Photo- and Electron-Production of Mesons on Nucleons and Nuclei

In these lectures I will show some results obtained with the chiral unitary approach applied to the photo and electroproduction of mesons. The results for photoproduction of $\eta \pi^0 p$ and $K^0 \pi^0 \Sigma^+$, together with related reactions will be shown, having with common denominator the excitation of the $\Delta(1700)$ resonance which is one of those dynamically generated in the chiral unitary approach. Then I will show results obtained for the $e^+ e^- \to \phi f_0(980)$ reaction which reproduce the bulk of the data except for a pronounced peak, giving support to a new mesonic resonance, X(2175). Results will also be shown for the electromagnetic form factors of the $N^*(1535)$ resonance, also dynamically generated in this approach. Finally, I will show some results on the photoproduction of the $\omega$ in nuclei, showing that present experimental results claiming a shift of the $\omega$ mass in the medium are tied to a particular choice of background and are not conclusive. One the other hand, the same experimental results show unambiguously a huge increase of the $\omega$ width in the nuclear medium.Comment: Lecture at the "International School of Nuclear Physics", 29th Course Quarks in Hadrons and Nuclei, Erice, Italy, September 2007. Note added in Proofs concerning the mixed events technique and other comments on omega productio

Unifying left–right symmetry and 331 electroweak theories

We propose a realistic theory based on the SU(3)c⊗SU(3)L⊗SU(3)R⊗U(1)X gauge group which requires the number of families to match the number of colors. In the simplest realization neutrino masses arise from the canonical seesaw mechanism and their smallness correlates with the observed V-A nature of the weak force. Depending on the symmetry breaking path to the Standard Model one recovers either a left–right symmetric theory or one based on the SU(3)c⊗SU(3)L⊗U(1) symmetry as the “next” step towards new physics

Scotogenic dark matter stability from gauged matter parity

We explore the idea that dark matter stability results from the presence of a matter-parity symmetry, arising naturally as a consequence of the spontaneous breaking of an extended SU(3)⊗SU(3)⊗U(1)⊗U(1) electroweak gauge symmetry with fully gauged B-L. Using this framework we construct a theory for scotogenic dark matter and analyze its main features.Peer Reviewe

Towards gauge coupling unification in left-right symmetric SU(3)c×SU(3)L×SU(3)R×U(1)X theories

We consider the possibility of gauge coupling unification within the simplest realizations of the SU(3)c×SU(3)L×SU(3)R×U(1)X gauge theory. We present a first exploration of the renormalization group equations governing the "bottom-up" evolution of the gauge couplings in a generic model with free normalization for the generators. Interestingly, we find that for a SU(3)c×SU(3)L×SU(3)R×U(1)X symmetry breaking scale MX as low as a few TeV one can achieve unification in the presence of leptonic octets. We briefly comment on possible grand unified theory frameworks which can embed the SU(3)c×SU(3)L×SU(3)R×U(1)X model as well as possible implications, such as lepton flavour violating physics at the LHC.by Chandan Hati, Sudhanwa Patra, Mario Reig, José W.F. Valle and C.A. Vaquera-Arauj

Strong Interaction Physics at the Luminosity Frontier with 22 GeV Electrons at Jefferson Lab

This document presents the initial scientific case for upgrading the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab (JLab) to 22 GeV. It is the result of a community effort, incorporating insights from a series of workshops conducted between March 2022 and April 2023. With a track record of over 25 years in delivering the world's most intense and precise multi-GeV electron beams, CEBAF's potential for a higher energy upgrade presents a unique opportunity for an innovative nuclear physics program, which seamlessly integrates a rich historical background with a promising future. The proposed physics program encompass a diverse range of investigations centered around the nonperturbative dynamics inherent in hadron structure and the exploration of strongly interacting systems. It builds upon the exceptional capabilities of CEBAF in high-luminosity operations, the availability of existing or planned Hall equipment, and recent advancements in accelerator technology. The proposed program cover various scientific topics, including Hadron Spectroscopy, Partonic Structure and Spin, Hadronization and Transverse Momentum, Spatial Structure, Mechanical Properties, Form Factors and Emergent Hadron Mass, Hadron-Quark Transition, and Nuclear Dynamics at Extreme Conditions, as well as QCD Confinement and Fundamental Symmetries. Each topic highlights the key measurements achievable at a 22 GeV CEBAF accelerator. Furthermore, this document outlines the significant physics outcomes and unique aspects of these programs that distinguish them from other existing or planned facilities. In summary, this document provides an exciting rationale for the energy upgrade of CEBAF to 22 GeV, outlining the transformative scientific potential that lies within reach, and the remarkable opportunities it offers for advancing our understanding of hadron physics and related fundamental phenomena