The Reach of the Fermilab Tevatron and CERN LHC for Gaugino Mediated SUSY Breaking Models

In supersymmetric models with gaugino mediated SUSY breaking (inoMSB), it is assumed that SUSY breaking on a hidden brane is communicated to the visible brane via gauge superfields which propagate in the bulk. This leads to GUT models where the common gaugino mass $m_{1/2}$ is the only soft SUSY breaking term to receive contributions at tree level. To obtain a viable phenomenology, it is assumed that the gaugino mass is induced at some scale $M_c$ beyond the GUT scale, and that additional renormalization group running takes place between $M_c$ and $M_{GUT}$ as in a SUSY GUT. We assume an SU(5) SUSY GUT above the GUT scale, and compute the SUSY particle spectrum expected in models with inoMSB. We use the Monte Carlo program ISAJET to simulate signals within the inoMSB model, and compute the SUSY reach including cuts and triggers approriate to Fermilab Tevatron and CERN LHC experiments. We find no reach for SUSY by the Tevatron collider in the trilepton channel. %either with or without %identified tau leptons. At the CERN LHC, values of $m_{1/2}=1000$ (1160) GeV can be probed with 10 (100) fb$^{-1}$ of integrated luminosity, corresponding to a reach in terms of $m_{\tg}$ of 2150 (2500) GeV. The inoMSB model and mSUGRA can likely only be differentiated at a linear $e^+e^-$ collider with sufficient energy to produce sleptons and charginos.Comment: 17 page revtex file with 9 PS figure

Probing Slepton Mass Non-Universality at e^+e^- Linear Colliders

There are many models with non-universal soft SUSY breaking sfermion mass parameters at the grand unification scale. Even in the mSUGRA model scalar mass unification might occur at a scale closer to M_Planck, and renormalization effects would cause a mass splitting at M_GUT. We identify an experimentally measurable quantity Delta that correlates strongly with delta m^2 = m^2_{selectron_R}(M_GUT) - m^2_{selectron_L}(M_GUT), and which can be measured at electron-positron colliders provided both selectrons and the chargino are kinematically accessible. We show that if these sparticle masses can be measured with a precision of 1% at a 500 GeV linear collider, the resulting precision in the determination of Delta may allow experiments to distinguish between scalar mass unification at the GUT scale from the corresponding unification at Q ~ M_Planck. Experimental determination of Delta would also provide a distinction between the mSUGRA model and the recently proposed gaugino-mediation model. Moreover, a measurement of Delta (or a related quantity Delta') would allow for a direct determination of delta m^2.Comment: 15 pages, RevTeX, 4 postscript figure

Hidden SUSY at the LHC: the light higgsino-world scenario and the role of a lepton collider

While the SUSY flavor, CP and gravitino problems seem to favor a very heavy spectrum of matter scalars, fine-tuning in the electroweak sector prefers low values of superpotential mass \mu. In the limit of low \mu, the two lightest neutralinos and light chargino are higgsino-like. The light charginos and neutralinos may have large production cross sections at LHC, but since they are nearly mass degenerate, there is only small energy release in three-body sparticle decays. Possible dilepton and trilepton signatures are difficult to observe after mild cuts due to the very soft p_T spectrum of the final state isolated leptons. Thus, the higgsino-world scenario can easily elude standard SUSY searches at the LHC. It should motivate experimental searches to focus on dimuon and trimuon production at the very lowest p_T(\mu) values possible. If the neutralino relic abundance is enhanced via non-standard cosmological dark matter production, then there exist excellent prospects for direct or indirect detection of higgsino-like WIMPs. While the higgsino-world scenario may easily hide from LHC SUSY searches, a linear e^+e^- collider or a muon collider operating in the \sqrt{s}\sim 0.5-1 TeV range would be able to easily access the chargino and neutralino pair production reactions.Comment: 20 pages including 12 .eps figure

Impact of Muon Anomalous Magnetic Moment on Supersymmetric Models

The recent measurement of a_\mu =\frac{g_\mu -2}{2} by the E821 Collaboration at Brookhaven deviates from the quoted Standard Model (SM) central value prediction by 2.6\sigma. The difference between SM theory and experiment may be easily accounted for in a variety of particle physics models employing weak scale supersymmetry (SUSY). Other supersymmetric models are distinctly disfavored. We evaluate a_\mu for various supersymmetric models, including minimal supergravity (mSUGRA), Yukawa unified SO(10) SUSY GUTs, models with inverted mass hierarchies (IMH), models with non-universal gaugino masses, gauge mediated SUSY breaking models (GMSB), anomaly-mediated SUSY breaking models (AMSB) and models with gaugino mediated SUSY breaking (inoMSB). Models with Yukawa coupling unification or multi-TeV first and second generation scalars are disfavored by the a_\mu measurement.Comment: 25 page REVTEX file with 10 PS figures. Minor rewording, typos corrected, references adde

Target dark matter detection rates in models with a well-tempered neutralino

In the post-LEP2 era, and in light of recent measurements of the cosmic abundance of cold dark matter (CDM) in the universe from WMAP, many supersymmetric models tend to predict 1. an overabundance of CDM and 2. pessimistically low rates for direct detection of neutralino dark matter. However, in models with a ``well-tempered neutralino'', where the neutralino composition is adjusted to give the measured abundance of CDM, the neutralino is typically of the mixed bino-wino or mixed bino-higgsino state. Along with the necessary enhancement to neutralino annihilation rates, these models tend to give elevated direct detection scattering rates compared to predictions from SUSY models with universal soft breaking terms. We present neutralino direct detection cross sections from a variety of models containing a well-tempered neutralino, and find cross section asymptotes with detectable scattering rates. These asymptotic rates provide targets that various direct CDM detection experiments should aim for. In contrast, in models where the neutralino mass rather than its composition is varied to give the WMAP relic density via either resonance annihilation or co-annihilation, the neutralino remains essentially bino-like, and direct detection rates may be below the projected reaches of all proposed experiments.Comment: 13 pages including 1 EPS figur

YAC contigs of the Rab1 and wobbler (wr) spinal muscular atrophy gene region on proximal mouse chromosome 11 and of the homologous region on human chromosome 2p

powerful tool to advance the identi®cation of gene com-Despite rapid progress in the physical characteriza- plexes and of disease genes. In this respect, the analysis tion of murine and human genomes, little molecular in- of human chromosomes 16 and 19 (Nowak, 1995) and formation is available on certain regions, e.g., proximal mouse chromosomes 1 (Hunter et al., 1994) and 17 (Cox mouse chromosome 11 (Chr 11) and human chromosome et al., 1993) as well as of human and murine X chromo-2p (Chr 2p). We have localized the wobbler spinal atrophy somes is particularly far advanced (Hamvas et al., 1993). gene wr to proximal mouse Chr 11, tightly linked toRab1, On the other hand, such extensive information is not a gene coding for a small GTP-binding protein, and Glns- available for mouse proximal chromosome 11 (Chr 11) ps1, an intronless pseudogene of the glutamine synthe- and human chromosome 2p (Chr 2p) (Fig. 1; cf. Berry et tase gene. We have now used these markers to construct al., 1995; Nowak, 1995), known to share at least the genesa 1.3-Mb yeast arti®cial chromosome (YAC) contig of the for the reticuloendotheliosis oncogene (Brownell et al.,Rab1 region on mouse Chr 11. Four YAC clones isolated 1985), for a brain-speci®cb-spectrin isoform (Bloom et al.,from two independent YAC libraries were characterized 1992), and for cytoplasmic malate dehydrogenase (Ball etby rare-cutting analysis, ¯uorescence in situ hybridiza-al., 1994). However, comparing the segregation map oftion (FISH), and sequence-tagged site (STS) isolation and the mouse with the human cytogenetic map, a colinearmapping. Rab1 and Glns-ps1 were found to be only 20

Probing Neutralino Resonance Annihilation via Indirect Detection of Dark Matter

The lightest neutralino of R-parity conserving supersymmetric models serves as a compelling candidate to account for the presence of cold dark matter in the universe. In the minimal supergravity (mSUGRA) model, a relic density can be found in accord with recent WMAP data for large values of the parameter $\tan\beta$, where neutralino annihilation in the early universe occurs via the broad s-channel resonance of the pseudoscalar Higgs boson $A$. We map out rates for indirect detection of neutralinos via 1. detection of neutrinos arising from neutralino annihilation in the core of the earth or sun and 2. detection of gamma rays, antiprotons and positrons arising from neutralino annihilation in the galactic halo. If indeed $A$-resonance annihilation is the main sink for neutralinos in the early universe, then signals may occur in the gamma ray, antiproton and positron channels, while a signal in the neutrino channel would likely be absent. This is in contrast to the hyperbolic branch/focus point (HB/FP) region where {\it all} indirect detection signals are likely to occur, and also in contrast to the stau co-annihilation region, where {\it none} of the indirect signals are likely to occur.Comment: 12 pages including 4 eps figure

Higgs-mediated leptonic decays of B_s and B_d mesons as probes of supersymmetry

If tan(beta) is large, down-type quark mass matrices and Yukawa couplings cannot be simultaneously diagonalized, and flavour violating couplings of the neutral Higgs bosons are induced at the 1-loop level. These couplings lead to Higgs-mediated contributions to the decays B_s -> mu+ mu- and B_d -> tau+ tau-, at a level that might be of interest for the current Tevatron run, or possibly, at B-factories. We evaluate the branching ratios for these decays within the framework of minimal gravity-, gauge- and anomaly-mediated SUSY breaking models, and also in SU(5) supergravity models with non-universal gaugino mass parameters at the GUT scale. We find that the contribution from gluino loops, which seems to have been left out in recent phenomenological analyses, is significant. We explore how the branching fraction varies in these models, emphasizing parameter regions consistent with other observations.Comment: Revised to accommodate minor changes in original text and update reference

Mixed Bino-Wino-Higgsino Dark Matter in Gauge Messenger Models

Almost degenerate bino and wino masses at the weak scale is one of unique features of gauge messenger models. The lightest neutralino is a mixture of bino, wino and higgsino and can produce the correct amount of the dark matter density if it is the lightest supersymmetric particle. Furthermore, as a result of squeezed spectrum of superpartners which is typical for gauge messenger models, various co-annihilation and resonance regions overlap and very often the correct amount of the neutralino relic density is generated as an interplay of several processes. This feature makes the explanation of the observed amount of the dark matter density much less sensitive to fundamental parameters. We calculate the neutralino relic density assuming thermal history and present both spin independent and spin dependent cross sections for the direct detection. We also discuss phenomenological constraints from b to s gamma and muon g-2 and compare results of gauge messenger models to well known results of the mSUGRA scenario.Comment: 27 pages, 9 figures, references added, version to appear at JCA

Gaugino Anomaly Mediated SUSY Breaking: phenomenology and prospects for the LHC

We examine the supersymmetry phenomenology of a novel scenario of supersymmetry (SUSY) breaking which we call Gaugino Anomaly Mediation, or inoAMSB. This is suggested by recent work on the phenomenology of flux compactified type IIB string theory. The essential features of this scenario are that the gaugino masses are of the anomaly-mediated SUSY breaking (AMSB) form, while scalar and trilinear soft SUSY breaking terms are highly suppressed. Renormalization group effects yield an allowable sparticle mass spectrum, while at the same time avoiding charged LSPs; the latter are common in models with negligible soft scalar masses, such as no-scale or gaugino mediation models. Since scalar and trilinear soft terms are highly suppressed, the SUSY induced flavor and CP-violating processes are also suppressed. The lightest SUSY particle is the neutral wino, while the heaviest is the gluino. In this model, there should be a strong multi-jet +etmiss signal from squark pair production at the LHC. We find a 100 fb^{-1} reach of LHC out to m_{3/2}\sim 118 TeV, corresponding to a gluino mass of \sim 2.6 TeV. A double mass edge from the opposite-sign/same flavor dilepton invariant mass distribution should be visible at LHC; this, along with the presence of short-- but visible-- highly ionizing tracks from quasi-stable charginos, should provide a smoking gun signature for inoAMSB.Comment: 30 pages including 14 .eps figure