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Michael E. Peskin

Publications and source records attributed to Michael E. Peskin.

At least 73 records · Page 4Linked to original sources

Determination of Dark Matter Properties at High-Energy Colliders

If the cosmic dark matter consists of weakly-interacting massive particles, these particles should be produced in reactions at the next generation of high-energy accelerators. Measurements at these accelerators can then be used to determine the microscopic properties of the dark matter. From this, we can predict the cosmic density, the annihilation cross sections, and the cross sections relevant to direct detection. In this paper, we present studies in supersymmetry models with neutralino dark matter that give quantitative estimates of the accuracy that can be expected. We show that these are well matched to the requirements of anticipated astrophysical observations of dark matter. The capabilities of the proposed International Linear Collider (ILC) are expected to play a particularly important role in this study.

hep-ph↗

The Role of the ILC in the Study of Cosmic Dark Matter

Though there is strong evidence that dark matter is a major component of the universe, most aspects of dark matter are completely mysterious. We do not know what dark matter is, and we do not know how it is distributed in our galaxy. To resolve these and related questions, we will need information both from particle physics and from astrophysics. In this article, we will describe a path toward the solution of the problems of dark matter, and we will highlight the important role that the ILC has to play in this study.

hep-ph↗

The Contribution from Neutrino Yukawa Couplings to Lepton Electric Dipole Moments

To explain the observed neutrino masses through the seesaw mechanism, a supersymmetric generalization of the Standard Model should include heavy right-handed neutrino supermultiplets. Then the neutrino Yukawa couplings can induce CP violation in the lepton sector. In this paper, we compute the contribution of these CP violating terms to lepton electric dipole moments. We introduce a new formalism that makes use of supersymmetry to expose the GIM cancellations. In the region of small tan beta, we find a different result from that given previously by Ellis, Hisano, Raidal, and Shimizu. We confirm the structure found by this group, but with a much smaller overall coefficient. In the region of large tan beta, we recompute the leading term that has been identified by Masina and confirm her result.We discuss the implications of these results for constraints on the neutrino Yukawa couplings.

hep-ph↗

Top Quarks and Electroweak Symmetry Breaking in Little Higgs Models

`Little Higgs' models, in which the Higgs particle arises as a pseudo-Goldstone boson, have a natural mechanism of electroweak symmetry breaking associated with the large value of the top quark Yukawa coupling. The mechanism typically involves a new heavy SU(2)_{L} singlet top quark, T. We discuss the relationship of the Higgs boson and the two top quarks. We suggest experimental tests of the Little Higgs mechanism of electroweak symmetry breaking using the production and decay of the T at the Large Hadron Collider.

hep-ph↗

Abstract Applets: a Method for Integrating Numerical Problem-Solving into the Undergraduate Physics Curriculum

In upper-division undergraduate physics courses, it is desirable to give numerical problem-solving exercises integrated naturally into weekly problem sets. I explain a method for doing this that makes use of the built-in class structure of the Java programming language. I also supply a Java class library that can assist instructors in writing programs of this type.

physics.ed-ph↗

Supersymmetry: the Next Spectroscopy

I describe the picture by which supersymmetry--the possible symmetry of Nature that converts fermions to bosons and vice versa--accounts for the next stage of physics beyond the Standard Model. I then survey the future experimental program implied by this theory, in which the spectrum of particles associated with supersymmetry will be determined with precision. [Invited lecture at the Werner Heisenberg Centennial Symposium, December, 2001.]

hep-ph↗

How Can a Heavy Higgs Boson be Consistent with the Precision Electroweak Measurements?

The fit of precision electroweak data to the Minimal Standard Model currently gives an upper limit on the Higgs boson mass of 170 GeV at 95% confidence. Nevertheless, it is often said that the Higgs boson could be much heavier in more general models. In this paper, we critically review models that have been proposed in the literature that allow a heavy Higgs boson consistent with the precision electroweak constraints. All have unusual features, and all can be distinguished from the Minimal Standard Model either by improved precision measurements or by other signatures accessible to next-generation colliders.

hep-ph↗

Selectron Studies at e-e- and e+e- Colliders

Selectrons may be studied in both e-e- and e+e- collisions at future linear colliders. Relative to e+e-, the e-e- mode benefits from negligible backgrounds and βthreshold behavior for identical selectron pair production, but suffers from luminosity degradation and increased initial state radiation and beamstrahlung. We include all of these effects and compare the potential for selectron mass measurements in the two modes. The virtues of the e-e- collider far outweigh its disadvantages. In particular, the selectron mass may be measured to 100 MeV with a total integrated luminosity of 1 fb^-1, while more than 100 fb^-1 is required in e+e- collisions for similar precision.

hep-ph↗

Theoretical Summary Lecture for EPS HEP99

This is the proceedings article for the concluding lecture of the 1999 High Energy Physics Conference of the European Physical Society. In this article, I review a number of topics that were highlighted at the meeting and have more general importance in high energy physics. The major topics discussed include: (1) precision electroweak physics, (2) CP violation, (3) new directions in QCD, (4) supersymmetry spectroscopy, (5) the experimental physics of extra dimensions.

hep-ph↗

TeV Strings and Collider Probes of Large Extra Dimensions

Arkani-Hamed, Dimopoulos, and Dvali have proposed that the fundamental gravitational scale is close to 1 TeV, and that the observed weakness of gravity at long distances is explained by the presence of large extra compact dimensions. If this scenario is realized in a string theory of quantum gravity, the string excited states of Standard Model particles will also have TeV masses. These states will be visible to experiment and in fact provide the first signatures of the presence of a low quantum gravity scale. Their presence also affects the more familiar signatures due to real and virtual graviton emission. We study the effects of these states in a simple string model.

hep-ph↗

Scalar Top Quark as the Next-to-Lightest Supersymmetric Particle

We study phenomenologically the scenario in which the scalar top quark is lighter than any other standard supersymmetric partner and also lighter than the top quark, so that it decays to the gravitino via stop -> W^+ b G. In this case, scalar top quark events would seem to be very difficult to separate from top quark pair production. However, we show that, even at a hadron collider, it is possible to distinguish these two reactions. We show also that the longitudinal polarization of the final $W^+$ gives insight into the scalar top and wino/Higgsino mixing parameters.

hep-ph↗

Event Generators for Linear Collider Physics

I review the array of event generators which have been written to provide simulations of high-energy e+e- reactions. (Session summary talk presented at the 1999 International Workshop on Linear Colliders, Sitges, Barcelona, Spain.)

hep-ph↗

Physics Goals of the Linear Collider

I review the most important objectives of the physics program of a next-generation e+e- linear collider. (Introductory theory lecture presented at the 1999 International Workshop on Linear Colliders, Sitges, Barcelona, Spain.)

hep-ph↗

Collider Signatures of New Large Space Dimensions

Recently, Arkani-Hamed, Dimopoulos, and Dvali have proposed that there are extra compact dimensions of space, accessible to gravity but not to ordinary matter, which could be macroscopically large. In this letter, we argue that high-energy collider processes in which gravitons are radiated into these new dimensions place significant, model-independent constraints on this picture. We present the constraints from anomalous single photon production at e+e- colliders and from monojet production at hadron colliders.

hep-ph↗

Transmission of Supersymmetry Breaking from a 4-Dimensional Boundary

In the strong-coupling limit of the heterotic string theory constructed by Horava and Witten, an 11-dimensional supergravity theory is coupled to matter multiplets confined to 10-dimensional mirror planes. This structure suggests that realistic unification models are obtained, after compactification of 6 dimensions, as theories of 5-dimensional supergravity in an interval, coupling to matter fields on 4-dimensional walls. Supersymmetry breaking may be communicated from one boundary to another by the 5-dimensional fields. In this paper, we study a toy model of this communication in which 5-dimensional super-Yang-Mills theory in the bulk couples to chiral multiplets on the walls. Using the auxiliary fields of the Yang-Mills multiplet, we find a simple algorithm for coupling the bulk and boundary fields. We demonstrate two different mechanisms for generating soft supersymmetry breaking terms in the boundary theory. We also compute the Casimir energy generated by supersymmetry breaking.

hep-th↗

Systematics of Slepton Production in e+e- and e-e- Collisions

I present the basic formulae for slepton production in e+e- and e-e- collisions in an especially simple form, using a helicity basis. This parametrization introduces the useful `neutralino functions' to connect the neutralino eigenstates to observable cross sections. [to appear in the proceedings of the 2nd International Workshop on Electron-Electron Interactions at TeV Energies (e-e-97), Santa Cruz, CA]

hep-ph↗

Beyond the Standard Model

These lectures constitute a short course in `Beyond the Standard Model' for students of experimental particle physics. I discuss the general ideas which guide the construction of models of physics beyond the Standard Model. The central principle, the one which most directly motivates the search for new physics, is the search for the mechanism of the spontaneous symmetry breaking observed in the theory of weak interactions. To illustrate models of weak-interaction symmetry breaking, I give a detailed discussion of the idea of supersymmetry and that of new strong interactions at the TeV energy scale. I discuss experiments that will probe the details of these models at future pp and e+e- colliders. [Lectures presented at the 1996 European School of High-Energy Physics.]

hep-ph↗