Top Partners at the LHC: Spin and Mass Measurement

If one takes naturalness seriously and also assumes a weakly coupled extension of the Standard Model (SM) then there are predictions for phenomenology that can be inferred in a model independent framework. The first such prediction is that there must be some colored particle with mass O(TeV) that cancels the top loop contribution to the quadratic divergence of the Higgs mass. In this paper we begin a model independent analysis of the phenomenology of this "top partner," t'. We make one additional assumption that it is odd under a parity which is responsible for the stability of a WIMP dark matter candidate, N. We focus on three questions to be explored at the LHC: discovery opportunities, mass determination, and spin determination of this top partner. We find that within a certain region of masses for the t' and N, t'\bar{t'} is easily discovered in the t\bar{t}+2N decay with the tops decaying fully hadronically. We show that without having to rely on other channels for new physics that for a a given t' spin the masses of t' and N can be measured using kinematic information (e.g. average MET or H_T) and total cross section. A degeneracy due to the spin remains, but with several hundred inverse fb of luminosity we demonstrate potentially useful new methods for determining the t' spin over a wide range of masses. Our methods could be useful for distinguishing supersymmetric and non-supersymmetric models.Comment: 28 pages, 5 figure

Odd Tracks at Hadron Colliders

New physics that exhibits irregular tracks such as kinks, intermittent hits or decay in flight may easily be missed at hadron colliders. We demonstrate this by studying viable models of light, O(10 GeV), colored particles that decay predominantly inside the tracker. Such particles can be produced at staggering rates, and yet may not be identified or even triggered on at the LHC, unless specifically searched for. In addition, the models we study provide an explanation for the original measurement of the anomalous charged track distribution by CDF. The presence of irregular tracks in these models reconcile that measurement with the subsequent reanalysis and the null results of ATLAS and CMS. Our study clearly illustrates the need for a comprehensive study of irregular tracks at the LHC.Comment: 6 pages, 1 figur

Charginos Hiding In Plain Sight

Recent 7 TeV 5/fb measurements by ATLAS and CMS have measured both overall and differential WW cross sections that differ from NLO SM predictions. While these measurements aren't statistically significant enough to rule out the SM, we demonstrate that the data from both experiments can be better fit with the inclusion of electroweak gauginos with masses of O(100) GeV. We show that these new states are consistent with other experimental searches/measurements and can have ramifications for Higgs phenomenology. Additionally, we show how the first measurements of the WW cross section at 8 TeV by CMS strengthen our conclusions.Comment: 7 pages, 3 figures v2:significant updates incorporating summer experimental results, conclusions strengthene

General Gauge Mediation

We give a general definition of gauge mediated supersymmetry breaking which encompasses all the known gauge mediation models. In particular, it includes both models with messengers as well as direct mediation models. A formalism for computing the soft terms in the generic model is presented. Such a formalism is necessary in strongly-coupled direct mediation models where perturbation theory cannot be used. It allows us to identify features of the entire class of gauge mediation models and to distinguish them from specific signatures of various subclasses.Comment: 19 pages, 1 figure, minor change