46 research outputs found

    Fast CP Violation

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    BB flavor tagging will be extensively studied at the asymmetric BB factories due to its importance in CP asymmetry measurements. The primary tagging modes are the semileptonic decays of the bb (lepton tag), or the hadronic bc(s)b \to c (\to s) decays (kaon tag). We suggest that looking for time dependent CP asymmetries in events where one BB is tagged leptonically and the other one is tagged with a kaon could result in an early detection of CP violation. Although in the Standard Model these asymmetries are expected to be small, 1\sim 1%, they could be measured with about the same amount of data as in the ``gold-plated'' decay BdψKSB_d \to \psi K_S. In the presence of physics beyond the Standard Model, these asymmetries could be as large as 5\sim 5%, and the first CP violation signal in the BB system may show up in these events. We give explicit examples of new physics scenarios where this occurs.Comment: 9 pages, revtex, no figures. Discussion of new physics effects on CP violation with two lepton tags expanded. Factors of 2 correcte

    The MSSM Electroweak Phase Transition on the Lattice

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    We study the MSSM finite temperature electroweak phase transition with lattice Monte Carlo simulations, for a large Higgs mass (m_H ~ 95 GeV) and light stop masses (m_tR ~ 150...160 GeV). We employ a 3d effective field theory approach, where the degrees of freedom appearing in the action are the SU(2) and SU(3) gauge fields, the weakly interacting Higgs doublet, and the strongly interacting stop triplet. We determine the phase diagram, the critical temperatures, the scalar field expectation values, the latent heat, the interface tension and the correlation lengths at the phase transition points. Extrapolating the results to the infinite volume and continuum limits, we find that the transition is stronger than indicated by 2-loop perturbation theory, guaranteeing that the MSSM phase transition is strong enough for baryogenesis in this regime. We also study the possibility of a two-stage phase transition, in which the stop field gets an expectation value in an intermediate phase. We find that a two-stage transition exists non-perturbatively, as well, but for somewhat smaller stop masses than in perturbation theory. Finally, the latter stage of the two-stage transition is found to be extremely strong, and thus it might not be allowed in the cosmological environment.Comment: 43 pages, 17 figure

    CP violation in chargino decays in the MSSM

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    In the minimal supersymmetric standard model (MSSM) with complex parameters, supersymmetric loop effects can lead to \emph{CP} violation. We calculate the rate asymmetries of decays of charginos into the lightest neutralino and a WW boson on the basis of the most important loop contributions in the third generation squark sectors. It turns out that the \emph{CP} violating asymmetries can be a few per cent in typical regions of the parameter space of the MSSM. These processes would provide very promising channels for probing \emph{CP} violation in the MSSM at future high-energy colliders.Comment: 15 pages, 5 figures, LaTeX2

    Signatures of Baryogenesis in the MSSM

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    We revisit the electroweak baryogenesis within the context of the minimal supersymmetric standard model (MSSM), studying its potential collider signatures. We find that this mechanism of baryogenesis does not give a new CP violating signal at the BB-factories. The first circumstantial evidence may come from enhanced BsB_s or BdB_d mixing. If a light right-handed scalar top and Higgs are found as required, a linear collider represents the best possibility for confirming the scenario.Comment: 5 pages, 2 figures. Minor typos fixed. Reference Adde

    Probing SUSY-induced CP violations at B factories

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    In the minimal supersymmetric standard model (MSSM), the \mu-parameter and the trilinear coupling A_t may be generically complex and can affect various observables at B factories. Imposing the edm constraints, we find that there is no new large phase shift in the B^0 - \bar{B^0} mixing, CP violating dilepton asymmetry is smaller than 0.1 %, and the direct CP violation in B\to X_s \gamma can be as large as \sim \pm 16 %.Comment: 4 pages, 2 figures. Version to appear in Phys. Rev. Let

    Proteomics of Human Dendritic Cell Subsets Reveals Subset-Specific Surface Markers and Differential Inflammasome Function.

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    Dendritic cells (DCs) play a key role in orchestrating adaptive immune responses. In human blood, three distinct subsets exist: plasmacytoid DCs (pDCs) and BDCA3+ and CD1c+ myeloid DCs. In addition, a DC-like CD16+ monocyte has been reported. Although RNA-expression profiles have been previously compared, protein expression data may provide a different picture. Here, we exploited label-free quantitative mass spectrometry to compare and identify differences in primary human DC subset proteins. Moreover, we integrated these proteomic data with existing mRNA data to derive robust cell-specific expression signatures with more than 400 differentially expressed proteins between subsets, forming a solid basis for investigation of subset-specific functions. We illustrated this by extracting subset identification markers and by demonstrating that pDCs lack caspase-1 and only express low levels of other inflammasome-related proteins. In accordance, pDCs were incapable of interleukin (IL)-1β secretion in response to ATP

    The Light Stop Scenario from Gauge Mediation

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    In this paper we embed the light stop scenario, a MSSM framework which explains the baryon asymmetry of the universe through a strong first order electroweak phase transition, in a top-down approach. The required low energy spectrum consists in the light SM-like Higgs, the right-handed stop, the gauginos and the Higgsinos while the remaining scalars are heavy. This spectrum is naturally driven by renormalization group evolution starting from a heavy scalar spectrum at high energies. The latter is obtained through a supersymmetry-breaking mix of gauge mediation, which provides the scalars masses by new gauge interactions, and gravity mediation, which generates gaugino and Higgsino masses. This supersymmetry breaking also explains the \mu\ and B_\mu\ parameters necessary for electroweak breaking and predicts small tri-linear mixing terms A_t in agreement with electroweak baryogenesis requirements. The minimal embedding predicts a Higgs mass around its experimental lower bound and by a small extension higher masses m_H\lesssim 127 GeV can be accommodated.Comment: 20 pages, 3 figures; v2: changes in the conventions; v3: more details on the Higgs mass prediction, version published in JHE

    Signals for CP-Violation in Scalar Tau Pair Production at Muon Colliders

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    We discuss signals for CP-violation in μ+μτ~iτ~j+\mu^+ \mu^- \to \tilde \tau_i^- \tilde \tau_j^+, where i,j=1,2i,j = 1,2 label the two scalar τ\tau mass eigenstates. We assume that these reactions can proceed through the production and decay of the heavy neutral Higgs bosons present in supersymmetric models. CP-violation in the Higgs sector can be probed through a rate asymmetry even with unpolarized beams, while the CP-odd phase associated with the τ~\tilde \tau mass matrix can be probed only if the polarization of at least one beam can be varied. These asymmetries might be O(1){\cal O}(1).Comment: 9 pages, LaTeX with equations.sty, 3 PS figures (included

    Model of the Quark Mixing Matrix

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    The structure of the Cabibbo-Kobayashi-Maskawa (CKM) matrix is analyzed from the standpoint of a composite model. A model is constructed with three families of quarks, by taking tensor products of sufficient numbers of spin-1/2 representations and imagining the dominant terms in the mass matrix to arise from spin-spin interactions. Generic results then obtained include the familiar relation Vus=(md/ms)1/2(mu/mc)1/2|V_{us}| = (m_d/m_s)^{1/2} - (m_u/m_c)^{1/2}, and a less frequently seen relation Vcb=2[(ms/mb)(mc/mt)]|V_{cb}| = \sqrt{2} [(m_s/m_b) - (m_c/m_t)]. The magnitudes of VubV_{ub} and VtdV_{td} come out naturally to be of the right order. The phase in the CKM matrix can be put in by hand, but its origin remains obscure.Comment: Presented by Mihir P. Worah at DPF 92 Meeting, Fermilab, November, 1992. 3 pages, LaTeX fil
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