Sneutrino Mass Measurements at e+e- Linear Colliders

It is generally accepted that experiments at an e+e- linear colliders will be able to extract the masses of the selectron as well as the associated sneutrinos with a precision of ~ 1% by determining the kinematic end points of the energy spectrum of daughter electrons produced in their two body decays to a lighter neutralino or chargino. Recently, it has been suggested that by studying the energy dependence of the cross section near the production threshold, this precision can be improved by an order of magnitude, assuming an integrated luminosity of 100 fb^-1. It is further suggested that these threshold scans also allow the masses of even the heavier second and third generation sleptons and sneutrinos to be determined to better than 0.5%. We re-examine the prospects for determining sneutrino masses. We find that the cross sections for the second and third generation sneutrinos are too small for a threshold scan to be useful. An additional complication arises because the cross section for sneutrino pair to decay into any visible final state(s) necessarily depends on an unknown branching fraction, so that the overall normalization in unknown. This reduces the precision with which the sneutrino mass can be extracted. We propose a different strategy to optimize the extraction of m(\tilde{\nu}_\mu) and m(\tilde{\nu}_\tau) via the energy dependence of the cross section. We find that even with an integrated luminosity of 500 fb^-1, these can be determined with a precision no better than several percent at the 90% CL. We also examine the measurement of m(\tilde{\nu}_e) and show that it can be extracted with a precision of about 0.5% (0.2%) with an integrated luminosity of 120 fb^-1 (500 fb^-1).Comment: RevTex, 46 pages, 15 eps figure

Photon deflection by a Coulomb field in noncommutative QED

In noncommutative QED photons present self-interactions in the form of triple and quartic interactions. The triple interaction implies that, even though the photon is electrically neutral, it will deflect when in the presence of an electromagnetic field. If detected, such deflection would be an undoubted signal of noncommutative space-time. In this work we derive the general expression for the deflection of a photon by any electromagnetic field. As an application we consider the case of the deflection of a photon by an external static Coulomb field.Comment: 07 pages, some typos corrected, accepted for publication in JP

Lepton Flavor Violation at the LHC

Recent results from Super Kamiokande suggest $\nu_\mu-\nu_\tau$ mixing and hence lepton flavor violation. In supersymmetric models, this flavor violation may have implications for the pattern of slepton masses and mixings. Possible signals for this mixing in the decays of sleptons produced at the LHC are discussed. The sensitivity expected is compared to that of rare decays such as $\tau\to \mu\gamma$.Comment: 14 pages, 9 figure

Threshold resummation for high-transverse-momentum Higgs production at the LHC

We study the resummation of large logarithmic QCD corrections for the process pp ->H+ X when the Higgs boson H is produced at high transverse momentum. The corrections arise near the threshold for partonic reaction and originate from soft gluon emission. We perform the all-order resummation at next-to-leading logarithmic accuracy and match the resummed result with the next-to-leading order perturbative predictions. The effect of resummation on the Higgs transverse momentum distribution at the LHC is discussed.Comment: 19 pages, 3 figure

Publishing Our Own Work: Contributing to the Professional Literature Through Systematizing Sharing of Library Reports

Library employees often work on teams, committees, or task forces to do research, and investigation as part of their responsibilities in carrying out the operations of a library; however, much of this work is not published in the professional literature and is only inconsistently recorded in committee documents. As such, this work is hidden both from others in the library who might use it and from the profession at large, meaning that other libraries were not able to benefit from it. To address these challenges, the University of Illinois Library (Urbana‐Champaign) established the Library Occasional Reports Series (LibORS) in 2015. This paper presents a case study of the ongoing process of establishing LibORS. Phases of work included exploring what it would mean to commit to publishing and promoting the University Library’s work as an organizational practice as well as creating workflows, acquisition criteria, editorial guidelines, a report template, and communication mechanisms

Recent Developments in Precision Electroweak Physics

Developments in precision electroweak physics in the two years since the symposium are briefly summarized.Comment: Update on recent developments, prepared for the publication of the Proceedings of Alberto Sirlin Symposium, New York University, October 2000. 10 pages, 1 figur

Field Theory in Noncommutative Minkowski Superspace

There is much discussion of scenarios where the space-time coordinates x^\mu are noncommutative. The discussion has been extended to include nontrivial anticommutation relations among spinor coordinates in superspace. A number of authors have studied field theoretical consequences of the deformation of N=1 superspace arising from nonanticommutativity of coordinates \theta, while leaving \bar{theta}'s anticommuting. This is possible in Euclidean superspace only. In this note we present a way to extend the discussion by making both \theta and \bar{theta} coordinates non-anticommuting in Minkowski superspace. We present a consistent algebra for the supercoordinates, find a star-product, and give the Wess-Zumino Lagrangian L_{WZ} within our model. It has two extra terms due to non(anti)commutativity. The Lagrangian in Minkowski superspace is always manifestly Hermitian and for L_{WZ} it preserves Lorentz invariance.Comment: 8 pages, added references, two-column format, published in PR

Signals of Supersymmetric Lepton Flavor Violation at the LHC

In a generic supersymmetric extension of the Standard Model, there will be lepton flavor violation at a neutral gaugino vertex due to misalignment between the lepton Yukawa couplings and the slepton soft masses. Sleptons produced at the LHC through the cascade decays of squarks and gluinos can give a sizable number of events with 4 leptons. This channel could give a clean signature of supersymmetric lepton flavor violation under conditions which are identified.Comment: 21 page

Comments on Non-Commutative Phenomenology

It is natural to ask whether non-commutative geometry plays a role in four dimensional physics. By performing explicit computations in various toy models, we show that quantum effects lead to violations of Lorentz invariance at the level of operators of dimension three or four. The resulting constraints are very stringent.Comment: Correction of an error in the U(1) and U(N) calculation leads to stronger limits than those given previously Clarifying comments and reference adde