Particle acceleration in sub-cycle optical cells

A single laser pulse with spot size smaller than half its wavelength ($w_0 < \lambda/2$) can provide a net energy gain to ultra-relativistic particles. In this paper, we discuss the properties of an optical cell consisting of $N$ sub-cycle pulses that propagate in the direction perpendicular to the electron motion. We show that the energy gain produced by the cell is proportional to $N$ and it is sizable even for $\mathcal{O}(1\mathrm{~TW})$ pulses.Comment: 13 pages, 7 figures. Version to appear in PRSTA

Neutrino oscillation experiments

In this paper, we give a short overview of neutrino oscillation experiments with emphasis on current European programmes of interest for INFN and on mid-term perspectives. In particular, we discuss the results that strengthen the standard three-family interpretation of leptonic mixing and the tension originating from the persistent LSND-Miniboone anomaly together with updated reactor data

An infrared origin of leptonic mixing and its test at DeepCore

Fermion mixing is generally believed to be a low-energy manifestation of an underlying theory whose energy scale is much larger than the electroweak scale. In this paper we investigate the possibility that the parameters describing lepton mixing actually arise from the low-energy behavior of the neutrino interacting fields. In particular, we conjecture that the measured value of the mixing angles for a given process depends on the number of unobservable flavor states at the energy of the process. We provide a covariant implementation of such conjecture, draw its consequences in a two neutrino family approximation and compare these findings with current experimental data. Finally we show that this infrared origin of mixing will be manifest at the Ice Cube DeepCore array, which measures atmospheric oscillations at energies much larger than the tau lepton mass; it will hence be experimentally tested in a short time scale.Comment: 14 pages, 1 figure; version to appear in Int.J.Mod.Phys.

Three-flavour oscillations with accelerator neutrino beams

The three-flavor neutrino oscillation paradigm is well established in particle physics thanks to the crucial contribution of accelerator neutrino beam experiments. In this paper we review the most important contributions of these experiments to the physics of massive neutrinos after the discovery of $\theta_{13}$ and future perspectives in such a lively field of research. Special emphasis is given to the technical challenges of high power beams and the oscillation results of T2K, OPERA, ICARUS and NO$\nu$A. We discuss in details the role of accelerator neutrino experiments in the precision era of neutrino physics in view of DUNE and Hyper-Kamiokande, the programme of systematic uncertainty reduction and the development of new beam facilities.Comment: 31 pages, 12 fugures. To appear in Univers

Experimental prospects to observe the g − 2 muon anomaly in the electron sector

The long-standing difference between the experimental measurement and the standard model prediction for the muon’s anomalous magnetic moment, aμ = (gμ − 2)/2, can be due to new particles flowing in loop contributions: such discrepancy might thus signal the presence of new physics at the TeV scale. The vast majority of models explaining the muon discrepancy in terms of new physics (NP) predict sizable effects in ae = (ge−2)/2, too. We discuss the experimental prospects to reach sub-ppb precision on ae and test the NP origin of the muon anomaly in its electron counterpart

CP violation and mass hierarchy at medium baselines in the large theta(13) era

The large value of theta(13) recently measured by rector and accelerator experiments opens unprecedented opportunities for precision oscillation physics. In this paper, we reconsider the physics reach of medium baseline superbeams. For theta(13) ~ 9 degree we show that facilities at medium baselines -- i.e. L ~ O(1000 km) -- remain optimal for the study of CP violation in the leptonic sector, although their ultimate precision strongly depends on experimental systematics. This is demonstrated in particular for facilities of practical interest in Europe: a CERN to Gran Sasso and CERN to Phyasalmi nu_mu beam based on the present SPS and on new high power 50 GeV proton driver. Due to the large value of theta(13), spectral information can be employed at medium baselines to resolve the sign ambiguity and determine the neutrino mass hierarchy. However, longer baselines, where matter effects dominate the nu_mu->nu_e transition, can achieve much stronger sensitivity to sign(Delta m^2) even at moderate exposures.Comment: 14 pages, 14 figures, version to appear in EPJ