3,001 research outputs found

    QCD corrections to stoponium production at hadron colliders

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    If the lighter top squark has no kinematically allowed two-body decays that conserve flavor, then it will live long enough to form hadronic bound states. The observation of the diphoton decays of stoponium could then provide a uniquely precise measurement of the top squark mass. In this paper, we calculate the cross section for the production of stoponium in a hadron collider at next-to-leading order (NLO) in QCD. We present numerical results for the cross section for production of stoponium at the LHC and study the dependence on beam energy, stoponium mass, and the renormalization and factorization scale. The cross-section is substantially increased by the NLO corrections, counteracting a corresponding decrease found earlier in the NLO diphoton branching ratio.Comment: 24 page

    Super No-Scale F-SU(5): A Dynamic Determination of M_{1/2} and tan beta

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    We study the Higgs potential in No-Scale F-SU(5), a model built on the tripodal foundations of the Flipped SU(5) x U(1)_X Grand Unified Theory, extra F-theory derived TeV scale vector-like particle multiplets, and the high scale boundary conditions of No-Scale Supergravity. V_min, the minimum of the potential following radiative electroweak symmetry breaking, is a function at fixed Z-Boson mass of the universal gaugino boundary mass M_{1/2} and tan{\beta}, the ratio of Higgs vacuum expectation values. The No-Scale nullification of the bilinear Higgs soft term B_mu at the boundary reduces V_min(M_{1/2}) to a one dimensional dependency, which may be secondarily minimized. This "Super No-Scale" condition dynamically fixes tan beta and M_{1/2} at the local minimum minimorum of V_min. Fantastically, the walls of this theoretically established secondary potential coalesce in descent to a striking concurrency with the previously phenomenologically favored "golden point" and "golden strip".Comment: V2, As accepted to Physics Letters B; 8 Pages, 2 Plots, 1 Tabl

    A Higgs Mass Shift to 125 GeV and A Multi-Jet Supersymmetry Signal: Miracle of the Flippons at the \sqrt{s} = 7 TeV LHC

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    We describe a model named No-Scale F-SU(5) which is simultaneously capable of explaining the dual signals emerging at the LHC of i) a 124-126 GeV Higgs boson mass m_h, and ii) tantalizing low-statistics excesses in the multi-jet data which may attributable to supersymmetry. These targets tend to be mutually exclusive in more conventional approaches. The unified mechanism responsible for both effects is the introduction of a rather unique set of vector-like multiplets at the TeV scale, dubbed flippons, which i) can elevate m_h by around 3-4 GeV via radiative loop corrections, and ii) flatten the running of the strong coupling and color-charged gaugino, resulting in a prominent collider signal from production of light gluino pairs. This well motivated theoretical framework maintains consistency with all key phenomenological constraints, and all residual parameterization freedom may in principle be fixed by a combination of the two experiments described. We project that the already collected luminosity of 5 fb^-1 may be sufficient to definitively establish the status of this model, given appropriate data selection cuts.Comment: Physics Letters B version, 10 pages, 3 figures, 2 tables. arXiv admin note: text overlap with arXiv:1105.398

    Testing No-Scale F-SU(5): A 125 GeV Higgs Boson and SUSY at the 8 TeV LHC

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    We celebrate the recent Higgs discovery announcement with our experimental colleagues at the LHC and look forward to the implications that this success will bring to bear upon the continuing search for supersymmetry (SUSY). The model framework named No-Scale F-SU(5) possesses the rather unique capacity to provide a light CP-even Higgs boson mass in the favored 124-126 GeV window while simultaneously retaining a testably light SUSY spectrum that is consistent with emerging low-statistics excesses beyond the Standard Model expectation in the ATLAS and CMS multijet data. In this letter we review the distinctive F-SU(5) mechanism that forges the physical 125 GeV Higgs boson and make a specific assessment of the ATLAS multijet SUSY search observables that may be expected for a 15/fb delivery of 8 TeV data in this model context. Based on our Monte Carlo study, we anticipate that the enticing hints of a SUSY signal observed in the 7 TeV data could be amplified in the 8 TeV results. Moreover, if the existing signal is indeed legitimate, we project that the rendered gains in significance will be sufficient to conclusively rule out an alternative attribution to statistical fluctuation at that juncture.Comment: Physics Letters B Version, 7 Pages, 1 Figur

    Natural Predictions for the Higgs Boson Mass and Supersymmetric Contributions to Rare Processes

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    In the context of No-Scale F-SU(5), a model defined by the convergence of the F-lipped SU(5) Grand Unified Theory, two pairs of hypothetical TeV scale vector-like supersymmetric multiplets with origins in F-theory, and the dynamically established boundary conditions of No-Scale Supergravity, we predict that the lightest CP-even Higgs boson mass lies within the range of 119.0 GeV to 123.5 GeV, exclusive of the vector-like particle contribution to the mass. With reports by the CMS, ATLAS, CDF, and D0 Collaborations detailing enticing statistical excesses in the vicinity of 120 GeV in searches for the Standard Model Higgs boson, all signs point to an imminent discovery. While basic supersymmetric constructions such as mSUGRA and the CMSSM have already suffered overwhelming reductions in viable parameterization during the LHC's initial year of operation, about 80% of the original No-Scale F-SU(5) model space remains viable after analysis of the first 1.1 fb^{-1} of integrated luminosity. This model is moreover capable of handily explaining the small excesses recently reported in the CMS multijet supersymmetry search, and also features a highly favorable "golden" subspace which may simultaneously account for the key rare process limits on the muon anomalous magnetic moment (g - 2) and the branching ratio of the flavor-changing neutral current decay b to s\gamma. In addition, the isolated mass parameter responsible for the global particle mass normalization, the gaugino boundary mass M_{1/2}, is dynamically determined at a secondary local minimization of the minimum of the Higgs potential V_{min}, in a manner which is deeply consistent with all precision measurements at the physical electroweak scale.Comment: Physics Letters B Version, 10 pages, 2 figures, 2 table

    The Ursinus Weekly, October 13, 1905

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    School of Theology • Football • Oyster supper • Society notes • College notes • Alumni • Ursinus Union • College world • Camp reunion • Literary Supplement: A plea for the children; Cut from life; Ludwig van Beethoven; Youth\u27s passion; A distinctive American literature; Experience of a View Agent; Carpe diem; Integrity in political life • Exchangeshttps://digitalcommons.ursinus.edu/weekly/2952/thumbnail.jp

    Higgs Bosons Strongly Coupled to the Top Quark

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    Several extensions of the Standard Model require the burden of electroweak symmetry breaking to be shared by multiple states or sectors. This leads to the possibility of the top quark interacting with a scalar more strongly than it does with the Standard Model Higgs boson. In top-quark condensation this possibility is natural. We also discuss how this might be realized in supersymmetric theories. The properties of a strongly coupled Higgs boson in top-quark condensation and supersymmetry are described. We comment on the difficulties of seeing such a state at the Tevatron and LEPII, and study the dramatic signatures it could produce at the LHC. The four top quark signature is especially useful in the search for a strongly coupled Higgs boson. We also calculate the rates of the more conventional Higgs boson signatures at the LHC, including the two photon and four lepton signals, and compare them to expectations in the Standard Model.Comment: 18 pages, latex, 9 figure

    Do Deep Inelastic Scattering Data Favor a Light Gluino

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    A next--to--leading order QCD analysis of deep inelastic scattering data is performed allowing for contributions due to a light gluino. We obtain the values of αs(MZ2)±δαsstat=0.108±0.002,0.124±0.001,0.145±0.009\alpha_s(M_Z^2) \pm \delta \alpha_s^{stat} = 0.108 \pm 0.002, 0.124 \pm 0.001, 0.145 \pm 0.009 for QCD, SUSY QCD with a Majorana gluino and a Dirac gluino respectively. The value of \alsm obtained in SUSY QCD with a Majorana gluino best agrees with the direct measurements of αs(MZ2)\alpha_s(M_Z^2) at LEP.Comment: 8 pages with 7 pages of figures, DESY 94-00

    Understanding the Astrophysics of Galaxy Evolution: the role of spectroscopic surveys in the next decade

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    Over the last decade optical spectroscopic surveys have characterized the low redshift galaxy population and uncovered populations of star-forming galaxies back to z ~ 7. This work has shown that the primary epoch of galaxy building and black hole growth occurs at redshifts of 2 to 3. The establishment of the concordance LCDM cosmology shifted the focus of galaxy population studies from constraining cosmological parameters to characterizing the processes which regulate the formation and evolution of galaxies.In the next decade, high redshift observers will attempt to formulate a coherent evolutionary picture connecting galaxies in the high redshift Universe to galaxies today. In order to link galaxy populations at different redshifts, we must not only characterize their evolution in a systematic way, we must establish which physical processes are responsible for it. Considerable progress has already been made in understanding how galaxies evolved from z ~ 1 to the present day. Large spectroscopic surveys in the near infrared are required to push these studies back towards the main epoch of galaxy building. Only then will we understand the full story of the formation of L* galaxies like our own Milky Way. A large near-IR spectroscopic survey will also provide the calibration needed to avoid systematics in the large photometric programs proposed to study the nature of dark matter and dark energy. We provide an outline design for a multi-object 0.4 to 1.8 micron spectrograph, which could be placed on an existing telescope, and which would allow a full characterization of the galaxy population out to z ~ 2. We strongly recommend a serious further study to design a real instrument, which will be required for galaxy formation studies to advance to the next frontier.Comment: White paper, primary author J.E. Gunn, submitted to Astro2010 Decadal Survey, see http://www7.nationalacademies.org/bpa/Astro2010_SWP_byTitle.htm
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