125847794
Soft supersymmetry breaking and radiative Higgs signatures
I review our recent formulation of the minimal FCNC schemes of the soft supersymmetry breaking via the squark mass-terms and scalar trilinear interactions, where the large O(1) mixings among scalar-tops and -charms are found to be consistent with all existing theoretical and experimental bounds. Such a feature is demonstrated in a class of attractive new models with horizontal U(1) symmetry which also explain the observed quark-mass pattern and solve the SUSY μ-problem. The soft SUSY breaking induced radiative H±bc and h0tc Higgs couplings are analyzed and are shown to provide exciting new discovery Higgs signatures at the Tevatron and LHC.
119518408
New Method for Detecting Charged Scalars at Colliders
We propose a new method for detecting a charged (pseudo)scalar at colliders, based upon the observation that its Yukawa coupling to charm and bottom quarks can be large due to a significant mixing of the top and charm quarks. After analyzing the typical flavor mixing allowed by low energy data in the topcolor and the generic two-Higgs doublet models, we study the physics potential of the Tevatron, LHC, and linear colliders for probing such an $s$-channel charged resonance via the single-top (as well as ${W}^{\ifmmode\pm\else\textpm\fi{}}{h}^{0}$) production. We show that studying its detection at colliders can also provide information on the dynamics of flavor-changing neutral current phenomena.
119496
The Equivalence theorem and its radiative correction - free formulation for all R(xi) gauges
The electroweak equivalence theorem quantitatively connects the physical amplitudes of longitudinal massive gauge bosons to those of the corresponding {ital unphysical} would-be Goldstone bosons. Its precise form depends on both the gauge-fixing condition and the renormalization scheme. Our previous modification-free schemes have applied to a broad class of R{sub {xi}} gauges including the `t Hooft{endash}Feynman gauge but excluding the Landau gauge. In this paper we construct a new renormalization scheme in which the radiative modification factor C{sub mod}{sup a} is equal to unity for all R{sub {xi}} gauges, including both `t Hooft{endash}Feynman and Landau gauges. This scheme makes C{sub mod}{sup a} equal to unity by specifying a convenient subtraction condition for the would-be Goldstone boson wave function renormalization constant Z{sub {phi}{sup a}}. We build the new scheme for both the standard model and the effective Lagrangian formulated electroweak theories (with either linearly or nonlinearly realized symmetry-breaking sector). Based upon these, a new prescription, called the {open_quotes}divided equivalence theorem,{close_quotes} is further proposed for extending the high energy region applicable to the equivalence theorem. {copyright} {ital 1997} {ital The American Physical Society}
73581246
Unitarity of deconstructed five-dimensional Yang–Mills theory
Abstract The low-energy properties of a compactified five-dimensional gauge theory can be reproduced in a four-dimensional theory with a replicated gauge group and an appropriate gauge symmetry breaking pattern. The lightest vector bosons in these “deconstructed” or “remodeled” theories have masses and couplings approximately equal to those of the Kaluza–Klein tower of massive vector states present in a compactified higher-dimensional gauge theory. We analyze the unitarity of low-energy scattering of the massive vector bosons in a deconstructed theory, and examine the relationship between the scale of unitarity violation and the scale of the underlying chiral symmetry breaking dynamics which breaks the replicated gauge groups. As in the case of compactified five-dimensional gauge theories, low-energy unitarity is ensured through an interlacing cancellation among contributions from the tower of massive vector bosons. We show that the behavior of these scattering amplitudes is manifest without such intricate cancellations in the scattering of the would-be Goldstone bosons of the deconstructed theory. Unlike compactified five-dimensional gauge theories, the amplitude for longitudinal vector boson scattering in deconstructed theories does grow with energy, though this effect is suppressed by 1/( N +1), with N +1 being the number of replicated gauge groups.
118551349
New Higgs Inflation in a No-Scale Supersymmetric SU(5) GUT
Higgs inflation is attractive because it identifies the inflaton with the electroweak Higgs boson. In this work, we construct a new class of supersymmetric Higgs inflationary models in the no-scale supergravity with an SU(5) GUT group. Extending the no-scale Kahler potential and SU(5) GUT superpotential, we derive a generic potential for Higgs inflation that includes the quadratic monomial potential and a Starobinsky-type potential as special limits. This type of models can accommodate a wide range of the tensor-to-scalar ratio $r = O(10^{-3}-10^{-1})$, as well as a scalar spectral index $n_s \sim 0.96$.
119248851
General Sum Rules for WW Scattering in Higgsless Models: Equivalence Theorem and Deconstruction Identities
We analyze inelastic 2{yields}2 scattering amplitudes for gauge bosons and Nambu-Goldstone bosons in deconstructed Higgsless models. Using the (KK) equivalence theorem in 4D (5D), we derive a set of general sum rules among the boson masses and multiboson couplings that are valid for arbitrary deconstructed models. Taking the continuum limit, our results naturally include the 5D Higgsless model sum rules for arbitrary 5D geometry and boundary conditions; they also reduce to the elastic sum rules when applied to the special case of elastic scattering. For the case of linear deconstructed Higgsless models, we demonstrate that the sum rules can also be derived from a set of general deconstruction identities and completeness relations. We apply these sum rules to the deconstructed 3-site Higgsless model and its extensions; we show that in 5D ignoring all higher KK modes (n>1) is inconsistent once the inelastic channels become important. Finally, we discuss how our results generalize beyond the case of linear Higgsless models.
122785032
RESULTS AND DEVELOPMENTS WITH LARGE MASS HIGHLY RADIOPURE NaI(Tl) AT LNGS
The low background DAMA/NaI experiment (' 100 kg highly radiopure NaI(Tl)) at the Gran Sasso National Laboratory of the I.N.F.N. had the unique feature to effectively investigate the presence of Dark Matter particle in the galactic halo by exploiting the model independent annual modulation signature. This experiment has collected data over seven annual cycles for a total exposure of more than 10 kg × day and has pointed out at 6.3 σ C.L. a modulation effect satisfying all the many peculiarities of the signature. Neither systematics nor side reactions able to account for the observed effect were found. Several (but still few with respect to the many possibilities) corollary model dependent quests for the candidate particle have also been carried out. At present the second generation DAMA/LIBRA set-up (' 250 kg highly radiopure NaI(Tl)) is in operation. A R&D towards possible ultimate 1 ton NaI(Tl) experiment is also in progress.
17766827
Investigating electron interacting dark matter
Some extensions of the standard model provide dark matter candidate particles which can have a dominant coupling with the lepton sector of the ordinary matter. Thus, such dark matter candidate particles (chi(0)) can be directly detected only through their interaction with electrons in the detectors of a suitable experiment, while they are lost by experiments based on the rejection of the electromagnetic component of the experimental counting rate. These candidates can also offer a possible source of the 511 keV photons observed from the galactic bulge. In this paper this scenario is investigated. Some theoretical arguments are developed and related phenomenological aspects are discussed. Allowed intervals and regions for the characteristic phenomenological parameters of the considered model and of the possible mediator of the interaction are also derived considering the DAMA/NaI data.
122909836
Particle dark matter: From DAMA/NaI to DAMA/LIBRA
DAMA is an observatory for rare processes and it is operative deep underground at the Gran Sasso National Laboratory of the INFN. Several low background setups have been realized and many rare processes have been investigated. In particular, the DAMA/Nal setup (≃100 kg of highly radiopure NaI(Tl)) has effectively investigated the model-independent annual modulation signature over seven annual cycles (total exposure of 107 731 kg day), obtaining 6.3σ C.L. model-independent evidence for the presence of a dark matter particle component in the galactic halo. Some of the many possible corollary model-dependent quests for the candidate particle have been investigated and others are in progress. At present, the second generation DAMA/LIBRA setup (≃250 kg of highly radiopure NaI(T1)) is in data taking deep underground.
2644347
Investigating pseudoscalar and scalar Dark Matter
In this paper another class of Dark Matter candidate particles - the pseudoscalar and scalar light bosonic candidates - is discussed. Particular care is devoted to the study of the processes for their detection (which only involves electrons and photons/X-rays) in a suitable underground experimental setup. For this purpose the needed calculations are developed and various related aspects and phenomenologies are discussed. In particular, it is shown that - in addition to the WIMP cases already discussed elsewhere - there is also possibility for a bosonic candidate to account for the 6.3 sigma C.L. model independent evidence for the presence of a particle DM component in the galactic halo observed by DAMA/NaI. Allowed regions in these scenarios are presented also paying particular care on the cosmological interest of the bosonic candidate.
123131101
Searching for signals from the dark universe by DAMA at Gran Sasso
The DAMA set-ups are running deep underground in the Gran Sasso National Laboratory of the I.N.F.N.. Results on various rare event searches have been achieved. In particular, the results obtained in the investigation of the WIMP annual modulation signature obtained in four annual cycles (total statistics: 57986 kg . day) are summarized.