Heavy Thresholds, Slepton Masses and the μ\mu Term in Anomaly Mediated Supersymmetry Breaking

The effects of heavy mass thresholds on anomaly-mediated soft supersymmetry breaking terms are discussed. While heavy thresholds completely decouple to lowest order in the supersymmetry breaking, it is argued that they do affect the breaking terms at higher orders. The relevant contributions typically occur at lower order in the loop expansion compared to purely anomaly mediated contributions. The non decoupling contributions may be used to render models in which the only source of supersymmetry breaking is anomaly mediation viable, by generating positive contributions to the sleptons' masses squared. They can also be used to generate acceptable mu- and B-terms.Comment: 25 pages, late

LHC Benchmarks from Flavored Gauge Mediation

We present benchmark points for LHC searches from flavored gauge mediation models, in which messenger-matter couplings give flavor-dependent squark masses. Our examples include spectra in which a single squark - stop, scharm, or sup - is much lighter than all other colored superpartners, motivating improved quark flavor tagging at the LHC. Many examples feature flavor mixing; in particular, large stop-scharm mixing is possible. The correct Higgs mass is obtained in some examples by virtue of the large stop A-term. We also revisit the general flavor and CP structure of the models. Even though the A-terms can be substantial, their contributions to EDM's are very suppressed, because of the particular dependence of the A-terms on the messenger coupling. This holds regardless of the messenger-coupling texture. More generally, the special structure of the soft terms often leads to stronger suppression of flavor- and CP-violating processes, compared to naive estimates.Comment: 32 pages, 11 figures. Updated to published versio

Standard model and supersymmetric flavor puzzles at the CERN large hadron collider

Can the Large Hadron Collider explain the masses and mixings of the known fermions? A promising possibility is that these masses and mixings are determined by flavor symmetries that also govern new particles that will appear at the LHC. We consider well-motivated examples in supersymmetry with both gravity- and gauge-mediation. Contrary to spreading belief, new physics need not be minimally flavor violating. We build non-minimally flavor violating models that successfully explain all known lepton masses and mixings, but span a wide range in their predictions for slepton flavor violation. In natural and favorable cases, these models have metastable sleptons and are characterized by fully reconstructible events. We outline many flavor measurements that are then possible and describe their prospects for resolving both the standard model and new physics flavor puzzles at the Large Hadron Collider

TRIPLE-PRODUCT SPIN-MOMENTUM CORRELATIONS IN POLARIZED Z DECAYS TO THREE JETS.

We discuss hard rescattering effects that can be measured using CP-even, T$_{\rm N}$-odd triple-product observables in polarized $Z$ decays to three jets. We show that the standard model contributions, from both QCD and electroweak rescattering, are very small. Thus these measurements are potentially sensitive to physics beyond the standard model. We investigate one such contribution which involves a new gauge boson coupling to baryon number.Comment: 4 pages, LaTeX file. One figure not included available upon request from [email protected]. Text with encapsulated figures also available in postscript form by anonymous ftp from ftp://preprint.slac.stanford.edu/preprints/hep-ph/9503 . Talk given at the 4th International Conference on Physics Beyond the Standard Model, Lake Tahoe, CA, December 94, by Y. S

Theoretical Expectations for the Muon's Electric Dipole Moment

We examine the muon's electric dipole moment \dmu from a variety of theoretical perspectives. We point out that the reported deviation in the muon's g-2 can be due partially or even entirely to a new physics contribution to the muon's {\em electric} dipole moment. In fact, the recent g-2 measurement provides the most stringent bound on \dmu to date. This ambiguity could be definitively resolved by the dedicated search for \dmu recently proposed. We then consider both model-independent and supersymmetric frameworks. Under the assumptions of scalar degeneracy, proportionality, and flavor conservation, the theoretical expectations for \dmu in supersymmetry fall just below the proposed sensitivity. However, non-degeneracy can give an order of magnitude enhancement, and lepton flavor violation can lead to \dmu of order $10^{-22}$ e cm, two orders of magnitude above the sensitivity of the \dmu experiment. We present compact expressions for leptonic dipole moments and lepton flavor violating amplitudes. We also derive new limits on the amount of flavor violation allowed and demonstrate that approximations previously used to obtain such limits are highly inaccurate in much of parameter space

Visible Effects of the Hidden Sector

The renormalization of operators responsible for soft supersymmetry breaking is usually calculated by starting at some high scale and including only visible sector interactions in the evolution equations, while ignoring hidden sector interactions. Here we explain why this is correct only for the most trivial structures in the hidden sector, and discuss possible implications. This investigation was prompted by the idea of conformal sequestering. In that framework hidden sector renormalizations by nearly conformal dynamics are critical. In the original models of conformal sequestering it was necessary to impose hidden sector flavor symmetries to achieve the sequestered form. We present models which can evade this requirement and lead to no-scale or anomaly mediated boundary conditions; but the necessary structures do not seem generic. More generally, the ratios of scalar masses to gaugino masses, the $\mu$-term, the $B\mu$-term, $A$-terms, and the gravitino mass can be significantly affected.Comment: 23 pages, no figure

Metastable Rank-Condition Supersymmetry Breaking in a Chiral Example

We discuss generalizations of Intriligator-Seiberg-Shih (ISS) vacua to chiral models. We study one example, of an s-confining theory, in detail. In the IR, this example reduces to two ISS-like sectors, and exhibits a supersymmetry-breaking vacuum with all pseudo-moduli stabilized at the origin, and with the R-symmetry unbroken. The IR theory is interesting from the point of view of R-symmetry breaking. This theory is an O'Raifeartaigh model with all charges zero or two, but the presence of a second R-charged pseudo-modulus with superpotential couplings to the messengers in principle allows for R-symmetry breaking.Comment: 9 page

Light GUT Triplets and Yukawa Splitting

Triplet-mediated proton decay in Grand Unified Theories (GUTs) is usually suppressed by arranging a large triplet mass. Here we explore instead a mechanism for suppressing the couplings of the triplets to the first and second generations compared to the Yukawa couplings, so that the triplets' mass can be below the GUT scale. This mechanism is based on a ``triplet symmetry'' in the context of product-group GUTs. We study two possibilities. One, which requires the top Yukawa to arise from a non-renormalizable operator at the GUT scale, is that all triplet couplings to matter are negligible, so that the triplets can be at the weak scale. The second is that some triplet couplings, and in particular $T t b$ and $T \bar{t} \bar{l}$, are equal to the corresponding Yukawa couplings. This would give a distinct signature of grand unification if the triplets were sufficiently light. However, we derive a model-independent bound on the triplet mass in this case, which is at least 10$^6$GeV. Finally, we construct a GUT model based on Yukawa splitting, with the triplets at 10$^{14}$GeV, as required for coupling unification to work.Comment: 5 pages, Revtex4, 1 EPS figure. To appear in PRD: Minor changes. Appendix droppe

Neutrino Parameters, Abelian Flavor Symmetries, and Charged Lepton Flavor Violation

Neutrino masses and mixings have important implications for models of fermion masses, and, most directly, for the charged lepton sector. We consider supersymmetric Abelian flavor models, where neutrino mass parameters are related to those of charged leptons and sleptons. We show that processes such as \tau to \mu\gamma, \mu to e\gamma and \mu-e conversion provide interesting probes. In particular, some existing models are excluded by current bounds, while many others predict rates within reach of proposed near future experiments. We also construct models in which the predicted rates for charged lepton flavor violation are below even the proposed experimental sensitivities, but argue that such models necessarily involve loss of predictive power.Comment: 27 pages, refs added, published versio