There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

https://biblio.ugent.be/publication/685594/file/1130605.pdf

Review of Particle Physics

The Pythia program can be used to generate high-energy-physics ''events'', i.e. sets of outgoing particles produced in the interactions between two incoming particles. The objective is to provide as accurate as possible a representation of event properties in a wide range of reactions, within and beyond the Standard Model, with emphasis on those where strong interactions play a role, directly or indirectly, and therefore multihadronic final states are produced. The physics is then not understood well enough to give an exact description; instead the program has to be based on a combination of analytical results and various QCD-based models. This physics input is summarized here, for areas such as hard subprocesses, initial- and final-state parton showers, underlying events and beam remnants, fragmentation and decays, and much more. Furthermore, extensive information is provided on all program elements: subroutines and functions, switches and parameters, and particle and process data. This should allow the user to tailor the generation task to the topics of interest.

/pdf/pythia-6-4-physics-and-manual-3dvwmijpnq.pdf

PYTHIA 6.4 Physics and Manual

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

Particle dark matter: Evidence, candidates and constraints

(Abridged) The Large Area Telescope (Fermi/LAT, hereafter LAT), the primary instrument on the Fermi Gamma-ray Space Telescope (Fermi) mission, is an imaging, wide field-of-view, high-energy gamma-ray telescope, covering the energy range from below 20 MeV to more than 300 GeV. This paper describes the LAT, its pre-flight expected performance, and summarizes the key science objectives that will be addressed. On-orbit performance will be presented in detail in a subsequent paper. The LAT is a pair-conversion telescope with a precision tracker and calorimeter, each consisting of a 4x4 array of 16 modules, a segmented anticoincidence detector that covers the tracker array, and a programmable trigger and data acquisition system. Each tracker module has a vertical stack of 18 x,y tracking planes, including two layers (x and y) of single-sided silicon strip detectors and high-Z converter material (tungsten) per tray. Every calorimeter module has 96 CsI(Tl) crystals, arranged in an 8 layer hodoscopic configuration with a total depth of 8.6 radiation lengths. The aspect ratio of the tracker (height/width) is 0.4 allowing a large field-of-view (2.4 sr). Data obtained with the LAT are intended to (i) permit rapid notification of high-energy gamma-ray bursts (GRBs) and transients and facilitate monitoring of variable sources, (ii) yield an extensive catalog of several thousand high-energy sources obtained from an all-sky survey, (iii) measure spectra from 20 MeV to more than 50 GeV for several hundred sources, (iv) localize point sources to 0.3 - 2 arc minutes, (v) map and obtain spectra of extended sources such as SNRs, molecular clouds, and nearby galaxies, (vi) measure the diffuse isotropic gamma-ray background up to TeV energies, and (vii) explore the discovery space for dark matter.

The Large Area Telescope on the Fermi Gamma-ray Space Telescope Mission

Feynman Diagrams and Quantum Electrodynamics * Invitation: Pair Production in e+e- Annihilation * The Klein-Gordon Field * The Dirac Field * Interacting Fields and Feynman Diagrams * Elementary Processes of Quantum Electrodynamics * Radiative Corrections: Introduction * Radiative Corrections: Some Formal Developments * Final Project: Radiation of Gluon Jets Renormalization * Invitation: Ultraviolet Cutoffs and Critical Fluctuations * Functional Methods * Systematics of Renormalization * Renormalization and Symmetry * The Renormalization Group * Critical Exponents and Scalar Field Theory * Final Project: The Coleman-Weinberg Potential Non-Albelian Gauge Theory * Invitation: The Parton Model of Hadron Structure * Non-Albein Gauge Invariance * Quantization of Non-Abelian Gauge Theories * Quantum Chromodynamics * Operator Products and Effective Vertices * Perturbation Theory Anomalies * Gauge Theories with Spontaneous Symmetry Breaking * Quantization of Spontaneously Broken Gauge Theories * Final Project: Decays of the Higgs Boson * Epilogue: Field Theory at the Frontier

/pdf/an-introduction-to-quantum-field-theory-508tfytcpy.pdf

An Introduction to Quantum Field Theory

I will first review the experimental limits placed on the oblique correction parameters S and T. Then, I will discuss how the value of S can be estimated for running and walking technicolor theories.

/pdf/estimation-of-oblique-electroweak-corrections-1puptfhw6n.pdf

Estimation of oblique electroweak corrections

We show that an integral S over the spectral function of spin-1 states of the Higgs sector is constrained by precision weak-interaction measurements. Current data exclude large technicolor models; asymmetry measurements at the CERN ${\mathit{e}}^{+}$${\mathit{e}}^{\mathrm{\ensuremath{-}}}$ collider LEP and the SLAC Linear Collider will soon provide more stringent limits on Higgs-boson strong interactions.

/pdf/new-constraint-on-a-strongly-interacting-higgs-sector-327uykot3b.pdf

New constraint on a strongly interacting Higgs sector

Author(s): Baer, Howard; Barklow, Tim; Fujii, Keisuke; Gao, Yuanning; Hoang, Andre; Kanemura, Shinya; List, Jenny; Logan, Heather E; Nomerotski, Andrei; Perelstein, Maxim; Peskin, Michael E; Poschl, Roman; Reuter, Jurgen; Riemann, Sabine; Savoy-Navarro, Aurore; Servant, Geraldine; Tait, Tim MP; Yu, Jaehoon | Abstract: The International Linear Collider Technical Design Report (TDR) describes in four volumes the physics case and the design of a 500 GeV centre-of-mass energy linear electron-positron collider based on superconducting radio-frequency technology using Niobium cavities as the accelerating structures. The accelerator can be extended to 1 TeV and also run as a Higgs factory at around 250 GeV and on the Z0 pole. A comprehensive value estimate of the accelerator is give, together with associated uncertainties. It is shown that no significant technical issues remain to be solved. Once a site is selected and the necessary site-dependent engineering is carried out, construction can begin immediately. The TDR also gives baseline documentation for two high-performance detectors that can share the ILC luminosity by being moved into and out of the beam line in a "push-pull" configuration. These detectors, ILD and SiD, are described in detail. They form the basis for a world-class experimental programme that promises to increase significantly our understanding of the fundamental processes that govern the evolution of the Universe.

Michael E. Peskin

Papers

An Introduction to Quantum Field Theory

Estimation of oblique electroweak corrections

An Introduction to Quantum Field Theory

New constraint on a strongly interacting Higgs sector

The International Linear Collider Technical Design Report - Volume 2: Physics