This write-up of lectures given at TASI 2020 provides an introduction into precision tests of the electroweak Standard Model. The lecture notes begin with a hands-on review of the (on-shell) renormalization procedure, and subsequently highlight a few subtleties that occur in the renormalization of a theory with electroweak symmetry breaking and massive gauge bosons. After that a set of typical electroweak precision observables is introduced, as well as a range of input parameter measurements that are needed for making predictions within the Standard Model. Finally, it is discussed how comparisons of the electroweak precision observables between experiment and theory can be used to stress-test the Standard Model and probe new physics.
These notes are a written version of a set of lectures given at TASI-02 on the topic of effective field theories. They are meant as an introduction to some of the latest techniques and applications in the field.
The phenomenology of large, warped, and universal extra dimensions is reviewed. Characteristic signals are emphasized rather than an extensive survey. This is the writeup of lectures given at the Theoretical Advanced Study Institute in 2004.
These lectures, presented at TASI 08 school, provide an introduction to supersymmetry and supersymmetry breaking. We present basic formalism of supersymmetry, supersymmetric non-renormalization theorems, and summarize non-perturbative dynamics of supersymmetric QCD. We then turn to discussion of tree level, non-perturbative, and metastable supersymmetry breaking. We introduce Minimal Supersymmetric Standard Model and discuss soft parameters in the Lagrangian. Finally we discuss several mechanisms for communicating the supersymmetry breaking between the hidden and visible sectors.
These lectures discuss the $θ$ parameter of QCD. After an introduction to anomalies in four and two dimensions, the parameter is introduced. That such topological parameters can have physical effects is illustrated with two dimensional models, and then explained in QCD using instantons and current algebra. Possible solutions including axions, a massless up quark, and spontaneous CP violation are discussed.
Based on lectures given at the 2008 Theoretical Advanced Study Institute (TASI), I review here some aspects of the phenomenology of particle dark matter, including the process of thermal freeze-out in the early universe, and the direct and indirect detection of WIMPs. I also describe some of the most popular particle candidates for dark matter and summarize the current status of the quest to discover dark matter's particle identity.
Jet physics is a rich and rapidly evolving field, with many applications to physics in and beyond the Standard Model. These notes, based on lectures delivered at the June 2012 Theoretical Advanced Study Institute, provide an introduction to jets at the Large Hadron Collider. Topics covered include sequential jet algorithms, jet shapes, jet grooming, and boosted Higgs and top tagging.
These TASI lectures consider low mass hidden sectors from Hidden Valleys, Quirks and Unparticles. We show how each corresponds to a different limit of the same class of models: hidden sectors with non-abelian gauge groups with mass gaps well below a TeV that communicate to the Standard Model through weak scale suppressed higher dimension operators. We provide concrete examples of such models and discuss LHC signatures. Lastly we turn to discussing the application of Hidden Valleys to dark matter sectors.
These notes overlap with lectures given at the TASI summer schools in 2014 and 2011, as well as at the European School of High Energy Physics in 2013. This is primarily an attempt at transcribing my hand-written notes, with emphasis on topics and ideas discussed in the lectures. It is not a comprehensive introduction or review of the field, nor does it include a complete list of references. I hope, however, that some may find it useful to better understand the reasons for excitement about recent progress and future opportunities in flavor physics.
In these lectures I briefly review the Higgs mechanism of spontaneous symmetry breaking and focus on the most relevant aspects of the phenomenology of the Standard Model and of the Minimal Supersymmetric Standard Model Higgs bosons at both hadron and lepton colliders. Some emphasis is put on the perturbative calculation of both Higgs boson branching ratios and production cross sections, including the most important radiative corrections.
The first part of these lectures provides a brief introduction to the concepts and techniques of effective field theory. The second part reviews precision electroweak constraints using effective theory methods. Several simple extensions of the Standard Model are considered as illustrations. The appendix contains some new results on the one-loop contributions of electroweak triplet scalars to the T parameter and contains a discussion of decoupling in that case.
These lectures, given at the 2014 Theoretical Advanced Study Institute (TASI), are an introduction to what we know at present about dark matter and the major current experimental and observational efforts to identify what it consists of. They attempt to present the complexities of the subject, making clear common simplifying assumptions, to better understand the reach of dark matter searches.
Compact spatial dimension at the TeV scale remain an intriguing possibility that is currently being tested at the LHC. We give an introductory review of extra-dimensional models and ideas, from a phenomenological perspective, but emphasizing the appropriate theoretical tools. We emphasize the power and limitations of such constructions, and give a self-contained account of the methods necessary to understand the associated physics. We also review a number of examples that illustrate how extra-dimensional ideas can shed light on open questions in the Standard Model. An introduction to holograph…
These lectures provide an introduction to the physics of particle colliders. Topics covered include a quantitative examination of the design and operational parameters of Large Hadron Collider, kinematics and observables at colliders, such as rapidity and transverse mass, and properties of distributions, such as Jacobian peaks. In addition, the lectures provide a practical introduction to the decay modes and signatures of important composite and elementary and particles in the Standard Model, from pions to the Higgs boson. The aim of these lectures is provide a bridge between theoretical and e…
In these lectures I briefly review the Higgs mechanism of electroweak symmetry breaking and focus on the most relevant aspects of the phenomenology of the Standard Model Higgs boson at hadron colliders, namely the Tevatron and the Large Hadron Collider. Emphasis is put in particular on the Higgs-physics program of both LHC experiments and on the theoretical activity that has entailed from the the need of providing accurate predictions for both signal and background in Higgs-boson searches.
We present a pedagogical review of neutrino physics. In the first lecture we describe the theoretical motivation for neutrino masses, and explain how neutrino flavor oscillation experiments can probe neutrino masses. In the second lecture we review the experimental data, and show that it is best explained if neutrinos are massive. In the third lecture we explain what are the theoretical implications of the data, in particular, what are the challenges they impose on models of physics beyond the SM. We give examples of theoretical models that cope with some of these challenges.
We give a brief introduction to theories with extra dimensions. We first introduce the basic formalism for studying extra-dimensional theories, including the Kaluza-Klein decomposition and the effective theory for 3-branes. We then focus on two types of scenarios: large extra dimensions as a solution to the hierarchy problem and TeV$^{-1}$-size extra dimensions with Standard Model fields propagating in them. We discuss the experimental tests and constraints on these scenarios, and also the questions in particle physics which may be addressed with the help of extra dimensions. This is the write…
These notes, based on work with Herbi Dreiner and Howie Haber, discuss how to do practical calculations of cross sections and decay rates using two-component fermion notation, as appropriate for supersymmetry and other beyond-the-Standard-Model theories. Included are a list of two-component fermion Feynman rules for the Minimal Supersymmetric Standard Model, and some example calculations.
This review is based on lectures on flavor physics given at TASI 2008. First I summarize our present knowledge on the fundamental parameters of the flavor sector. Then I discuss various scenarios going beyond the standard model which attempt to explain aspects of the "flavor puzzle". Relating quark masses and mixing angles via flavor symmetry is explored. Explaining the mass hierarchy via the Froggatt-Nielsen mechanism is reviewed and illustrated. Grand unification ideas are pursued to seek a pattern in the observed masses and mixings of quarks and leptons. Generating light fermion masses as r…
This is an introduction to theories where the Higgs is a composite Nambu-Goldstone boson of a new strongly-interacting dynamics not much above the weak scale. A general discussion is presented based on the pattern of global symmetries at low energy, and the analogy with the QCD pion is analyzed. The last part of the lectures shows how a composite Higgs can emerge as the hologram of a 5-dimensional gauge field.
This is a pedagogical introduction into theories with branes and extra dimensions. We first discuss the construction of such models from an effective field theory point of view, and then discuss large extra dimensions and some of their phenomenological consequences. Various possible phenomena (split fermions, mediation of supersymmetry breaking and orbifold breaking of symmetries) are discussed next. The second half of this review is entirely devoted to warped extra dimensions, including the construction of the Randall-Sundrum solution, intersecting branes, radius stabilization, KK phenomenolo…
We provide an introduction to the physics of a warped extra dimension and the AdS/CFT correspondence. An AdS/CFT dictionary is given which leads to a 4D holographic view of the 5th dimension. With a particular emphasis on beyond the standard model physics, this provides a window into the strong dynamics associated with either electroweak symmetry breaking or supersymmetry breaking. In this way hierarchies associated with either the electroweak or supersymmetry breaking scale, together with the fermion mass spectrum, can be addressed in a consistent framework.
I give a pedagogical introduction to the physics of electroweak symmetry breaking and the uses of effective field theory in the context of Higgs physics. Higgs boson production and decay at the LHC and the consistency of the Higgs measurements with triviality arguments, vacuum stability, and precision electroweak measurements are discussed. Effective Lagrangian techniques are used to understand potential deviations from the Standard Model (SM) predictions. Finally, I end with a brief discussion of the future of Higgs physics.
I discuss, in a semi-pedagogical way, our current understanding of neutrino physics. I present a brief history of how the neutrino came to be ``invented'' and observed, and discuss the evidence that led to the recent discovery that neutrinos change flavor. I then spend some time presenting mass-induced neutrino flavor change (neutrino oscillation), and how it pieces all the neutrino puzzles except for the LSND anomaly, which is also briefly discussed. I conclude by highlighting the importance of determining the nature of the neutrinos, i.e., are they Dirac or Majorana fermions.
I give a basic introduction to precision electroweak analysis, beginning with calculation at tree-level which most simply illustrates the procedure. I then work out the formalism for one-loop corrections to the vector boson self energies (oblique corrections). This is a tractable subset of the complete electroweak program. Not only does this exercise provide an analytically accessible demonstration of the theory involved in electroweak precision analyses, it also teaches students a useful technique to analyze a large class of theories beyond the Standard Model.
This is a pedagogical introduction into the possible uses and effects of extra dimensions in electroweak (TeV scale) physics, and in particular to models of electroweak symmetry breaking via boundary conditions ("higgsless models"). It is self contained: all the aspects of extra dimensional and electroweak physics used here are reviewed, before we apply these concepts to higgsless models. In the first lecture gauge theories in an extra dimension and on an interval are discussed. In the second lecture we describe the basic structure of higgsless models, while in the third lecture we discuss fer…
These lectures provide a self-contained introduction to the essential aspects of non-supersymmetric beyond the Standard Model (BSM) physics for beginning graduate students who are already familiar with quantum field theory. After a detailed review of the physical meaning of the hierarchy problem, we introduce the key ingredients of the physics of Goldstone bosons necessary for many non-supersymmetric new physics models. Next we discuss the concept of collective symmetry breaking and present the main elements leading to little Higgs/composite Higgs models. We then turn to extra dimensional theo…
These lectures contain a pedagogical review of non-perturbative results from holomorphy and Seiberg duality with applications to dynamical SUSY breaking. Background material on anomalies, instantons, unitarity bounds from superconformal symmetry, and gauge mediation are also included.
These lectures give an overview of aspects of missing E_T signatures from new physics at the LHC, along with their important connection to dark matter physics. Mostly, I will concentrate on supersymmetric (SUSY) sources of missing E_T, but will also mention Little Higgs models with T-parity (LHT) and universal extra dimensions (UED) models with KK-parity. Lecture 1 covers SUSY basics, model building and spectra computation. Lecture 2 addresses sparticle production and decay mechanisms at hadron colliders and event generation. Lecture 3 covers SUSY signatures at LHC, along with LHT and UED sign…
A somewhat eclectic choice of topics: Review of Flavor in the quark sector of the SM, the appearance of the CKM matrix and determination of its elements, FCNCs, the GIM mechanism. Minimal Flavor Violation. A close look at neutral meson mixing. CP asymmetries. Effective Field Theory in Weak interactions.
These lectures review the main motivations for future high-energy colliders, focusing on the understanding of electroweak symmetry breaking and on the search for physics beyond the Standard Model. The open questions and the challenges are common to all future projects; for concreteness, I will use studies of the potential of $\rm e^+e^-$ and pp circular colliders to provide examples of the anticipated physics reach.
These lectures are a brief introduction to scattering amplitudes. We begin with a review of basic kinematical concepts like the spinor helicity formalism, followed by a tutorial on bootstrapping tree-level scattering amplitudes. Afterwards, we discuss on-shell recursion relations and soft theorems, emphasizing their broad applicability to gravity, gauge theory, and effective field theories. Lastly, we report on some of the new field theoretic structures which have emerged from the on-shell picture, focusing primarily on color-kinematics duality.
Observational evidence and theoretical motivation for dark matter are presented and connections to the CMB and BBN are made. Problems for baryonic and neutrino dark matter are summarized. Emphasis is placed on the prospects for supersymmetric dark matter.
The origin of the asymmetry between matter and anti-matter of the Universe has been one of the great challenges in particle physics and cosmology. Leptogenesis as a mechanism for generating the cosmological baryon asymmetry of the Universe has gained significant interests ever since the advent of the evidence of non-zero neutrino masses. In these lectures presented at TASI 2006, I review various realizations of leptogenesis and allude to recent developments in this subject.
These proceedings summarize lectures that were delivered as part of the 2002 and 2003 Theoretical Advanced Study Institutes in elementary particle physics (TASI) at the University of Colorado at Boulder. They are intended to provide a pedagogical introduction to cosmology aimed at advanced graduate students in particle physics and string theory.
These lectures, presented at TASI 2018, provide a concise introduction to inflation, baryogenesis, and aspects of dark matter not covered by the other lectures. The emphasis for inflation is an intuitive understanding and techniques for constraining inflationary models. For baryogenesis we focus on two examples, leptogenesis and electroweak baryogenesis, with attention to singlet-assisted two-step phase transitions. Concerning dark matter, we review different classes of models distinguished by their mechanisms for obtaining the observed relic density, including thermal freeze-out, asymmetric d…
These lectures provide an introduction to models and direct detection of dark matter. We summarize the general features and motivations for candidates in the full dark matter mass range, and then restrict to the keV-TeV mass window. Candidates in this window can be produced by thermal mechanisms in the standard cosmology, and are an important target for experimental searches. We then turn to sub-GeV dark matter (light dark matter) and dark sectors, an area where many new models and experiments are currently being proposed. We discuss the cosmology of dark sectors, specific portal realizations,…
Neutrino astronomy is on the verge of discovering new sources, and this will lead to important advances in astrophysics, cosmology, particle physics, and nuclear physics. This paper is meant for non-experts, so that they might better understand the basic issues in this field.
The standard model picture of flavor and CP violation is now experimentally verified, hence strong bounds on the flavor structure of new physics follow. We begin by discussing in detail the unique way that flavor conversion and CP violation arise in the standard model. The description provided is based on a spurion, symmetry oriented, analysis, and a covariant basis for describing flavor transition processes is introduced, in order to make the discussion transparent for non-experts. We show how to derive model independent bounds on generic new physics models. Furthermore, we demonstrate, using…
These notes provide a brief introduction to modern cosmology, focusing primarily on theoretical issues. Some attention is paid to aspects of potential interest to students of string theory, on both sides of the two-way street of cosmological constraints on string theory and stringy contributions to cosmology. Slightly updated version of lectures at the 1999 Theoretical Advanced Study Institute at the University of Colorado, Boulder.
These lectures cover aspects of primordial cosmology with a focus on observational tests of physics beyond the Standard Model. The presentation is divided into two parts: In Part I, we study the production of new light particles in the hot big bang and describe their effects on the anisotropies of the cosmic microwave background. In Part II, we investigate the possibility of very massive particles being created during inflation and determine their imprints in higher-order cosmological correlations.
These proceedings are a summary of four lectures given at the Theoretical Advanced Study Institute in Elementary Particle Physics (TASI) in 2009. These lectures provide a basic introduction to experimental particle physics and the Large Hadron Collider experiments at CERN, with many general examples from the (still running) Fermilab Tevatron.
These lectures start with a detailed pedagogical introduction to electroweak symmetry breaking in the Standard Model, including gauge boson and fermion mass generation and the resulting predictions for Higgs boson interactions. I then survey Higgs boson decays and production mechanisms at hadron and $e^+e^-$ colliders. I finish with two case studies of Higgs physics beyond the Standard Model: two-Higgs-doublet models, which I use to illustrate the concept of minimal flavor violation, and models with isospin-triplet scalar(s), which I use to illustrate the concept of custodial symmetry.
These lectures from the TASI 2012 summer school outline the basics of supersymmetry (SUSY) in 3+1 dimensions. Starting from a ground-up development of superspace, we develop all of the tools necessary to construct SUSY lagrangians. While aimed at an introductory level, these lectures incorporate a number of "super-tricks" for SUSY aficionados, including SUSY-covariant derivatives, equations of motion in superspace, background field methods, and non-linear realizations of goldstinos.
These lectures, presented at TASI 2016: Anticipating the Next Discoveries in Particle Physics, provide an introduction to some key methods and tools of indirect dark matter searches. Topics covered include estimation of dark matter signals, thermal freezeout and related scenarios, potential effects of dark matter annihilation on the early universe, modeling photon signals from annihilation or decay, and a brief and qualitative introduction to diffusive propagation of cosmic rays. The second half of the notes gives a status report (circa summer 2016) on selected experimental searches, the resul…
The lecture note consists of four parts. In the first part, we review a 2+1 dimensional lattice model which realizes emergent supersymmetry at a quantum critical point. The second part is devoted to a phenomenon called fractionalization where gauge boson and fractionalized particles emerge as low energy excitations as a result of strong interactions between gauge neutral particles. In the third part, we discuss about stability and low energy effective theory of a critical spin liquid state where stringy excitations emerge in a large N limit. In the last part, we discuss about an attempt to com…
I introduce the consequences of neutrino mass and mixing in the dense environments of the early Universe and in astrophysical environments. Thermal and matter effects are reviewed in the context of a two-neutrino formalism, with methods of extension to multiple neutrinos. The observed large neutrino mixing angles place the strongest constraint on cosmological lepton (or neutrino) asymmetries, while new sterile neutrinos provide a wealth of possible new physics, including lepton asymmetry generation as well as candidates for dark matter. I also review cosmic microwave background and large-scale…
In a series of five lectures I review inflationary cosmology. I begin with a description of the initial conditions problems of the Friedmann-Robertson-Walker (FRW) cosmology and then explain how inflation, an early period of accelerated expansion, solves these problems. Next, I describe how inflation transforms microscopic quantum fluctuations into macroscopic seeds for cosmological structure formation. I present in full detail the famous calculation for the primordial spectra of scalar and tensor fluctuations. I then define the inverse problem of extracting information on the inflationary era…
The energy density of the vacuum, Lambda, is at least 60 orders of magnitude smaller than several known contributions to it. Approaches to this problem are tightly constrained by data ranging from elementary observations to precision experiments. Absent overwhelming evidence to the contrary, dark energy can only be interpreted as vacuum energy, so the venerable assumption that Lambda=0 conflicts with observation. The possibility remains that Lambda is fundamentally variable, though constant over large spacetime regions. This can explain the observed value, but only in a theory satisfying a num…
In these lectures, I describe a variety of efforts to identify or constrain the identity of dark matter by detecting the annihilation or decay products of these particles, or their effects. After reviewing the motivation for indirect searches, I discuss what we have learned about dark matter from observations of gamma rays, cosmic rays and neutrinos, as well as the cosmic microwave background. Measurements such as these have been used to significantly constrain a wide range of thermal relic dark matter candidates, in particular those with masses below a few hundred GeV. I also discuss a number…
