Phenomenology of SIDIS unpolarized cross sections and azimuthal asymmetries

I review the phenomenology of unpolarized cross sections and azimuthal asymmetries in semi-inclusive deeply inelastic scattering (SIDIS). The general theoretical framework is presented and the validity of the Gaussian model is discussed. A brief account of the existing analyses is provided.Comment: 12 pages, 5 figures, invited talk at "Transversity 2011", Veli Losinj, Croati

Hadronic and electromagnetic probes of hot and dense matter in a Boltzmann+Hydrodynamics model of relativistic nuclear collisions

We present recent results on bulk observables and electromagnetic probes obtained using a hybrid approach based on the Ultrarelativistic Quantum Molecular Dynamics transport model with an intermediate hydrodynamic stage for the description of heavy-ion collisions at AGS, SPS and RHIC energies. After briefly reviewing the main results for particle multiplicities, elliptic flow, transverse momentum and rapidity spectra, we focus on photon and dilepton emission from hot and dense hadronic matter.Comment: To appear in the proceedings of WISH 2010: International Workshop on Interplay between Soft and Hard interactions in particle production at ultrarelativistic energies, Catania, Italy, 8-10 September 201

Pair Photoproduction in Constant and Homogeneous Electromagnetic Fields

The process of pair creation by a photon in a constant and homogeneous electromagnetic field of an arbitrary configuration is investigating. At high energy the correction to the standard quasiclassical approximation (SQA) has been calculated. In the region of intermediate photon energies where SQA is inapplicable the new approximation, developed recently by authors, is used. The influence of weak electric field on the process in a magnetic field is considered. In particular, in the presence of electric field the root divergence in the probability of pair creation on the Landau energy levels is vanished. For smaller photon energies the low energy approximation is used. The found probability describes the absorption of soft photon by particles created by field. At low photon energy the electric field action dominates and the influence of magnetic field on the process is connected with the interaction of it and the magnetic moment of creating particles.Comment: 11 page

The Z' boson of the minimal B-L model at future Linear Colliders in e+e- --> mu+mu-

We study the capabilities of future electron-positron Linear Colliders, with centre-of-mass energy at the TeV scale, in accessing the parameter space of a $Z'$ boson within the minimal $B-L$ model. We carry out a detailed comparison between the discovery regions mapped over a two-dimensional configuration space ($Z'$ mass and coupling) at the Large Hadron Collider and possible future Linear Colliders for the case of di-muon production. As known in the literature for other $Z'$ models, we confirm that leptonic machines, as compared to the CERN hadronic accelerator, display an additional potential in discovering a $Z'$ boson as well as in allowing one to study its properties at a level of precision well beyond that of any of the existing colliders.Comment: 5 pages, proceeding of LC09 (Perugia), published by the Italian Physical Society in the Nuovo Cimento C (Colloquia

Three-body Casimir-Polder interactions

As part of our program to develop the description of three-body effects in quantum vacuum phenomena, we study the three-body interaction of two anisotropically polarizable atoms with a perfect electrically conducting plate, a generalization of earlier work. Three- and four-scattering effects are important, and lead to nonmonotonic behavior.Comment: 10 pages, 5 figures, for the proceedings of the conference Mathematical Structures in Quantum Systems, Benasque, Spain, July 2012, to be published in Nuovo Ciment

Recent progress in QCD at the LHC

Perturbative Quantum Chromodynamics has experienced an impressive progress in the last few years, boosted by the requirements of the LHC experimental program. In this contribution, I briefly review a selection of recent results in QCD and LHC phenomenology, covering progress in parton distribution functions, automation of NLO calculations, merging and matching at NLO, new calculations at NNLO accuracy and their matching to parton showers, and new developments and techniques in jet physics and jet substructure tools.Comment: 10 pages, 3 figures, to appear in the proceedings of the "Rencontres de physique de la Vallee d'Aoste 2014" Conference, La Thuile, Italy, February 201

Spatial variations of the SrI 4607\AA scattering polarization signals at subgranular scale observed with ZIMPOL at GREGOR telescope

Sr I 4607\AA spectral line shows one of the strongest scattering polarization signals in the visible solar spectrum. The amplitudes of these signals are expected to vary at granular spatial scales. This variation can be due to changes in the magnetic field intensity and orientation (Hanle effect) as well as due to spatial and temporal variations in the plasma properties. Measuring the spatial variation of such polarization signal would allow us to study the properties of the magnetic fields at subgranular region. But, the observations are challenging since both high spatial resolution and high spectropolarimetric sensitivity are required at the same time. To the aim of measuring these spatial variations at granular scale, we carried out a spectro-polarimetric measurement with the Zurich IMaging POLarimeter (ZIMPOL), at the GREGOR solar telescope at different limb distances on solar disk. Our results show a spatial variation of scattering linear polarization signals in Sr I 4607\AA line at the granular scale at every $\mu$, starting from 0.2 to 0.8. The correlation between the polarization signal amplitude and the continuum intensity imply statistically that the scattering polarization is higher at the granular regions than in the intergranular lanes.Comment: 4 pages, 3 figures, Proceeding of Third Meeting of the Italian Solar and Heliospheric Community, OCTOBER 28-31, 2018 - TURI

The Importance of Off-Axis Beaming in Jet Models

Gamma-Ray Bursts (GRBs) are widely thought to originate from collimated jets of material moving at relativistic velocities. Emission from such a jet should be visible even when viewed from outside the angle of collimation. Using Monte Carlo population synthesis methods and including the effects of this off-axis beaming, we can compare various GRB jet models against the global properties of observed bursts. We explore whether or not the X-Ray Flashes (XRFs) seen by HETE-2 and BeppoSAX can be explained as classical GRBs viewed off-axis, and begin to address the more general question of the importance of off-axis beaming in current burst samples.Comment: 4 pages, 1 figure. Poster presented at the 4th Workshop Gamma-Ray Bursts in the Afterglow Era, Rome,18-22 October 2004. Editors: L. Piro, L. Amati, S. Covino, and B. Gendre. Il Nuovo Cimento, in pres

The highest energy neutrinos: first evidence for cosmic origin

Developments in neutrino astronomy have been to a great extent motivated by the search for the sources of the cosmic rays, leading at a very early stage to the concept of a cubic kilometer neutrino detector. Almost four decades later such an instrument, IceCube, is taking data and has produced the first evidence for a flux of high-energy neutrinos of cosmic origin. After a brief review of the history of the field, we will introduce IceCube and describe the first analysis of data taken with the completed instrument. The atmospheric neutrino flux cannot accommodate an excess of 28 neutrinos observed with energies above 60 TeV. We will briefly speculate on the origin of these events. Readers interested specifically in IceCube results may refer directly to section 3.Comment: 22 pages, 8 figures, Pontecorvo 201

Higgs sector of the MSSM: lepton flavor violation at colliders and neutralino dark matter

We examine the prospects for the detection of Higgs mediated lepton flavor violation at LHC and at a photon collider in the minimal supersymmetric standard model with large lepton flavor violating mass insertions in the $\mu-\tau$ sector constraining the parameter space with several experimental bounds. We find rates probably too small to be observed at future experiments if models have to accommodate for a neutralino relic density as measured by WMAP and explain the $(g-2)_{\mu}$ anomaly: better prospects are found if these two constraints are applied only as upper bounds. The spin-independent neutralino-nucleon cross section in the studied constrained parameter space is just below the present CDMS limit while gamma rates from neutralino annihilation in the halo are strongly suppressed.Comment: 6 pages, 2 figures, Prepared for the proceedings of the workshop: "LC09: $e^+ e^-$ Physics at the TeV Scale and the Dark Matter Connection", 21-24 September 2009, Perugia, Ital