Challenges in Double Beta Decay

In the past ten years, neutrino oscillation experiments have provided the incontrovertible evidence that neutrinos mix and have finite masses. These results represent the strongest demonstration that the electroweak Standard Model is incomplete and that new Physics beyond it must exist. In this scenario, a unique role is played by the Neutrinoless Double Beta Decay searches which can probe lepton number conservation and investigate the Dirac/Majorana nature of the neutrinos and their absolute mass scale (hierarchy problem) with unprecedented sensitivity. Today Neutrinoless Double Beta Decay faces a new era where large-scale experiments with a sensitivity approaching the so-called degenerate-hierarchy region are nearly ready to start and where the challenge for the next future is the construction of detectors characterized by a tonne-scale size and an incredibly low background. A number of new proposed projects took up this challenge. These are based either on large expansions of the present experiments or on new ideas to improve the technical performance and/or reduce the background contributions. In this paper, a review of the most relevant ongoing experiments is given. The most relevant parameters contributing to the experimental sensitivity are discussed and a critical comparison of the future projects is proposed

Supersymmetric black holes and attractors in gauged supergravity with hypermultiplets

We consider four-dimensional N = 2 supergravity coupled to vector- and hypermultiplets, where abelian isometries of the quaternionic Kähler hypermultiplet scalar manifold are gauged. Using the recipe given by Meessen and Ortín in arXiv:1204.0493, we analytically construct a supersymmetric black hole solution for the case of just one vector multiplet with prepotential ℱ = − i χ 0 χ 1 $$\mathrm{\mathcal{F}}=-i{\chi}^0{\chi}^1$$ , and the universal hypermultiplet. This solution has a running dilaton, and it interpolates between AdS 2 × H 2 at the horizon and a hyperscaling-violating type geometry at infinity, conformal to AdS 2 × H 2 . It carries two magnetic charges that are completely fixed in terms of the parameters that appear in the Killing vector used for the gauging

Yang-Lee edge singularities from extended activity expansions of the dimer density for bipartite lattices of dimensionality 2 <= d <= 7

We have extended, in most cases through 24th order, the series expansions of the dimer density in powers of the activity in the case of bipartite ((hyper)-simple-cubic and (hyper)-body-centered-cubic) lattices of dimensionalities 2<= d <= 7. A numerical analysis of these data yields estimates of the exponents characterizing the Yang-Lee edge-singularities for lattice ferromagnetic spin-models as d varies between the lower and the upper critical dimensionalities. Our results are consistent with, but more extensive and sometimes more accurate than those obtained from the existing dimer series or from the estimates of related exponents for lattice animals, branched polymers and fluids. We mention also that it is possible to obtain estimates of the dimer constants from our series for the various lattices

Attractors, black objects and holographic RG flows in 5d maximal gauged supergravities

We perform a systematic search for static solutions in different sectors of 5d $\mathcal{N}$ = 8 supergravities with compact and non-compact gauged R-symmetry groups, finding new and listing already known backgrounds. Due to the variety of possible gauge groups and resulting scalar potentials, the maximally symmetric vacua we encounter in these theories can be Minkowski, de Sitter, or anti-de Sitter. There exist BPS and non-BPS near-horizon geometries and full solutions with all these three types of asymptotics, corresponding to black holes, branes, strings, rings, and other black objects with more exotic horizon topologies, supported by U(1) and SU(2) charges. The asymptotically AdS 5 solutions also have a clear holographic interpretation as RG flows of field theories on D3 branes, wrapped on compact 2- and 3-manifolds

Pure spinor equations to lift gauged supergravity

We rewrite the equations for ten-dimensional supersymmetry in a way formally identical to a necessary and sufficient G -structure system in $\mathcal{N}$  = 2 gauged supergravity, where all four-dimensional quantities are replaced by combinations of pure spinors and fluxes in the internal space. This provides a way to look for lifts of BPS solutions without having to reduce or even rewrite the ten-dimensional action. In particular this avoids the problem of consistent truncation, and the introduction of unphysical gravitino multiplets

BPS black holes in a non-homogeneous deformation of the stu model of N = 2, D = 4 gauged supergravity

We consider a deformation of the well-known stu model of N = 2, D = 4 supergravity, characterized by a non-homogeneous special Kähler manifold, and by the smallest electric-magnetic duality Lie algebra consistent with its upliftability to five dimensions. We explicitly solve the BPS attractor equations and construct static supersymmetric black holes with radial symmetry, in the context of U(1) dyonic Fayet-Iliopoulos gauging, focussing on axion-free solutions. Due to non-homogeneity of the scalar manifold, the model evades the analysis recently given in the literature. The relevant physical properties of the resulting black hole solution are discussed

Perturbative QCD description of jet data from LHC Run-I and Tevatron Run-II

We present a systematic comparison of jet predictions at the LHC and the Tevatron, with accuracy up to next-to-next-to-leading order (NNLO). The exact computation at NNLO is completed for the gluons-only channel, so we compare the exact predictions for this channel with an approximate prediction based on threshold resummation, in order to determine the regions where this approximation is reliable at NNLO. The kinematic regions used in this study are identical to the experimental setup used by recently published jet data from the ATLAS and CMS experiments at the LHC, and CDF and D0 experiments at the Tevatron. We study the effect of choosing different renormalisation and factorisation scales for the NNLO exact prediction and as an exercise assess their impact on a PDF fit including these corrections. Finally we provide numerical values of the NNLO k -factors relevant for the LHC and Tevatron experiments

Steering efficiency of a ultrarelativistic proton beam in a thin bent crystal

Crystals with small thickness along the beam exhibit top performance for steering particle beams through planar channeling. For such crystals, the effect of nuclear dechanneling plays an important role because it affects their efficiency. We addressed the problem through experimental work carried out with 400 GeV/c protons at fixed-target facilities of CERN-SPS. The dependence of efficiency vs. curvature radius has been investigated and compared favourably to the results of modeling. A realistic estimate of the performance of a crystal designed for LHC energy including nuclear dechanneling has been achieved

Three-jet production in POWHEG

We present an implementation of the production of three jets at NLO plus parton-shower effects in the POWHEG BOX. Using the recently introduced MiNLO procedure for setting the renormalization and factorization scales, we are able to obtain a generator that is also well behaved when the third jet becomes unresolved. We compare key distributions computed at the NLO level, at the level of the POWHEG hard emission and after full shower by PYTHIA, PYTHIA 8 and HERWIG6. We also compare our three-jet generator with the already available dijet POWHEG generator

Search for axioelectric effect of solar axions using BGO scintillating bolometer

A search for axioelectric absorption of solar axions produced in the p+d→3He+γ(5.5MeV) reaction has been performed with a BGO detector placed in a low-background setup. A model-independent limit on the combination of axion–nucleon and axion–electron coupling constants has been obtained: |gAe×gAN3|<1.9×10-10 for 90 % confidence level. The constraint of the axion–electron coupling constant has been obtained for hadronic axion with masses of (0.1–1) MeV: |gAe|≤(0.96-8.2)×10-8