122742101
Results with the DAMA/NaI(Tl) experiment at LNGS
DAMA experiment is an observatory for rare events mainly devoted to WIMP search at the Gran Sasso National Laboratory of the I.N.F.N.. In this paper, the results obtained with the similar or equal to 100 kg NaI(Tl) set-up will be summarized, pointing out in particular those regarding the investigation of the WIMP annual modulation signature.
119701812
Signals from dark Universe: DAMA/LIBRA at LNGS
The DAMA/LIBRA set-up (about 250 kg highly radiopure NaI(Tl) sensitive mass) is running at the Gran Sasso National Laboratory of the INFN. The first DAMA/LIBRA results point out the presence of a dark matter particle component in the galactic halo, as well as the former DAMA/NaI set-up; cumulatively the data support such evidence at 8.2σ CL and satisfy all the peculiarities of the dark matter annual modulation signature.
117048271
First DAMA/LIBRA Results and Beyond
The DAMA project is an observatory for rare processes and it is operative deep underground at the Gran Sasso National Laboratory of the I.N.F.N. Its main apparatus is the DAMA/LIBRA set-up, consisting of ≃250 kg highly radiopure NaI(Tl) detectors. Its first results — obtained by exploiting over four annual cycles the model independent annual modulation signature for Dark Matter (DM) particles — confirm by those of the former DAMA/NaI, supporting the evidence for Dark Matter presence in the galactic halo at 8.2 σ C.L.. The DAMA/NaI and DAMA/LIBRA data, in fact, satisfy all the many peculiarities of the DM annual modulation signature. Neither systematic effects nor side reactions able to account for the observed modulation amplitude and to contemporaneously satisfy all the several requirements of the DM signature are available. Future perspectives are also addressed.
124862840
DIRECT DETECTION OF DARK MATTER PARTICLES
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.
118311956
DAMA investigations on Dark Matter at Gran Sasso: results and perspectives
The 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 particles in the galactic halo by exploiting the model independent annual modulation signature. A total exposure of more than 105 kg × day, collected over seven annual cycles, has pointed out at 6.3 σ C.L. an effect which satisfies all the many peculiarities of the signature. Neither systematics nor side reactions able to account for the observed effect were found. No experiment whose result can be directly compared in a model independent way with the experimental one of DAMA/NaI is available so far. Searches in space experiments are not in contradiction with DAMA/NaI. Several (but still few with respect to the possibilities) corollary model dependent quests for the candidate particle have also been carried out; others are in progress. At present the second generation DAMA/LIBRA set‐up (≃ 250 kg highly radiopure NaI(...
18272273
PRECISION ELECTROWEAK CONSTRAINTS ON HIDDEN LOCAL SYMMETRIES
In this talk we discuss the phenomenology of models with replicated electroweak gauge symmetries, based on a framework with the gauge structure [SU(2) or U(1)] x U(1) x SU(2) x SU(2).
10448516
Neutrino Mass and Baryon Asymmetry from Dirac Seesaw
We extend the visible content of the standard model (SM) with a hidden sector composed of three right-handed singlet neutrinos and one singlet Higgs. These extra singlets are charged under a new U(1)X gauge symmetry while the SM particles are not. Two heavy scalar doublets are introduced to play the role of the messengers between the visible and hidden sectors. The neutrinos naturally acquire tiny Dirac masses because the ratio of weak scale over the heavy messenger masses is highly suppressed. Furthermore, the heavy messengers simultaneously generate baryon asymmetry of the universe through their out-of-equilibrium CP-violating decays.
54990227
Higgsless Models: Lessons from Deconstruction
This talk reviews recent progress in Higgsless models of electroweak symmetry breaking, and summarizes relevant points of model‐building and phenomenology.
1310354
Unitarity of compactified five-dimensional Yang-Mills theory
Abstract Compactified five-dimensional Yang–Mills theory results in an effective four-dimensional theory with a Kaluza–Klein (KK) tower of massive vector bosons. We explicitly demonstrate that the scattering of the massive vector bosons is unitary at tree-level for low energies, and analyze the relationship between the unitarity violation scale in the KK theory and the nonrenormalizability scale in the five-dimensional gauge theory. In the compactified theory, low-energy unitarity is ensured through an interlacing cancellation among contributions from the relevant KK levels. Such cancellations can be understood using a Kaluza–Klein equivalence theorem which results from the geometric “Higgs” mechanism of compactification. In these theories, the unitarity violation is delayed to energy scales higher than the customary limit through the introduction of additional vector bosons rather than Higgs scalars.
16541870
Ideal fermion delocalization in Higgsless models
In this note we examine the properties of deconstructed Higgsless models for the case of a fermion whose SU(2) properties arise from delocalization over many sites of the deconstructed lattice. We derive expressions for the correlation functions and use these to establish a generalized consistency relation among correlation functions. We discuss the form of the W boson wavefunction and show that if the probability distribution of the delocalized fermions is appropriately related to the W wavefunction, then deviations in precision electroweak parameters are minimized. In particular, we show that this ''ideal fermion delocalization'' results in the vanishing of three of the four leading zero-momentum electroweak parameters defined by Barbieri et al. We then discuss ideal fermion delocalization in the context of two continuum Higgsless models, one in Anti-deSitter space and one in flat space. Our results may be applied to any Higgsless linear moose model with multiple SU(2) groups, including those with only a few extra vector bosons.