119630724
PARTICLE DARK MATTER IN THE GALACTIC HALO: RESULTS FROM DAMA/LIBRA
The DAMA/LIBRA experiment, running at the Gran Sasso National Laboratory of the I.N.F.N. in Italy, has a sensitive mass of about 250 kg highly radiopure NaI(Tl). It 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 experiment and the former DAMA/NaI one (the first generation experiment having an exposed mass of about 100 kg) have cumulatively released so far the results obtained with the data collected over 13 annual cycles; the total exposure is 1.17 ton × yr. They give a model independent evidence of the presence of DM particles in the galactic halo at 8.9 σ C.L. on the basis of the investigated DM signature. Few aspects of the obtained results are summarized and some comments 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.
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.
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(...
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.
6985151
The Structure of electroweak corrections due to extended gauge symmetries
This paper studies models with extended electroweak gauge sectors of the form SU(2) x SU(2) x U(1) x [SU(2) or U(1)]. We establish the general behavior of corrections to precision electroweak observables in this class of theories and connect our results to previous work on specific models whose electroweak sectors are special cases of our extended group.
119248663
LHC Higgs signatures from extended electroweak gauge symmetry
A bstractWe study LHC Higgs signatures from the extended electroweak gauge symmetry SU(2) ⊗ SU(2) ⊗ U(1). Under this gauge structure, we present an effective UV completion of the 3-site moose model with ideal fermion delocalization, which contains two neutral Higgs states (h, H) plus three new gauge bosons (W′, Z′). We study the unitarity, and reveal that the exact E2 cancellation in the longitudinal VLVL scattering amplitudes is achieved by the joint role of exchanging both spin-1 new gauge bosons W′/Z′ and spin-0 Higgs bosons h/H. We identify the lighter Higgs state h with mass 125 GeV, and derive the unitarity bound on the mass of heavier Higgs boson H. The parameter space of this model is highly predictive. We study the production and decay signals of this 125 GeV Higgs boson h at the LHC. We demonstrate that the h Higgs boson can naturally have enhanced signals in the diphoton channel gg → h → γγ, while the event rates in the reactions gg → h → W W∗ and gg → h → ZZ∗ are generally suppressed relative to the SM expectation. Searching the h Higgs boson via the associated production and the vector boson fusions are also discussed for our model. We further analyze the LHC signals of the heavier Higgs boson H as a new physics discriminator from the SM. For wide mass-ranges of H, we derive constraints from the existing LHC searches, and study the discovery potential of H at the LHC (8 TeV) and LHC (14 TeV).
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.
14029700
Higgsless Deconstruction Without Boundary Condition
Deconstruction is a powerful means to explore the rich dynamics of gauge theories in four and higher dimensions. We demonstrate that gauge symmetry breaking in a compactified higher dimensional theory can be formulated via deconstructed 4D moose theory with {\it spontaneous symmetry breaking} and {\it without boundary condition.} The proper higher-D boundary conditions are automatically induced in the continuum limit rather than being imposed. We identify and analyze the moose theories which exhibit {\it delayed unitarity violation} (effective unitarity) as a {\it collective effect} of many gauge groups, without resorting to any known 5D geometry. Relevant phenomenological constraints are also addressed.