New Mechanism of Flavor Symmetry Breaking from Supersymmetric Strong Dynamics

We present a class of supersymmetric models in which flavor symmetries are broken dynamically, by a set of composite flavon fields. The strong dynamics that is responsible for confinement in the flavor sector also drives flavor symmetry breaking vacuum expectation values, as a consequence of a quantum-deformed moduli space. Yukawa couplings result as a power series in the ratio of the confinement to Planck scale, and the fermion mass hierarchy depends on the differing number of preons in different flavor symmetry-breaking operators. We present viable non-Abelian and Abelian flavor models that incorporate this mechanism.Comment: 24 pp. LaTe

Dilaton as the Higgs boson

We propose a model where the role of the electroweak Higgs field is played by the dilaton. The model contains terms which explicitly violate gauge invariance, however it is shown that this violation is fictitious, so that the model is a consistent low energy effective theory. In the simplest version of the idea the resulting low energy effective theory is the same as the top mode standard model.Comment: 6 pages, v2 with expanded discussio

Unitarity in Dirichlet Higgs Model

We show that a five dimensional Universal Extra Dimension model, compactified on a line segment, is consistently formulated even when the gauge symmetry is broken solely by non-zero Dirichlet boundary conditions on a bulk Higgs field, without any quartic interaction. We find that the longitudinal W+W- elastic scattering amplitude, under the absence of the Higgs zero-mode, is unitarized by exchange of infinite towers of KK Higgs bosons. Resultant amplitude scales linearly with the scattering energy, exhibiting five dimensional nature. A tree-level partial-wave unitarity condition is satisfied up to 6.7 (5.7) TeV for the KK scale 430 (500) GeV, favored by the electroweak data within 90% CL.Comment: 14pages, 2 figures (v1); References added (v2); Trivial error corrected: u -> t and \cos\theta -> -\cos\theta, references added (v3); comments added, a reference added, version to appear in Eur. Phys. J. C (v4); Expressions matched to EPJC style, obsolete affiliation (on leave) has been removed (v5

Parity (and time-reversal) anomaly in a semiconductor

The physics of a parity anomaly, potentially observable in a narrow-gap semiconductor, is revisited. Fradkin, Dagotto, and Boyanovsky have suggested that a Hall current of anomalous parity can be induced by a Peierls distortion on a domain wall. I argue that a perturbation inducing the parity anomaly must break the time reversal symmetry, which rules out the Peierls distortion as a potential cause. I list all possible perturbations that can generate the anomaly.Comment: 11 pages, 1 figure. Sign errors fixe

A Supersymmetric Stueckelberg U(1) Extension of the MSSM

A Stueckelberg extension of the MSSM with only one abelian vector and one chiral superfield as an alternative to an abelian extension with Higgs scalars is presented. The bosonic sector contains a new gauge boson Z' which is a sharp resonance, and a new CP-even scalar, which combines with the MSSM Higgs bosons to produce three neutral CP-even massive states. The neutral fermionic sector has two additional fermions which mix with the four MSSM neutralinos to produce an extended 6x6 neutralino mass matrix. For the case when the LSP is composed mostly of the Stueckelberg fermions, the LSP of the MSSM will be unstable, which leads to exotic decays of sparticles with many leptons in final states. Prospects for supersymmetry searches and for dark matter are discussed.Comment: 10 page

Next-to-leading Corrections to the Higgs Boson Transverse Momentum Spectrum in Gluon Fusion

We present a fully analytic calculation of the Higgs boson transverse momentum and rapidity distributions, for nonzero Higgs $p_\perp$, at next-to-leading order in the infinite-top-mass approximation. We separate the cross section into a part that contains the dominant soft, virtual, collinear, and small-$p_\perp$-enhanced contributions, and the remainder, which is organized by the contributions due to different parton helicities. We use this cross section to investigate analytically the small-$p_\perp$ limit and compare with the expectation from the resummation of large logarithms of the type $\ln{m_H/p_\perp}$. We also compute numerically the cross section at moderate $p_\perp$ where a fixed-order calculation is reliable. We find a $K$-factor that varies from $\approx1.6-1.8$, and a reduction in the scale dependence, as compared to leading order. Our analysis suggests that the contribution of current parton distributions to the total uncertainty on this cross section at the LHC is probably less than that due to uncalculated higher orders.Comment: 40 pages, 10 figures, JHEP style (minor changes, added reference

Measurement of the Higgs Boson Mass with a Linear e+e- Collider

The potential of a linear e+e- collider operated at a centre-of-mass energy of 350 GeV is studied for the measurement of the Higgs boson mass. An integrated luminosity of 500 fb-1 is assumed. For Higgs boson masses of 120, 150 and 180 GeV the uncertainty on the Higgs boson mass measurement is estimated to be 40, 65 and 70 MeV, respectively. The effects of beam related systematics, namely a bias in the beam energy measurement, the beam energy spread and the luminosity spectrum due to beamstrahlung, on the precision of the Higgs boson mass measurement are investigated. In order to keep the systematic uncertainty on the Higgs boson mass well below the level of the statistical error, the beam energy measurement must be controlled with a relative precision better than 10-4.Comment: 19 pages, 10 Figure

Pair production of neutralinos via gluon-gluon collisions

The production of a neutralino pair via gluon-gluon fusion is studied in the minimal supersymmetric model(MSSM) at proton-proton colliders. The numerical analysis of their production rates are carried out in the mSUGRA scenario. The results show that this cross section may reach about 80 femto barn for $\tilde{\chi}^{0}_{1}\tilde{\chi}^{0}_{2}$ pair production and 23 femto barn for $\tilde{\chi}^{0}_{2}\tilde{\chi}^{0}_{2}$ pair production with suitable input parameters at the future LHC collider. It shows that this loop mediated process can be competitive with the quark-antiquark annihilation process at the LHC.Comment: LaTex file, l4 pages, 5 EPS figure

Physical Unitarity for Massive Non-abelian Gauge Theories in the Landau Gauge: Stueckelberg and Higgs

We discuss the problem of unitarity for Yang-Mills theory in the Landau gauge with a mass term a la Stueckelberg. We assume that the theory (non-renormalizable) makes sense in some subtraction scheme (in particular the Slavnov-Taylor identities should be respected!) and we devote the paper to the study of the space of the unphysical modes. We find that the theory is unitary only under the hypothesis that the 1-PI two-point function of the vector mesons has no poles (at p^2=0). This normalization condition might be rather crucial in the very definition of the theory. With all these provisos the theory is unitary. The proof of unitarity is given both in a form that allows a direct transcription in terms of Feynman amplitudes (cutting rules) and in the operatorial form. The same arguments and conclusions apply verbatim to the case of non-abelian gauge theories where the mass of the vector meson is generated via Higgs mechanism. To the best of our knowledge, there is no mention in the literature on the necessary condition implied by physical unitarity.Comment: References added. 22 pages. Final version to appear in the journa

Pair Production of the Lightest Chargino via Gluon-Gluon Collisions

The production of the lightest chargino pair from gluon-gluon fusion is studied in the minimal supersymmetric model(MSSM) at proton-proton colliders. We find that with the chosen parameters, the production rate of the subprocess can be over 2.7 femto barn when the chargino is higgsino-like, and the corresponding total cross section in proton-proton collider can reach 56 femto barn at the LHC in the CP-conserving MSSM. It shows that this loop mediated subprocess can be competitive with the standard Drell-Yan subprocess in proton-proton colliders, especially at the LHC. Furthermore, our calculation shows it would be possible to extract information about some CP-violating phase parameters, if we collected enough chargino pair events.Comment: 39 pages, LaTex, 8 figure