17529257
Direct detection of dark-matter particles
In this conference the model-independent result on the presence of 
dark-matter particles in the galactic halo obtained over seven annual cycles by the 
 100 kg highly radiopure NaI(Tl) DAMA/NaI has been presented and several corollary 
investigations have also been discussed. More recently the model-independent 
result obtained over the first four annual cycles by the second generation 250 kg 
highly radiopure NaI(Tl) DAMA/LIBRA set-up at the Gran Sasso National Laboratory 
of the INFN has also been released. Both the experiments have the unique 
feature to effectively investigate the presence of dark-matter particles in the galactic 
halo by exploiting the model-independent annual modulation signature. The 
data collected by the two experiments over eleven annual cycles for a total exposure 
of 0.82 ton × y have pointed out at 8.2σ CL a positive result; several corollary 
model-dependent quests for the candidate particle(s) and related astrophysical, nuclear 
and particle physics scenarios are under updating. The future experimental 
activity can give rise to many new interesting results.
55768496
Particle Dark Matter in the galactic halo: results from DAMA/LIBRA
The DAMA/LIBRA experiment has a sensitive mass of about 250 kg highly radiopure NaI(Tl). It is running at the Gran Sasso National Laboratory of the INFN in Italy and is mainly devoted to the investigation of dark matter (DM) particles in the galactic halo by exploiting the model-independent DM annual modulation signature. The present DAMA/LIBRA and the former DAMA/NaI experiments (the first generation experiment having an exposed mass of about 100 kg) have thus far cumulatively released the results of data collected over 13 annual cycles (total exposure: 1.17 t year). They give model-independent evidence of the presence of DM particles in the galactic halo on the basis of the investigated DM signature at 8.9 sigma C.L. for the cumulative exposure. The main aspects of the obtained results are summarized and some comments are addressed.
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.
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.
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.
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(...
14324310
Minimal schemes for large neutrino mixings with inverted hierarchy
Abstract Existing oscillation data point to non-zero neutrino masses with large mixings. We analyze the generic features of the neutrino Majorana mass matrix with inverted hierarchy and construct realistic minimal schemes for the neutrino mass matrix that can explain the large (but not maximal) ν e – ν μ mixing of MSW-LAM as well as the nearly maximal ν μ – ν τ mixing and the small (or negligible) ν e → ν τ transition. These minimal schemes are quite unique and turn out to be extremely predictive. Implications for neutrinoless double beta decay, tritium beta decay and cosmology are analyzed.
119267356
Extending Higgs inflation with TeV scale new physics
Higgs inflation is among the most economical and predictive inflation models, although the original Higgs inflation requires tuning the Higgs or top mass away from its current experimental value by more than 2 sigma deviations, and generally gives a negligible tensor-to-scalar ratio r similar to 10(-3) (if away from the vicinity of critical point). In this work, we construct a minimal extension of Higgs inflation, by adding only two new weak-singlet particles at TeV scale, a vector-quark T and a real scalar S. The presence of singlets (T, S) significantly impact the renormalization group running of the Higgs boson self-coupling. With this, our model provides a wider range of the tensor-to-scalar ratio r = O(0.1) - O(10(-3)) consistent with the favored r values by either BICEP2 or Planck data, while keeping the successful prediction of the spectral index n(s) similar or equal to 0.96. It allows the Higgs and top masses to fully fit the collider measurements. We also discuss implications for searching the predicted TeV-scale vector-quark T and scalar S at the LHC and future high energy pp colliders.
8637975
A Three Site Higgsless Model
We analyze the spectrum and properties of a highly deconstructed Higgsless model with only three sites. Such a model contains sufficient complexity to incorporate interesting physics issues related to fermion masses and electroweak observables, yet remains simple enough that it could be encoded in a Matrix Element Generator program for use with Monte Carlo simulations. The gauge sector of this model is equivalent to that of the Breaking Electroweak Symmetry Strongly (BESS) model; the new physics of interest here lies in the fermion sector. We analyze the form of the fermion Yukawa couplings required to produce the ideal fermion delocalization that causes tree-level precision electroweak corrections to vanish. We discuss the size of one-loop corrections to b{yields}s{gamma}, the weak-isospin violating parameter {alpha}T and the decay Z{yields}bb. We find that the new fermiophobic vector states (the analogs of the gauge-boson Kaluza-Klein modes in a continuum model) can be reasonably light, with a mass as low as 380 GeV, while the extra (approximately vectorial) quark and lepton states (the analogs of the fermion Kaluza-Klein modes) must be heavier than 1.8 TeV.
119221143
Octahedral symmetry with geometrical breaking: New prediction for neutrino mixing angle theta(13) and CP violation
We propose octahedral group O-h as the family symmetry of the neutrino-lepton sector. We find that O-h contains subgroups Z(2)(mu tau) circle times Z(2)(s) and Z(4)(l) for realizing the bimaximal (BM) mixings theta(23) = theta(12) = 45 degrees, where Z(2)(mu tau) circle times Z(2)(s) and Z(4)(l) serve as the residual symmetries of neutrinos and charged leptons, respectively. We present geometric interpretations of BM mixing in the octahedron, and construct natural geometrical breaking of Z(4)(l), leading to nontrivial deviations from the BM mixings. Our theory makes truly simple predictions of a relatively large reactor angle, theta(13) similar or equal to 45 degrees - theta(12) = 7.5 degrees-13.7 degrees(3 sigma), the nearly maximal atmospheric angle and the approximate maximal Dirac CP violation. These agree well with the current neutrino data, and will be further probed by the on-going and upcoming oscillation experiments.
119095037
Collider tests of compact space dimensions using weak gauge bosons
We present collider tests of the recent proposal for weak-scale quantum gravity due to new large compact space dimensions in which only the graviton $(G)$ propagates. We show that the existing high precision LEP-I $Z$-pole data can impose nontrivial constraints on the scale of the new dimensions, via the decay mode $Z\ensuremath{\rightarrow}f\overline{f}+G$ $(f\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}q,\ensuremath{\ell})$. These bounds are comparable to those obtained at high energy colliders and provide the first sensitive probe of the scalar graviton. We also study $W(Z)+G$ production and the anomalous $\mathrm{WW}(\mathrm{ZZ})$ signal from virtual $G$-states at the Fermilab Tevatron and compare them with the LEP-I bound and those from LEP-II and future linear colliders.