical picture of a boosted hadron.
119295352
QCD at nonzero chemical potential: Recent progress on the lattice
We summarise recent progress in simulating QCD at nonzero baryon density using complex Langevin dynamics. After a brief outline of the main idea, we discuss gauge cooling as a means to control the evolution. Subsequently we present a status report for heavy dense QCD and its phase structure, full QCD with staggered quarks, and full QCD with Wilson quarks, both directly and using the hopping parameter expansion to all orders.