arXiv subjects
Publications and source records attributed to Michael E. Peskin.
We summarize the physics case for the International Linear Collider (ILC). We review the key motivations for the ILC presented in the literature, updating the projected measurement uncertainties for the ILC experiments in accord with the expected schedule of operation of the accelerator and the results of the most recent simulation studies.
We discuss the sources of uncertainty in calculations of the partial widths of the Higgs boson within the Standard Model. The uncertainties come from two sources: the truncation of perturbation theory and the uncertainties in input parameters. We review the current status of perturbative calculations and note that these are already reaching the parts-per-mil level of accuracy for the major decay modes. The main sources of uncertainty will then come from the parametric dependences on alpha_s, m_b, and m_c. Knowledge of these parameters is systematically improvable through lattice gauge theory calculations. We estimate the precision that lattice QCD will achieve in the next decade and the corresponding precision of the Standard Model predictions for Higgs boson partial widths.
Ken Wilson's ideas on the renormalization group were shaped by his attempts to build a theory of the strong interactions based on the concepts of quantum field theory. I describe the development of his ideas by reviewing four of Wilson's most important papers. [contribution to the Journal of Statistical Physics Special Issue in Memory of K. G. Wilson]
We present a new mechanism for creating the observed cosmic matter-antimatter asymmetry which satisfies all three Sakharov conditions from one common thread, gravitational waves. We generate lepton number through the gravitational anomaly in the lepton number current. The source term comes from elliptically polarizated gravity waves that are produced during inflation if the inflaton field contains a CP-odd component. In simple inflationary scenarios, the generated matter asymmetry is very small. We describe some special conditions in which our mechanism can give a matter asymmetry of realistic size.
This paper discusses some aspects of the estimates of Higgs boson coupling sensitivities for LHC and ILC presented at the Snowmass 2013 meeting. I estimate the measurement accuracies underlying the CMS presentation to Snowmass. I present new fits for the ILC capabilities. I present some joints fits to prospective LHC and ILC data that demonstrates the synergy of the High-Luminosity LHC and ILC programs. Contributed to the proceedings of the Snowmass 2013 Community Summer Study.
This document describes the novel techniques used to simulate the common Snowmass 2013 Energy Frontier Standard Model backgrounds for future hadron colliders. The purpose of many Energy Frontier studies is to explore the reach of high luminosity data sets at a variety of high energy colliders. The generation of high statistics samples which accurately model large integrated luminosities for multiple center-of-mass energies and pile-up environments is not possible using an unweighted event generation strategy -- an approach which relies on event weighting was necessary. Even with these improvements in efficiency, extensive computing resources were required. This document describes the specific approach to event generation using Madgraph5 to produce parton-level processes, followed by parton showering and hadronization with Pythia6, and pile-up and detector simulation with Delphes3. The majority of Standard Model processes for pp interactions at $\sqrt(s)$ = 14, 33, and 100 TeV with 0, 50, and 140 additional pile-up interactions are publicly available.
This document describes the simulation framework used in the Snowmass Energy Frontier studies for future Hadron Colliders. An overview of event generation with {\sc Madgraph}5 along with parton shower and hadronization with {\sc Pythia}6 is followed by a detailed description of pile-up and detector simulation with {\sc Delphes}3. Details of event generation are included in a companion paper cited within this paper. The input parametrization is chosen to reflect the best object performance expected from the future ATLAS and CMS experiments; this is referred to as the "Combined Snowmass Detector". We perform simulations of $pp$ interactions at center-of-mass energies $\sqrt{s}=$ 14, 33, and 100 TeV with 0, 50, and 140 additional $pp$ pile-up interactions. The object performance with multi-TeV $pp$ collisions are studied for the first time using large pile-up interactions.
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.
We present several benchmark points in the phenomenological Minimal Supersymmetric Standard Model (pMSSM). We select these models as experimentally well-motivated examples of the MSSM which predict the observed Higgs mass and dark matter relic density while evading the current LHC searches. We also use benchmarks to generate spokes in parameter space by scaling the mass parameters in a manner which keeps the Higgs mass and relic density approximately constant.
I estimate the accuracies on Higgs boson coupling constants that experiments at the Large Hadron Collider and the International Linear Collider are capable of reaching over the long term.
In this lecture, I review some of the perspectives on the Higgs boson discussed at the Higgs Hunting 2012 Worshop and discuss the short- and long-term aspects of Higgs physics.
In this lecture, I summarize developments presented at the Lepton Photon 2011 conference and give my perspective on the current situation in high-energy physics.
An antenna shower is a parton shower in which the basic move is a color-coherent 2-to-3 parton splitting process. In this paper, we give compact forms for the spin-dependent antenna splitting functions involving massive partons of spin 0 and spin 1/2.
These lectures give a pedagogical discussion of the computation of QCD tree amplitudes for collider physics. The topics reviewed are: spinor products, color ordering, MHV amplitudes, and the Britto-Cachazo-Feng-Witten recursion formula. The lectures were presented at the XIII Mexican School of Particles and Fields, 2008, and at the LHC Physics Summer School at Tsinghua University, 2010.
The anomalous magnetic moment of the top quark may be measured during the first run of the LHC at 7 TeV. For these measurements, it will be useful to have available tree amplitudes with ttbar and arbitrarily many photons and gluons, including both QED and color anomalous magnetic moments. In this paper, we present a method for computing these amplitudes using the Britto-Cachazo-Feng-Witten (BCFW) recursion formula. Because we deal with an effective theory with higher-dimension couplings, there are roadblocks to a direct computation with the BCFW method. We evade these by using an auxiliary scalar theory to compute a subset of the amplitudes.
We consider parton showers based on radiation from QCD dipoles or `antennae'. These showers are built from 2->3 parton splitting processes. The question then arises of what functions replace the Altarelli-Parisi splitting functions in this approach. We give a detailed answer to this question, applicable to antenna showers in which partons carry definite helicity, and to both initial- and final-state emissions.
These lectures, presented at the 2006 TASI summer school, give a general introduction to supersymmetry, emphasizing its application to models of elementary particle physics at the 100 GeV energy scale. I discuss the following topics: the construction of supersymmetric Lagrangians with scalars, fermions, and gauge bosons, the structure and mass spectrum of the Minimal Supersymmetric Standard Model (MSSM), the measurement of the parameters of the MSSM at high-energy colliders, and the solutions that the MSSM gives to the problems of electroweak symmetry breaking and dark matter.
[A brief review intended for a general physics colloquium audience.] Astrophysicists now know that 80% of the matter in the universe is `dark matter', composed of neutral and weakly interacting elementary particles that are not part of the Standard Model of particle physics. I will summarize the evidence for dark matter. I will explain why I expect dark matter particles to be produced at the CERN LHC. We will then need to characterize the new weakly interacting particles and demonstrate that they are the same particles that are found in the cosmos. I will describe how this might be done.