Chiral Perturbation Theory at Finite Volume and/or with Twisted Boundary Conditions

In this talk we discuss a number of ChPT calculations relevant for lattice QCD. These include the finite volume corrections at two-loop order for masses and decay constants. The second part is about hadronic vacuum polarization where we present the two-loop ChPT estimate for the disconnected and strange quark contributions. We also present the finite volume corrections at two-loop order. The final part is the one-loop finite volume with twisted boundary conditions contribution to $f_+(q^2)$ and the full $K_{\ell3}$ amplitudeComment: 7 pages, talk presented at 34th annual International Symposium on Lattice Field Theory, 24-30 July 2016, University of Southampton, U

Chiral Meson Physics at Two Loops

An overview of Chiral Perturbation Theory calculations in the mesonic sector at the two Loop level is given. Discussed in some detail are the partially quenched case relevant for lattice QCD, the general fitting procedures and $\pi\pi$,$\pi K$ scattering as well as the determination of $V_{us}$ and $K_{\ell3}$ decays.Comment: 7 pages, Invited plenary talk presented at the 19th European Few-Body conference, Groningen, The Netherlands, August 23-27, 200

Vector two-point functions in finite volume using partially quenched chiral perturbation theory

We calculate vector-vector correlation functions at two loops using partially quenched chiral perturbation theory including finite volume effects and twisted boundary conditions. We present expressions for the flavor neutral cases and the flavor charged case with equal masses. Using these expressions we give an estimate for the ratio of disconnected to connected contributions for the strange part of the electromagnetic current. We give numerical examples for the effects of partial quenching, finite volume and twisting and suggest the use of different twists to check the size of finite volume effects. The main use of this work is expected to be for lattice QCD calculations of the hadronic vacuum polarization contribution to the muon anomalous magnetic moment.Comment: 31 pages, some sentences added regarding partial twisting, reformatted equations in appendix to make them more legibl

A web-based tool to design and analyze single- and double-stage acceptance sampling plans

Acceptance sampling plans are used to determine whether production lots can be accepted or rejected. Existing tools only provide a limited functionality for the two-point design and the risk analysis of such plans. In this article, a web-based tool is presented to study single- and double-stage sampling plans. In contrast to existing solutions, the tool is an interactive applet that is freely available. Analytic properties are derived to support the development of search strategies for the design of double-stage sampling plans that are more efficient and accurate in comparison with existing routines. Several case studies are presented

Scalar Kinetic Mixing and the Renormalization Group

Quantum field theories containing scalar fields with equal quantum numbers allow for a mixed kinetic term in the Lagrangian. It has been argued that this mixing must be taken into consideration when performing renormalization group (RG) analyses of such a theory. However, from the fact that scalar kinetic mixing does not correspond to a physical observable, we show that no extra parameters need to be introduced. Using a toy model, we explicitly derive the 1-loop RG equations (RGEs) in three different renormalization schemes to demonstrate how this issue can be dealt with. In schemes without kinetic mixing, either the fields mix during renormalization to produce non-diagonal anomalous dimensions or the RGEs explicitly depend on the scalar masses. Finally, we show how the different schemes are related to each other by scale dependent field redefinitions.Comment: 7 pages, journal versio

Low energy paths for octahedral tilting in inorganic halide perovskites

Instabilities relating to cooperative octahedral tilting is common in materials with perovskite structures, and in particular in the sub class of halide perovskites. In this work, the energetics of octahedral tilting in the inorganic metal halide perovskites CsPbI$_3$ and CsSnI$_3$ are investigated using first-principles density functional theory calculations. Several low energy paths between symmetry equivalent variants of the stable orthorhombic (\textit{Pnma}) perovskite variant are identified and investigated. The results are in favor of the presence of dynamic disorder in the octahedral tilting phase transitions of inorganic halide perovskites. In particular, one specific type of path, corresponding to an out-of-phase "tilt switch", is found to have significantly lower energy barrier than the others, which indicates the existence of a temperature range where the dynamic fluctuations of the octahedra follow only this type of path. This could produce a time averaged structure corresponding to the intermediate tetragonal (\textit{P4/mbm}) structure observed in experiments. Deficiencies of the commonly employed simple one-dimensional "double well" potentials in describing the dynamics of the octahedra are pointed out and discussed.Comment: Revised versio

Towards a Sustainable European Agricultural Policy for the 21st Century. Report of the CEPS Task Force on the Common Agricultural Policy in the 21st century: DOHA, mid-term review, and enlargement. CEPS Task Force Reports No. 42, 1 September 2002

The debate on agricultural policy in the EU has been very lively and politically prominent over the past months. The Common Agricultural Policy (CAP) of the EU has undergone major changes since it was first implemented at the end of the 1960s. Commentators suggest that the CAP changes made in the Agenda 2000 reform package were insufficient to address the problems facing the CAP in the coming years. These include enlargement, new trade negotiations and the demand by European society for a safe, sustainable agri-food system, to name but a few. This report highlights the most pressing challenges to creating a sustainable CAP for the 21st century. It focuses on strategic policy options that are closely linked to the CAP system to be ‘hands on’; but the report refrains from becoming too specific on policy details, focusing instead on the important strategic questions. It offers six recommendations for good governance, that aim to remove bureaucratic constraints from the food industry, yet strengthen consistency and good practice

Chiral Perturbation Theory at Two Loops and the Measurement of VusV_{us}

I give an overview of the calculations done in three-flavour Chiral perturbation theory at next-to-next-to-leading order with an emphasis on those relevant for an improvement in the accuracy of the measurement of $V_{us}$. It is pointed out that all needed low energy constants can be obtained from experiment via the scalar form-factor in $K_{\ell3}$ decaysComment: 4 pages, talk given at 38th Rencontres de Moriond on QCD and High-Energy Hadronic Interactions, Les Arcs, Savoie, France, 22-29 Mar 200