1. Samples of Hall B Results with Strong Italian Impact
Hadron Spectroscopy
Structure of the Nucleon
Transition between Hadronic and Partonic Degrees of Freedom
11/11/2018
INFN visit at JLab

2. Hadron spectroscopy in CLAS and CLAS12
Hunting for new configurations beyond qq and qqq
Quantitative understanding of quark and gluon confinement
Revealing the nature of the mass of the hadrons
See the QCD degrees of freedom at work accessing gluonic degrees of freedom
Validate lattice-QCD predictions
Photoproduction experiments with high statistics and high precision with showed the discovery potential of Jefferson Lab
First observation of the f0(980) in a photoproduction experiment
f0(980)
Meson Spectroscopy Program with CLAS12
Study the meson spectrum in the 1-3 GeV mass range to study qq interaction and identify gluonic excitation of mesons (hybrids) with 'exotic' quantum numbers
Study strangeness-rich mesons exploiting the unique combination of particle Id and resolution of the CLAS12 detector
Launch a new program to strengthen the role of JLab in hadron spectroscopy

3. The Forward Tagging Facility for CLAS12: Quasi-real electroproduction at Low Q2
A tagged photon beam will open new possibility
for high quality physics beyond the already approved program
Exotic meson search
Hadron spectroscopy
J/y threshold production
...
Electron scattering at “0” degrees (2° - 5°)  low Q2 virtual photon  real photon
Photon tagged by detecting the scattered
electron at low angles
Quasi-real photons are linearly polarized  Polarization ~ 65% - 20%
High Equivalent Luminosity  Ng ~ 5 x107 g/s
(unique opportunity to run thin gas target!)
Calorimeter +
Tracking
Veto
Electron energy/momentum
Photon energy (n=E-E')
Polarization e-1 ~ 1 + n2/2EE'
Electron angles
Q2= 4 E E' sin2J/2
j polarization plane
To separate photons from electrons and to define the trigger
Complementary to Hall-D (GLUEX)
Exploits the unique PID & resolution of CLAS12
Institutions:
Edinburgh U., Glasgow U., INFN (project coordination), JLab, NSU, Orsay, Saclay

4. Experimental Equipment for Hall B
Polarized Target for electron beam
~700K$
Cerenkov Counter for low-Q2
~300K$
Important contributions to base equipment and specific apparatus
Large Angle Calorimeter for detection of neutrals
~4M$
Upgrade of the Bonus Electronics ~45K$
HD target fridge
~500K$
Start Counter for photon beam
~47K$
Tagger Electronics Upgrade
~70K$