How large could the R-parity violating couplings be?

We investigate in detail the predictions coming from the d=4 operators for proton decay. We find the most general constraints for the R-parity violating couplings coming from proton decay, taking into account all fermion mixing and in different supersymmetric scenarios.Comment: 8 pages, several corrections, to appear in J.Phys.G (2005

Can we distinguish between h^{SM} and h^0 in split supersymmetry?

We investigate the possibility to distinguish between the Standard Model Higgs boson and the lightest Higgs boson in Split Supersymmetry. We point out that the best way to distinguish between these two Higgs bosons is through the decay into two photons. It is shown that there are large differences of several percent between the predictions for \Gamma(h\to\gamma\gamma) in the two models, making possible the discrimination at future photon-photon colliders. Once the charginos are discovered at the next generation of collider experiments, the well defined predictions for the Higgs decay into two photons will become a cross check to identify the light Higgs boson in Split Supersymmetry.Comment: 8 pages, 3 Figures, typos fixed, version published in J.Phys. G31 (2005) 563-56

Models of Neutrino Masses and Mixings

We review theoretical ideas, problems and implications of neutrino masses and mixing angles. We give a general discussion of schemes with three light neutrinos. Several specific examples are analyzed in some detail, particularly those that can be embedded into grand unified theories.Comment: 44 pages, 2 figures, version accepted for publication on the Focus Issue on 'Neutrino Physics' edited by F.Halzen, M.Lindner and A. Suzuki, to be published in New Journal of Physics

Large underground, liquid based detectors for astro-particle physics in Europe: scientific case and prospects

This document reports on a series of experimental and theoretical studies conducted to assess the astro-particle physics potential of three future large-scale particle detectors proposed in Europe as next generation underground observatories. The proposed apparatus employ three different and, to some extent, complementary detection techniques: GLACIER (liquid Argon TPC), LENA (liquid scintillator) and MEMPHYS (\WC), based on the use of large mass of liquids as active detection media. The results of these studies are presented along with a critical discussion of the performance attainable by the three proposed approaches coupled to existing or planned underground laboratories, in relation to open and outstanding physics issues such as the search for matter instability, the detection of astrophysical- and geo-neutrinos and to the possible use of these detectors in future high-intensity neutrino beams.Comment: 50 pages, 26 figure

The Hunt for New Physics at the Large Hadron Collider

The Large Hadron Collider presents an unprecedented opportunity to probe the realm of new physics in the TeV region and shed light on some of the core unresolved issues of particle physics. These include the nature of electroweak symmetry breaking, the origin of mass, the possible constituent of cold dark matter, new sources of CP violation needed to explain the baryon excess in the universe, the possible existence of extra gauge groups and extra matter, and importantly the path Nature chooses to resolve the hierarchy problem - is it supersymmetry or extra dimensions. Many models of new physics beyond the standard model contain a hidden sector which can be probed at the LHC. Additionally, the LHC will be a top factory and accurate measurements of the properties of the top and its rare decays will provide a window to new physics. Further, the LHC could shed light on the origin of neutralino masses if the new physics associated with their generation lies in the TeV region. Finally, the LHC is also a laboratory to test the hypothesis of TeV scale strings and D-brane models. An overview of these possibilities is presented in the spirit that it will serve as a companion to the Technical Design Reports (TDRs) by the particle detector groups ATLAS and CMS to facilitate the test of the new theoretical ideas at the LHC. Which of these ideas stands the test of the LHC data will govern the course of particle physics in the subsequent decades

Desperately Seeking Supersymmetry [SUSY]

In this article we try to clarify why supersymmetry [SUSY] and supersymmetric grand unified theories [SUSY GUTs] are the new standard model of particle physics, i.e. the standard by which all other theories and experiments are measured.Comment: 69 pages, 15 figures, new references adde

Perspectives in neutrino physics

There are mounting evidences that neutrinos are superposition of mass eigenstates with large mixing angles and moderate mass hierarchy. (abridged

On supersymmetry at high temperature

Consiglio Nazionale delle Ricerche (CNR). Biblioteca Centrale / CNR - Consiglio Nazionale delle RichercheSIGLEITItal