No Arabic abstract
Investigation at a $phi$--factory can shed light on several debated issues in particle physics. We discuss: i) recent theoretical development and experimental progress in kaon physics relevant for the Standard Model tests in the flavor sector, ii) the sensitivity we can reach in probing CPT and Quantum Mechanics from time evolution of entangled kaon states, iii) the interest for improving on the present measurements of non-leptonic and radiative decays of kaons and eta/eta$^prime$ mesons, iv) the contribution to understand the nature of light scalar mesons, and v) the opportunity to search for narrow di-lepton resonances suggested by recent models proposing a hidden dark-matter sector. We also report on the $e^+ e^-$ physics in the continuum with the measurements of (multi)hadronic cross sections and the study of gamma gamma processes.
Prospective presentation is given for the experimental program of the KLOE-2 Collaboration, to be performed using the DA$Phi$NE $e^+e^-$ collider upgraded in luminosity. Data with the total luminosity of 25 fb$^{-1}$ are aimed to be collected in 3 years. Major modifications of the accelerator and the spectrometer are described. The KLOE-2 physics program contains: CKM unitarity and lepton universality tests, $gammagamma$ physics, search for quantum decoherence and testing CPT conservation, low-energy QCD, rare kaon decays, physics of $eta$ and $eta^prime$, structure of low-mass scalars, contribution of vacuum polarization to $(g-2)_{mu}$, possible search for WIMP dark matter. In this paper only selected physics subjects are reported.
This document reviews the physics program of the KLOE-2 detector at DA$Phi$NE upgraded in energy and provides a simple solution to run the collider above the $phi$-peak (up to 2, possibly 2.5 GeV). It is shown how a precise measurement of the multihadronic cross section in the energy region up to 2 (possibly 2.5) GeV would have a major impact on the tests of the Standard Model through a precise determination of the anomalous magnetic moment of the muon and the effective fine-structure constant at the $M_Z$ scale. With a luminosity of about $10^{32}$cm$^{-2}$s$^{-1}$, DA$Phi$NE upgraded in energy can perform a scan in the region from 1 to 2.5 GeV in one year by collecting an integrated luminosity of 20 pb$^{-1}$ (corresponding to a few days of data taking) for single point, assuming an energy step of 25 MeV. A few years of data taking in this region would provide important tests of QCD and effective theories by $gammagamma$ physics with open thresholds for pseudo-scalar (like the $eta$), scalar ($f_0,f_0$, etc...) and axial-vector ($a_1$, etc...) mesons; vector-mesons spectroscopy and baryon form factors; tests of CVC and searches for exotics. In the final part of the document a technical solution for the energy upgrade of DA$Phi$NE is proposed.
Recently the peak luminosity achieved on the DA{Phi}NE collider has been improved by almost a factor three by implementing a novel collision scheme based on large Piwinski angle and Crab-Waist. This encouraging result opened new perspectives for physics research and a new run with the KLOE-2 detector has been scheduled to start by spring 2010. The KLOE-2 installation is a complex operation requiring a careful design effort and a several months long shutdown. The high luminosity interaction region has been deeply revised in order to take into account the effect on the beam caused by the solenoidal field of the experimental detector and to ensure background rejection. The shutdown has been also used to implement several other modifications aimed at improving beam dynamics: the wiggler poles have been displaced from the magnet axis in order to cancel high order terms in the field, the feedback systems have been equipped with stronger power supplies and more efficient kickers and electrodes have been inserted inside the wiggler and the dipole vacuum chambers, in the positron ring, to avoid the e-cloud formation. A low level RF feedback has been added to the cavity control in both rings.
DA$Phi$NE $e^+ e^-$ collider is an abundant source of low energy $K bar K$ pairs suitable to explore different fields of non perturbative QCD regime. Two different experiments, DEAR and FINUDA, using different experimental techniq ues are trying to shed new light on the strong interaction at the nucleon scale by producing high precision results at this energy range. The DEAR experiment is studying kaonic atoms in order to determine antikaon-nucleon scattering lengths. FINUDA aims to produce hypernuclei to study nuclear structure and $Lambda$-N interaction.
We present recent results obtained by the KLOE-2 Collaboration at the DAPHNE e+e- collider. The first class of results concerns search for dark forces at the scale of 1 GeV in associated production of gamma and the U boson, in search for the Higgsstrahlung and in possible decays of phi into eta and U. The second is in neutral kaon physics, on testing the CPT and Lorentz invariance, and on search for quantum decoherence effects in entangled pairs of kaons. The third class of results concerns precision measurements in hadronic physics at low energy where transition form factors of phi to pseudoscalar mesons pi0 and eta are determined.